Re: Processes hang in an unkillable state

Américo Wang
2011-04-12T12:44:36Z

2011/4/12 Robert Święcki <robert@swiecki.net>:
> Hi, while fuzzing Linux system calls (32bit fuzzer, 64bi linux
> kernel), it happens after some time (10-20mins) that some processes
> enter a state which makes them un-killable. They are either in R or D
> state.
>
> # strace ps wwuax
> ...
> ...
> open("/proc/450/cmdline", O_RDONLY)     = 6
> read(6,  -             hangs....
>
> # kill -9 450
> # kill -9 450 (no ESRCH)
>
> More data in the attachment - I'll keep it in the kdb session for
> further examination.

Hmm, it must be stuck at

lib/rwsem.c

/* wait to be given the lock */
for (;;) {
if (!waiter.task)
break;
schedule();
set_task_state(tsk, TASK_UNINTERRUPTIBLE);
}

don't know why it still can't acquire the ->mmap_sem...

Cc'ing Oleg...