syzbot


KCSAN: data-race in blkdev_llseek / invalidate_disk

Status: auto-closed as invalid on 2022/03/05 01:23
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 311d, last: 311d

Sample crash report:
==================================================================
BUG: KCSAN: data-race in blkdev_llseek / invalidate_disk

write to 0xffff888101b934d8 of 8 bytes by task 20935 on cpu 0:
 i_size_write include/linux/fs.h:907 [inline]
 set_capacity block/genhd.c:62 [inline]
 invalidate_disk+0x86/0xb0 block/genhd.c:653
 __loop_clr_fd+0x3d1/0x5d0 drivers/block/loop.c:1142
 loop_rundown_workfn+0x3e/0xb0 drivers/block/loop.c:1185
 process_one_work+0x3f6/0x960 kernel/workqueue.c:2307
 worker_thread+0x616/0xa70 kernel/workqueue.c:2454
 kthread+0x1bf/0x1e0 kernel/kthread.c:377
 ret_from_fork+0x1f/0x30

read to 0xffff888101b934d8 of 8 bytes by task 18327 on cpu 1:
 i_size_read include/linux/fs.h:885 [inline]
 blkdev_llseek+0x4c/0x80 block/fops.c:454
 vfs_llseek fs/read_write.c:300 [inline]
 ksys_lseek fs/read_write.c:313 [inline]
 __do_sys_lseek fs/read_write.c:324 [inline]
 __se_sys_lseek fs/read_write.c:322 [inline]
 __x64_sys_lseek+0xf0/0x150 fs/read_write.c:322
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x0000000000011800 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 18327 Comm: udevd Not tainted 5.17.0-rc1-syzkaller-00316-gdf0001545b27-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================
Buffer I/O error on dev loop0, logical block 0, async page read
I/O error, dev loop1, sector 0 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
Buffer I/O error on dev loop1, logical block 0, async page read

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-upstream-kcsan-gce 2022/01/29 01:17 upstream df0001545b27 495e00c5 .config log report info KCSAN: data-race in blkdev_llseek / invalidate_disk
* Struck through repros no longer work on HEAD.