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When a CPU that was in an extended quiescent state wakes
up and catches up with grace periods that remote CPUs
completed on its behalf, we update the completed field
but not the gpnum that keeps a stale value of a backward
grace period ID.
Later, note_new_gpnum() will interpret the shift between
the local CPU and the node grace period ID as some new grace
period to handle and will then start to hunt quiescent state.
But if every grace periods have already been completed, this
interpretation becomes broken. And we'll be stuck in clusters
of spurious softirqs because rcu_report_qs_rdp() will make
this broken state run into infinite loop.
The solution, as suggested by Lai Jiangshan, is to ensure that
the gpnum and completed fields are well synchronized when we catch
up with completed grace periods on their behalf by other cpus.
This way we won't start noting spurious new grace periods.
Suggested-by: Lai Jiangshan <[email protected]>
Signed-off-by: Frederic Weisbecker <[email protected]>
Cc: Paul E. McKenney <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Steven Rostedt <[email protected]
Signed-off-by: Paul E. McKenney <[email protected]>
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When a CPU is idle and others CPUs handled its extended
quiescent state to complete grace periods on its behalf,
it will catch up with completed grace periods numbers
when it wakes up.
But at this point there might be no more grace period to
complete, but still the woken CPU always keeps its stale
qs_pending value and will then continue to chase quiescent
states even if its not needed anymore.
This results in clusters of spurious softirqs until a new
real grace period is started. Because if we continue to
chase quiescent states but we have completed every grace
periods, rcu_report_qs_rdp() is puzzled and makes that
state run into infinite loops.
As suggested by Lai Jiangshan, just reset qs_pending if
someone completed every grace periods on our behalf.
Suggested-by: Lai Jiangshan <[email protected]>
Signed-off-by: Frederic Weisbecker <[email protected]>
Cc: Paul E. McKenney <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Steven Rostedt <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
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The fix in commit #6a0cc49 requires more than three concurrent instances
of synchronize_sched_expedited() before batching is possible. This
patch uses a ticket-counter-like approach that is also not unrelated to
Lai Jiangshan's Ring RCU to allow sharing of expedited grace periods even
when there are only two concurrent instances of synchronize_sched_expedited().
This commit builds on Tejun's original posting, which may be found at
http://lkml.org/lkml/2010/11/9/204, adding memory barriers, avoiding
overflow of signed integers (other than via atomic_t), and fixing the
detection of batching.
Signed-off-by: Tejun Heo <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
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The synchronize_srcu_expedited() function is currently quick if there
are no active readers, but will delay a full jiffy if there are any.
If these readers leave their SRCU read-side critical sections quickly,
this is way too long to wait. So this commit first waits ten microseconds,
and only then falls back to jiffy-at-a-time waiting.
Reported-by: Avi Kivity <[email protected]>
Reported-by: Marcelo Tosatti <[email protected]>
Tested-by: Takuya Yoshikawa <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
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The new (early 2010) implementation of synchronize_sched_expedited() uses
try_stop_cpu() to force a context switch on every CPU. It also permits
concurrent calls to synchronize_sched_expedited() to share a single call
to try_stop_cpu() through use of an atomically incremented
synchronize_sched_expedited_count variable. Unfortunately, this is
subject to failure as follows:
o Task A invokes synchronize_sched_expedited(), try_stop_cpus()
succeeds, but Task A is preempted before getting to the atomic
increment of synchronize_sched_expedited_count.
o Task B also invokes synchronize_sched_expedited(), with exactly
the same outcome as Task A.
o Task C also invokes synchronize_sched_expedited(), again with
exactly the same outcome as Tasks A and B.
o Task D also invokes synchronize_sched_expedited(), but only
gets as far as acquiring the mutex within try_stop_cpus()
before being preempted, interrupted, or otherwise delayed.
o Task E also invokes synchronize_sched_expedited(), but only
gets to the snapshotting of synchronize_sched_expedited_count.
o Tasks A, B, and C all increment synchronize_sched_expedited_count.
o Task E fails to get the mutex, so checks the new value
of synchronize_sched_expedited_count. It finds that the
value has increased, so (wrongly) assumes that its work
has been done, returning despite there having been no
expedited grace period since it began.
The solution is to have the lowest-numbered CPU atomically increment
the synchronize_sched_expedited_count variable within the
synchronize_sched_expedited_cpu_stop() function, which is under
the protection of the mutex acquired by try_stop_cpus(). However, this
also requires that piggybacking tasks wait for three rather than two
instances of try_stop_cpu(), because we cannot control the order in
which the per-CPU callback function occur.
Cc: Tejun Heo <[email protected]>
Cc: Lai Jiangshan <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
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Lai's RCU-callback immediate-adoption patch changes the RCU tracing
output, so update tracing.txt. Also update a few comments to clarify
the synchronization design.
Signed-off-by: Paul E. McKenney <[email protected]>
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When we handle the CPU_DYING notifier, the whole system is stopped except
for the current CPU. We therefore need no synchronization with the other
CPUs. This allows us to move any orphaned RCU callbacks directly to the
list of any online CPU without needing to run them through the global
orphan lists. These global orphan lists can therefore be dispensed with.
This commit makes thes changes, though currently victimizes CPU 0 @@@.
Signed-off-by: Lai Jiangshan <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
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The first version of synchronize_sched_expedited() used the migration
code in the scheduler, and was therefore implemented in kernel/sched.c.
However, the more recent version of this code no longer uses the
migration code, so this commit moves it to the main RCU source files.
Signed-off-by: Lai Jiangshan <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
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The TREE_RCU tracing had obsolete rcuclassic_trace_init() and
rcuclassic_trace_cleanup() function names. This commit brings them
up to date: rcutree_trace_init() and rcutree_trace_cleanup(),
respectively.
Signed-off-by: Paul E. McKenney <[email protected]>
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RCU priority boosting's tracing did not distinguish between ongoing
boosting and completion of boosting. This commit therefore adds this
capability.
Signed-off-by: Paul E. McKenney <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
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Add the required verbiage to Documentation/RCU/trace.txt.
Signed-off-by: Paul E. McKenney <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
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Add tracing for the tiny RCU implementations, including statistics on
boosting in the case of TINY_PREEMPT_RCU and RCU_BOOST.
Signed-off-by: Paul E. McKenney <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
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Add priority boosting, but only for TINY_PREEMPT_RCU. This is enabled
by the default-off RCU_BOOST kernel parameter. The priority to which to
boost preempted RCU readers is controlled by the RCU_BOOST_PRIO kernel
parameter (defaulting to real-time priority 1) and the time to wait
before boosting the readers blocking a given grace period is controlled
by the RCU_BOOST_DELAY kernel parameter (defaulting to 500 milliseconds).
Signed-off-by: Paul E. McKenney <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
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If RCU priority boosting is to be meaningful, callback invocation must
be boosted in addition to preempted RCU readers. Otherwise, in presence
of CPU real-time threads, the grace period ends, but the callbacks don't
get invoked. If the callbacks don't get invoked, the associated memory
doesn't get freed, so the system is still subject to OOM.
But it is not reasonable to priority-boost RCU_SOFTIRQ, so this commit
moves the callback invocations to a kthread, which can be boosted easily.
Signed-off-by: Paul E. McKenney <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
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Add an optional test to force long-term preemption of RCU read-side
critical sections, controlled by new test_boost, test_boost_interval,
and test_boost_duration module parameters. This is to be used to
test RCU priority boosting.
Signed-off-by: Paul E. McKenney <[email protected]>
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This addresses the following RCU lockdep splat:
[0.051203] CPU0: AMD QEMU Virtual CPU version 0.12.4 stepping 03
[0.052999] lockdep: fixing up alternatives.
[0.054105]
[0.054106] ===================================================
[0.054999] [ INFO: suspicious rcu_dereference_check() usage. ]
[0.054999] ---------------------------------------------------
[0.054999] kernel/sched.c:616 invoked rcu_dereference_check() without protection!
[0.054999]
[0.054999] other info that might help us debug this:
[0.054999]
[0.054999]
[0.054999] rcu_scheduler_active = 1, debug_locks = 1
[0.054999] 3 locks held by swapper/1:
[0.054999] #0: (cpu_add_remove_lock){+.+.+.}, at: [<ffffffff814be933>] cpu_up+0x42/0x6a
[0.054999] #1: (cpu_hotplug.lock){+.+.+.}, at: [<ffffffff810400d8>] cpu_hotplug_begin+0x2a/0x51
[0.054999] #2: (&rq->lock){-.-...}, at: [<ffffffff814be2f7>] init_idle+0x2f/0x113
[0.054999]
[0.054999] stack backtrace:
[0.054999] Pid: 1, comm: swapper Not tainted 2.6.35 #1
[0.054999] Call Trace:
[0.054999] [<ffffffff81068054>] lockdep_rcu_dereference+0x9b/0xa3
[0.054999] [<ffffffff810325c3>] task_group+0x7b/0x8a
[0.054999] [<ffffffff810325e5>] set_task_rq+0x13/0x40
[0.054999] [<ffffffff814be39a>] init_idle+0xd2/0x113
[0.054999] [<ffffffff814be78a>] fork_idle+0xb8/0xc7
[0.054999] [<ffffffff81068717>] ? mark_held_locks+0x4d/0x6b
[0.054999] [<ffffffff814bcebd>] do_fork_idle+0x17/0x2b
[0.054999] [<ffffffff814bc89b>] native_cpu_up+0x1c1/0x724
[0.054999] [<ffffffff814bcea6>] ? do_fork_idle+0x0/0x2b
[0.054999] [<ffffffff814be876>] _cpu_up+0xac/0x127
[0.054999] [<ffffffff814be946>] cpu_up+0x55/0x6a
[0.054999] [<ffffffff81ab562a>] kernel_init+0xe1/0x1ff
[0.054999] [<ffffffff81003854>] kernel_thread_helper+0x4/0x10
[0.054999] [<ffffffff814c353c>] ? restore_args+0x0/0x30
[0.054999] [<ffffffff81ab5549>] ? kernel_init+0x0/0x1ff
[0.054999] [<ffffffff81003850>] ? kernel_thread_helper+0x0/0x10
[0.056074] Booting Node 0, Processors #1lockdep: fixing up alternatives.
[0.130045] #2lockdep: fixing up alternatives.
[0.203089] #3 Ok.
[0.275286] Brought up 4 CPUs
[0.276005] Total of 4 processors activated (16017.17 BogoMIPS).
The cgroup_subsys_state structures referenced by idle tasks are never
freed, because the idle tasks should be part of the root cgroup,
which is not removable.
The problem is that while we do in-fact hold rq->lock, the newly spawned
idle thread's cpu is not yet set to the correct cpu so the lockdep check
in task_group():
lockdep_is_held(&task_rq(p)->lock)
will fail.
But this is a chicken and egg problem. Setting the CPU's runqueue requires
that the CPU's runqueue already be set. ;-)
So insert an RCU read-side critical section to avoid the complaint.
Signed-off-by: Peter Zijlstra <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
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Using ACCESS_ONCE() to observe the jiffies_stall/rnp->qsmask value
due to the caller didn't hold the root_rcu/rnp node's lock. Although
use without ACCESS_ONCE() is safe due to the value loaded being used
but once, the ACCESS_ONCE() is a good documentation aid -- the variables
are being loaded without the services of a lock.
Signed-off-by: Dongdong Deng <[email protected]>
CC: Dipankar Sarma <[email protected]>
CC: Paul E. McKenney <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
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> ===================================================
> [ INFO: suspicious rcu_dereference_check() usage. ]
> ---------------------------------------------------
> /home/greearb/git/linux.wireless-testing/kernel/sched.c:618 invoked rcu_dereference_check() without protection!
>
> other info that might help us debug this:
>
> rcu_scheduler_active = 1, debug_locks = 1
> 1 lock held by ifup/23517:
> #0: (&rq->lock){-.-.-.}, at: [<c042f782>] task_fork_fair+0x3b/0x108
>
> stack backtrace:
> Pid: 23517, comm: ifup Not tainted 2.6.36-rc6-wl+ #5
> Call Trace:
> [<c075e219>] ? printk+0xf/0x16
> [<c0455842>] lockdep_rcu_dereference+0x74/0x7d
> [<c0426854>] task_group+0x6d/0x79
> [<c042686e>] set_task_rq+0xe/0x57
> [<c042f79e>] task_fork_fair+0x57/0x108
> [<c042e965>] sched_fork+0x82/0xf9
> [<c04334b3>] copy_process+0x569/0xe8e
> [<c0433ef0>] do_fork+0x118/0x262
> [<c076302f>] ? do_page_fault+0x16a/0x2cf
> [<c044b80c>] ? up_read+0x16/0x2a
> [<c04085ae>] sys_clone+0x1b/0x20
> [<c04030a5>] ptregs_clone+0x15/0x30
> [<c0402f1c>] ? sysenter_do_call+0x12/0x38
Here a newly created task is having its runqueue assigned. The new task
is not yet on the tasklist, so cannot go away. This is therefore a false
positive, suppress with an RCU read-side critical section.
Reported-by: Ben Greear <[email protected]
Signed-off-by: Paul E. McKenney <[email protected]>
Tested-by: Ben Greear <[email protected]
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> ===================================================
> [ INFO: suspicious rcu_dereference_check() usage. ]
> ---------------------------------------------------
> include/linux/cgroup.h:542 invoked rcu_dereference_check() without protection!
>
> other info that might help us debug this:
>
>
> rcu_scheduler_active = 1, debug_locks = 0
> 1 lock held by swapper/1:
> #0: (net_mutex){+.+.+.}, at: [<ffffffff813e9010>]
> register_pernet_subsys+0x1f/0x47
>
> stack backtrace:
> Pid: 1, comm: swapper Not tainted 2.6.35.4-28.fc14.x86_64 #1
> Call Trace:
> [<ffffffff8107bd3a>] lockdep_rcu_dereference+0xaa/0xb3
> [<ffffffff813e04b9>] sock_update_classid+0x7c/0xa2
> [<ffffffff813e054a>] sk_alloc+0x6b/0x77
> [<ffffffff8140b281>] __netlink_create+0x37/0xab
> [<ffffffff813f941c>] ? rtnetlink_rcv+0x0/0x2d
> [<ffffffff8140cee1>] netlink_kernel_create+0x74/0x19d
> [<ffffffff8149c3ca>] ? __mutex_lock_common+0x339/0x35b
> [<ffffffff813f7e9c>] rtnetlink_net_init+0x2e/0x48
> [<ffffffff813e8d7a>] ops_init+0xe9/0xff
> [<ffffffff813e8f0d>] register_pernet_operations+0xab/0x130
> [<ffffffff813e901f>] register_pernet_subsys+0x2e/0x47
> [<ffffffff81db7bca>] rtnetlink_init+0x53/0x102
> [<ffffffff81db835c>] netlink_proto_init+0x126/0x143
> [<ffffffff81db8236>] ? netlink_proto_init+0x0/0x143
> [<ffffffff810021b8>] do_one_initcall+0x72/0x186
> [<ffffffff81d78ebc>] kernel_init+0x23b/0x2c9
> [<ffffffff8100aae4>] kernel_thread_helper+0x4/0x10
> [<ffffffff8149e2d0>] ? restore_args+0x0/0x30
> [<ffffffff81d78c81>] ? kernel_init+0x0/0x2c9
> [<ffffffff8100aae0>] ? kernel_thread_helper+0x0/0x10
The sock_update_classid() function calls task_cls_classid(current),
but the calling task cannot go away, so there is no danger of
the associated structures disappearing. Insert an RCU read-side
critical section to suppress the false positive.
Reported-by: Subrata Modak <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
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Merge reason: Update from -rc3 to -rc7.
Signed-off-by: Ingo Molnar <[email protected]>
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git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-2.6-rcu into core/rcu
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* 'upstream' of git://git.linux-mips.org/pub/scm/upstream-linus:
MIPS: Octeon: Place cnmips_cu2_setup in __init memory.
MIPS: Don't place cu2 notifiers in __cpuinitdata
MIPS: Calculate VMLINUZ_LOAD_ADDRESS based on the length of vmlinux.bin
MIPS: Alchemy: Resolve prom section mismatches
MIPS: Fix syscall 64 bit number comments.
MIPS: Hookup fanotify_init, fanotify_mark, and prlimit64 syscalls.
MIPS: TX49xx: Rename ARCH_KMALLOC_MINALIGN to ARCH_DMA_MINALIGN
MIPS: N32: Fix getdents64 syscall for n32
MIPS: Remove pr_<level> uses of KERN_<level>
MIPS: PNX8550: Sort out machine halt, restart and powerdown functions.
MIPS: GIC: Remove dependencies from Malta files.
MIPS: Kconfig: Fix and clarify kconfig help text for VSMP and SMTC.
MIPS: DMA: Fix computation of DMA flags from device's coherent_dma_mask.
MIPS: Audit: Fix hang in entry.S.
MIPS: Document why RELOC_HIDE is there.
MIPS: Octeon: Determine if helper needs to be built
MIPS: Use generic atomic64 for 32-bit kernels
MIPS: RM7000: Symbol should be static
MIPS: kspd: Adjust confusing if indentation
MIPS: Fix a typo.
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* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
writeback: always use sb->s_bdi for writeback purposes
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git://xenbits.xen.org/people/sstabellini/linux-pvhvm
* 'v2.6.36-rc6-urgent-fixes' of git://xenbits.xen.org/people/sstabellini/linux-pvhvm:
xen: do not initialize PV timers on HVM if !xen_have_vector_callback
xen: do not set xenstored_ready before xenbus_probe on hvm
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git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
fuse: Initialize total_len in fuse_retrieve()
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Since powerpc uses -Werror on arch powerpc, the build was broken like
this:
cc1: warnings being treated as errors
arch/powerpc/kernel/module.c: In function 'module_finalize':
arch/powerpc/kernel/module.c:66: error: unused variable 'err'
Signed-off-by: Stephen Rothwell <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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As suggested by Linus, push the irqs_disabled() down to the
rcu_read_lock_bh_held() level so that all callers get the benefit
of the correct check.
Signed-off-by: Paul E. McKenney <[email protected]>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
rcu: rcu_read_lock_bh_held(): disabling irqs also disables bh
generic-ipi: Fix deadlock in __smp_call_function_single
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
perf trace scripting: Fix extern struct definitions
perf ui hist browser: Fix segfault on 'a' for annotate
perf tools: Fix build breakage
perf, x86: Handle in flight NMIs on P4 platform
oprofile, ARM: Release resources on failure
oprofile: Add Support for Intel CPU Family 6 / Model 29
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The "flags" member of "struct wait_queue_t" is used in several places in
the kernel code without beeing initialized by init_wait(). "flags" is
used in bitwise operations.
If "flags" not initialized then unexpected behaviour may take place.
Incorrect flags might used later in code.
Added initialization of "wait_queue_t.flags" with zero value into
"init_wait".
Signed-off-by: Evgeny Kuznetsov <[email protected]>
[ The bit we care about does end up being initialized by both
prepare_to_wait() and add_to_wait_queue(), so this doesn't seem to
cause actual bugs, but is definitely the right thing to do -Linus ]
Signed-off-by: Linus Torvalds <[email protected]>
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With all the recent module loading cleanups, we've minimized the code
that sits under module_mutex, fixing various deadlocks and making it
possible to do most of the module loading in parallel.
However, that whole conversion totally missed the rather obscure code
that adds a new module to the list for BUG() handling. That code was
doubly obscure because (a) the code itself lives in lib/bugs.c (for
dubious reasons) and (b) it gets called from the architecture-specific
"module_finalize()" rather than from generic code.
Calling it from arch-specific code makes no sense what-so-ever to begin
with, and is now actively wrong since that code isn't protected by the
module loading lock any more.
So this commit moves the "module_bug_{finalize,cleanup}()" calls away
from the arch-specific code, and into the generic code - and in the
process protects it with the module_mutex so that the list operations
are now safe.
Future fixups:
- move the module list handling code into kernel/module.c where it
belongs.
- get rid of 'module_bug_list' and just use the regular list of modules
(called 'modules' - imagine that) that we already create and maintain
for other reasons.
Reported-and-tested-by: Thomas Gleixner <[email protected]>
Cc: Rusty Russell <[email protected]>
Cc: Adrian Bunk <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: [email protected]
Signed-off-by: Linus Torvalds <[email protected]>
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if !xen_have_vector_callback do not initialize PV timer unconditionally
because we still don't know how many cpus are available and if there is
more than one we won't be able to receive the timer interrupts on
cpu > 0.
This patch fixes an hang at boot when Xen does not support vector
callbacks and the guest has multiple vcpus.
Signed-off-by: Stefano Stabellini <[email protected]>
Acked-by: Jeremy Fitzhardinge <[email protected]>
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Register_xenstore_notifier should guarantee that the caller gets
notified even if xenstore is already up.
Therefore we revert "do not notify callers from
register_xenstore_notifier" and set xenstored_read at the right time for
PV on HVM guests too.
In fact in case of PV on HVM guests xenstored is ready only after the
platform pci driver has completed the initialization, so do not set
xenstored_ready before the call to xenbus_probe().
This patch fixes a shutdown_event watcher registration bug that causes
"xm shutdown" not to work properly.
Signed-off-by: Stefano Stabellini <[email protected]>
Acked-by: Jeremy Fitzhardinge <[email protected]>
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git://git.kernel.org/pub/scm/linux/kernel/git/lrg/voltage-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/lrg/voltage-2.6:
regulator: max8649 - fix setting extclk_freq
regulator: fix typo in current units
regulator: fix device_register() error handling
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* 'merge-powerpc' of git://git.secretlab.ca/git/linux-2.6:
powerpc/5200: tighten up ac97 reset timing
powerpc/5200: efika.c: Add of_node_put to avoid memory leak
powerpc/512x: fix clk_get() return value
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git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6
* 'fix/misc' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6:
ALSA: i2c/other/ak4xx-adda: Fix a compile warning with CONFIG_PROCFS=n
ALSA: prevent heap corruption in snd_ctl_new()
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git://git.kernel.org/pub/scm/linux/kernel/git/groeck/staging
* 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/staging:
hwmon: f71882fg: use a muxed resource lock for the Super I/O port
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git://git.kernel.org/pub/scm/linux/kernel/git/davej/cpufreq
* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/davej/cpufreq:
[CPUFREQ] Fix memory leaks in pcc_cpufreq_do_osc
[CPUFREQ] acpi-cpufreq: add missing __percpu markup
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* 'merge-spi' of git://git.secretlab.ca/git/linux-2.6:
of/spi: Fix OF-style driver binding of spi devices
spi: spi-gpio.c tests SPI_MASTER_NO_RX bit twice, but not SPI_MASTER_NO_TX
spi/mpc8xxx: fix buffer overrun on large transfers
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* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6:
vlan: dont drop packets from unknown vlans in promiscuous mode
Phonet: Correct header retrieval after pskb_may_pull
um: Proper Fix for f25c80a4: remove duplicate structure field initialization
ip_gre: Fix dependencies wrt. ipv6.
net-2.6: SYN retransmits: Add new parameter to retransmits_timed_out()
iwl3945: queue the right work if the scan needs to be aborted
mac80211: fix use-after-free
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git://git.kernel.org/pub/scm/linux/kernel/git/ickle/drm-intel
* 'drm-intel-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/ickle/drm-intel:
drm/i915: Rephrase pwrite bounds checking to avoid any potential overflow
drm/i915: Sanity check pread/pwrite
drm/i915: Use pipe state to tell when pipe is off
drm/i915: vblank status not valid while training display port
drivers/gpu/drm/i915/i915_gem.c: Add missing error handling code
drm/i915: Fix refleak during eviction.
drm/i915: fix GMCH power reporting
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Building under memory pressure, with KSM on 2.6.36-rc5, collapsed with
an internal compiler error: typically indicating an error in swapping.
Perhaps there's a timing issue which makes it now more likely, perhaps
it's just a long time since I tried for so long: this bug goes back to
KSM swapping in 2.6.33.
Notice how reuse_swap_page() allows an exclusive page to be reused, but
only does SetPageDirty if it can delete it from swap cache right then -
if it's currently under Writeback, it has to be left in cache and we
don't SetPageDirty, but the page can be reused. Fine, the dirty bit
will get set in the pte; but notice how zap_pte_range() does not bother
to transfer pte_dirty to page_dirty when unmapping a PageAnon.
If KSM chooses to share such a page, it will look like a clean copy of
swapcache, and not be written out to swap when its memory is needed;
then stale data read back from swap when it's needed again.
We could fix this in reuse_swap_page() (or even refuse to reuse a
page under writeback), but it's more honest to fix my oversight in
KSM's write_protect_page(). Several days of testing on three machines
confirms that this fixes the issue they showed.
Signed-off-by: Hugh Dickins <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Andrea Arcangeli <[email protected]>
Cc: [email protected]
Signed-off-by: Linus Torvalds <[email protected]>
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2.6.36-rc1 commit 21d0d443cdc1658a8c1484fdcece4803f0f96d0e "rmap:
resurrect page_address_in_vma anon_vma check" was right to resurrect
that check; but now that it's comparing anon_vma->roots instead of
just anon_vmas, there's a danger of oopsing on a NULL anon_vma.
In most cases no NULL anon_vma ever gets here; but it turns out that
occasionally KSM, when enabled on a forked or forking process, will
itself call page_address_in_vma() on a "half-KSM" page left over from
an earlier failed attempt to merge - whose page_anon_vma() is NULL.
It's my bug that those should be getting here at all: I thought they
were already dealt with, this oops proves me wrong, I'll fix it in
the next release - such pages are effectively pinned until their
process exits, since rmap cannot find their ptes (though swapoff can).
For now just work around it by making page_address_in_vma() safe (and
add a comment on why that check is wanted anyway). A similar check
in __page_check_anon_rmap() is safe because do_page_add_anon_rmap()
already excluded KSM pages.
Signed-off-by: Hugh Dickins <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Andrea Arcangeli <[email protected]>
Cc: Rik van Riel <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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It is an early_initcall, so it should be in __init memory.
Signed-off-by: David Daney <[email protected]>
To: [email protected]
Patchwork: https://patchwork.linux-mips.org/patch/1593/
Signed-off-by: Ralf Baechle <[email protected]>
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The notifiers may be called at any time, so the notifier_block cannot
be in init memory.
Signed-off-by: David Daney <[email protected]>
To: [email protected]
Patchwork: https://patchwork.linux-mips.org/patch/1592/
Signed-off-by: Ralf Baechle <[email protected]>
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Fix VMLINUZ_LOAD_ADDRESS calculation to be based on the length of
vmlinux.bin, the actual uncompressed kernel binary.
Previously it was based on the length of KBUILD_IMAGE (the unstripped ELF
vmlinux), which is bigger than vmlinux.bin. As a result, vmlinuz was
loaded into a memory address higher then actually needed - a problem for
small memory platforms.
Signed-off-by: Shmulik Ladkani <[email protected]>
To: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Patchwork: https://patchwork.linux-mips.org/patch/1564/
Acked-by: Wu Zhangjin <[email protected]>
Signed-off-by: Ralf Baechle <[email protected]>
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The function prom_init_cmdline() references the variable __initdata
arcs_cmdline.
The function prom_get_ethernet_addr() references the variable __initdata
arcs_cmdline.
Annotate prom_init_cmdline() as __init, unexport and annotate
prom_get_ethernet_addr() since it's no longer called from within
driver code.
Signed-off-by: Manuel Lauss <[email protected]>
To: Linux-MIPS <[email protected]>
Patchwork: https://patchwork.linux-mips.org/patch/1547/
Signed-off-by: Ralf Baechle <[email protected]>
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Noticed and original patch by Philby John <[email protected]>.
Signed-off-by: Ralf Baechle <[email protected]>
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Signed-off-by: David Daney <[email protected]>
To: [email protected]
Patchwork: https://patchwork.linux-mips.org/patch/1553/
Signed-off-by: Ralf Baechle <[email protected]>
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