Ceph

Easy to reproduce with debug bdev = 40 and bluestore.

(gdb) bt
#0  0x00007fba82f0a20b in raise (sig=11) at ../nptl/sysdeps/unix/sysv/linux/pt-raise.c:37
#1  0x000055b6208558bd in reraise_fatal (signum=11) at global/signal_handler.cc:71
#2  handle_fatal_signal (signum=11) at global/signal_handler.cc:128
#3  <signal handler called>
#4  __memcpy_sse2_unaligned () at ../sysdeps/x86_64/multiarch/memcpy-sse2-unaligned.S:79
#5  0x000055b62090927e in memcpy (__len=20693287, __src=<optimized out>, __dest=<optimized out>) at /usr/include/x86_64-linux-gnu/bits/string3.h:51
#6  PrebufferedStreambuf::snprintf (this=this@entry=0x55b62cc4a020, dst=dst@entry=0x7fba7eadcc4b "bdev(/var/lib/ceph/osd/ceph-0/block) data: 00000000  49 27 6d 20 74 68 65 20  20 20 20 20 20 20 20 20  |I'm the         |\n00000010  20 20 20 20 20 20 20 30  74 68 20 6f 70 21 00 7a  |       0th op!.z|"..., 
    avail=avail@entry=20709464) at common/PrebufferedStreambuf.cc:89
#7  0x000055b62088a4ce in snprintf (avail=20709464, dst=0x7fba7eadcc4b "bdev(/var/lib/ceph/osd/ceph-0/block) data: 00000000  49 27 6d 20 74 68 65 20  20 20 20 20 20 20 20 20  |I'm the         |\n00000010  20 20 20 20 20 20 20 30  74 68 20 6f 70 21 00 7a  |       0th op!.z|"..., this=0x55b62cc4a000)
    at log/Entry.h:92
#8  ceph::log::Log::_flush (this=this@entry=0x55b62bdb5500, t=t@entry=0x7fba7fe9cdd0, requeue=requeue@entry=0x55b62bdb5608, crash=crash@entry=false) at log/Log.cc:288
#9  0x000055b62088a8e9 in ceph::log::Log::flush (this=this@entry=0x55b62bdb5500) at log/Log.cc:254
#10 0x000055b62088aade in ceph::log::Log::entry (this=0x55b62bdb5500) at log/Log.cc:408
#11 0x00007fba82f02182 in start_thread (arg=0x7fba7fe9e700) at pthread_create.c:312
#12 0x00007fba8103047d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111