| Age | Commit message (Collapse) | Author | Files | Lines |
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Use memdup_user when user data is immediately copied into the
allocated region.
The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)
// <smpl>
@@
expression from,to,size,flag;
position p;
identifier l1,l2;
@@
- to = \(kmalloc@p\|kzalloc@p\)(size,flag);
+ to = memdup_user(from,size);
if (
- to==NULL
+ IS_ERR(to)
|| ...) {
<+... when != goto l1;
- -ENOMEM
+ PTR_ERR(to)
...+>
}
- if (copy_from_user(to, from, size) != 0) {
- <+... when != goto l2;
- -EFAULT
- ...+>
- }
// </smpl>
Signed-off-by: Julia Lawall <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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kasprintf combines kmalloc and sprintf, and takes care of the size
calculation itself.
The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)
// <smpl>
@@
expression a,flag;
expression list args;
statement S;
@@
a =
- \(kmalloc\|kzalloc\)(...,flag)
+ kasprintf(flag,args)
<... when != a
if (a == NULL || ...) S
...>
- sprintf(a,args);
// </smpl>
Signed-off-by: Julia Lawall <[email protected]>
Cc: Michael Buesch <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Ramoops, like mtdoops, can log oops/panic information but in RAM. It can
be used with persistent RAM for systems without flash support. In
addition, for this systems, with this driver, it's no more needed add to
the kernel the mtd subsystem with advantage in footprint.
It can be used in a very easy way with persistent RAM for systems without
flash support. For these systems, with this driver, it is no longer
required to cinlude mtd subsystem with an advantage in footprint. In
addition, you can save flash space and store this information only in RAM.
Signed-off-by: Marco Stornelli <[email protected]>
Cc: Simon Kagstrom <[email protected]>
Cc: David Woodhouse <[email protected]>
Cc; Anders Grafstrom <[email protected]>
Cc: Yuasa Yoichi <[email protected]>
Cc: Jamie Lokier <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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If run_to_completion flag is set, it means that we are running in a
single-threaded mode, and thus no locks are held.
This fixes a deadlock when IPMI notifier is being called during panic.
Signed-off-by: Jiri Kosina <[email protected]>
Acked-by: Corey Minyard <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Update core IPMI driver printk()'s with dev_printk(), and its constructs,
to provide additional device topology information.
An example of the additional device topology for a PNP device -
ipmi_si 00:02: probing via ACPI
ipmi_si 00:02: [io 0x0ca2-0x0ca3] regsize 1 spacing 1 irq 0
ipmi_si 00:02: Found new BMC (man_id: 0x00000b, prod_id: 0x0000, ...
ipmi_si 00:02: IPMI kcs interface initialized
and for a PCI device -
ipmi_si 0000:01:04.6: probing via PCI
ipmi_si 0000:01:04.6: PCI INT A -> GSI 21 (level, low) -> IRQ 21
ipmi_si 0000:01:04.6: [mem 0xf1ef0000-0xf1ef00ff] regsize 1 spaci...
ipmi_si 0000:01:04.6: IPMI kcs interface initialized
[[email protected]: rework to fix rejects, extended it a bit]
[[email protected]: coding-style fixes]
Signed-off-by: Myron Stowe <[email protected]>
Signed-off-by: Corey Minyard <[email protected]>
Cc: Zhao Yakui <[email protected]>
Cc: Len Brown <[email protected]>
Cc: Bjorn Helgaas <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Convert PNP patch (git 9e368fa011d4e0aa050db348d69514900520e40b) to
maintain a pointer to a PNP device, 'pnp_dev', instead of the ACPI device,
'acpi_dev', that is currently being tracked with PNP based IPMI device
discovery.
Signed-off-by: Myron Stowe <[email protected]>
Acked-by: Zhao Yakui <[email protected]>
Acked-by: Corey Minyard <[email protected]>
Cc: Len Brown <[email protected]>
Cc: Bjorn Helgaas <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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The timeouts in IPMI are in the 1-5 second range in message handling, so a
1 second timeout is a reasonable thing to do. This should help with
reducing power consumption on idle systems.
Signed-off-by: Corey Minyard <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Some odd systems may have multiple BMCs, and we want to be able to support
them. Let's make the assumption that if a system legitimately has
multiple BMCs then each BMC's SI will be of the same type, and also that
we won't see multiple SIs of the same type unless we have multiple BMCs.
If these hold true then we should register all SIs of the same type.
Signed-off-by: Matthew Garrett <[email protected]>
Signed-off-by: Corey Minyard <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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We can reasonably alter the poll rate depending on whether we're
performing a transaction or merely waiting for an event.
Signed-off-by: Matthew Garrett <[email protected]>
Signed-off-by: Corey Minyard <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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If we're not currently in the middle of a transaction, and if we have
interrupts, there's no real reason to poll the controller more frequently
than the core IPMI code does. Set the interrupt_disabled flag
appropriately as the interrupt state changes, and make the timeout code
reset itself only if the transaction is incomplete or we have no
interrupts.
Signed-off-by: Matthew Garrett <[email protected]>
Signed-off-by: Corey Minyard <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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The ipmi spec provides an ordering for si discovery. Change the driver to
match, with the exception of preferring smbios to SPMI as HPs (at least)
contain accurate information in the former but not the latter.
Signed-off-by: Matthew Garrett <[email protected]>
Signed-off-by: Corey Minyard <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Only register one si per bmc. Use any user-provided devices first,
followed by the first device with an irq, followed by the first device
discovered.
Signed-off-by: Matthew Garrett <[email protected]>
Signed-off-by: Corey Minyard <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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The ipmi spec indicates that we should only make use of one si per bmc, so
separate device discovery and registration to make that possible.
[[email protected]: fix mutex use]
Signed-off-by: Matthew Garrett <[email protected]>
Signed-off-by: Corey Minyard <[email protected]>
Signed-off-by: Tomas Henzl <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Switch from a char* to an enum to identify the address source of SIs,
making it easier to handle them appropriately during registration.
Signed-off-by: Matthew Garrett <[email protected]>
Signed-off-by: Corey Minyard <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Use ERR_CAST(x) rather than ERR_PTR(PTR_ERR(x)). The former makes more
clear what is the purpose of the operation, which otherwise looks like a
no-op.
The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)
// <smpl>
@@
type T;
T x;
identifier f;
@@
T f (...) { <+...
- ERR_PTR(PTR_ERR(x))
+ x
...+> }
@@
expression x;
@@
- ERR_PTR(PTR_ERR(x))
+ ERR_CAST(x)
// </smpl>
Signed-off-by: Julia Lawall <[email protected]>
Cc: Manfred Spraul <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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ipc/sem.c begins with a 15 year old description about bugs in the initial
implementation in Linux-1.0. The patch replaces that with a top level
description of the current code.
A TODO could be derived from this text:
The opengroup man page for semop() does not mandate FIFO. Thus there is
no need for a semaphore array list of pending operations.
If
- this list is removed
- the per-semaphore array spinlock is removed (possible if there is no
list to protect)
- sem_otime is moved into the semaphores and calculated on demand during
semctl()
then the array would be read-mostly - which would significantly improve
scaling for applications that use semaphore arrays with lots of entries.
The price would be expensive semctl() calls:
for(i=0;i<sma->sem_nsems;i++) spin_lock(sma->sem_lock);
<do stuff>
for(i=0;i<sma->sem_nsems;i++) spin_unlock(sma->sem_lock);
I'm not sure if the complexity is worth the effort, thus here is the
documentation of the current behavior first.
Signed-off-by: Manfred Spraul <[email protected]>
Cc: Chris Mason <[email protected]>
Cc: Zach Brown <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Nick Piggin <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Cacheline align the spinlock for sysv semaphores. Without the patch, the
spinlock and sem_otime [written by every semop that modified the array]
and sem_base [read in the hot path of try_atomic_semop()] can be in the
same cacheline.
Signed-off-by: Manfred Spraul <[email protected]>
Cc: Chris Mason <[email protected]>
Cc: Zach Brown <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Nick Piggin <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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The wake-up part of semtimedop() consists out of two steps:
- the right tasks must be identified.
- they must be woken up.
Right now, both steps run while the array spinlock is held. This patch
reorders the code and moves the actual wake_up_process() behind the point
where the spinlock is dropped.
The code also moves setting sem->sem_otime to one place: It does not make
sense to set the last modify time multiple times.
[[email protected]: repair kerneldoc]
[[email protected]: fix uninitialised retval]
Signed-off-by: Manfred Spraul <[email protected]>
Cc: Chris Mason <[email protected]>
Cc: Zach Brown <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Nick Piggin <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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The following series of patches tries to fix the spinlock contention
reported by Chris Mason - his benchmark exposes problems of the current
code:
- In the worst case, the algorithm used by update_queue() is O(N^2).
Bulk wake-up calls can enter this worst case. The patch series fix
that.
Note that the benchmark app doesn't expose the problem, it just should
be fixed: Real world apps might do the wake-ups in another order than
perfect FIFO.
- The part of the code that runs within the semaphore array spinlock is
significantly larger than necessary.
The patch series fixes that. This change is responsible for the main
improvement.
- The cacheline with the spinlock is also used for a variable that is
read in the hot path (sem_base) and for a variable that is unnecessarily
written to multiple times (sem_otime). The last step of the series
cacheline-aligns the spinlock.
This patch:
The SysV semaphore code allows to perform multiple operations on all
semaphores in the array as atomic operations. After a modification,
update_queue() checks which of the waiting tasks can complete.
The algorithm that is used to identify the tasks is O(N^2) in the worst
case. For some cases, it is simple to avoid the O(N^2).
The patch adds a detection logic for some cases, especially for the case
of an array where all sleeping tasks are single sembuf operations and a
multi-sembuf operation is used to wake up multiple tasks.
A big database application uses that approach.
The patch fixes wakeup due to semctl(,,SETALL,) - the initial version of
the patch breaks that.
[[email protected]: make do_smart_update() static]
Signed-off-by: Manfred Spraul <[email protected]>
Cc: Chris Mason <[email protected]>
Cc: Zach Brown <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Nick Piggin <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Currently idr_remove_all will fail with a use after free error if
idr::layers is bigger than 2, which on 32 bit systems corresponds to items
more than 1024. This is due to stepping back too many levels during
backtracking. For simplicity let's assume that IDR_BITS=1 -> we have 2
nodes at each level below the root node and each leaf node stores two IDs.
(In reality for 32 bit systems IDR_BITS=5, with 32 nodes at each sub-root
level and 32 IDs in each leaf node). The sequence of freeing the nodes at
the moment is as follows:
layer
1 -> a(7)
2 -> b(3) c(5)
3 -> d(1) e(2) f(4) g(6)
Until step 4 things go fine, but then node c is freed, whereas node g
should be freed first. Since node c contains the pointer to node g we'll
have a use after free error at step 6.
How many levels we step back after visiting the leaf nodes is currently
determined by the msb of the id we are currently visiting:
Step
1. node d with IDs 0,1 is freed, current ID is advanced to 2.
msb of the current ID bit 1. This means we need to step back
1 level to node b and take the next sibling, node e.
2-3. node e with IDs 2,3 is freed, current ID is 4, msb is bit 2.
This means we need to step back 2 levels to node a, freeing
node b on the way.
4-5. node f with IDs 4,5 is freed, current ID is 6, msb is still
bit 2. This means we again need to step back 2 levels to node
a and free c on the way.
6. We should visit node g, but its pointer is not available as
node c was freed.
The fix changes how we determine the number of levels to step back.
Instead of deducting this merely from the msb of the current ID, we should
really check if advancing the ID causes an overflow to a bit position
corresponding to a given layer. In the above example overflow from bit 0
to bit 1 should mean stepping back 1 level. Overflow from bit 1 to bit 2
should mean stepping back 2 levels and so on.
The fix was tested with IDs up to 1 << 20, which corresponds to 4 layers
on 32 bit systems.
Signed-off-by: Imre Deak <[email protected]>
Reviewed-by: Tejun Heo <[email protected]>
Cc: Eric Paris <[email protected]>
Cc: "Paul E. McKenney" <[email protected]>
Cc: <[email protected]> [2.6.34.1]
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Since when CONFIG_HOTPLUG_CPU=n, get_online_cpus() do nothing, so we don't
need cpu_hotplug_begin() either.
This patch moves cpu_hotplug_begin()/cpu_hotplug_done() into the code
block of CONFIG_HOTPLUG_CPU=y.
Signed-off-by: Lai Jiangshan <[email protected]>
Cc: Gautham R Shenoy <[email protected]>
Cc: Ingo Molnar <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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I used this module to test the series of modification to the cpu notifiers
code.
Example1: inject CPU offline error (-1 == -EPERM)
# modprobe cpu-notifier-error-inject cpu_down_prepare_error=-1
# echo 0 > /sys/devices/system/cpu/cpu1/online
bash: echo: write error: Operation not permitted
Example2: inject CPU online error (-2 == -ENOENT)
# modprobe cpu-notifier-error-inject cpu_up_prepare_error=-2
# echo 1 > /sys/devices/system/cpu/cpu1/online
bash: echo: write error: No such file or directory
[[email protected]: fix Kconfig help text]
Signed-off-by: Akinobu Mita <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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By the previous modification, the cpu notifier can return encapsulate
errno value. This converts the cpu notifiers for raid5.
Signed-off-by: Akinobu Mita <[email protected]>
Cc: Neil Brown <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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By the previous modification, the cpu notifier can return encapsulate
errno value. This converts the cpu notifiers for s390.
Signed-off-by: Akinobu Mita <[email protected]>
Cc: Martin Schwidefsky <[email protected]>
Cc: Heiko Carstens <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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By the previous modification, the cpu notifier can return encapsulate
errno value. This converts the cpu notifiers for ehca.
Signed-off-by: Akinobu Mita <[email protected]>
Cc: Hoang-Nam Nguyen <[email protected]>
Cc: Christoph Raisch <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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By the previous modification, the cpu notifier can return encapsulate
errno value. This converts the cpu notifiers for iucv.
Signed-off-by: Akinobu Mita <[email protected]>
Cc: Ursula Braun <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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By the previous modification, the cpu notifier can return encapsulate
errno value. This converts the cpu notifiers for slab.
Signed-off-by: Akinobu Mita <[email protected]>
Cc: Christoph Lameter <[email protected]>
Acked-by: Pekka Enberg <[email protected]>
Cc: Matt Mackall <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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By the previous modification, the cpu notifier can return encapsulate
errno value. This converts the cpu notifiers for kernel/*.c
Signed-off-by: Akinobu Mita <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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By the previous modification, the cpu notifier can return encapsulate
errno value. This converts the cpu notifiers for topology.
Signed-off-by: Akinobu Mita <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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By the previous modification, the cpu notifier can return encapsulate
errno value. This converts the cpu notifiers for msr, cpuid, and
therm_throt.
Signed-off-by: Akinobu Mita <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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This changes notifier_from_errno(0) to be NOTIFY_OK instead of
NOTIFY_STOP_MASK | NOTIFY_OK.
Currently, the notifiers which return encapsulated errno value have to
do something like this:
err = do_something(); // returns -errno
if (err)
return notifier_from_errno(err);
else
return NOTIFY_OK;
This change makes the above code simple:
err = do_something(); // returns -errno
return return notifier_from_errno(err);
Signed-off-by: Akinobu Mita <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Currently, onlining or offlining a CPU failure by one of the cpu notifiers
error always cause -EINVAL error. (i.e. writing 0 or 1 to
/sys/devices/system/cpu/cpuX/online gets EINVAL)
To get better error reporting rather than always getting -EINVAL, This
changes cpu_notify() to return -errno value with notifier_to_errno() and
fix the callers. Now that cpu notifiers can return encapsulate errno
value.
Currently, all cpu hotplug notifiers return NOTIFY_OK, NOTIFY_BAD, or
NOTIFY_DONE. So cpu_notify() can returns 0 or -EPERM with this change for
now.
(notifier_to_errno(NOTIFY_OK) == 0, notifier_to_errno(NOTIFY_DONE) == 0,
notifier_to_errno(NOTIFY_BAD) == -EPERM)
Forthcoming patches convert several cpu notifiers to return encapsulate
errno value with notifier_from_errno().
Signed-off-by: Akinobu Mita <[email protected]>
Cc: Rusty Russell <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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No functional change. These are just wrappers of
raw_cpu_notifier_call_chain.
Signed-off-by: Akinobu Mita <[email protected]>
Cc: Rusty Russell <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Extend KCORE_TEXT to cover the pages between _text and _stext, to allow
examining some important page table pages.
`readelf -a` output on x86_64 before and after patch:
Type Offset VirtAddr PhysAddr
before LOAD 0x00007fff8100c000 0xffffffff81009000 0x0000000000000000
after LOAD 0x00007fff81003000 0xffffffff81000000 0x0000000000000000
The newly covered pages are:
0xffffffff81000000 <startup_64> etc.
0xffffffff81001000 <init_level4_pgt>
0xffffffff81002000 <level3_ident_pgt>
0xffffffff81003000 <level3_kernel_pgt>
0xffffffff81004000 <level2_fixmap_pgt>
0xffffffff81005000 <level1_fixmap_pgt>
0xffffffff81006000 <level2_ident_pgt>
0xffffffff81007000 <level2_kernel_pgt>
0xffffffff81008000 <level2_spare_pgt>
Before patch, /proc/kcore shows outdated contents for the above page
table pages, for example:
(gdb) p level3_ident_pgt
$1 = {<text variable, no debug info>} 0xffffffff81002000 <level3_ident_pgt>
(gdb) p/x *((pud_t *)&level3_ident_pgt)@512
$2 = {{pud = 0x1006063}, {pud = 0x0} <repeats 511 times>}
while the real content is:
root@hp /home/wfg# hexdump -s 0x1002000 -n 4096 /dev/mem
1002000 6063 0100 0000 0000 8067 0000 0000 0000
1002010 0000 0000 0000 0000 0000 0000 0000 0000
*
1003000
That is, on a x86_64 box with 2GB memory, we can see first-1GB / full-2GB
identity mapping before/after patch:
(gdb) p/x *((pud_t *)&level3_ident_pgt)@512
before $1 = {{pud = 0x1006063}, {pud = 0x0} <repeats 511 times>}
after $1 = {{pud = 0x1006063}, {pud = 0x8067}, {pud = 0x0} <repeats 510 times>}
Obviously the content before patch is wrong.
Signed-off-by: Wu Fengguang <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: KAMEZAWA Hiroyuki <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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A quick test shows these comments are obsolete, so just remove them.
Signed-off-by: WANG Cong <[email protected]>
Cc: Alexey Dobriyan <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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I removed 3 unused assignments. The first two get reset on the first
statement of their functions. For "err" in root.c we don't return an
error and we don't use the variable again.
Signed-off-by: Dan Carpenter <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Acked-by: Serge Hallyn <[email protected]>
Reviewed-by: KOSAKI Motohiro <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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No functional changes, just s/atomic_t count/int nr_threads/.
With the recent changes this counter has a single user, get_nr_threads()
And, none of its callers need the really accurate number of threads, not
to mention each caller obviously races with fork/exit. It is only used to
report this value to the user-space, except first_tid() uses it to avoid
the unnecessary while_each_thread() loop in the unlikely case.
It is a bit sad we need a word in struct signal_struct for this, perhaps
we can change get_nr_threads() to approximate the number of threads using
signal->live and kill ->nr_threads later.
[[email protected]: coding-style fixes]
Signed-off-by: Oleg Nesterov <[email protected]>
Cc: Alexey Dobriyan <[email protected]>
Cc: "Eric W. Biederman" <[email protected]>
Acked-by: Roland McGrath <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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No functional changes.
keyctl_session_to_parent() is the only user of signal->count which needs
the correct value. Change it to use thread_group_empty() instead, this
must be strictly equivalent under tasklist, and imho looks better.
Signed-off-by: Oleg Nesterov <[email protected]>
Acked-by: David Howells <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Acked-by: Roland McGrath <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Trivial, use get_nr_threads() helper to read signal->count which we are
going to change.
Like other callers, proc_sched_show_task() doesn't need the exactly
precise nr_threads.
David said:
: Note that get_nr_threads() isn't completely equivalent (it can return 0
: where proc_sched_show_task() will display a 1). But I don't think this
: should be a problem.
Signed-off-by: Oleg Nesterov <[email protected]>
Acked-by: David Howells <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Acked-by: Roland McGrath <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Now that task->signal can't go away get_nr_threads() doesn't need
->siglock to read signal->count.
Also, make it inline, move into sched.h, and convert 2 other proc users of
signal->count to use this (now trivial) helper.
Henceforth get_nr_threads() is the only valid user of signal->count, we
are ready to turn it into "int nr_threads" or, perhaps, kill it.
Signed-off-by: Oleg Nesterov <[email protected]>
Cc: Alexey Dobriyan <[email protected]>
Cc: David Howells <[email protected]>
Cc: "Eric W. Biederman" <[email protected]>
Acked-by: Roland McGrath <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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check_unshare_flags(CLONE_SIGHAND) adds CLONE_THREAD to *flags_ptr if the
task is multithreaded to ensure unshare_thread() will fail.
Not only this is a bit strange way to return the error, this is absolutely
meaningless. If signal->count > 1 then sighand->count must be also > 1,
and unshare_sighand() will fail anyway.
In fact, all CLONE_THREAD/SIGHAND/VM checks inside sys_unshare() do not
look right. Fortunately this code doesn't really work anyway.
Signed-off-by: Oleg Nesterov <[email protected]>
Cc: Balbir Singh <[email protected]>
Acked-by: Roland McGrath <[email protected]>
Cc: Veaceslav Falico <[email protected]>
Cc: Stanislaw Gruszka <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Move taskstats_tgid_free() from __exit_signal() to free_signal_struct().
This way signal->stats never points to nowhere and we can read ->stats
lockless.
Signed-off-by: Oleg Nesterov <[email protected]>
Cc: Balbir Singh <[email protected]>
Cc: Roland McGrath <[email protected]>
Cc: Veaceslav Falico <[email protected]>
Cc: Stanislaw Gruszka <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Kill the empty thread_group_cputime_free() helper. It was needed to free
the per-cpu data which we no longer have.
Signed-off-by: Oleg Nesterov <[email protected]>
Cc: Balbir Singh <[email protected]>
Cc: Roland McGrath <[email protected]>
Cc: Veaceslav Falico <[email protected]>
Cc: Stanislaw Gruszka <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Cleanup:
- Add the boolean, group_dead = thread_group_leader(), for clarity.
- Do not test/set sig == NULL to detect the all-dead case, use this
boolean.
- Pass this boolen to __unhash_process() and use it instead of another
thread_group_leader() call which needs ->group_leader.
This can be considered as microoptimization, but hopefully this also
allows us do do other cleanups later.
Signed-off-by: Oleg Nesterov <[email protected]>
Cc: Balbir Singh <[email protected]>
Cc: Roland McGrath <[email protected]>
Cc: Veaceslav Falico <[email protected]>
Cc: Stanislaw Gruszka <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Now that task->signal can't go away we can revert the horrible hack added
by ad474caca3e2a0550b7ce0706527ad5ab389a4d4 ("fix for
account_group_exec_runtime(), make sure ->signal can't be freed under
rq->lock").
And we can do more cleanups sched_stats.h/posix-cpu-timers.c later.
Signed-off-by: Oleg Nesterov <[email protected]>
Cc: Alan Cox <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Acked-by: Roland McGrath <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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When the last thread exits signal->tty is freed, but the pointer is not
cleared and points to nowhere.
This is OK. Nobody should use signal->tty lockless, and it is no longer
possible to take ->siglock. However this looks wrong even if correct, and
the nice OOPS is better than subtle and hard to find bugs.
Change __exit_signal() to clear signal->tty under ->siglock.
Note: __exit_signal() needs more cleanups. It should not check "sig !=
NULL" to detect the all-dead case and we have the same issues with
signal->stats.
Signed-off-by: Oleg Nesterov <[email protected]>
Cc: Alan Cox <[email protected]>
Cc: Ingo Molnar <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Acked-by: Roland McGrath <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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We have a lot of problems with accessing task_struct->signal, it can
"disappear" at any moment. Even current can't use its ->signal safely
after exit_notify(). ->siglock helps, but it is not convenient, not
always possible, and sometimes it makes sense to use task->signal even
after this task has already dead.
This patch adds the reference counter, sigcnt, into signal_struct. This
reference is owned by task_struct and it is dropped in
__put_task_struct(). Perhaps it makes sense to export
get/put_signal_struct() later, but currently I don't see the immediate
reason.
Rename __cleanup_signal() to free_signal_struct() and unexport it. With
the previous changes it does nothing except kmem_cache_free().
Change __exit_signal() to not clear/free ->signal, it will be freed when
the last reference to any thread in the thread group goes away.
Note:
- when the last thead exits signal->tty can point to nowhere, see
the next patch.
- with or without this patch signal_struct->count should go away,
or at least it should be "int nr_threads" for fs/proc. This will
be addressed later.
Signed-off-by: Oleg Nesterov <[email protected]>
Cc: Alan Cox <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Acked-by: Roland McGrath <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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tty_kref_put() has two callsites in copy_process() paths,
1. if copy_process() suceeds it is called before we copy
signal->tty from parent
2. otherwise it is called from __cleanup_signal() under
bad_fork_cleanup_signal: label
In both cases tty_kref_put() is not right and unneeded because we don't
have the balancing tty_kref_get(). Fortunately, this is harmless because
this can only happen without CLONE_THREAD, and in this case signal->tty
must be NULL.
Remove tty_kref_put() from copy_process() and __cleanup_signal(), and
change another caller of __cleanup_signal(), __exit_signal(), to call
tty_kref_put() by hand.
I hope this change makes sense by itself, but it is also needed to make
->signal refcountable.
Signed-off-by: Oleg Nesterov <[email protected]>
Acked-by: Alan Cox <[email protected]>
Acked-by: Roland McGrath <[email protected]>
Cc: Greg KH <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Preparation to make task->signal immutable, no functional changes.
It doesn't matter which pointer we check under tasklist to ensure the task
was not released, ->signal or ->sighand. But we are going to make
->signal refcountable, change the code to use ->sighand.
Note: this code doesn't need this check and tasklist_lock at all, it
should be converted to use lock_task_sighand(). And, the code under
SIGNAL_STOP_STOPPED check looks wrong.
Signed-off-by: Oleg Nesterov <[email protected]>
Cc: Fenghua Yu <[email protected]>
Cc: Roland McGrath <[email protected]>
Cc: Stanislaw Gruszka <[email protected]>
Cc: Tony Luck <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Preparation to make task->signal immutable, no functional changes.
posix-cpu-timers.c checks task->signal != NULL to ensure this task is
alive and didn't pass __exit_signal(). This is correct but we are going
to change the lifetime rules for ->signal and never reset this pointer.
Change the code to check ->sighand instead, it doesn't matter which
pointer we check under tasklist, they both are cleared simultaneously.
As Roland pointed out, some of these changes are not strictly needed and
probably it makes sense to revert them later, when ->signal will be pinned
to task_struct. But this patch tries to ensure the subsequent changes in
fork/exit can't make any visible impact on posix cpu timers.
Signed-off-by: Oleg Nesterov <[email protected]>
Cc: Fenghua Yu <[email protected]>
Acked-by: Roland McGrath <[email protected]>
Cc: Stanislaw Gruszka <[email protected]>
Cc: Tony Luck <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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