Petr Mladek
8197b3d43b
kthread: detect when a kthread work is used by more workers ...
Nothing currently prevents a work from queuing for a kthread worker when
it is already running on another one. This means that the work might run
in parallel on more than one worker. Also some operations are not
reliable, e.g. flush.
This problem will be even more visible after we add kthread_cancel_work()
function. It will only have "work" as the parameter and will use
worker->lock to synchronize with others.
Well, normally this is not a problem because the API users are sane.
But bugs might happen and users also might be crazy.
This patch adds a warning when we try to insert the work for another
worker. It does not fully prevent the misuse because it would make the
code much more complicated without a big benefit.
It adds the same warning also into kthread_flush_work() instead of the
repeated attempts to get the right lock.
A side effect is that one needs to explicitly reinitialize the work if it
must be queued into another worker. This is needed, for example, when the
worker is stopped and started again. It is a bit inconvenient. But it
looks like a good compromise between the stability and complexity.
I have double checked all existing users of the kthread worker API and
they all seems to initialize the work after the worker gets started.
Just for completeness, the patch adds a check that the work is not already
in a queue.
The patch also puts all the checks into a separate function. It will be
reused when implementing delayed works.
Link: http://lkml.kernel.org/r/1470754545-17632-8-git-send-email-pmladek@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Borislav Petkov <bp@suse.de>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-11 15:06:33 -07:00
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
2016-10-10 20:16:43 -07:00
config: android: enable CONFIG_SECCOMP
2016-10-11 15:06:32 -07:00
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next
2016-10-05 10:11:24 -07:00
gcov: add support for gcc version >= 6
2016-07-15 14:54:27 +09:00
genirq: Make function __irq_do_set_handler() static
2016-09-25 16:46:52 -04:00
livepatch/module: make TAINT_LIVEPATCH module-specific
2016-08-26 14:42:08 +02:00
locking/lglock: Remove lglock implementation
2016-09-22 15:25:56 +02:00
oom, suspend: fix oom_killer_disable vs. pm suspend properly
2016-10-07 18:46:27 -07:00
Merge branch 'printk-cleanups'
2016-10-10 09:29:50 -07:00
Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2016-10-03 12:15:00 -07:00
nmi_backtrace: generate one-line reports for idle cpus
2016-10-07 18:46:30 -07:00
timekeeping: Fix __ktime_get_fast_ns() regression
2016-10-05 15:44:46 +02:00
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
2016-10-07 12:24:08 -07:00
Merge branch 'stable-4.9' of git://git.infradead.org/users/pcmoore/audit
2016-10-04 14:21:41 -07:00
Merge branch 'stable-4.8' of git://git.infradead.org/users/pcmoore/audit
2016-07-29 17:54:17 -07:00
Merge branch 'stable-4.8' of git://git.infradead.org/users/pcmoore/audit
2016-09-01 15:55:56 -07:00
audit: add fields to exclude filter by reusing user filter
2016-06-27 11:01:00 -04:00
Merge branch 'stable-4.9' of git://git.infradead.org/users/pcmoore/audit
2016-10-04 14:21:41 -07:00
kernel: Add noaudit variant of ns_capable()
2016-06-06 20:16:18 +10:00
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
2016-10-06 09:52:23 -07:00
cgroup: Use lld instead of ld when printing pids controller events_limit
2016-06-21 15:03:36 -04:00
Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2016-10-03 19:43:08 -07:00
cpuset: fix non static symbol warning
2016-09-16 11:31:17 -04:00
cred: Reject inodes with invalid ids in set_create_file_as()
2016-06-30 18:05:09 -05:00
mm, oom: enforce exit_oom_victim on current task
2016-10-07 18:46:28 -07:00
thp: reduce usage of huge zero page's atomic counter
2016-10-07 18:46:28 -07:00
freezer, oom: check TIF_MEMDIE on the correct task
2016-07-28 16:07:41 -07:00
futex: Add some more function commentry
2016-09-05 17:20:18 +02:00
cred: simpler, 1D supplementary groups
2016-10-07 18:46:30 -07:00
locking/hung_task: Show all locks
2016-08-24 12:16:13 +02:00
powerpc updates for 4.8 #2
2016-08-05 09:00:54 -04:00
kernel/kcov: unproxify debugfs file's fops
2016-06-15 04:56:35 -07:00
kexec: allow architectures to override boot mapping
2016-08-02 19:35:27 -04:00
kexec: add restriction on kexec_load() segment sizes
2016-08-02 19:35:31 -04:00
kexec: fix double-free when failing to relocate the purgatory
2016-09-01 17:52:01 -07:00
kprobes: include <asm/sections.h> instead of <asm-generic/sections.h>
2016-10-11 15:06:31 -07:00
kexec: add a kexec_crash_loaded() function
2016-08-02 19:35:30 -04:00
kthread: detect when a kthread work is used by more workers
2016-10-11 15:06:33 -07:00
userns: Add per user namespace sysctls.
2016-08-08 13:18:58 -05:00
mm: fix cache mode of dax pmd mappings
2016-09-09 17:34:46 -07:00
livepatch/module: make TAINT_LIVEPATCH module-specific
2016-08-26 14:42:08 +02:00
padata: Convert to hotplug state machine
2016-09-19 21:44:30 +02:00
x86/panic: replace smp_send_stop() with kdump friendly version in panic path
2016-10-11 15:06:32 -07:00
remove lots of IS_ERR_VALUE abuses
2016-05-27 15:26:11 -07:00
Merge branch 'nsfs-ioctls' into HEAD
2016-09-22 20:00:36 -05:00
profile: Convert to hotplug state machine
2016-07-15 10:41:42 +02:00
ptrace: clear TIF_SYSCALL_TRACE on ptrace detach
2016-10-11 15:06:32 -07:00
relay: Use irq_work instead of plain timer for deferred wakeup
2016-10-11 15:06:32 -07:00
seccomp: Fix tracer exit notifications during fatal signals
2016-08-30 16:12:46 -07:00
x86/signal: Add SA_{X32,IA32}_ABI sa_flags
2016-09-14 21:28:11 +02:00
smp: Allocate smp_call_on_cpu() workqueue on stack too
2016-09-22 14:49:10 +02:00
kthread/smpboot: do not park in kthread_create_on_cpu()
2016-10-11 15:06:33 -07:00
Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2016-10-03 19:43:08 -07:00
Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2016-10-03 13:39:00 -07:00
prctl: make PR_SET_THP_DISABLE wait for mmap_sem killable
2016-05-23 17:04:14 -07:00
x86/pkeys: Fix pkeys build breakage for some non-x86 arches
2016-09-13 14:41:36 +02:00
Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
2016-10-10 13:04:49 -07:00
kernel/sysctl_binary.c: use generic UUID library
2016-05-20 17:58:30 -07:00
task_work: use READ_ONCE/lockless_dereference, avoid pi_lock if !task_works
2016-08-02 19:35:02 -04:00
torture: Convert torture_shutdown() to hrtimer
2016-08-22 10:01:49 -07:00
mntns: Add a limit on the number of mount namespaces.
2016-08-31 07:28:35 -05:00
cred: simpler, 1D supplementary groups
2016-10-07 18:46:30 -07:00
smp: Add function to execute a function synchronously on a CPU
2016-09-05 13:52:39 +02:00
Merge branch 'nsfs-ioctls' into HEAD
2016-09-22 20:00:36 -05:00
Merge branch 'nsfs-ioctls' into HEAD
2016-09-22 20:00:36 -05:00
Revert "perf/x86/intel, watchdog: Switch NMI watchdog to ref cycles on x86"
2016-07-10 20:58:36 +02:00
kthread: rename probe_kthread_data() to kthread_probe_data()
2016-10-11 15:06:33 -07:00
8197b3d43b