Re: [Qemu-stable] qemu segfault in librbd / aio_notify

[Stefan Priebe]

Hi,

even with
+From 271c0f68b4eae72691721243a1c37f46a3232d61 Mon Sep 17 00:00:00 2001
+From: Fam Zheng <address@hidden>
+Date: Wed, 21 May 2014 10:42:13 +0800
+Subject: [PATCH] aio: Fix use-after-free in cancellation path

applied i saw today segfault with the following backtrace:

Program terminated with signal 11, Segmentation fault.
#0  0x00007f9dd633343f in event_notifier_set (e=0x124) at 
util/event_notifier-posix.c:97
97      util/event_notifier-posix.c: No such file or directory.
(gdb) bt
#0  0x00007f9dd633343f in event_notifier_set (e=0x124) at 
util/event_notifier-posix.c:97
#1  0x00007f9dd5f4eafc in aio_notify (ctx=0x0) at async.c:246
#2  0x00007f9dd5f4e697 in qemu_bh_schedule (bh=0x7f9b98eeeb30) at 
async.c:128
#3  0x00007f9dd5fa2c44 in rbd_finish_aiocb (c=0x7f9dd9069ad0, 
rcb=0x7f9dd85f1770) at block/rbd.c:585
#4  0x00007f9dd38d5e44 in librbd::AioCompletion::complete() () from 
/usr/lib/librbd.so.1
#5  0x00007f9dd38d5832 in 
librbd::AioCompletion::complete_request(CephContext*, long) () from 
/usr/lib/librbd.so.1
#6  0x00007f9dd3dab6ba in Context::complete(int) () from 
/usr/lib/librados.so.2
#7  0x00007f9dd3908e85 in ObjectCacher::C_WaitForWrite::finish(int) () 
from /usr/lib/librbd.so.1
#8  0x00007f9dd3dab6ba in Context::complete(int) () from 
/usr/lib/librados.so.2
#9  0x00007f9dd3e4e3c8 in Finisher::finisher_thread_entry() () from 
/usr/lib/librados.so.2
#10 0x00007f9dcde5ab50 in start_thread () from 
/lib/x86_64-linux-gnu/libpthread.so.0
#11 0x00007f9dcdba513d in clone () from /lib/x86_64-linux-gnu/libc.so.6
#12 0x0000000000000000 in ?? ()


Am 28.05.2014 21:44, schrieb Stefan Priebe:
> is this:
> commit 271c0f68b4eae72691721243a1c37f46a3232d61
> Author: Fam Zheng <address@hidden>
> Date:   Wed May 21 10:42:13 2014 +0800
>
>      aio: Fix use-after-free in cancellation path
>
> Stefan
>
> Am 28.05.2014 21:40, schrieb Stefan Priebe:
> > Hello,
> >
> > i mean since using qemu 2.0 i've now seen several times the following
> > segfault:
> > (gdb) bt
> > #0  0x00007f2af1196433 in event_notifier_set (e=0x124) at
> > util/event_notifier-posix.c:97
> > #1  0x00007f2af0db1afc in aio_notify (ctx=0x0) at async.c:246
> > #2  0x00007f2af0db1697 in qemu_bh_schedule (bh=0x7f2ad401bec0) at
> > async.c:128
> > #3  0x00007f2af0e05c44 in rbd_finish_aiocb (c=0x7f2ad5ec4590,
> > rcb=0x7f2ad63c5df0) at block/rbd.c:585
> > #4  0x00007f2aee738e44 in librbd::AioCompletion::complete() () from
> > /usr/lib/librbd.so.1
> > #5  0x00007f2aee738832 in
> > librbd::AioCompletion::complete_request(CephContext*, long) () from
> > /usr/lib/librbd.so.1
> > #6  0x00007f2aeec0e6ba in Context::complete(int) () from
> > /usr/lib/librados.so.2
> > #7  0x00007f2aee76be85 in ObjectCacher::C_WaitForWrite::finish(int) ()
> > from /usr/lib/librbd.so.1
> > #8  0x00007f2aeec0e6ba in Context::complete(int) () from
> > /usr/lib/librados.so.2
> > #9  0x00007f2aeecb13c8 in Finisher::finisher_thread_entry() () from
> > /usr/lib/librados.so.2
> > #10 0x00007f2ae8cbdb50 in start_thread () from
> > /lib/x86_64-linux-gnu/libpthread.so.0
> > #11 0x00007f2ae8a080ed in clone () from /lib/x86_64-linux-gnu/libc.so.6
> > #12 0x0000000000000000 in ?? ()
> > (gdb)
> >
> >
> > from another VM:
> > #0  0x00007f89565ec433 in event_notifier_set (e=0x124) at
> > util/event_notifier-posix.c:97
> > #1  0x00007f8956207afc in aio_notify (ctx=0x0) at async.c:246
> > #2  0x00007f8956207697 in qemu_bh_schedule (bh=0x7f882dd6d340) at
> > async.c:128
> > #3  0x00007f895625bc44 in rbd_finish_aiocb (c=0x7f882d4c34a0,
> > rcb=0x7f882c0ae350) at block/rbd.c:585
> > #4  0x00007f8953b8ee44 in librbd::AioCompletion::complete() () from
> > /usr/lib/librbd.so.1
> > #5  0x00007f8953b8e832 in
> > librbd::AioCompletion::complete_request(CephContext*, long) () from
> > /usr/lib/librbd.so.1
> > #6  0x00007f89540646ba in Context::complete(int) () from
> > /usr/lib/librados.so.2
> > #7  0x00007f8953bc1e85 in ObjectCacher::C_WaitForWrite::finish(int) ()
> > from /usr/lib/librbd.so.1
> > #8  0x00007f89540646ba in Context::complete(int) () from
> > /usr/lib/librados.so.2
> > #9  0x00007f89541073c8 in Finisher::finisher_thread_entry() () from
> > /usr/lib/librados.so.2
> > #10 0x00007f894e113b50 in start_thread () from
> > /lib/x86_64-linux-gnu/libpthread.so.0
> > #11 0x00007f894de5e0ed in clone () from /lib/x86_64-linux-gnu/libc.so.6
> > #12 0x0000000000000000 in ?? ()
> >
> > Stefan