syzbot


KCSAN: data-race in atime_needs_update / file_remove_privs (4)

Status: auto-closed as invalid on 2021/06/05 14:49
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 472d, last: 472d
similar bugs (3):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in atime_needs_update / file_remove_privs (2) 1 695d 695d 0/23 auto-closed as invalid on 2020/10/25 20:28
upstream KCSAN: data-race in atime_needs_update / file_remove_privs 3 742d 764d 0/23 auto-closed as invalid on 2020/09/07 22:38
upstream KCSAN: data-race in atime_needs_update / file_remove_privs (3) 1 569d 569d 0/23 auto-closed as invalid on 2021/02/28 05:27

Sample crash report:
==================================================================
BUG: KCSAN: data-race in atime_needs_update / file_remove_privs

write to 0xffff888105e432cc of 4 bytes by task 32734 on cpu 1:
 inode_has_no_xattr include/linux/fs.h:3655 [inline]
 file_remove_privs+0x312/0x3a0 fs/inode.c:1947
 file_modified+0x16/0x80 fs/inode.c:2010
 ext4_dio_write_checks fs/ext4/file.c:458 [inline]
 ext4_dio_write_iter fs/ext4/file.c:522 [inline]
 ext4_file_write_iter+0x744/0x11d0 fs/ext4/file.c:678
 call_write_iter include/linux/fs.h:2116 [inline]
 new_sync_write fs/read_write.c:518 [inline]
 vfs_write+0x69d/0x770 fs/read_write.c:605
 ksys_write+0xce/0x180 fs/read_write.c:658
 __do_sys_write fs/read_write.c:670 [inline]
 __se_sys_write fs/read_write.c:667 [inline]
 __x64_sys_write+0x3e/0x50 fs/read_write.c:667
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888105e432cc of 4 bytes by task 32736 on cpu 0:
 atime_needs_update+0x29/0x390 fs/inode.c:1795
 touch_atime+0x54/0x240 fs/inode.c:1831
 file_accessed include/linux/fs.h:2458 [inline]
 splice_direct_to_actor+0x562/0x650 fs/splice.c:909
 do_splice_direct+0xf5/0x170 fs/splice.c:979
 do_sendfile+0x773/0xda0 fs/read_write.c:1260
 __do_sys_sendfile64 fs/read_write.c:1325 [inline]
 __se_sys_sendfile64 fs/read_write.c:1311 [inline]
 __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1311
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 32736 Comm: syz-executor.0 Not tainted 5.12.0-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 2021/05/01 14:47 upstream 9f67672a817e 77e2b668 .config log report info KCSAN: data-race in atime_needs_update / file_remove_privs