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KCSAN: data-race in fsnotify / fsnotify_free_mark

Status: auto-closed as invalid on 2020/04/12 12:50
Subsystems: fs
[Documentation on labels]
First crash: 1516d, last: 1516d

Sample crash report:
==================================================================
BUG: KCSAN: data-race in fsnotify / fsnotify_free_mark

read to 0xffff8881175eb8fc of 4 bytes by task 15468 on cpu 1:
 send_to_group fs/notify/fsnotify.c:205 [inline]
 fsnotify+0x3f7/0x7d0 fs/notify/fsnotify.c:368
 __fsnotify_parent+0x1d6/0x230 fs/notify/fsnotify.c:168
 fsnotify_parent include/linux/fsnotify.h:40 [inline]
 fsnotify_path include/linux/fsnotify.h:50 [inline]
 fsnotify_modify include/linux/fsnotify.h:256 [inline]
 do_iter_write fs/read_write.c:974 [inline]
 do_iter_write+0x1e7/0x3c0 fs/read_write.c:951
 vfs_iter_write+0x5c/0x80 fs/read_write.c:983
 iter_file_splice_write+0x530/0x840 fs/splice.c:760
 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 0xffff8881175eb8fc of 4 bytes by task 15459 on cpu 0:
 fsnotify_free_mark+0x76/0xe0 fs/notify/mark.c:414
 fsnotify_clear_marks_by_group+0x2a9/0x320 fs/notify/mark.c:759
 fsnotify_destroy_group+0x66/0x190 fs/notify/group.c:60
 fanotify_release+0x212/0x240 fs/notify/fanotify/fanotify_user.c:488
 __fput+0x1e1/0x520 fs/file_table.c:280
 ____fput+0x1f/0x30 fs/file_table.c:313
 task_work_run+0xf6/0x130 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop+0x2b4/0x2c0 arch/x86/entry/common.c:164
 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:278 [inline]
 do_syscall_64+0x384/0x3a0 arch/x86/entry/common.c:304
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 15459 Comm: syz-executor.1 Not tainted 5.5.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/02/02 12:45 https://github.com/google/ktsan.git kcsan 245a43005292 93e5e335 .config console log report ci2-upstream-kcsan-gce
* Struck through repros no longer work on HEAD.