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-- | 3.1 KB |
Makefile | -rw-r--r-- | 577 bytes |
associola.c | -rw-r--r-- | 48.0 KB |
auth.c | -rw-r--r-- | 23.9 KB |
bind_addr.c | -rw-r--r-- | 13.7 KB |
chunk.c | -rw-r--r-- | 9.5 KB |
debug.c | -rw-r--r-- | 4.2 KB |
endpointola.c | -rw-r--r-- | 13.0 KB |
input.c | -rw-r--r-- | 30.8 KB |
inqueue.c | -rw-r--r-- | 6.2 KB |
ipv6.c | -rw-r--r-- | 28.7 KB |
objcnt.c | -rw-r--r-- | 4.0 KB |
output.c | -rw-r--r-- | 22.3 KB |
outqueue.c | -rw-r--r-- | 52.1 KB |
primitive.c | -rw-r--r-- | 7.3 KB |
probe.c | -rw-r--r-- | 5.9 KB |
proc.c | -rw-r--r-- | 14.4 KB |
protocol.c | -rw-r--r-- | 42.3 KB |
sm_make_chunk.c | -rw-r--r-- | 102.6 KB |
sm_sideeffect.c | -rw-r--r-- | 48.8 KB |
sm_statefuns.c | -rw-r--r-- | 197.1 KB |
sm_statetable.c | -rw-r--r-- | 31.2 KB |
socket.c | -rw-r--r-- | 207.8 KB |
ssnmap.c | -rw-r--r-- | 3.1 KB |
sysctl.c | -rw-r--r-- | 12.3 KB |
transport.c | -rw-r--r-- | 19.7 KB |
tsnmap.c | -rw-r--r-- | 9.5 KB |
ulpevent.c | -rw-r--r-- | 29.1 KB |
ulpqueue.c | -rw-r--r-- | 29.0 KB |
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