syzbot


KCSAN: data-race in atime_needs_update / ext4_rename2

Status: auto-closed as invalid on 2021/12/17 13:06
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 381d, last: 381d

Sample crash report:
==================================================================
BUG: KCSAN: data-race in atime_needs_update / ext4_rename2

write to 0xffff88812bdc9bb0 of 8 bytes by task 5031 on cpu 0:
 ext4_cross_rename fs/ext4/namei.c:4044 [inline]
 ext4_rename2+0x1c00/0x2900 fs/ext4/namei.c:4096
 vfs_rename+0x9d9/0xe00 fs/namei.c:4626
 do_renameat2+0x6d7/0xa20 fs/namei.c:4777
 __do_sys_renameat2 fs/namei.c:4810 [inline]
 __se_sys_renameat2 fs/namei.c:4807 [inline]
 __x64_sys_renameat2+0x82/0x90 fs/namei.c:4807
 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

read to 0xffff88812bdc9bb0 of 8 bytes by task 5027 on cpu 1:
 timespec64_compare include/linux/time64.h:56 [inline]
 relatime_need_update fs/inode.c:1748 [inline]
 atime_needs_update+0x27c/0x390 fs/inode.c:1836
 touch_atime+0x63/0x2e0 fs/inode.c:1851
 pick_link fs/namei.c:1746 [inline]
 step_into+0x859/0xee0 fs/namei.c:1826
 walk_component+0x1a1/0x360 fs/namei.c:1976
 link_path_walk+0x56b/0x930
 path_parentat fs/namei.c:2496 [inline]
 filename_parentat+0x123/0x480 fs/namei.c:2519
 filename_create+0x72/0x270 fs/namei.c:3637
 do_symlinkat+0x70/0x380 fs/namei.c:4267
 __do_sys_symlinkat fs/namei.c:4294 [inline]
 __se_sys_symlinkat fs/namei.c:4291 [inline]
 __x64_sys_symlinkat+0x5e/0x70 fs/namei.c:4291
 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: 0x00000000618e66cb -> 0x00000000618e66cc

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 5027 Comm: syz-executor.0 Not tainted 5.15.0-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 2021/11/12 13:06 upstream 5833291ab6de 75b04091 .config log report info KCSAN: data-race in atime_needs_update / ext4_rename2
* Struck through repros no longer work on HEAD.