xemu/block
Stefan Hajnoczi 1d719ddc35 block: fix bdrv_aio_cancel() for ENOMEDIUM requests
bdrv_aio_cancel() calls aio_poll() on the AioContext for the given I/O
request until it has completed. ENOMEDIUM requests are special because
there is no BlockDriverState when the drive has no medium!

Define a .get_aio_context() function for BlkAioEmAIOCB requests so that
bdrv_aio_cancel() can find the AioContext where the completion BH is
pending. Without this function bdrv_aio_cancel() aborts on ENOMEDIUM
requests!

libFuzzer triggered the following assertion:

  cat << EOF | qemu-system-i386 -M pc-q35-5.0 \
    -nographic -monitor none -serial none \
    -qtest stdio -trace ide\*
  outl 0xcf8 0x8000fa24
  outl 0xcfc 0xe106c000
  outl 0xcf8 0x8000fa04
  outw 0xcfc 0x7
  outl 0xcf8 0x8000fb20
  write 0x0 0x3 0x2780e7
  write 0xe106c22c 0xd 0x1130c218021130c218021130c2
  write 0xe106c218 0x15 0x110010110010110010110010110010110010110010
  EOF
  ide_exec_cmd IDE exec cmd: bus 0x56170a77a2b8; state 0x56170a77a340; cmd 0xe7
  ide_reset IDEstate 0x56170a77a340
  Aborted (core dumped)

  (gdb) bt
  #1  0x00007ffff4f93895 in abort () at /lib64/libc.so.6
  #2  0x0000555555dc6c00 in bdrv_aio_cancel (acb=0x555556765550) at block/io.c:2745
  #3  0x0000555555dac202 in blk_aio_cancel (acb=0x555556765550) at block/block-backend.c:1546
  #4  0x0000555555b1bd74 in ide_reset (s=0x555557213340) at hw/ide/core.c:1318
  #5  0x0000555555b1e3a1 in ide_bus_reset (bus=0x5555572132b8) at hw/ide/core.c:2422
  #6  0x0000555555b2aa27 in ahci_reset_port (s=0x55555720eb50, port=2) at hw/ide/ahci.c:650
  #7  0x0000555555b29fd7 in ahci_port_write (s=0x55555720eb50, port=2, offset=44, val=16) at hw/ide/ahci.c:360
  #8  0x0000555555b2a564 in ahci_mem_write (opaque=0x55555720eb50, addr=556, val=16, size=1) at hw/ide/ahci.c:513
  #9  0x000055555598415b in memory_region_write_accessor (mr=0x55555720eb80, addr=556, value=0x7fffffffb838, size=1, shift=0, mask=255, attrs=...) at softmmu/memory.c:483

Looking at bdrv_aio_cancel:

2728 /* async I/Os */
2729
2730 void bdrv_aio_cancel(BlockAIOCB *acb)
2731 {
2732     qemu_aio_ref(acb);
2733     bdrv_aio_cancel_async(acb);
2734     while (acb->refcnt > 1) {
2735         if (acb->aiocb_info->get_aio_context) {
2736             aio_poll(acb->aiocb_info->get_aio_context(acb), true);
2737         } else if (acb->bs) {
2738             /* qemu_aio_ref and qemu_aio_unref are not thread-safe, so
2739              * assert that we're not using an I/O thread.  Thread-safe
2740              * code should use bdrv_aio_cancel_async exclusively.
2741              */
2742             assert(bdrv_get_aio_context(acb->bs) == qemu_get_aio_context());
2743             aio_poll(bdrv_get_aio_context(acb->bs), true);
2744         } else {
2745             abort();     <===============
2746         }
2747     }
2748     qemu_aio_unref(acb);
2749 }

Fixes: 02c50efe08 ("block: Add bdrv_aio_cancel_async")
Reported-by: Alexander Bulekov <alxndr@bu.edu>
Buglink: https://bugs.launchpad.net/qemu/+bug/1878255
Originally-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20200720100141.129739-1-stefanha@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
2020-07-21 12:00:38 +02:00
..
monitor blockdev: Split off basic bitmap operations for qemu-img 2020-05-19 10:32:14 -05:00
accounting.c block: add empty account cookie type 2019-10-10 10:56:18 +02:00
aio_task.c block: introduce aio task pool 2019-10-10 10:56:17 +02:00
amend.c block/core: add generic infrastructure for x-blockdev-amend qmp command 2020-07-06 08:49:28 +02:00
backup-top.c block: Drop @child_class from bdrv_child_perm() 2020-05-18 19:05:25 +02:00
backup-top.h block: introduce backup-top filter driver 2019-10-10 10:56:18 +02:00
backup.c backup: Make sure that source and target size match 2020-05-08 13:26:35 +02:00
blkdebug.c error: Eliminate error_propagate() with Coccinelle, part 2 2020-07-10 15:18:08 +02:00
blklogwrites.c error: Eliminate error_propagate() with Coccinelle, part 2 2020-07-10 15:18:08 +02:00
blkreplay.c block: Use bdrv_default_perms() 2020-05-18 19:05:25 +02:00
blkverify.c error: Eliminate error_propagate() with Coccinelle, part 2 2020-07-10 15:18:08 +02:00
block-backend.c block: fix bdrv_aio_cancel() for ENOMEDIUM requests 2020-07-21 12:00:38 +02:00
block-copy.c block/block-copy: block_copy_dirty_clusters: fix failure check 2020-07-06 08:33:06 +02:00
bochs.c block: Use bdrv_default_perms() 2020-05-18 19:05:25 +02:00
cloop.c block: Use bdrv_default_perms() 2020-05-18 19:05:25 +02:00
commit.c block: Drop @child_class from bdrv_child_perm() 2020-05-18 19:05:25 +02:00
copy-on-read.c block: Drop @child_class from bdrv_child_perm() 2020-05-18 19:05:25 +02:00
create.c block/create: Do not abort if a block driver is not available 2019-09-13 12:18:37 +02:00
crypto.c block/crypto: disallow write sharing by default 2020-07-21 10:49:02 +02:00
crypto.h block/crypto: implement the encryption key management 2020-07-06 08:49:28 +02:00
curl.c error: Eliminate error_propagate() with Coccinelle, part 1 2020-07-10 15:18:08 +02:00
dirty-bitmap.c block/dirty-bitmap: add bdrv_has_named_bitmaps helper 2020-05-28 13:15:22 -05:00
dmg-bz2.c Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
dmg-lzfse.c block: adding lzfse decompressing support as a module. 2018-12-14 11:52:40 +01:00
dmg.c block: Use bdrv_default_perms() 2020-05-18 19:05:25 +02:00
dmg.h Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
file-posix.c file-posix: Fix leaked fd in raw_open_common() error path 2020-07-17 14:20:57 +02:00
file-win32.c error: Eliminate error_propagate() with Coccinelle, part 2 2020-07-10 15:18:08 +02:00
filter-compress.c block: Use bdrv_default_perms() 2020-05-18 19:05:25 +02:00
gluster.c error: Reduce unnecessary error propagation 2020-07-10 15:18:08 +02:00
io_uring.c io_uring: use io_uring_cq_ready() to check for ready cqes 2020-06-05 09:54:48 +01:00
io.c block: drop unallocated_blocks_are_zero 2020-07-06 10:34:14 +02:00
iscsi-opts.c Include qemu/module.h where needed, drop it from qemu-common.h 2019-06-12 13:18:33 +02:00
iscsi.c iscsi: return -EIO when sense fields are meaningless 2020-07-10 18:02:23 -04:00
linux-aio.c misc: Replace zero-length arrays with flexible array member (automatic) 2020-03-16 22:07:42 +01:00
Makefile.objs Remove VXHS block device 2020-07-17 14:20:57 +02:00
mirror.c block: Drop @child_class from bdrv_child_perm() 2020-05-18 19:05:25 +02:00
nbd.c nbd: Avoid off-by-one in long export name truncation 2020-07-13 09:01:01 -05:00
nfs.c qapi: Smooth another visitor error checking pattern 2020-07-10 15:18:08 +02:00
null.c replay: add BH oneshot event for block layer 2019-10-14 17:12:48 +02:00
nvme.c block/nvme: support nested aio_poll() 2020-06-23 15:46:08 +01:00
parallels.c error: Avoid error_propagate() after migrate_add_blocker() 2020-07-10 15:18:08 +02:00
parallels.h Clean up includes 2018-02-09 05:05:11 +01:00
qapi-sysemu.c block: Move system emulator QMP commands to block/qapi-sysemu.c 2020-03-06 17:15:38 +01:00
qapi.c block: Fix VM size field width in snapshot dump 2020-02-20 16:43:42 +01:00
qcow2-bitmap.c qcow2: Tweak comments on qcow2_get_persistent_dirty_bitmap_size 2020-06-17 14:53:39 +02:00
qcow2-cache.c core: replace getpagesize() with qemu_real_host_page_size 2019-10-26 15:38:06 +02:00
qcow2-cluster.c qcow2: Support BDRV_REQ_ZERO_WRITE for truncate 2020-04-30 17:51:07 +02:00
qcow2-refcount.c block: Comment cleanups 2020-05-05 13:17:36 +02:00
qcow2-snapshot.c qcow2: Allow resize of images with internal snapshots 2020-05-05 13:17:36 +02:00
qcow2-threads.c qcow2: add zstd cluster compression 2020-05-13 14:20:31 +02:00
qcow2.c block: Add support to warn on backing file change without format 2020-07-14 15:18:59 +02:00
qcow2.h qcow2: Expose bitmaps' size during measure 2020-05-28 13:16:16 -05:00
qcow.c qcow: Tolerate backing_fmt= 2020-07-14 15:18:59 +02:00
qed-check.c block/qed: add missed coroutine_fn markers 2019-04-30 15:29:00 +02:00
qed-cluster.c qed: protect table cache with CoMutex 2017-07-17 11:34:11 +08:00
qed-l2-cache.c qed: protect table cache with CoMutex 2017-07-17 11:34:11 +08:00
qed-table.c block/qed: add missed coroutine_fn markers 2019-04-30 15:29:00 +02:00
qed.c qapi: Smooth another visitor error checking pattern 2020-07-10 15:18:08 +02:00
qed.h qed: Simplify backing reads 2020-07-06 10:34:14 +02:00
quorum.c error: Reduce unnecessary error propagation 2020-07-10 15:18:08 +02:00
raw-format.c error: Eliminate error_propagate() with Coccinelle, part 2 2020-07-10 15:18:08 +02:00
rbd.c qapi: Smooth another visitor error checking pattern 2020-07-10 15:18:08 +02:00
replication.c error: Reduce unnecessary error propagation 2020-07-10 15:18:08 +02:00
sheepdog.c sheepdog: Add trivial backing_fmt support 2020-07-14 15:18:59 +02:00
snapshot.c block/snapshot: rename Error ** parameter to more common errp 2019-12-18 08:43:19 +01:00
ssh.c qapi: Smooth another visitor error checking pattern 2020-07-10 15:18:08 +02:00
stream.c block: Add support to warn on backing file change without format 2020-07-14 15:18:59 +02:00
throttle-groups.c error: Eliminate error_propagate() with Coccinelle, part 1 2020-07-10 15:18:08 +02:00
throttle.c error: Eliminate error_propagate() with Coccinelle, part 2 2020-07-10 15:18:08 +02:00
trace-events Remove VXHS block device 2020-07-17 14:20:57 +02:00
vdi.c error: Avoid error_propagate() after migrate_add_blocker() 2020-07-10 15:18:08 +02:00
vhdx-endian.c Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
vhdx-log.c block: Add flags to bdrv(_co)_truncate() 2020-04-30 17:51:07 +02:00
vhdx.c error: Avoid error_propagate() after migrate_add_blocker() 2020-07-10 15:18:08 +02:00
vhdx.h block/vhdx: Use IEC binary prefixes for size constants 2019-04-30 15:29:00 +02:00
vmdk.c vmdk: Add trivial backing_fmt support 2020-07-14 15:18:59 +02:00
vpc.c error: Avoid error_propagate() after migrate_add_blocker() 2020-07-10 15:18:08 +02:00
vvfat.c error: Avoid error_propagate() after migrate_add_blocker() 2020-07-10 15:18:08 +02:00
win32-aio.c Include qemu/module.h where needed, drop it from qemu-common.h 2019-06-12 13:18:33 +02:00
write-threshold.c qapi: Drop qapi_event_send_FOO()'s Error ** argument 2018-08-28 18:21:38 +02:00