Hello,
syzbot found the following crash on:
HEAD commit: 245a4300 Merge branch 'rcu/kcsan' into tip/locking/kcsan
git tree:
https://github.com/google/ktsan.git kcsan
console output:
https://syzkaller.appspot.com/x/log.txt?x=1303b515e00000
kernel config:
https://syzkaller.appspot.com/x/.config?x=a4b9db179318d21f
dashboard link:
https://syzkaller.appspot.com/bug?extid=44f9b37d2de57637dbfd
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
CC: [
ax...@kernel.dk linux...@vger.kernel.org
linux-...@vger.kernel.org el...@google.com]
Unfortunately, I don't have any reproducer for this crash yet.
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by:
syzbot+44f9b3...@syzkaller.appspotmail.com
==================================================================
BUG: KCSAN: data-race in blk_mq_sched_dispatch_requests /
blk_mq_sched_dispatch_requests
read to 0xffff88812a222150 of 8 bytes by task 22571 on cpu 0:
blk_mq_sched_dispatch_requests+0x104/0x380 block/blk-mq-sched.c:181
__blk_mq_run_hw_queue+0xb7/0x160 block/blk-mq.c:1368
__blk_mq_delay_run_hw_queue+0x31b/0x3a0 block/blk-mq.c:1436
blk_mq_run_hw_queue+0xfd/0x1c0 block/blk-mq.c:1473
blk_mq_sched_insert_requests+0x198/0x260 block/blk-mq-sched.c:444
blk_mq_flush_plug_list+0x572/0x6c0 block/blk-mq.c:1733
blk_flush_plug_list+0x271/0x2a0 block/blk-core.c:1768
blk_finish_plug block/blk-core.c:1785 [inline]
blk_finish_plug+0x60/0x84 block/blk-core.c:1781
ext4_writepages+0xe32/0x2500 fs/ext4/inode.c:2832
do_writepages+0x6b/0x170 mm/page-writeback.c:2344
__filemap_fdatawrite_range+0x1c5/0x230 mm/filemap.c:421
file_write_and_wait_range+0xfd/0x160 mm/filemap.c:782
ext4_sync_file+0x266/0xaf0 fs/ext4/fsync.c:153
vfs_fsync_range+0x82/0x150 fs/sync.c:197
generic_write_sync include/linux/fs.h:2856 [inline]
ext4_buffered_write_iter+0x222/0x290 fs/ext4/file.c:259
ext4_file_write_iter+0xf4/0xd40 fs/ext4/file.c:547
call_write_iter include/linux/fs.h:1902 [inline]
do_iter_readv_writev+0x487/0x5b0 fs/read_write.c:693
do_iter_write fs/read_write.c:970 [inline]
do_iter_write+0x13b/0x3c0 fs/read_write.c:951
vfs_iter_write+0x5c/0x80 fs/read_write.c:983
ovl_write_iter+0x366/0x550 fs/overlayfs/file.c:278
call_write_iter include/linux/fs.h:1902 [inline]
new_sync_write+0x388/0x4a0 fs/read_write.c:483
__vfs_write+0xb1/0xc0 fs/read_write.c:496
__kernel_write+0xb8/0x240 fs/read_write.c:515
write_pipe_buf+0xb6/0xf0 fs/splice.c:809
splice_from_pipe_feed fs/splice.c:512 [inline]
__splice_from_pipe+0x295/0x4a0 fs/splice.c:636
splice_from_pipe+0xbb/0x100 fs/splice.c:671
default_file_splice_write+0x45/0x90 fs/splice.c:821
do_splice_from fs/splice.c:863 [inline]
direct_splice_actor+0xa0/0xc0 fs/splice.c:1037
splice_direct_to_actor+0x22b/0x540 fs/splice.c:992
do_splice_direct+0x161/0x1e0 fs/splice.c:1080
do_sendfile+0x384/0x7f0 fs/read_write.c:1464
__do_sys_sendfile64 fs/read_write.c:1519 [inline]
__se_sys_sendfile64 fs/read_write.c:1511 [inline]
__x64_sys_sendfile64+0xbe/0x140 fs/read_write.c:1511
do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
entry_SYSCALL_64_after_hwframe+0x44/0xa9
write to 0xffff88812a222150 of 8 bytes by task 2499 on cpu 1:
blk_mq_sched_dispatch_requests+0x118/0x380 block/blk-mq-sched.c:181
__blk_mq_run_hw_queue+0xb7/0x160 block/blk-mq.c:1368
blk_mq_run_work_fn+0x57/0x70 block/blk-mq.c:1597
process_one_work+0x3d4/0x890 kernel/workqueue.c:2264
worker_thread+0xa0/0x800 kernel/workqueue.c:2410
kthread+0x1d4/0x200 drivers/block/aoe/aoecmd.c:1253
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:352
Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 2499 Comm: kworker/1:1H Not tainted 5.5.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Workqueue: kblockd blk_mq_run_work_fn
==================================================================
---
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