Re: iotest 030 still occasionally intermittently failing

[Vladimir Sementsov-Ogievskiy]

16.11.2020 20:59, Peter Maydell wrote:
> On Mon, 16 Nov 2020 at 17:34, Alberto Garcia <berto@igalia.com> wrote:
> > Do you know if there is a core dump or stack trace available ?
> Nope, sorry. What you get is what the 'vm-build-netbsd' etc targets
> produce, so if you want more diagnostics on failures you have to
> arrange for the test harness to produce them...
>
> thanks
> -- PMM
Hi!

After some iterations I've reproduced on SIGABRT:

#0  0x00007feb701bae35 in raise () at /lib64/libc.so.6
#1  0x00007feb701a5895 in abort () at /lib64/libc.so.6
#2  0x00007feb701a5769 in _nl_load_domain.cold () at /lib64/libc.so.6
#3  0x00007feb701b3566 in annobin_assert.c_end () at /lib64/libc.so.6
#4  0x000055a93374f7d3 in bdrv_replace_child (child=0x55a9363a3a00, new_bs=0x0) 
at ../block.c:2648
#5  0x000055a93374fd5a in bdrv_detach_child (child=0x55a9363a3a00) at 
../block.c:2777
#6  0x000055a93374fd9c in bdrv_root_unref_child (child=0x55a9363a3a00) at 
../block.c:2789
#7  0x000055a933722e8b in block_job_remove_all_bdrv (job=0x55a935f4f4b0) at 
../blockjob.c:191
#8  0x000055a933722bb2 in block_job_free (job=0x55a935f4f4b0) at 
../blockjob.c:88
#9  0x000055a9337755fa in job_unref (job=0x55a935f4f4b0) at ../job.c:380
#10 0x000055a9337767a6 in job_exit (opaque=0x55a935f4f4b0) at ../job.c:894
#11 0x000055a93386037e in aio_bh_call (bh=0x55a9352e16b0) at ../util/async.c:136
#12 0x000055a933860488 in aio_bh_poll (ctx=0x55a9351366f0) at 
../util/async.c:164
#13 0x000055a93383151e in aio_dispatch (ctx=0x55a9351366f0) at 
../util/aio-posix.c:381
#14 0x000055a9338608b9 in aio_ctx_dispatch (source=0x55a9351366f0, 
callback=0x0, user_data=0x0)
    at ../util/async.c:306
#15 0x00007feb71349ecd in g_main_context_dispatch () at /lib64/libglib-2.0.so.0
#16 0x000055a933840300 in glib_pollfds_poll () at ../util/main-loop.c:221
#17 0x000055a93384037a in os_host_main_loop_wait (timeout=0) at 
../util/main-loop.c:244
#18 0x000055a933840482 in main_loop_wait (nonblocking=0) at 
../util/main-loop.c:520
#19 0x000055a933603979 in qemu_main_loop () at ../softmmu/vl.c:1678
#20 0x000055a933190046 in main (argc=20, argv=0x7ffd48c31138, 
envp=0x7ffd48c311e0)

(gdb) fr 4
#4  0x000055a93374f7d3 in bdrv_replace_child (child=0x55a9363a3a00, new_bs=0x0) 
at ../block.c:2648
2648            assert(tighten_restrictions == false);
(gdb) list
2643            int ret;
2644
2645            bdrv_get_cumulative_perm(old_bs, &perm, &shared_perm);
2646            ret = bdrv_check_perm(old_bs, NULL, perm, shared_perm, NULL,
2647                                  &tighten_restrictions, NULL);
2648            assert(tighten_restrictions == false);
2649            if (ret < 0) {
2650                /* We only tried to loosen restrictions, so errors are not 
fatal */
2651                bdrv_abort_perm_update(old_bs);
2652            } else {
(gdb) p tighten_restrictions
$1 = true


Hm. it seems that the problem is that tighten_restrictions is not initialized. 
I'll send a patch.

--
Best regards,
Vladimir