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Paul E. McKenney authored
There is a loop in do_mlockall() that lacks a preemption point, which means that the following can happen on non-preemptible builds of the kernel. Dave Jones reports: "My fuzz tester keeps hitting this. Every instance shows the non-irq stack came in from mlockall. I'm only seeing this on one box, but that has more ram (8gb) than my other machines, which might explain it. INFO: rcu_preempt self-detected stall on CPU { 3} (t=6500 jiffies g=470344 c=470343 q=0) sending NMI to all CPUs: NMI backtrace for cpu 3 CPU: 3 PID: 29664 Comm: trinity-child2 Not tainted 3.11.0-rc1+ #32 Call Trace: lru_add_drain_all+0x15/0x20 SyS_mlockall+0xa5/0x1a0 tracesys+0xdd/0xe2" This commit addresses this problem by inserting the required preemption point. Reported-by:
Dave Jones <davej@redhat.com> Signed-off-by:
Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: KOSAKI Motohiro <kosaki.motohiro@gmail.com> Cc: Michel Lespinasse <walken@google.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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