https://github.com/torvalds/linux
Revision 093e5840ae76f1082633503964d035f40ed0216d authored by Sebastian Andrzej Siewior on 21 December 2015, 17:17:10 UTC, committed by Ingo Molnar on 06 January 2016, 10:01:07 UTC
In the following commit: 7675104990ed ("sched: Implement lockless wake-queues") we gained lockless wake-queues. The -RT kernel managed to lockup itself with those. There could be multiple attempts for task X to enqueue it for a wakeup _even_ if task X is already running. The reason is that task X could be runnable but not yet on CPU. The the task performing the wakeup did not leave the CPU it could performe multiple wakeups. With the proper timming task X could be running and enqueued for a wakeup. If this happens while X is performing a fork() then its its child will have a !NULL `wake_q` member copied. This is not a problem as long as the child task does not participate in lockless wakeups :) Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: 7675104990ed ("sched: Implement lockless wake-queues") Link: http://lkml.kernel.org/r/20151221171710.GA5499@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Tip revision: 093e5840ae76f1082633503964d035f40ed0216d authored by Sebastian Andrzej Siewior on 21 December 2015, 17:17:10 UTC
sched/core: Reset task's lockless wake-queues on fork()
sched/core: Reset task's lockless wake-queues on fork()
Tip revision: 093e584
File | Mode | Size |
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Kconfig | -rw-r--r-- | 9.6 KB |
Makefile | -rw-r--r-- | 702 bytes |
acorn.c | -rw-r--r-- | 12.3 KB |
acorn.h | -rw-r--r-- | 488 bytes |
aix.c | -rw-r--r-- | 6.2 KB |
aix.h | -rw-r--r-- | 59 bytes |
amiga.c | -rw-r--r-- | 3.7 KB |
amiga.h | -rw-r--r-- | 89 bytes |
atari.c | -rw-r--r-- | 3.9 KB |
atari.h | -rw-r--r-- | 1.0 KB |
check.c | -rw-r--r-- | 4.2 KB |
check.h | -rw-r--r-- | 1.1 KB |
cmdline.c | -rw-r--r-- | 2.2 KB |
cmdline.h | -rw-r--r-- | 57 bytes |
efi.c | -rw-r--r-- | 22.7 KB |
efi.h | -rw-r--r-- | 4.4 KB |
ibm.c | -rw-r--r-- | 9.3 KB |
ibm.h | -rw-r--r-- | 47 bytes |
karma.c | -rw-r--r-- | 1.1 KB |
karma.h | -rw-r--r-- | 124 bytes |
ldm.c | -rw-r--r-- | 44.1 KB |
ldm.h | -rw-r--r-- | 5.4 KB |
mac.c | -rw-r--r-- | 3.5 KB |
mac.h | -rw-r--r-- | 1.2 KB |
msdos.c | -rw-r--r-- | 15.8 KB |
msdos.h | -rw-r--r-- | 124 bytes |
osf.c | -rw-r--r-- | 1.9 KB |
osf.h | -rw-r--r-- | 123 bytes |
sgi.c | -rw-r--r-- | 2.2 KB |
sgi.h | -rw-r--r-- | 128 bytes |
sun.c | -rw-r--r-- | 3.7 KB |
sun.h | -rw-r--r-- | 169 bytes |
sysv68.c | -rw-r--r-- | 1.9 KB |
sysv68.h | -rw-r--r-- | 62 bytes |
ultrix.c | -rw-r--r-- | 1.2 KB |
ultrix.h | -rw-r--r-- | 90 bytes |
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