I've attached patch which resolves bug, but actually it's just workaround and may be not unsafe, because it's just ignore assert.
** Patch added: "workaround patch" https://bugs.launchpad.net/qemu/+bug/1708442/+attachment/4926546/+files/0001-util-async-ignore-self-co-enter-instead-of-assert.patch -- You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1708442 Title: Crash(assert) during reading image from http url through qemu-nbd Status in QEMU: New Bug description: Description: During reading image from nbd device mounted by qemu-nbd server with url backend I/O error happens "blk_update_request: I/O error, dev nbd0, sector 42117" dmesg. After some investigation I found that qemu-nbd server aborts in aio_co_enter() assert in util/async.c:468. Steps to reproduce: 1) sudo go run qemu-nbd-bug-report/qemu-nbd-bug.go (see qemu-nbd-bug- report.tar.gz) or try directly 1) qemu-nbd -c /dev/nbd0 -r -v --aio=native -f qcow2 json:{"file.driver":"http","file.url":"http://localhost:9666/image","file.readahead":3276800 2) try read whole nbd device while error "blk_update_request: I/O error, dev nbd0, sector 42117" appears in dmesg Versions: 1) qemu built from sources(/configure --target-list=x86_64-softmmu --disable-user --enable-curl --enable-linux-aio --enable-virtfs --enable-debug --disable-pie , top commit 5619c179057e24195ff19c8fe6d6a6cbcb16ed28): qemu-nbd -v qemu-nbd 2.9.90 (v2.10.0-rc0-67-g5619c17) 2) libcurl(built from sources, top commit 1767adf4399bb3be29121435e1bb1cc2bc05f7bf): curl -V curl 7.55.0-DEV (Linux) libcurl/7.55.0-DEV OpenSSL/1.0.2g zlib/1.2.8 Backtrace: (gdb) bt #0 0x00007f7131426428 in __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:54 #1 0x00007f713142802a in __GI_abort () at abort.c:89 #2 0x00007f713141ebd7 in __assert_fail_base (fmt=<optimized out>, assertion=assertion@entry=0x54c924 "self != co", file=file@entry=0x54c871 "util/async.c", line=line@entry=468, function=function@entry=0x54c980 <__PRETTY_FUNCTION__.24766> "aio_co_enter") at assert.c:92 #3 0x00007f713141ec82 in __GI___assert_fail (assertion=0x54c924 "self != co", file=0x54c871 "util/async.c", line=468, function=0x54c980 <__PRETTY_FUNCTION__.24766> "aio_co_enter") at assert.c:101 #4 0x00000000004fe6a2 in aio_co_enter (ctx=0xf0ddb0, co=0xf14650) at util/async.c:468 #5 0x00000000004fe637 in aio_co_wake (co=0xf14650) at util/async.c:456 #6 0x0000000000495c8a in curl_read_cb (ptr=0xf566d9, size=1, nmemb=16135, opaque=0xf1cb90) at block/curl.c:275 #7 0x00007f713242ac24 in Curl_client_chop_write () from /usr/lib/x86_64-linux-gnu/libcurl.so #8 0x00007f713242ae03 in Curl_client_write () from /usr/lib/x86_64-linux-gnu/libcurl.so #9 0x00007f713244e1cf in readwrite_data () from /usr/lib/x86_64-linux-gnu/libcurl.so #10 0x00007f713244eb6f in Curl_readwrite () from /usr/lib/x86_64-linux-gnu/libcurl.so #11 0x00007f713245c1bb in multi_runsingle () from /usr/lib/x86_64-linux-gnu/libcurl.so #12 0x00007f713245d819 in multi_socket () from /usr/lib/x86_64-linux-gnu/libcurl.so #13 0x00007f713245e067 in curl_multi_socket_action () from /usr/lib/x86_64-linux-gnu/libcurl.so #14 0x0000000000497555 in curl_setup_preadv (bs=0xf16820, acb=0x7f712d379860) at block/curl.c:918 #15 0x00000000004975fb in curl_co_preadv (bs=0xf16820, offset=6556160, bytes=512, qiov=0x7f712d379b40, flags=0) at block/curl.c:935 #16 0x000000000047730f in bdrv_driver_preadv (bs=0xf16820, offset=6556160, bytes=512, qiov=0x7f712d379b40, flags=0) at block/io.c:836 #17 0x0000000000477c1f in bdrv_aligned_preadv (child=0xf1be20, req=0x7f712d379a60, offset=6556160, bytes=512, align=1, qiov=0x7f712d379b40, flags=0) at block/io.c:1086 #18 0x0000000000478109 in bdrv_co_preadv (child=0xf1be20, offset=6556160, bytes=512, qiov=0x7f712d379b40, flags=0) at block/io.c:1180 #19 0x0000000000437498 in qcow2_co_preadv (bs=0xf0fdc0, offset=21563904, bytes=512, qiov=0x7f712d379e80, flags=0) at block/qcow2.c:1812 #20 0x000000000047730f in bdrv_driver_preadv (bs=0xf0fdc0, offset=21563904, bytes=512, qiov=0x7f712d379e80, flags=0) at block/io.c:836 #21 0x0000000000477c1f in bdrv_aligned_preadv (child=0xf1c0d0, req=0x7f712d379d30, offset=21563904, bytes=512, align=1, qiov=0x7f712d379e80, flags=0) at block/io.c:1086 #22 0x0000000000478109 in bdrv_co_preadv (child=0xf1c0d0, offset=21563904, bytes=512, qiov=0x7f712d379e80, flags=0) at block/io.c:1180 #23 0x00000000004645ad in blk_co_preadv (blk=0xf1be90, offset=21563904, bytes=512, qiov=0x7f712d379e80, flags=0) at block/block-backend.c:991 #24 0x00000000004646fa in blk_read_entry (opaque=0x7f712d379ea0) at block/block-backend.c:1038 #25 0x000000000046481c in blk_prw (blk=0xf1be90, offset=21563904, ---Type <return> to continue, or q <return> to quit--- buf=0xf7f000 "2,NV\241t!\ti\312\vp\364\017Kl*\354\021\a\177\021\260\b\027\212\347\027\004\322\nG\340b\\\306pG\332\313\060\341;\002\360\063L\240\027T \211\341\305\022АE\230\356DǮ}\211\bx\016\a\b\313\350\316\064.\017\372\032-R\376z\261\263\350|cQ<\016S_L\340A\221\366~L#\001+\271\204\065~\327\023\027I\211\343\361\276zT$4\336\273ˏ\353ʪ\234\016_Z|TMk\"\370\002\363~\334\332.\a\375\265mӌ{/%\304֎\374sF<E\371\031o&\202\217\226\276>I\356\302\375F\340\332\324\021\202\232>\026\261\233\303tv\023\304\006\243\037\062BϏ\b\324rs\360'"..., bytes=512, co_entry=0x4646aa <blk_read_entry>, flags=0) at block/block-backend.c:1074 #26 0x0000000000464f81 in blk_pread (blk=0xf1be90, offset=21563904, buf=0xf7f000, count=512) at block/block-backend.c:1227 #27 0x00000000004906cb in nbd_trip (opaque=0xf5a940) at nbd/server.c:1380 #28 0x000000000051c0a5 in coroutine_trampoline (i0=15812176, i1=0) at util/coroutine-ucontext.c:79 #29 0x00007f713143b5d0 in ?? () from /lib/x86_64-linux-gnu/libc.so.6 #30 0x00007f712d47a770 in ?? () #31 0x0000000000000000 in ?? () Backtrace stopped: Cannot access memory at address 0x7f712d37a000 To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1708442/+subscriptions
