syzbot


KCSAN: data-race in do_iter_write / setattr_copy

Status: auto-closed as invalid on 2021/11/12 05:10
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 424d, last: 424d

Sample crash report:
==================================================================
BUG: KCSAN: data-race in do_iter_write / setattr_copy

write to 0xffff88813b93f358 of 2 bytes by task 10910 on cpu 0:
 setattr_copy+0x1af/0x1c0 fs/attr.c:247
 ext4_setattr+0x5ea/0xef0 fs/ext4/inode.c:5472
 notify_change+0x8a3/0xac0 fs/attr.c:410
 chmod_common+0x13c/0x270 fs/open.c:581
 do_fchmodat fs/open.c:620 [inline]
 __do_sys_chmod fs/open.c:638 [inline]
 __se_sys_chmod fs/open.c:636 [inline]
 __x64_sys_chmod+0x9b/0x120 fs/open.c:636
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88813b93f358 of 2 bytes by task 10893 on cpu 1:
 fsnotify_parent include/linux/fsnotify.h:65 [inline]
 fsnotify_file include/linux/fsnotify.h:99 [inline]
 fsnotify_modify include/linux/fsnotify.h:264 [inline]
 do_iter_write+0x227/0x5c0 fs/read_write.c:859
 vfs_iter_write+0x4c/0x70 fs/read_write.c:896
 iter_file_splice_write+0x43a/0x790 fs/splice.c:689
 do_splice_from fs/splice.c:767 [inline]
 direct_splice_actor+0x80/0xa0 fs/splice.c:936
 splice_direct_to_actor+0x345/0x650 fs/splice.c:891
 do_splice_direct+0x106/0x190 fs/splice.c:979
 do_sendfile+0x63e/0xbb0 fs/read_write.c:1249
 __do_sys_sendfile64 fs/read_write.c:1308 [inline]
 __se_sys_sendfile64 fs/read_write.c:1300 [inline]
 __x64_sys_sendfile64+0xb9/0x140 fs/read_write.c:1300
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x8000 -> 0x80a4

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 10893 Comm: syz-executor.5 Tainted: G        W         5.15.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-upstream-kcsan-gce 2021/10/08 05:02 upstream 4a16df549d23 efe0f24d .config log report info KCSAN: data-race in do_iter_write / setattr_copy
* Struck through repros no longer work on HEAD.