Re: Linux 3.19-rc3

[Sedat Dilek]

[ Please CC me I am not subscribed to LKML ]

[ QUOTE ]

On Mon, Jan 05, 2015 at 05:46:15PM -0800, Linus Torvalds wrote:
 > It's a day delayed - not because of any particular development issues,
 > but simply because I was tiling a bathroom yesterday. But rc3 is out
 > there now, and things have stayed reasonably calm. I really hope that
 > implies that 3.19 is looking good, but it's equally likely that it's
 > just that people are still recovering from the holiday season.
 >
 > A bit over three quarters of the changes here are drivers - mostly
 > networking, thermal, input layer, sound, power management. The rest is
 > misc - filesystems, core networking, some arch fixes, etc. But all of
 > it is pretty small.
 >
 > So go out and test,

This has been there since just before rc1. Is there a fix for this
stalled in someones git tree maybe ?

[    7.952588] WARNING: CPU: 0 PID: 299 at kernel/sched/core.c:7303
__might_sleep+0x8d/0xa0()
[    7.952592] do not call blocking ops when !TASK_RUNNING; state=1
set at [<ffffffff910a0f7a>] prepare_to_wait+0x2a/0x90
[    7.952595] CPU: 0 PID: 299 Comm: systemd-readahe Not tainted
3.19.0-rc3+ #100
[    7.952597]  0000000000001c87 00000000720a2c76 ffff8800b2513c88
ffffffff915b47c7
[    7.952598]  ffffffff910a3648 ffff8800b2513ce0 ffff8800b2513cc8
ffffffff91062c30
[    7.952599]  0000000000000000 ffffffff91796fb2 000000000000026d
0000000000000000
[    7.952600] Call Trace:
[    7.952603]  [<ffffffff915b47c7>] dump_stack+0x4c/0x65
[    7.952604]  [<ffffffff910a3648>] ? down_trylock+0x28/0x40
[    7.952606]  [<ffffffff91062c30>] warn_slowpath_common+0x80/0xc0
[    7.952607]  [<ffffffff91062cc0>] warn_slowpath_fmt+0x50/0x70
[    7.952608]  [<ffffffff910a0f7a>] ? prepare_to_wait+0x2a/0x90
[    7.952610]  [<ffffffff910a0f7a>] ? prepare_to_wait+0x2a/0x90
[    7.952611]  [<ffffffff910867ed>] __might_sleep+0x8d/0xa0
[    7.952614]  [<ffffffff915b8ea9>] mutex_lock_nested+0x39/0x3e0
[    7.952616]  [<ffffffff910a77ad>] ? trace_hardirqs_on+0xd/0x10
[    7.952617]  [<ffffffff910a0fac>] ? prepare_to_wait+0x5c/0x90
[    7.952620]  [<ffffffff911a63e0>] fanotify_read+0xe0/0x5b0
[    7.952622]  [<ffffffff91090801>] ? sched_clock_cpu+0xc1/0xd0
[    7.952624]  [<ffffffff91242459>] ? selinux_file_permission+0xb9/0x130
[    7.952626]  [<ffffffff910a14d0>] ? prepare_to_wait_event+0xf0/0xf0
[    7.952628]  [<ffffffff91162513>] __vfs_read+0x13/0x50
[    7.952629]  [<ffffffff911625d8>] vfs_read+0x88/0x140
[    7.952631]  [<ffffffff911626e7>] SyS_read+0x57/0xd0
[    7.952633]  [<ffffffff915bd952>] system_call_fastpath+0x12/0x17

[ /QUOTE ]

I am seeing a similiar call-trace/warning.
It is reproducible when running fio (latest: v2.2.4) while my loop-mq
tests (see block.git#for-next)

Some people tend to say it's coming from the linux-aio area [1], but I
am not sure.
1st I thought this is a Linux-next problem but I am seeing it also
with my rc-kernels.
For parts of aio there is a patch discussed in [2].
The experimental patchset of Ken from [3] made the "aio" call-trace go
away here.

I tried also a patch pending in peterz/queue.git#sched/core from Eric Sandeen.
It's "check for stack overflow in ___might_sleep".
Unfortunately, it did not help in case of my loop-mq tests.
( BTW, this is touching ___might_sleep() (note: triple-underscore VS.
affected __might_sleep() <--- double-underscrore). )

Let me hear your feedback.

Have more fun!

- Sedat -

[1] http://marc.info/?l=linux-aio&m=142033318411355&w=2
[2] http://marc.info/?l=linux-aio&m=142035799514685&w=2
[3] http://evilpiepirate.org/git/linux-bcache.git/log/?h=aio_ring_fix
[4] http://git.kernel.org/cgit/linux/kernel/git/peterz/queue.git/patch/?id=48e615e4c3ebed488fecb6bfb40b372151f62db2
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