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KCSAN: data-race in __lookup_mnt / __se_sys_pivot_root (4)

Status: auto-obsoleted due to no activity on 2024/02/04 14:49
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+25ba88ea0d6efd892d0e@syzkaller.appspotmail.com
First crash: 146d, last: 146d
Similar bugs (4)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in __lookup_mnt / __se_sys_pivot_root (2) fs 1 632d 632d 0/26 auto-closed as invalid on 2022/10/06 11:23
upstream KCSAN: data-race in __lookup_mnt / __se_sys_pivot_root (3) fs 1 361d 361d 0/26 auto-obsoleted due to no activity on 2023/07/04 03:34
upstream KCSAN: data-race in __lookup_mnt / __se_sys_pivot_root (5) fs 1 76d 76d 0/26 auto-obsoleted due to no activity on 2024/04/14 19:06
upstream KCSAN: data-race in __lookup_mnt / __se_sys_pivot_root fs 1 888d 888d 0/26 auto-closed as invalid on 2022/01/23 16:01

Sample crash report:
==================================================================
BUG: KCSAN: data-race in __lookup_mnt / __se_sys_pivot_root

write to 0xffff8881409da650 of 8 bytes by task 7236 on cpu 1:
 unhash_mnt fs/namespace.c:905 [inline]
 umount_mnt fs/namespace.c:920 [inline]
 __do_sys_pivot_root fs/namespace.c:4235 [inline]
 __se_sys_pivot_root+0x642/0x1090 fs/namespace.c:4168
 __x64_sys_pivot_root+0x31/0x40 fs/namespace.c:4168
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffff8881409da650 of 8 bytes by task 7239 on cpu 0:
 __lookup_mnt+0x83/0xf0 fs/namespace.c:696
 __follow_mount_rcu fs/namei.c:1508 [inline]
 handle_mounts fs/namei.c:1538 [inline]
 step_into+0x430/0x800 fs/namei.c:1840
 walk_component+0x164/0x230 fs/namei.c:2008
 lookup_last fs/namei.c:2459 [inline]
 path_lookupat+0x10a/0x2a0 fs/namei.c:2483
 filename_lookup+0x126/0x300 fs/namei.c:2512
 user_path_at_empty+0x42/0x110 fs/namei.c:2911
 user_path_at include/linux/namei.h:57 [inline]
 do_mount fs/namespace.c:3674 [inline]
 __do_sys_mount fs/namespace.c:3886 [inline]
 __se_sys_mount+0x24b/0x2d0 fs/namespace.c:3863
 __x64_sys_mount+0x67/0x80 fs/namespace.c:3863
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0xffff888144a8fdc0 -> 0xffff888144a8fc80

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 7239 Comm: syz-executor.3 Not tainted 6.7.0-rc7-syzkaller-00049-g453f5db0619e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/12/31 14:48 upstream 453f5db0619e fb427a07 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __lookup_mnt / __se_sys_pivot_root
* Struck through repros no longer work on HEAD.