aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
-rw-r--r--Documentation/RCU/Design/Data-Structures/Data-Structures.html3
-rw-r--r--Documentation/RCU/Design/Expedited-Grace-Periods/Expedited-Grace-Periods.html4
-rw-r--r--Documentation/RCU/Design/Memory-Ordering/Tree-RCU-Memory-Ordering.html5
-rw-r--r--Documentation/RCU/NMI-RCU.txt13
-rw-r--r--Documentation/RCU/UP.txt6
-rw-r--r--Documentation/RCU/checklist.txt91
-rw-r--r--Documentation/RCU/rcu.txt8
-rw-r--r--Documentation/RCU/rcu_dereference.txt103
-rw-r--r--Documentation/RCU/rcubarrier.txt27
-rw-r--r--Documentation/RCU/whatisRCU.txt10
-rw-r--r--Documentation/admin-guide/kernel-parameters.txt4
-rw-r--r--Documentation/kprobes.txt6
-rw-r--r--MAINTAINERS16
-rw-r--r--drivers/nvme/host/core.c2
-rw-r--r--include/linux/rcupdate.h6
-rw-r--r--include/linux/srcu.h36
-rw-r--r--kernel/locking/locktorture.c2
-rw-r--r--kernel/rcu/rcuperf.c5
-rw-r--r--kernel/rcu/rcutorture.c21
-rw-r--r--kernel/rcu/srcutiny.c9
-rw-r--r--kernel/rcu/srcutree.c32
-rw-r--r--kernel/rcu/tiny.c2
-rw-r--r--kernel/rcu/tree.c29
-rw-r--r--kernel/rcu/tree_exp.h4
-rw-r--r--kernel/rcu/tree_plugin.h44
-rw-r--r--kernel/torture.c2
-rw-r--r--net/ipv4/netfilter/ipt_CLUSTERIP.c2
-rwxr-xr-xtools/testing/selftests/rcutorture/bin/configNR_CPUS.sh17
-rwxr-xr-xtools/testing/selftests/rcutorture/bin/config_override.sh17
-rwxr-xr-xtools/testing/selftests/rcutorture/bin/configcheck.sh19
-rwxr-xr-xtools/testing/selftests/rcutorture/bin/configinit.sh17
-rwxr-xr-xtools/testing/selftests/rcutorture/bin/cpus2use.sh17
-rw-r--r--tools/testing/selftests/rcutorture/bin/functions.sh17
-rwxr-xr-xtools/testing/selftests/rcutorture/bin/jitter.sh17
-rwxr-xr-xtools/testing/selftests/rcutorture/bin/kvm-build.sh17
-rwxr-xr-xtools/testing/selftests/rcutorture/bin/kvm-find-errors.sh5
-rwxr-xr-xtools/testing/selftests/rcutorture/bin/kvm-recheck-lock.sh17
-rwxr-xr-xtools/testing/selftests/rcutorture/bin/kvm-recheck-rcu.sh17
-rwxr-xr-xtools/testing/selftests/rcutorture/bin/kvm-recheck-rcuperf-ftrace.sh17
-rwxr-xr-xtools/testing/selftests/rcutorture/bin/kvm-recheck-rcuperf.sh17
-rwxr-xr-xtools/testing/selftests/rcutorture/bin/kvm-recheck.sh17
-rwxr-xr-xtools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh17
-rwxr-xr-xtools/testing/selftests/rcutorture/bin/kvm.sh17
-rwxr-xr-xtools/testing/selftests/rcutorture/bin/mkinitrd.sh15
-rwxr-xr-xtools/testing/selftests/rcutorture/bin/parse-build.sh17
-rwxr-xr-xtools/testing/selftests/rcutorture/bin/parse-console.sh17
-rw-r--r--tools/testing/selftests/rcutorture/configs/lock/ver_functions.sh17
-rw-r--r--tools/testing/selftests/rcutorture/configs/rcu/ver_functions.sh17
-rw-r--r--tools/testing/selftests/rcutorture/configs/rcuperf/ver_functions.sh17
49 files changed, 333 insertions, 521 deletions
diff --git a/Documentation/RCU/Design/Data-Structures/Data-Structures.html b/Documentation/RCU/Design/Data-Structures/Data-Structures.html
index 18f179807563..c30c1957c7e6 100644
--- a/Documentation/RCU/Design/Data-Structures/Data-Structures.html
+++ b/Documentation/RCU/Design/Data-Structures/Data-Structures.html
@@ -155,8 +155,7 @@ keeping lock contention under control at all tree levels regardless
of the level of loading on the system.
</p><p>RCU updaters wait for normal grace periods by registering
-RCU callbacks, either directly via <tt>call_rcu()</tt> and
-friends (namely <tt>call_rcu_bh()</tt> and <tt>call_rcu_sched()</tt>),
+RCU callbacks, either directly via <tt>call_rcu()</tt>
or indirectly via <tt>synchronize_rcu()</tt> and friends.
RCU callbacks are represented by <tt>rcu_head</tt> structures,
which are queued on <tt>rcu_data</tt> structures while they are
diff --git a/Documentation/RCU/Design/Expedited-Grace-Periods/Expedited-Grace-Periods.html b/Documentation/RCU/Design/Expedited-Grace-Periods/Expedited-Grace-Periods.html
index 19e7a5fb6b73..57300db4b5ff 100644
--- a/Documentation/RCU/Design/Expedited-Grace-Periods/Expedited-Grace-Periods.html
+++ b/Documentation/RCU/Design/Expedited-Grace-Periods/Expedited-Grace-Periods.html
@@ -56,6 +56,7 @@ sections.
RCU-preempt Expedited Grace Periods</a></h2>
<p>
+<tt>CONFIG_PREEMPT=y</tt> kernels implement RCU-preempt.
The overall flow of the handling of a given CPU by an RCU-preempt
expedited grace period is shown in the following diagram:
@@ -139,6 +140,7 @@ or offline, among other things.
RCU-sched Expedited Grace Periods</a></h2>
<p>
+<tt>CONFIG_PREEMPT=n</tt> kernels implement RCU-sched.
The overall flow of the handling of a given CPU by an RCU-sched
expedited grace period is shown in the following diagram:
@@ -146,7 +148,7 @@ expedited grace period is shown in the following diagram:
<p>
As with RCU-preempt, RCU-sched's
-<tt>synchronize_sched_expedited()</tt> ignores offline and
+<tt>synchronize_rcu_expedited()</tt> ignores offline and
idle CPUs, again because they are in remotely detectable
quiescent states.
However, because the
diff --git a/Documentation/RCU/Design/Memory-Ordering/Tree-RCU-Memory-Ordering.html b/Documentation/RCU/Design/Memory-Ordering/Tree-RCU-Memory-Ordering.html
index 8d21af02b1f0..c64f8d26609f 100644
--- a/Documentation/RCU/Design/Memory-Ordering/Tree-RCU-Memory-Ordering.html
+++ b/Documentation/RCU/Design/Memory-Ordering/Tree-RCU-Memory-Ordering.html
@@ -34,12 +34,11 @@ Similarly, any code that happens before the beginning of a given RCU grace
period is guaranteed to see the effects of all accesses following the end
of that grace period that are within RCU read-side critical sections.
-<p>This guarantee is particularly pervasive for <tt>synchronize_sched()</tt>,
-for which RCU-sched read-side critical sections include any region
+<p>Note well that RCU-sched read-side critical sections include any region
of code for which preemption is disabled.
Given that each individual machine instruction can be thought of as
an extremely small region of preemption-disabled code, one can think of
-<tt>synchronize_sched()</tt> as <tt>smp_mb()</tt> on steroids.
+<tt>synchronize_rcu()</tt> as <tt>smp_mb()</tt> on steroids.
<p>RCU updaters use this guarantee by splitting their updates into
two phases, one of which is executed before the grace period and
diff --git a/Documentation/RCU/NMI-RCU.txt b/Documentation/RCU/NMI-RCU.txt
index 687777f83b23..881353fd5bff 100644
--- a/Documentation/RCU/NMI-RCU.txt
+++ b/Documentation/RCU/NMI-RCU.txt
@@ -81,18 +81,19 @@ currently executing on some other CPU. We therefore cannot free
up any data structures used by the old NMI handler until execution
of it completes on all other CPUs.
-One way to accomplish this is via synchronize_sched(), perhaps as
+One way to accomplish this is via synchronize_rcu(), perhaps as
follows:
unset_nmi_callback();
- synchronize_sched();
+ synchronize_rcu();
kfree(my_nmi_data);
-This works because synchronize_sched() blocks until all CPUs complete
-any preemption-disabled segments of code that they were executing.
-Since NMI handlers disable preemption, synchronize_sched() is guaranteed
+This works because (as of v4.20) synchronize_rcu() blocks until all
+CPUs complete any preemption-disabled segments of code that they were
+executing.
+Since NMI handlers disable preemption, synchronize_rcu() is guaranteed
not to return until all ongoing NMI handlers exit. It is therefore safe
-to free up the handler's data as soon as synchronize_sched() returns.
+to free up the handler's data as soon as synchronize_rcu() returns.
Important note: for this to work, the architecture in question must
invoke nmi_enter() and nmi_exit() on NMI entry and exit, respectively.
diff --git a/Documentation/RCU/UP.txt b/Documentation/RCU/UP.txt
index 90ec5341ee98..53bde717017b 100644
--- a/Documentation/RCU/UP.txt
+++ b/Documentation/RCU/UP.txt
@@ -86,10 +86,8 @@ even on a UP system. So do not do it! Even on a UP system, the RCU
infrastructure -must- respect grace periods, and -must- invoke callbacks
from a known environment in which no locks are held.
-It -is- safe for synchronize_sched() and synchronize_rcu_bh() to return
-immediately on an UP system. It is also safe for synchronize_rcu()
-to return immediately on UP systems, except when running preemptable
-RCU.
+Note that it -is- safe for synchronize_rcu() to return immediately on
+UP systems, including !PREEMPT SMP builds running on UP systems.
Quick Quiz #3: Why can't synchronize_rcu() return immediately on
UP systems running preemptable RCU?
diff --git a/Documentation/RCU/checklist.txt b/Documentation/RCU/checklist.txt
index 6f469864d9f5..e98ff261a438 100644
--- a/Documentation/RCU/checklist.txt
+++ b/Documentation/RCU/checklist.txt
@@ -182,16 +182,13 @@ over a rather long period of time, but improvements are always welcome!
when publicizing a pointer to a structure that can
be traversed by an RCU read-side critical section.
-5. If call_rcu(), or a related primitive such as call_rcu_bh(),
- call_rcu_sched(), or call_srcu() is used, the callback function
- will be called from softirq context. In particular, it cannot
- block.
+5. If call_rcu() or call_srcu() is used, the callback function will
+ be called from softirq context. In particular, it cannot block.
-6. Since synchronize_rcu() can block, it cannot be called from
- any sort of irq context. The same rule applies for
- synchronize_rcu_bh(), synchronize_sched(), synchronize_srcu(),
- synchronize_rcu_expedited(), synchronize_rcu_bh_expedited(),
- synchronize_sched_expedite(), and synchronize_srcu_expedited().
+6. Since synchronize_rcu() can block, it cannot be called
+ from any sort of irq context. The same rule applies
+ for synchronize_srcu(), synchronize_rcu_expedited(), and
+ synchronize_srcu_expedited().
The expedited forms of these primitives have the same semantics
as the non-expedited forms, but expediting is both expensive and
@@ -212,20 +209,20 @@ over a rather long period of time, but improvements are always welcome!
of the system, especially to real-time workloads running on
the rest of the system.
-7. If the updater uses call_rcu() or synchronize_rcu(), then the
- corresponding readers must use rcu_read_lock() and
- rcu_read_unlock(). If the updater uses call_rcu_bh() or
- synchronize_rcu_bh(), then the corresponding readers must
- use rcu_read_lock_bh() and rcu_read_unlock_bh(). If the
- updater uses call_rcu_sched() or synchronize_sched(), then
- the corresponding readers must disable preemption, possibly
- by calling rcu_read_lock_sched() and rcu_read_unlock_sched().
- If the updater uses synchronize_srcu() or call_srcu(), then
- the corresponding readers must use srcu_read_lock() and
+7. As of v4.20, a given kernel implements only one RCU flavor,
+ which is RCU-sched for PREEMPT=n and RCU-preempt for PREEMPT=y.
+ If the updater uses call_rcu() or synchronize_rcu(),
+ then the corresponding readers my use rcu_read_lock() and
+ rcu_read_unlock(), rcu_read_lock_bh() and rcu_read_unlock_bh(),
+ or any pair of primitives that disables and re-enables preemption,
+ for example, rcu_read_lock_sched() and rcu_read_unlock_sched().
+ If the updater uses synchronize_srcu() or call_srcu(),
+ then the corresponding readers must use srcu_read_lock() and
srcu_read_unlock(), and with the same srcu_struct. The rules for
the expedited primitives are the same as for their non-expedited
counterparts. Mixing things up will result in confusion and
- broken kernels.
+ broken kernels, and has even resulted in an exploitable security
+ issue.
One exception to this rule: rcu_read_lock() and rcu_read_unlock()
may be substituted for rcu_read_lock_bh() and rcu_read_unlock_bh()
@@ -288,8 +285,7 @@ over a rather long period of time, but improvements are always welcome!
d. Periodically invoke synchronize_rcu(), permitting a limited
number of updates per grace period.
- The same cautions apply to call_rcu_bh(), call_rcu_sched(),
- call_srcu(), and kfree_rcu().
+ The same cautions apply to call_srcu() and kfree_rcu().
Note that although these primitives do take action to avoid memory
exhaustion when any given CPU has too many callbacks, a determined
@@ -322,7 +318,7 @@ over a rather long period of time, but improvements are always welcome!
11. Any lock acquired by an RCU callback must be acquired elsewhere
with softirq disabled, e.g., via spin_lock_irqsave(),
- spin_lock_bh(), etc. Failing to disable irq on a given
+ spin_lock_bh(), etc. Failing to disable softirq on a given
acquisition of that lock will result in deadlock as soon as
the RCU softirq handler happens to run your RCU callback while
interrupting that acquisition's critical section.
@@ -335,13 +331,16 @@ over a rather long period of time, but improvements are always welcome!
must use whatever locking or other synchronization is required
to safely access and/or modify that data structure.
- RCU callbacks are -usually- executed on the same CPU that executed
- the corresponding call_rcu(), call_rcu_bh(), or call_rcu_sched(),
- but are by -no- means guaranteed to be. For example, if a given
- CPU goes offline while having an RCU callback pending, then that
- RCU callback will execute on some surviving CPU. (If this was
- not the case, a self-spawning RCU callback would prevent the
- victim CPU from ever going offline.)
+ Do not assume that RCU callbacks will be executed on the same
+ CPU that executed the corresponding call_rcu() or call_srcu().
+ For example, if a given CPU goes offline while having an RCU
+ callback pending, then that RCU callback will execute on some
+ surviving CPU. (If this was not the case, a self-spawning RCU
+ callback would prevent the victim CPU from ever going offline.)
+ Furthermore, CPUs designated by rcu_nocbs= might well -always-
+ have their RCU callbacks executed on some other CPUs, in fact,
+ for some real-time workloads, this is the whole point of using
+ the rcu_nocbs= kernel boot parameter.
13. Unlike other forms of RCU, it -is- permissible to block in an
SRCU read-side critical section (demarked by srcu_read_lock()
@@ -381,11 +380,11 @@ over a rather long period of time, but improvements are always welcome!
SRCU's expedited primitive (synchronize_srcu_expedited())
never sends IPIs to other CPUs, so it is easier on
- real-time workloads than is synchronize_rcu_expedited(),
- synchronize_rcu_bh_expedited() or synchronize_sched_expedited().
+ real-time workloads than is synchronize_rcu_expedited().
- Note that rcu_dereference() and rcu_assign_pointer() relate to
- SRCU just as they do to other forms of RCU.
+ Note that rcu_assign_pointer() relates to SRCU just as it does to
+ other forms of RCU, but instead of rcu_dereference() you should
+ use srcu_dereference() in order to avoid lockdep splats.
14. The whole point of call_rcu(), synchronize_rcu(), and friends
is to wait until all pre-existing readers have finished before
@@ -405,6 +404,9 @@ over a rather long period of time, but improvements are always welcome!
read-side critical sections. It is the responsibility of the
RCU update-side primitives to deal with this.
+ For SRCU readers, you can use smp_mb__after_srcu_read_unlock()
+ immediately after an srcu_read_unlock() to get a full barrier.
+
16. Use CONFIG_PROVE_LOCKING, CONFIG_DEBUG_OBJECTS_RCU_HEAD, and the
__rcu sparse checks to validate your RCU code. These can help
find problems as follows:
@@ -428,22 +430,19 @@ over a rather long period of time, but improvements are always welcome!
These debugging aids can help you find problems that are
otherwise extremely difficult to spot.
-17. If you register a callback using call_rcu(), call_rcu_bh(),
- call_rcu_sched(), or call_srcu(), and pass in a function defined
- within a loadable module, then it in necessary to wait for
- all pending callbacks to be invoked after the last invocation
- and before unloading that module. Note that it is absolutely
- -not- sufficient to wait for a grace period! The current (say)
- synchronize_rcu() implementation waits only for all previous
- callbacks registered on the CPU that synchronize_rcu() is running
- on, but it is -not- guaranteed to wait for callbacks registered
- on other CPUs.
+17. If you register a callback using call_rcu() or call_srcu(), and
+ pass in a function defined within a loadable module, then it in
+ necessary to wait for all pending callbacks to be invoked after
+ the last invocation and before unloading that module. Note that
+ it is absolutely -not- sufficient to wait for a grace period!
+ The current (say) synchronize_rcu() implementation is -not-
+ guaranteed to wait for callbacks registered on other CPUs.
+ Or even on the current CPU if that CPU recently went offline
+ and came back online.
You instead need to use one of the barrier functions:
o call_rcu() -> rcu_barrier()
- o call_rcu_bh() -> rcu_barrier()
- o call_rcu_sched() -> rcu_barrier()
o call_srcu() -> srcu_barrier()
However, these barrier functions are absolutely -not- guaranteed
diff --git a/Documentation/RCU/rcu.txt b/Documentation/RCU/rcu.txt
index 721b3e426515..c818cf65c5a9 100644
--- a/Documentation/RCU/rcu.txt
+++ b/Documentation/RCU/rcu.txt
@@ -52,10 +52,10 @@ o If I am running on a uniprocessor kernel, which can only do one
o How can I see where RCU is currently used in the Linux kernel?
Search for "rcu_read_lock", "rcu_read_unlock", "call_rcu",
- "rcu_read_lock_bh", "rcu_read_unlock_bh", "call_rcu_bh",
- "srcu_read_lock", "srcu_read_unlock", "synchronize_rcu",
- "synchronize_net", "synchronize_srcu", and the other RCU
- primitives. Or grab one of the cscope databases from:
+ "rcu_read_lock_bh", "rcu_read_unlock_bh", "srcu_read_lock",
+ "srcu_read_unlock", "synchronize_rcu", "synchronize_net",
+ "synchronize_srcu", and the other RCU primitives. Or grab one
+ of the cscope databases from:
http://www.rdrop.com/users/paulmck/RCU/linuxusage/rculocktab.html
diff --git a/Documentation/RCU/rcu_dereference.txt b/Documentation/RCU/rcu_dereference.txt
index ab96227bad42..bf699e8cfc75 100644
--- a/Documentation/RCU/rcu_dereference.txt
+++ b/Documentation/RCU/rcu_dereference.txt
@@ -351,3 +351,106 @@ garbage values.
In short, rcu_dereference() is -not- optional when you are going to
dereference the resulting pointer.
+
+
+WHICH MEMBER OF THE rcu_dereference() FAMILY SHOULD YOU USE?
+
+First, please avoid using rcu_dereference_raw() and also please avoid
+using rcu_dereference_check() and rcu_dereference_protected() with a
+second argument with a constant value of 1 (or true, for that matter).
+With that caution out of the way, here is some guidance for which
+member of the rcu_dereference() to use in various situations:
+
+1. If the access needs to be within an RCU read-side critical
+ section, use rcu_dereference(). With the new consolidated
+ RCU flavors, an RCU read-side critical section is entered
+ using rcu_read_lock(), anything that disables bottom halves,
+ anything that disables interrupts, or anything that disables
+ preemption.
+
+2. If the access might be within an RCU read-side critical section
+ on the one hand, or protected by (say) my_lock on the other,
+ use rcu_dereference_check(), for example:
+
+ p1 = rcu_dereference_check(p->rcu_protected_pointer,
+ lockdep_is_held(&my_lock));
+
+
+3. If the access might be within an RCU read-side critical section
+ on the one hand, or protected by either my_lock or your_lock on
+ the other, again use rcu_dereference_check(), for example:
+
+ p1 = rcu_dereference_check(p->rcu_protected_pointer,
+ lockdep_is_held(&my_lock) ||
+ lockdep_is_held(&your_lock));
+
+4. If the access is on the update side, so that it is always protected
+ by my_lock, use rcu_dereference_protected():
+
+ p1 = rcu_dereference_protected(p->rcu_protected_pointer,
+ lockdep_is_held(&my_lock));
+
+ This can be extended to handle multiple locks as in #3 above,
+ and both can be extended to check other conditions as well.
+
+5. If the protection is supplied by the caller, and is thus unknown
+ to this code, that is the rare case when rcu_dereference_raw()
+ is appropriate. In addition, rcu_dereference_raw() might be
+ appropriate when the lockdep expression would be excessively
+ complex, except that a better approach in that case might be to
+ take a long hard look at your synchronization design. Still,
+ there are data-locking cases where any one of a very large number
+ of locks or reference counters suffices to protect the pointer,
+ so rcu_dereference_raw() does have its place.
+
+ However, its place is probably quite a bit smaller than one
+ might expect given the number of uses in the current kernel.
+ Ditto for its synonym, rcu_dereference_check( ... , 1), and
+ its close relative, rcu_dereference_protected(... , 1).
+
+
+SPARSE CHECKING OF RCU-PROTECTED POINTERS
+
+The sparse static-analysis tool checks for direct access to RCU-protected
+pointers, which can result in "interesting" bugs due to compiler
+optimizations involving invented loads and perhaps also load tearing.
+For example, suppose someone mistakenly does something like this:
+
+ p = q->rcu_protected_pointer;
+ do_something_with(p->a);
+ do_something_else_with(p->b);
+
+If register pressure is high, the compiler might optimize "p" out
+of existence, transforming the code to something like this:
+
+ do_something_with(q->rcu_protected_pointer->a);
+ do_something_else_with(q->rcu_protected_pointer->b);
+
+This could fatally disappoint your code if q->rcu_protected_pointer
+changed in the meantime. Nor is this a theoretical problem: Exactly
+this sort of bug cost Paul E. McKenney (and several of his innocent
+colleagues) a three-day weekend back in the early 1990s.
+
+Load tearing could of course result in dereferencing a mashup of a pair
+of pointers, which also might fatally disappoint your code.
+
+These problems could have been avoided simply by making the code instead
+read as follows:
+
+ p = rcu_dereference(q->rcu_protected_pointer);
+ do_something_with(p->a);
+ do_something_else_with(p->b);
+
+Unfortunately, these sorts of bugs can be extremely hard to spot during
+review. This is where the sparse tool comes into play, along with the
+"__rcu" marker. If you mark a pointer declaration, whether in a structure
+or as a formal parameter, with "__rcu", which tells sparse to complain if
+this pointer is accessed directly. It will also cause sparse to complain
+if a pointer not marked with "__rcu" is accessed using rcu_dereference()
+and friends. For example, ->rcu_protected_pointer might be declared as
+follows:
+
+ struct foo __rcu *rcu_protected_pointer;
+
+Use of "__rcu" is opt-in. If you choose not to use it, then you should
+ignore the sparse warnings.
diff --git a/Documentation/RCU/rcubarrier.txt b/Documentation/RCU/rcubarrier.txt
index 5d7759071a3e..a2782df69732 100644
--- a/Documentation/RCU/rcubarrier.txt
+++ b/Documentation/RCU/rcubarrier.txt
@@ -83,16 +83,15 @@ Pseudo-code using rcu_barrier() is as follows:
2. Execute rcu_barrier().
3. Allow the module to be unloaded.
-There are also rcu_barrier_bh(), rcu_barrier_sched(), and srcu_barrier()
-functions for the other flavors of RCU, and you of course must match
-the flavor of rcu_barrier() with that of call_rcu(). If your module
-uses multiple flavors of call_rcu(), then it must also use multiple
+There is also an srcu_barrier() function for SRCU, and you of course
+must match the flavor of rcu_barrier() with that of call_rcu(). If your
+module uses multiple flavors of call_rcu(), then it must also use multiple
flavors of rcu_barrier() when unloading that module. For example, if
-it uses call_rcu_bh(), call_srcu() on srcu_struct_1, and call_srcu() on
+it uses call_rcu(), call_srcu() on srcu_struct_1, and call_srcu() on
srcu_struct_2(), then the following three lines of code will be required
when unloading:
- 1 rcu_barrier_bh();
+ 1 rcu_barrier();
2 srcu_barrier(&srcu_struct_1);
3 srcu_barrier(&srcu_struct_2);
@@ -185,12 +184,12 @@ module invokes call_rcu() from timers, you will need to first cancel all
the timers, and only then invoke rcu_barrier() to wait for any remaining
RCU callbacks to complete.
-Of course, if you module uses call_rcu_bh(), you will need to invoke
-rcu_barrier_bh() before unloading. Similarly, if your module uses
-call_rcu_sched(), you will need to invoke rcu_barrier_sched() before
-unloading. If your module uses call_rcu(), call_rcu_bh(), -and-
-call_rcu_sched(), then you will need to invoke each of rcu_barrier(),
-rcu_barrier_bh(), and rcu_barrier_sched().
+Of course, if you module uses call_rcu(), you will need to invoke
+rcu_barrier() before unloading. Similarly, if your module uses
+call_srcu(), you will need to invoke srcu_barrier() before unloading,
+and on the same srcu_struct structure. If your module uses call_rcu()
+-and- call_srcu(), then you will need to invoke rcu_barrier() -and-
+srcu_barrier().
Implementing rcu_barrier()
@@ -223,8 +222,8 @@ shown below. Note that the final "1" in on_each_cpu()'s argument list
ensures that all the calls to rcu_barrier_func() will have completed
before on_each_cpu() returns. Line 9 then waits for the completion.
-This code was rewritten in 2008 to support rcu_barrier_bh() and
-rcu_barrier_sched() in addition to the original rcu_barrier().
+This code was rewritten in 2008 and several times thereafter, but this
+still gives the general idea.
The rcu_barrier_func() runs on each CPU, where it invokes call_rcu()
to post an RCU callback, as follows:
diff --git a/Documentation/RCU/whatisRCU.txt b/Documentation/RCU/whatisRCU.txt
index 1ace20815bb1..981651a8b65d 100644
--- a/Documentation/RCU/whatisRCU.txt
+++ b/Documentation/RCU/whatisRCU.txt
@@ -310,7 +310,7 @@ reader, updater, and reclaimer.
rcu_assign_pointer()
- +--------+
+ +--------+
+---------------------->| reader |---------+
| +--------+ |
| | |
@@ -318,12 +318,12 @@ reader, updater, and reclaimer.
| | | rcu_read_lock()
| | | rcu_read_unlock()
| rcu_dereference() | |
- +---------+ | |
- | updater |<---------------------+ |
- +---------+ V
+ +---------+ | |
+ | updater |<----------------+ |
+ +---------+ V
| +-----------+
+----------------------------------->| reclaimer |
- +-----------+
+ +-----------+
Defer:
synchronize_rcu() & call_rcu()
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 2b8ee90bb644..d377a2166b79 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -3623,7 +3623,9 @@
see CONFIG_RAS_CEC help text.
rcu_nocbs= [KNL]
- The argument is a cpu list, as described above.
+ The argument is a cpu list, as described above,
+ except that the string "all" can be used to
+ specify every CPU on the system.
In kernels built with CONFIG_RCU_NOCB_CPU=y, set
the specified list of CPUs to be no-callback CPUs.
diff --git a/Documentation/kprobes.txt b/Documentation/kprobes.txt
index 10f4499e677c..ee60e519438a 100644
--- a/Documentation/kprobes.txt
+++ b/Documentation/kprobes.txt
@@ -243,10 +243,10 @@ Optimization
^^^^^^^^^^^^
The Kprobe-optimizer doesn't insert the jump instruction immediately;
-rather, it calls synchronize_sched() for safety first, because it's
+rather, it calls synchronize_rcu() for safety first, because it's
possible for a CPU to be interrupted in the middle of executing the
-optimized region [3]_. As you know, synchronize_sched() can ensure
-that all interruptions that were active when synchronize_sched()
+optimized region [3]_. As you know, synchronize_rcu() can ensure
+that all interruptions that were active when synchronize_rcu()
was called are done, but only if CONFIG_PREEMPT=n. So, this version
of kprobe optimization supports only kernels with CONFIG_PREEMPT=n [4]_.
diff --git a/MAINTAINERS b/MAINTAINERS
index e17ebf70b548..a9b5270d006e 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -8983,7 +8983,7 @@ R: Daniel Lustig <[email protected]>
S: Supported
-T: git git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git
+T: git git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git dev
F: tools/memory-model/
F: Documentation/atomic_bitops.txt
F: Documentation/atomic_t.txt
@@ -13031,9 +13031,9 @@ M: Josh Triplett <[email protected]>
R: Steven Rostedt <[email protected]>
R: Mathieu Desnoyers <[email protected]>
R: Lai Jiangshan <[email protected]>
S: Supported
-T: git git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git
+T: git git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git dev
F: tools/testing/selftests/rcutorture
RDC R-321X SoC
@@ -13079,10 +13079,10 @@ R: Steven Rostedt <[email protected]>
R: Mathieu Desnoyers <[email protected]>
R: Lai Jiangshan <[email protected]>
R: Joel Fernandes <[email protected]>
W: http://www.rdrop.com/users/paulmck/RCU/
S: Supported
-T: git git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git
+T: git git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git dev
F: Documentation/RCU/
X: Documentation/RCU/torture.txt
F: include/linux/rcu*
@@ -14234,10 +14234,10 @@ M: "Paul E. McKenney" <[email protected]>
M: Josh Triplett <[email protected]>
R: Steven Rostedt <[email protected]>
R: Mathieu Desnoyers <[email protected]>
W: http://www.rdrop.com/users/paulmck/RCU/
S: Supported
-T: git git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git
+T: git git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git dev
F: include/linux/srcu*.h
F: kernel/rcu/srcu*.c
@@ -15684,7 +15684,7 @@ M: "Paul E. McKenney" <[email protected]>
M: Josh Triplett <[email protected]>
S: Supported
-T: git git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git
+T: git git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git dev
F: Documentation/RCU/torture.txt
F: kernel/torture.c
F: kernel/rcu/rcutorture.c
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 470601980794..739c5b4830d7 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -388,7 +388,7 @@ static void nvme_free_ns_head(struct kref *ref)
nvme_mpath_remove_disk(head);
ida_simple_remove(&head->subsys->ns_ida, head->instance);
list_del_init(&head->entry);
- cleanup_srcu_struct_quiesced(&head->srcu);
+ cleanup_srcu_struct(&head->srcu);
nvme_put_subsystem(head->subsys);
kfree(head);
}
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 6cdb1db776cf..922bb6848813 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -878,9 +878,11 @@ static inline void rcu_head_init(struct rcu_head *rhp)
static inline bool
rcu_head_after_call_rcu(struct rcu_head *rhp, rcu_callback_t f)
{
- if (READ_ONCE(rhp->func) == f)
+ rcu_callback_t func = READ_ONCE(rhp->func);
+
+ if (func == f)
return true;
- WARN_ON_ONCE(READ_ONCE(rhp->func) != (rcu_callback_t)~0L);
+ WARN_ON_ONCE(func != (rcu_callback_t)~0L);
return false;
}
diff --git a/include/linux/srcu.h b/include/linux/srcu.h
index c495b2d51569..e432cc92c73d 100644
--- a/include/linux/srcu.h
+++ b/include/linux/srcu.h
@@ -56,45 +56,11 @@ struct srcu_struct { };
void call_srcu(struct srcu_struct *ssp, struct rcu_head *head,
void (*func)(struct rcu_head *head));
-void _cleanup_srcu_struct(struct srcu_struct *ssp, bool quiesced);
+void cleanup_srcu_struct(struct srcu_struct *ssp);
int __srcu_read_lock(struct srcu_struct *ssp) __acquires(ssp);
void __srcu_read_unlock(struct srcu_struct *ssp, int idx) __releases(ssp);
void synchronize_srcu(struct srcu_struct *ssp);
-/**
- * cleanup_srcu_struct - deconstruct a sleep-RCU structure
- * @ssp: structure to clean up.
- *
- * Must invoke this after you are finished using a given srcu_struct that
- * was initialized via init_srcu_struct(), else you leak memory.
- */
-static inline void cleanup_srcu_struct(struct srcu_struct *ssp)
-{
- _cleanup_srcu_struct(ssp, false);
-}
-
-/**
- * cleanup_srcu_struct_quiesced - deconstruct a quiesced sleep-RCU structure
- * @ssp: structure to clean up.
- *
- * Must invoke this after you are finished using a given srcu_struct that
- * was initialized via init_srcu_struct(), else you leak memory. Also,
- * all grace-period processing must have completed.
- *
- * "Completed" means that the last synchronize_srcu() and
- * synchronize_srcu_expedited() calls must have returned before the call
- * to cleanup_srcu_struct_quiesced(). It also means that the callback
- * from the last call_srcu() must have been invoked before the call to
- * cleanup_srcu_struct_quiesced(), but you can use srcu_barrier() to help
- * with this last. Violating these rules will get you a WARN_ON() splat
- * (with high probability, anyway), and will also cause the srcu_struct
- * to be leaked.
- */
-static inline void cleanup_srcu_struct_quiesced(struct srcu_struct *ssp)
-{
- _cleanup_srcu_struct(ssp, true);
-}
-
#ifdef CONFIG_DEBUG_LOCK_ALLOC
/**
diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
index ad40a2617063..80a463d31a8d 100644
--- a/kernel/locking/locktorture.c
+++ b/kernel/locking/locktorture.c
@@ -829,7 +829,9 @@ static void lock_torture_cleanup(void)
"End of test: SUCCESS");
kfree(cxt.lwsa);
+ cxt.lwsa = NULL;
kfree(cxt.lrsa);
+ cxt.lrsa = NULL;
end:
torture_cleanup_end();
diff --git a/kernel/rcu/rcuperf.c b/kernel/rcu/rcuperf.c
index c29761152874..7a6890b23c5f 100644
--- a/kernel/rcu/rcuperf.c
+++ b/kernel/rcu/rcuperf.c
@@ -494,6 +494,10 @@ rcu_perf_cleanup(void)
if (torture_cleanup_begin())
return;
+ if (!cur_ops) {
+ torture_cleanup_end();
+ return;
+ }
if (reader_tasks) {
for (i = 0; i < nrealreaders; i++)
@@ -614,6 +618,7 @@ rcu_perf_init(void)
pr_cont("\n");
WARN_ON(!IS_MODULE(CONFIG_RCU_PERF_TEST));
firsterr = -EINVAL;
+ cur_ops = NULL;
goto unwind;
}
if (cur_ops->init)
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index f14d1b18a74f..efaa5b3f4d3f 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -299,7 +299,6 @@ struct rcu_torture_ops {
int irq_capable;
int can_boost;
int extendables;
- int ext_irq_conflict;
const char *name;
};
@@ -592,12 +591,7 @@ static void srcu_torture_init(void)
static void srcu_torture_cleanup(void)
{
- static DEFINE_TORTURE_RANDOM(rand);
-
- if (torture_random(&rand) & 0x800)
- cleanup_srcu_struct(&srcu_ctld);
- else
- cleanup_srcu_struct_quiesced(&srcu_ctld);
+ cleanup_srcu_struct(&srcu_ctld);
srcu_ctlp = &srcu_ctl; /* In case of a later rcutorture run. */
}
@@ -1160,7 +1154,7 @@ rcutorture_extend_mask(int oldmask, struct torture_random_state *trsp)
unsigned long randmask2 = randmask1 >> 3;
WARN_ON_ONCE(mask >> RCUTORTURE_RDR_SHIFT);
- /* Most of the time lots of bits, half the time only one bit. */
+ /* Mostly only one bit (need preemption!), sometimes lots of bits. */
if (!(randmask1 & 0x7))
mask = mask & randmask2;
else
@@ -1170,10 +1164,6 @@ rcutorture_extend_mask(int oldmask, struct torture_random_state *trsp)
((!(mask & RCUTORTURE_RDR_BH) && (oldmask & RCUTORTURE_RDR_BH)) ||
(!(mask & RCUTORTURE_RDR_RBH) && (oldmask & RCUTORTURE_RDR_RBH))))
mask |= RCUTORTURE_RDR_BH | RCUTORTURE_RDR_RBH;
- if ((mask & RCUTORTURE_RDR_IRQ) &&
- !(mask & cur_ops->ext_irq_conflict) &&
- (oldmask & cur_ops->ext_irq_conflict))
- mask |= cur_ops->ext_irq_conflict; /* Or if readers object. */
return mask ?: RCUTORTURE_RDR_RCU;
}
@@ -1848,7 +1838,7 @@ static int rcutorture_oom_notify(struct notifier_block *self,
WARN(1, "%s invoked upon OOM during forward-progress testing.\n",
__func__);
rcu_torture_fwd_cb_hist();
- rcu_fwd_progress_check(1 + (jiffies - READ_ONCE(rcu_fwd_startat) / 2));
+ rcu_fwd_progress_check(1 + (jiffies - READ_ONCE(rcu_fwd_startat)) / 2);
WRITE_ONCE(rcu_fwd_emergency_stop, true);
smp_mb(); /* Emergency stop before free and wait to avoid hangs. */
pr_info("%s: Freed %lu RCU callbacks.\n",
@@ -2094,6 +2084,10 @@ rcu_torture_cleanup(void)
cur_ops->cb_barrier();
return;
}
+ if (!cur_ops) {
+ torture_cleanup_end();
+ return;
+ }
rcu_torture_barrier_cleanup();
torture_stop_kthread(rcu_torture_fwd_prog, fwd_prog_task);
@@ -2267,6 +2261,7 @@ rcu_torture_init(void)
pr_cont("\n");
WARN_ON(!IS_MODULE(CONFIG_RCU_TORTURE_TEST));
firsterr = -EINVAL;
+ cur_ops = NULL;
goto unwind;
}
if (cur_ops->fqs == NULL && fqs_duration != 0) {
diff --git a/kernel/rcu/srcutiny.c b/kernel/rcu/srcutiny.c
index 5d4a39a6505a..44d6606b8325 100644
--- a/kernel/rcu/srcutiny.c
+++ b/kernel/rcu/srcutiny.c
@@ -76,19 +76,16 @@ EXPORT_SYMBOL_GPL(init_srcu_struct);
* Must invoke this after you are finished using a given srcu_struct that
* was initialized via init_srcu_struct(), else you leak memory.
*/
-void _cleanup_srcu_struct(struct srcu_struct *ssp, bool quiesced)
+void cleanup_srcu_struct(struct srcu_struct *ssp)
{
WARN_ON(ssp->srcu_lock_nesting[0] || ssp->srcu_lock_nesting[1]);
- if (quiesced)
- WARN_ON(work_pending(&ssp->srcu_work));
- else
- flush_work(&ssp->srcu_work);
+ flush_work(&ssp->srcu_work);
WARN_ON(ssp->srcu_gp_running);
WARN_ON(ssp->srcu_gp_waiting);
WARN_ON(ssp->srcu_cb_head);
WARN_ON(&ssp->srcu_cb_head != ssp->srcu_cb_tail);
}
-EXPORT_SYMBOL_GPL(_cleanup_srcu_struct);
+EXPORT_SYMBOL_GPL(cleanup_srcu_struct);
/*
* Removes the count for the old reader from the appropriate element of
diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c
index a60b8ba9e1ac..9b761e546de8 100644
--- a/kernel/rcu/srcutree.c
+++ b/kernel/rcu/srcutree.c
@@ -360,8 +360,14 @@ static unsigned long srcu_get_delay(struct srcu_struct *ssp)
return SRCU_INTERVAL;
}
-/* Helper for cleanup_srcu_struct() and cleanup_srcu_struct_quiesced(). */
-void _cleanup_srcu_struct(struct srcu_struct *ssp, bool quiesced)
+/**
+ * cleanup_srcu_struct - deconstruct a sleep-RCU structure
+ * @ssp: structure to clean up.
+ *
+ * Must invoke this after you are finished using a given srcu_struct that
+ * was initialized via init_srcu_struct(), else you leak memory.
+ */
+void cleanup_srcu_struct(struct srcu_struct *ssp)
{
int cpu;
@@ -369,24 +375,14 @@ void _cleanup_srcu_struct(struct srcu_struct *ssp, bool quiesced)
return; /* Just leak it! */
if (WARN_ON(srcu_readers_active(ssp)))
return; /* Just leak it! */
- if (quiesced) {
- if (WARN_ON(delayed_work_pending(&ssp->work)))
- return; /* Just leak it! */
- } else {
- flush_delayed_work(&ssp->work);
- }
+ flush_delayed_work(&ssp->work);
for_each_possible_cpu(cpu) {
struct srcu_data *sdp = per_cpu_ptr(ssp->sda, cpu);
- if (quiesced) {
- if (WARN_ON(timer_pending(&sdp->delay_work)))
- return; /* Just leak it! */
- if (WARN_ON(work_pending(&sdp->work)))
- return; /* Just leak it! */
- } else {
- del_timer_sync(&sdp->delay_work);
- flush_work(&sdp->work);
- }
+ del_timer_sync(&sdp->delay_work);
+ flush_work(&sdp->work);
+ if (WARN_ON(rcu_segcblist_n_cbs(&sdp->srcu_cblist)))
+ return; /* Forgot srcu_barrier(), so just leak it! */
}
if (WARN_ON(rcu_seq_state(READ_ONCE(ssp->srcu_gp_seq)) != SRCU_STATE_IDLE) ||
WARN_ON(srcu_readers_active(ssp))) {
@@ -397,7 +393,7 @@ void _cleanup_srcu_struct(struct srcu_struct *ssp, bool quiesced)
free_percpu(ssp->sda);
ssp->sda = NULL;
}
-EXPORT_SYMBOL_GPL(_cleanup_srcu_struct);
+EXPORT_SYMBOL_GPL(cleanup_srcu_struct);
/*
* Counts the new reader in the appropriate per-CPU element of the
diff --git a/kernel/rcu/tiny.c b/kernel/rcu/tiny.c
index 911bd9076d43..477b4eb44af5 100644
--- a/kernel/rcu/tiny.c
+++ b/kernel/rcu/tiny.c
@@ -52,7 +52,7 @@ void rcu_qs(void)
local_irq_save(flags);
if (rcu_ctrlblk.donetail != rcu_ctrlblk.curtail) {
rcu_ctrlblk.donetail = rcu_ctrlblk.curtail;
- raise_softirq(RCU_SOFTIRQ);
+ raise_softirq_irqoff(RCU_SOFTIRQ);
}
local_irq_restore(flags);
}
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 4cb1ebd93b0c..ec77ec336f58 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -144,7 +144,7 @@ static void sync_sched_exp_online_cleanup(int cpu);
/* rcuc/rcub kthread realtime priority */
static int kthread_prio = IS_ENABLED(CONFIG_RCU_BOOST) ? 1 : 0;
-module_param(kthread_prio, int, 0644);
+module_param(kthread_prio, int, 0444);
/* Delay in jiffies for grace-period initialization delays, debug only. */
@@ -401,7 +401,7 @@ static bool rcu_kick_kthreads;
*/
static ulong jiffies_till_sched_qs = ULONG_MAX;
module_param(jiffies_till_sched_qs, ulong, 0444);
-static ulong jiffies_to_sched_qs; /* Adjusted version of above if not default */
+static ulong jiffies_to_sched_qs; /* See adjust_jiffies_till_sched_qs(). */
module_param(jiffies_to_sched_qs, ulong, 0444); /* Display only! */
/*
@@ -419,6 +419,7 @@ static void adjust_jiffies_till_sched_qs(void)
WRITE_ONCE(jiffies_to_sched_qs, jiffies_till_sched_qs);
return;
}
+ /* Otherwise, set to third fqs scan, but bound below on large system. */
j = READ_ONCE(jiffies_till_first_fqs) +
2 * READ_ONCE(jiffies_till_next_fqs);
if (j < HZ / 10 + nr_cpu_ids / RCU_JIFFIES_FQS_DIV)
@@ -1202,7 +1203,7 @@ static bool rcu_future_gp_cleanup(struct rcu_node *rnp)
static void rcu_gp_kthread_wake(void)
{
if ((current == rcu_state.gp_kthread &&
- !in_interrupt() && !in_serving_softirq()) ||
+ !in_irq() && !in_serving_softirq()) ||
!READ_ONCE(rcu_state.gp_flags) ||
!rcu_state.gp_kthread)
return;
@@ -1912,11 +1913,10 @@ rcu_report_qs_rdp(int cpu, struct rcu_data *rdp)
return;
}
mask = rdp->grpmask;
+ rdp->core_needs_qs = false;
if ((rnp->qsmask & mask) == 0) {
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
} else {
- rdp->core_needs_qs = false;
-
/*
* This GP can't end until cpu checks in, so all of our
* callbacks can be processed during the next GP.
@@ -2165,11 +2165,11 @@ void rcu_sched_clock_irq(int user)
}
/*
- * Scan the leaf rcu_node structures, processing dyntick state for any that
- * have not yet encountered a quiescent state, using the function specified.
- * Also initiate boosting for any threads blocked on the root rcu_node.
- *
- * The caller must have suppressed start of new grace periods.
+ * Scan the leaf rcu_node structures. For each structure on which all
+ * CPUs have reported a quiescent state and on which there are tasks
+ * blocking the current grace period, initiate RCU priority boosting.
+ * Otherwise, invoke the specified function to check dyntick state for
+ * each CPU that has not yet reported a quiescent state.
*/
static void force_qs_rnp(int (*f)(struct rcu_data *rdp))
{
@@ -3081,13 +3081,11 @@ static int rcu_pm_notify(struct notifier_block *self,
switch (action) {
case PM_HIBERNATION_PREPARE:
case PM_SUSPEND_PREPARE:
- if (nr_cpu_ids <= 256) /* Expediting bad for large systems. */
- rcu_expedite_gp();
+ rcu_expedite_gp();
break;
case PM_POST_HIBERNATION:
case PM_POST_SUSPEND:
- if (nr_cpu_ids <= 256) /* Expediting bad for large systems. */
- rcu_unexpedite_gp();
+ rcu_unexpedite_gp();
break;
default:
break;
@@ -3264,8 +3262,7 @@ static void __init rcu_init_geometry(void)
jiffies_till_first_fqs = d;
if (jiffies_till_next_fqs == ULONG_MAX)
jiffies_till_next_fqs = d;
- if (jiffies_till_sched_qs == ULONG_MAX)
- adjust_jiffies_till_sched_qs();
+ adjust_jiffies_till_sched_qs();
/* If the compile-time values are accurate, just leave. */
if (rcu_fanout_leaf == RCU_FANOUT_LEAF &&
diff --git a/kernel/rcu/tree_exp.h b/kernel/rcu/tree_exp.h
index 7be3e085ddd6..9c990df880d1 100644
--- a/kernel/rcu/tree_exp.h
+++ b/kernel/rcu/tree_exp.h
@@ -634,7 +634,7 @@ static void rcu_exp_handler(void *unused)
raw_spin_lock_irqsave_rcu_node(rnp, flags);
if (rnp->expmask & rdp->grpmask) {
rdp->deferred_qs = true;
- WRITE_ONCE(t->rcu_read_unlock_special.b.exp_hint, true);
+ t->rcu_read_unlock_special.b.exp_hint = true;
}
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
return;
@@ -649,7 +649,7 @@ static void rcu_exp_handler(void *unused)
*
* If the CPU is fully enabled (or if some buggy RCU-preempt
* read-side critical section is being used from idle), just
- * invoke rcu_preempt_defer_qs() to immediately report the
+ * invoke rcu_preempt_deferred_qs() to immediately report the
* quiescent state. We cannot use rcu_read_unlock_special()
* because we are in an interrupt handler, which will cause that
* function to take an early exit without doing anything.
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index a1f9d7c15bd8..1102765f91fd 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -285,7 +285,7 @@ static void rcu_qs(void)
TPS("cpuqs"));
__this_cpu_write(rcu_data.cpu_no_qs.b.norm, false);
barrier(); /* Coordinate with rcu_flavor_sched_clock_irq(). */
- current->rcu_read_unlock_special.b.need_qs = false;
+ WRITE_ONCE(current->rcu_read_unlock_special.b.need_qs, false);
}
}
@@ -710,19 +710,25 @@ static void rcu_flavor_sched_clock_irq(int user)
/*
* Check for a task exiting while in a preemptible-RCU read-side
- * critical section, clean up if so. No need to issue warnings,
- * as debug_check_no_locks_held() already does this if lockdep
- * is enabled.
+ * critical section, clean up if so. No need to issue warnings, as
+ * debug_check_no_locks_held() already does this if lockdep is enabled.
+ * Besides, if this function does anything other than just immediately
+ * return, there was a bug of some sort. Spewing warnings from this
+ * function is like as not to simply obscure important prior warnings.
*/
void exit_rcu(void)
{
struct task_struct *t = current;
- if (likely(list_empty(&current->rcu_node_entry)))
+ if (unlikely(!list_empty(&current->rcu_node_entry))) {
+ t->rcu_read_lock_nesting = 1;
+ barrier();
+ WRITE_ONCE(t->rcu_read_unlock_special.b.blocked, true);
+ } else if (unlikely(t->rcu_read_lock_nesting)) {
+ t->rcu_read_lock_nesting = 1;
+ } else {
return;
- t->rcu_read_lock_nesting = 1;
- barrier();
- t->rcu_read_unlock_special.b.blocked = true;
+ }
__rcu_read_unlock();
rcu_preempt_deferred_qs(current);
}
@@ -1064,8 +1070,6 @@ static int rcu_boost_kthread(void *arg)
static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags)
__releases(rnp->lock)
{
- struct task_struct *t;
-
raw_lockdep_assert_held_rcu_node(rnp);
if (!rcu_preempt_blocked_readers_cgp(rnp) && rnp->exp_tasks == NULL) {
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
@@ -1079,9 +1083,8 @@ static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags)
if (rnp->exp_tasks == NULL)
rnp->boost_tasks = rnp->gp_tasks;
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
- t = rnp->boost_kthread_task;
- if (t)
- rcu_wake_cond(t, rnp->boost_kthread_status);
+ rcu_wake_cond(rnp->boost_kthread_task,
+ rnp->boost_kthread_status);
} else {
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
}
@@ -1553,11 +1556,22 @@ static void rcu_cleanup_after_idle(void)
*/
-/* Parse the boot-time rcu_nocb_mask CPU list from the kernel parameters. */
+/*
+ * Parse the boot-time rcu_nocb_mask CPU list from the kernel parameters.
+ * The string after the "rcu_nocbs=" is either "all" for all CPUs, or a
+ * comma-separated list of CPUs and/or CPU ranges. If an invalid list is
+ * given, a warning is emitted and all CPUs are offloaded.
+ */
static int __init rcu_nocb_setup(char *str)
{
alloc_bootmem_cpumask_var(&rcu_nocb_mask);
- cpulist_parse(str, rcu_nocb_mask);
+ if (!strcasecmp(str, "all"))
+ cpumask_setall(rcu_nocb_mask);
+ else
+ if (cpulist_parse(str, rcu_nocb_mask)) {
+ pr_warn("rcu_nocbs= bad CPU range, all CPUs set\n");
+ cpumask_setall(rcu_nocb_mask);
+ }
return 1;
}
__setup("rcu_nocbs=", rcu_nocb_setup);
diff --git a/kernel/torture.c b/kernel/torture.c
index 8faa1a9aaeb9..17b2be9bde12 100644
--- a/kernel/torture.c
+++ b/kernel/torture.c
@@ -88,6 +88,8 @@ bool torture_offline(int cpu, long *n_offl_attempts, long *n_offl_successes,
if (!cpu_online(cpu) || !cpu_is_hotpluggable(cpu))
return false;
+ if (num_online_cpus() <= 1)
+ return false; /* Can't offline the last CPU. */
if (verbose > 1)
pr_alert("%s" TORTURE_FLAG
diff --git a/net/ipv4/netfilter/ipt_CLUSTERIP.c b/net/ipv4/netfilter/ipt_CLUSTERIP.c
index 835d50b279f5..a2a88ab07f7b 100644
--- a/net/ipv4/netfilter/ipt_CLUSTERIP.c
+++ b/net/ipv4/netfilter/ipt_CLUSTERIP.c
@@ -56,7 +56,7 @@ struct clusterip_config {
#endif
enum clusterip_hashmode hash_mode; /* which hashing mode */
u_int32_t hash_initval; /* hash initialization */
- struct rcu_head rcu; /* for call_rcu_bh */
+ struct rcu_head rcu; /* for call_rcu */
struct net *net; /* netns for pernet list */
char ifname[IFNAMSIZ]; /* device ifname */
};
diff --git a/tools/testing/selftests/rcutorture/bin/configNR_CPUS.sh b/tools/testing/selftests/rcutorture/bin/configNR_CPUS.sh
index 43540f1828cc..2deea2169fc2 100755
--- a/tools/testing/selftests/rcutorture/bin/configNR_CPUS.sh
+++ b/tools/testing/selftests/rcutorture/bin/configNR_CPUS.sh
@@ -1,4 +1,5 @@
#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0+
#
# Extract the number of CPUs expected from the specified Kconfig-file
# fragment by checking CONFIG_SMP and CONFIG_NR_CPUS. If the specified
@@ -7,23 +8,9 @@
#
# Usage: configNR_CPUS.sh config-frag
#
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 2 of the License, or
-# (at your option) any later version.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, you can access it online at
-# http://www.gnu.org/licenses/gpl-2.0.html.
-#
# Copyright (C) IBM Corporation, 2013
#
-# Authors: Paul E. McKenney <[email protected]>
+# Authors: Paul E. McKenney <[email protected]>
cf=$1
if test ! -r $cf
diff --git a/tools/testing/selftests/rcutorture/bin/config_override.sh b/tools/testing/selftests/rcutorture/bin/config_override.sh
index ef7fcbac3d42..90016c359e83 100755
--- a/tools/testing/selftests/rcutorture/bin/config_override.sh
+++ b/tools/testing/selftests/rcutorture/bin/config_override.sh
@@ -1,4 +1,5 @@
#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0+
#
# config_override.sh base override
#
@@ -6,23 +7,9 @@
# that conflict with any in override, concatenating what remains and
# sending the result to standard output.
#
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 2 of the License, or
-# (at your option) any later version.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, you can access it online at
-# http://www.gnu.org/licenses/gpl-2.0.html.
-#
# Copyright (C) IBM Corporation, 2017
#
-# Authors: Paul E. McKenney <[email protected]>
+# Authors: Paul E. McKenney <[email protected]>
base=$1
if test -r $base
diff --git a/tools/testing/selftests/rcutorture/bin/configcheck.sh b/tools/testing/selftests/rcutorture/bin/configcheck.sh
index 197deece7c7c..31584cee84d7 100755
--- a/tools/testing/selftests/rcutorture/bin/configcheck.sh
+++ b/tools/testing/selftests/rcutorture/bin/configcheck.sh
@@ -1,23 +1,11 @@
#!/bin/bash
-# Usage: configcheck.sh .config .config-template
-#
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 2 of the License, or
-# (at your option) any later version.
+# SPDX-License-Identifier: GPL-2.0+
#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, you can access it online at
-# http://www.gnu.org/licenses/gpl-2.0.html.
+# Usage: configcheck.sh .config .config-template
#
# Copyright (C) IBM Corporation, 2011
#
-# Authors: Paul E. McKenney <[email protected]>
+# Authors: Paul E. McKenney <[email protected]>
T=${TMPDIR-/tmp}/abat-chk-config.sh.$$
trap 'rm -rf $T' 0
@@ -26,6 +14,7 @@ mkdir $T
cat $1 > $T/.config
cat $2 | sed -e 's/\(.*\)=n/# \1 is not set/' -e 's/^#CHECK#//' |
+grep -v '^CONFIG_INITRAMFS_SOURCE' |
awk '
{
print "if grep -q \"" $0 "\" < '"$T/.config"'";
diff --git a/tools/testing/selftests/rcutorture/bin/configinit.sh b/tools/testing/selftests/rcutorture/bin/configinit.sh
index 65541c21a544..40359486b3a8 100755
--- a/tools/testing/selftests/rcutorture/bin/configinit.sh
+++ b/tools/testing/selftests/rcutorture/bin/configinit.sh
@@ -1,4 +1,5 @@
#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0+
#
# Usage: configinit.sh config-spec-file build-output-dir results-dir
#
@@ -14,23 +15,9 @@
# for example, "O=/tmp/foo". If this argument is omitted, the .config
# file will be generated directly in the current directory.
#
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 2 of the License, or
-# (at your option) any later version.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, you can access it online at
-# http://www.gnu.org/licenses/gpl-2.0.html.
-#
# Copyright (C) IBM Corporation, 2013
#
-# Authors: Paul E. McKenney <[email protected]>
+# Authors: Paul E. McKenney <[email protected]>
T=${TMPDIR-/tmp}/configinit.sh.$$
trap 'rm -rf $T' 0
diff --git a/tools/testing/selftests/rcutorture/bin/cpus2use.sh b/tools/testing/selftests/rcutorture/bin/cpus2use.sh
index bb99cde3f5f9..ff7102212703 100755
--- a/tools/testing/selftests/rcutorture/bin/cpus2use.sh
+++ b/tools/testing/selftests/rcutorture/bin/cpus2use.sh
@@ -1,26 +1,13 @@
#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0+
#
# Get an estimate of how CPU-hoggy to be.
#
# Usage: cpus2use.sh
#
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 2 of the License, or
-# (at your option) any later version.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, you can access it online at
-# http://www.gnu.org/licenses/gpl-2.0.html.
-#
# Copyright (C) IBM Corporation, 2013
#
-# Authors: Paul E. McKenney <[email protected]>
+# Authors: Paul E. McKenney <[email protected]>
ncpus=`grep '^processor' /proc/cpuinfo | wc -l`
idlecpus=`mpstat | tail -1 | \
diff --git a/tools/testing/selftests/rcutorture/bin/functions.sh b/tools/testing/selftests/rcutorture/bin/functions.sh
index 65f6655026f0..6bcb8b5b2ff2 100644
--- a/tools/testing/selftests/rcutorture/bin/functions.sh
+++ b/tools/testing/selftests/rcutorture/bin/functions.sh
@@ -1,24 +1,11 @@
#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0+
#
# Shell functions for the rest of the scripts.
#
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 2 of the License, or
-# (at your option) any later version.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, you can access it online at
-# http://www.gnu.org/licenses/gpl-2.0.html.
-#
# Copyright (C) IBM Corporation, 2013
#
-# Authors: Paul E. McKenney <[email protected]>
+# Authors: Paul E. McKenney <[email protected]>
# bootparam_hotplug_cpu bootparam-string
#
diff --git a/tools/testing/selftests/rcutorture/bin/jitter.sh b/tools/testing/selftests/rcutorture/bin/jitter.sh
index 3633828375e3..435b60933985 100755
--- a/tools/testing/selftests/rcutorture/bin/jitter.sh
+++ b/tools/testing/selftests/rcutorture/bin/jitter.sh
@@ -1,4 +1,5 @@
#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0+
#
# Alternate sleeping and spinning on randomly selected CPUs. The purpose
# of this script is to inflict random OS jitter on a concurrently running
@@ -11,23 +12,9 @@
# sleepmax: Maximum microseconds to sleep, defaults to one second.
# spinmax: Maximum microseconds to spin, defaults to one millisecond.
#
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 2 of the License, or
-# (at your option) any later version.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, you can access it online at
-# http://www.gnu.org/licenses/gpl-2.0.html.
-#
# Copyright (C) IBM Corporation, 2016
#
-# Authors: Paul E. McKenney <[email protected]>
+# Authors: Paul E. McKenney <[email protected]>
me=$(($1 * 1000))
duration=$2
diff --git a/tools/testing/selftests/rcutorture/bin/kvm-build.sh b/tools/testing/selftests/rcutorture/bin/kvm-build.sh
index 9115fcdb5617..c27a0bbb9c02 100755
--- a/tools/testing/selftests/rcutorture/bin/kvm-build.sh
+++ b/tools/testing/selftests/rcutorture/bin/kvm-build.sh
@@ -1,26 +1,13 @@
#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0+
#
# Build a kvm-ready Linux kernel from the tree in the current directory.
#
# Usage: kvm-build.sh config-template build-dir resdir
#
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 2 of the License, or
-# (at your option) any later version.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, you can access it online at
-# http://www.gnu.org/licenses/gpl-2.0.html.
-#
# Copyright (C) IBM Corporation, 2011
#
-# Authors: Paul E. McKenney <[email protected]>
+# Authors: Paul E. McKenney <[email protected]>
config_template=${1}
if test -z "$config_template" -o ! -f "$config_template" -o ! -r "$config_template"
diff --git a/tools/testing/selftests/rcutorture/bin/kvm-find-errors.sh b/tools/testing/selftests/rcutorture/bin/kvm-find-errors.sh
index 98f650c9bf54..8426fe1f15ee 100755
--- a/tools/testing/selftests/rcutorture/bin/kvm-find-errors.sh
+++ b/tools/testing/selftests/rcutorture/bin/kvm-find-errors.sh
@@ -1,4 +1,5 @@
#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0+
#
# Invoke a text editor on all console.log files for all runs with diagnostics,
# that is, on all such files having a console.log.diags counterpart.
@@ -10,6 +11,10 @@
#
# The "directory" above should end with the date/time directory, for example,
# "tools/testing/selftests/rcutorture/res/2018.02.25-14:27:27".
+#
+# Copyright (C) IBM Corporation, 2018
+#
+# Author: Paul E. McKenney <[email protected]>
rundir="${1}"
if test -z "$rundir" -o ! -d "$rundir"
diff --git a/tools/testing/selftests/rcutorture/bin/kvm-recheck-lock.sh b/tools/testing/selftests/rcutorture/bin/kvm-recheck-lock.sh
index 2de92f43ee8c..f3a7a5e2b89d 100755
--- a/tools/testing/selftests/rcutorture/bin/kvm-recheck-lock.sh
+++ b/tools/testing/selftests/rcutorture/bin/kvm-recheck-lock.sh
@@ -1,26 +1,13 @@
#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0+
#
# Analyze a given results directory for locktorture progress.
#
# Usage: kvm-recheck-lock.sh resdir
#
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 2 of the License, or
-# (at your option) any later version.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, you can access it online at
-# http://www.gnu.org/licenses/gpl-2.0.html.
-#
# Copyright (C) IBM Corporation, 2014
#
-# Authors: Paul E. McKenney <[email protected]>
+# Authors: Paul E. McKenney <[email protected]>
i="$1"
if test -d "$i" -a -r "$i"
diff --git a/tools/testing/selftests/rcutorture/bin/kvm-recheck-rcu.sh b/tools/testing/selftests/rcutorture/bin/kvm-recheck-rcu.sh
index 0fa8a61ccb7b..2a7f3f4756a7 100755
--- a/tools/testing/selftests/rcutorture/bin/kvm-recheck-rcu.sh
+++ b/tools/testing/selftests/rcutorture/bin/kvm-recheck-rcu.sh
@@ -1,26 +1,13 @@
#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0+
#
# Analyze a given results directory for rcutorture progress.
#
# Usage: kvm-recheck-rcu.sh resdir
#
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 2 of the License, or
-# (at your option) any later version.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, you can access it online at
-# http://www.gnu.org/licenses/gpl-2.0.html.
-#
# Copyright (C) IBM Corporation, 2014
#
-# Authors: Paul E. McKenney <[email protected]>
+# Authors: Paul E. McKenney <[email protected]>
i="$1"
if test -d "$i" -a -r "$i"
diff --git a/tools/testing/selftests/rcutorture/bin/kvm-recheck-rcuperf-ftrace.sh b/tools/testing/selftests/rcutorture/bin/kvm-recheck-rcuperf-ftrace.sh
index 8948f7926b21..7d3c2be66c64 100755
--- a/tools/testing/selftests/rcutorture/bin/kvm-recheck-rcuperf-ftrace.sh
+++ b/tools/testing/selftests/rcutorture/bin/kvm-recheck-rcuperf-ftrace.sh
@@ -1,4 +1,5 @@
#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0+
#
# Analyze a given results directory for rcuperf performance measurements,
# looking for ftrace data. Exits with 0 if data was found, analyzed, and
@@ -7,23 +8,9 @@
#
# Usage: kvm-recheck-rcuperf-ftrace.sh resdir
#
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 2 of the License, or
-# (at your option) any later version.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, you can access it online at
-# http://www.gnu.org/licenses/gpl-2.0.html.
-#
# Copyright (C) IBM Corporation, 2016
#
-# Authors: Paul E. McKenney <[email protected]>
+# Authors: Paul E. McKenney <[email protected]>
i="$1"
. functions.sh
diff --git a/tools/testing/selftests/rcutorture/bin/kvm-recheck-rcuperf.sh b/tools/testing/selftests/rcutorture/bin/kvm-recheck-rcuperf.sh
index ccebf772fa1e..db0375a57f28 100755
--- a/tools/testing/selftests/rcutorture/bin/kvm-recheck-rcuperf.sh
+++ b/tools/testing/selftests/rcutorture/bin/kvm-recheck-rcuperf.sh
@@ -1,26 +1,13 @@
#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0+
#
# Analyze a given results directory for rcuperf performance measurements.
#
# Usage: kvm-recheck-rcuperf.sh resdir
#
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 2 of the License, or
-# (at your option) any later version.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, you can access it online at
-# http://www.gnu.org/licenses/gpl-2.0.html.
-#
# Copyright (C) IBM Corporation, 2016
#
-# Authors: Paul E. McKenney <[email protected]>
+# Authors: Paul E. McKenney <[email protected]>
i="$1"
if test -d "$i" -a -r "$i"
diff --git a/tools/testing/selftests/rcutorture/bin/kvm-recheck.sh b/tools/testing/selftests/rcutorture/bin/kvm-recheck.sh
index c9bab57a77eb..2adde6aaafdb 100755
--- a/tools/testing/selftests/rcutorture/bin/kvm-recheck.sh
+++ b/tools/testing/selftests/rcutorture/bin/kvm-recheck.sh
@@ -1,4 +1,5 @@
#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0+
#
# Given the results directories for previous KVM-based torture runs,
# check the build and console output for errors. Given a directory
@@ -6,23 +7,9 @@
#
# Usage: kvm-recheck.sh resdir ...
#
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 2 of the License, or
-# (at your option) any later version.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, you can access it online at
-# http://www.gnu.org/licenses/gpl-2.0.html.
-#
# Copyright (C) IBM Corporation, 2011
#
-# Authors: Paul E. McKenney <[email protected]>
+# Authors: Paul E. McKenney <[email protected]>
PATH=`pwd`/tools/testing/selftests/rcutorture/bin:$PATH; export PATH
. functions.sh
diff --git a/tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh b/tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh
index 58ca758a5786..0eb1ec16d78a 100755
--- a/tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh
+++ b/tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh
@@ -1,4 +1,5 @@
#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0+
#
# Run a kvm-based test of the specified tree on the specified configs.
# Fully automated run and error checking, no graphics console.
@@ -20,23 +21,9 @@
#
# More sophisticated argument parsing is clearly needed.
#
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 2 of the License, or
-# (at your option) any later version.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, you can access it online at
-# http://www.gnu.org/licenses/gpl-2.0.html.
-#
# Copyright (C) IBM Corporation, 2011
#
-# Authors: Paul E. McKenney <[email protected]>
+# Authors: Paul E. McKenney <[email protected]>
T=${TMPDIR-/tmp}/kvm-test-1-run.sh.$$
trap 'rm -rf $T' 0
diff --git a/tools/testing/selftests/rcutorture/bin/kvm.sh b/tools/testing/selftests/rcutorture/bin/kvm.sh
index 19864f1cb27a..8f1e337b9b54 100755
--- a/tools/testing/selftests/rcutorture/bin/kvm.sh
+++ b/tools/testing/selftests/rcutorture/bin/kvm.sh
@@ -1,4 +1,5 @@
#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0+
#
# Run a series of tests under KVM. By default, this series is specified
# by the relevant CFLIST file, but can be overridden by the --configs
@@ -6,23 +7,9 @@
#
# Usage: kvm.sh [ options ]
#
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 2 of the License, or
-# (at your option) any later version.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, you can access it online at
-# http://www.gnu.org/licenses/gpl-2.0.html.
-#
# Copyright (C) IBM Corporation, 2011
#
-# Authors: Paul E. McKenney <[email protected]>
+# Authors: Paul E. McKenney <[email protected]>
scriptname=$0
args="$*"
diff --git a/tools/testing/selftests/rcutorture/bin/mkinitrd.sh b/tools/testing/selftests/rcutorture/bin/mkinitrd.sh
index 83552bb007b4..6fa9bd1ddc09 100755
--- a/tools/testing/selftests/rcutorture/bin/mkinitrd.sh
+++ b/tools/testing/selftests/rcutorture/bin/mkinitrd.sh
@@ -1,21 +1,8 @@
#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0+
#
# Create an initrd directory if one does not already exist.
#
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 2 of the License, or
-# (at your option) any later version.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, you can access it online at
-# http://www.gnu.org/licenses/gpl-2.0.html.
-#
# Copyright (C) IBM Corporation, 2013
#
# Author: Connor Shu <[email protected]>
diff --git a/tools/testing/selftests/rcutorture/bin/parse-build.sh b/tools/testing/selftests/rcutorture/bin/parse-build.sh
index 24fe5f822b28..0701b3bf6ade 100755
--- a/tools/testing/selftests/rcutorture/bin/parse-build.sh
+++ b/tools/testing/selftests/rcutorture/bin/parse-build.sh
@@ -1,4 +1,5 @@
#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0+
#
# Check the build output from an rcutorture run for goodness.
# The "file" is a pathname on the local system, and "title" is
@@ -8,23 +9,9 @@
#
# Usage: parse-build.sh file title
#
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 2 of the License, or
-# (at your option) any later version.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, you can access it online at
-# http://www.gnu.org/licenses/gpl-2.0.html.
-#
# Copyright (C) IBM Corporation, 2011
#
-# Authors: Paul E. McKenney <[email protected]>
+# Authors: Paul E. McKenney <[email protected]>
F=$1
title=$2
diff --git a/tools/testing/selftests/rcutorture/bin/parse-console.sh b/tools/testing/selftests/rcutorture/bin/parse-console.sh
index 84933f6aed77..4508373a922f 100755
--- a/tools/testing/selftests/rcutorture/bin/parse-console.sh
+++ b/tools/testing/selftests/rcutorture/bin/parse-console.sh
@@ -1,4 +1,5 @@
#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0+
#
# Check the console output from an rcutorture run for oopses.
# The "file" is a pathname on the local system, and "title" is
@@ -6,23 +7,9 @@
#
# Usage: parse-console.sh file title
#
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 2 of the License, or
-# (at your option) any later version.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, you can access it online at
-# http://www.gnu.org/licenses/gpl-2.0.html.
-#
# Copyright (C) IBM Corporation, 2011
#
-# Authors: Paul E. McKenney <[email protected]>
+# Authors: Paul E. McKenney <[email protected]>
T=${TMPDIR-/tmp}/parse-console.sh.$$
file="$1"
diff --git a/tools/testing/selftests/rcutorture/configs/lock/ver_functions.sh b/tools/testing/selftests/rcutorture/configs/lock/ver_functions.sh
index 80eb646e1319..d3e4b2971f92 100644
--- a/tools/testing/selftests/rcutorture/configs/lock/ver_functions.sh
+++ b/tools/testing/selftests/rcutorture/configs/lock/ver_functions.sh
@@ -1,24 +1,11 @@
#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0+
#
# Kernel-version-dependent shell functions for the rest of the scripts.
#
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 2 of the License, or
-# (at your option) any later version.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, you can access it online at
-# http://www.gnu.org/licenses/gpl-2.0.html.
-#
# Copyright (C) IBM Corporation, 2014
#
-# Authors: Paul E. McKenney <[email protected]>
+# Authors: Paul E. McKenney <[email protected]>
# locktorture_param_onoff bootparam-string config-file
#
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/ver_functions.sh b/tools/testing/selftests/rcutorture/configs/rcu/ver_functions.sh
index 7bab8246392b..effa415f9b92 100644
--- a/tools/testing/selftests/rcutorture/configs/rcu/ver_functions.sh
+++ b/tools/testing/selftests/rcutorture/configs/rcu/ver_functions.sh
@@ -1,24 +1,11 @@
#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0+
#
# Kernel-version-dependent shell functions for the rest of the scripts.
#
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 2 of the License, or
-# (at your option) any later version.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, you can access it online at
-# http://www.gnu.org/licenses/gpl-2.0.html.
-#
# Copyright (C) IBM Corporation, 2013
#
-# Authors: Paul E. McKenney <[email protected]>
+# Authors: Paul E. McKenney <[email protected]>
# rcutorture_param_n_barrier_cbs bootparam-string
#
diff --git a/tools/testing/selftests/rcutorture/configs/rcuperf/ver_functions.sh b/tools/testing/selftests/rcutorture/configs/rcuperf/ver_functions.sh
index d36b8fd6f0fc..777d5b0c190f 100644
--- a/tools/testing/selftests/rcutorture/configs/rcuperf/ver_functions.sh
+++ b/tools/testing/selftests/rcutorture/configs/rcuperf/ver_functions.sh
@@ -1,24 +1,11 @@
#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0+
#
# Torture-suite-dependent shell functions for the rest of the scripts.
#
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 2 of the License, or
-# (at your option) any later version.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, you can access it online at
-# http://www.gnu.org/licenses/gpl-2.0.html.
-#
# Copyright (C) IBM Corporation, 2015
#
-# Authors: Paul E. McKenney <[email protected]>
+# Authors: Paul E. McKenney <[email protected]>
# per_version_boot_params bootparam-string config-file seconds
#