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From: Kevin Wolf <kwolf@redhat.com>
To: qemu-block@nongnu.org
Cc: jsnow@redhat.com, qemu-devel@nongnu.org, mreitz@redhat.com
Subject: Re: [PATCH 0/2] mirror: Fix hang (operation waiting for itself/circular dependency)
Date: Wed, 25 Mar 2020 18:49:02 +0100	[thread overview]
Message-ID: <20200325174902.GC6756@linux.fritz.box> (raw)
In-Reply-To: <20200325172326.22347-1-kwolf@redhat.com>

Am 25.03.2020 um 18:23 hat Kevin Wolf geschrieben:
> The recent fix didn't actually fix the whole problem. Operations can't
> only wait for themselves, but we can also end up with circular
> dependencies like two operations waiting for each other to complete.
> 
> This reverts the first fix and implements another approach.

Hm, somehow this seems to break iotests 151. I don't actually understand
the backtrace, because that's during job initialisation, so my changes
shouldn't have had any effect yet:

(gdb) bt
#0  0x00007fba6d85057f in raise () at /lib64/libc.so.6
#1  0x00007fba6d83a895 in abort () at /lib64/libc.so.6
#2  0x00005624d94d109a in bitmap_new (nbits=<optimized out>) at /home/kwolf/source/qemu/include/qemu/bitmap.h:103
#3  0x00005624d94d109a in mirror_run (job=0x5624dc8d5560, errp=<optimized out>) at block/mirror.c:922
#4  0x00005624d988053f in job_co_entry (opaque=0x5624dc8d5560) at job.c:878
#5  0x00005624d998d3bb in coroutine_trampoline (i0=<optimized out>, i1=<optimized out>) at util/coroutine-ucontext.c:115
#6  0x00007fba6d866250 in __start_context () at /lib64/libc.so.6
#7  0x00007fffa2d48130 in  ()
#8  0x0000000000000000 in  ()

Something to check tomorrow.

Kevin



      parent reply	other threads:[~2020-03-25 17:51 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-25 17:23 [PATCH 0/2] mirror: Fix hang (operation waiting for itself/circular dependency) Kevin Wolf
2020-03-25 17:23 ` [PATCH 1/2] Revert "mirror: Don't let an operation wait for itself" Kevin Wolf
2020-03-25 17:36   ` Eric Blake
2020-03-25 17:23 ` [PATCH 2/2] mirror: Wait only for in-flight operations Kevin Wolf
2020-03-25 17:39   ` Eric Blake
2020-03-25 17:49 ` Kevin Wolf [this message]

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