syzbot


upstream test error: KCSAN: data-race in fill_mg_cmtime / shmem_unlink

Status: moderation: reported on 2024/11/26 10:56
Subsystems: mm
[Documentation on labels]
Reported-by: syzbot+f955a9fb207e527f2313@syzkaller.appspotmail.com
First crash: 12h37m, last: 12h37m

Sample crash report:
==================================================================
BUG: KCSAN: data-race in fill_mg_cmtime / shmem_unlink

write to 0xffff888104d4cc94 of 4 bytes by task 3933 on cpu 0:
 inode_set_mtime_to_ts include/linux/fs.h:1648 [inline]
 shmem_unlink+0x13b/0x170 mm/shmem.c:3803
 vfs_unlink+0x275/0x430 fs/namei.c:4523
 do_unlinkat+0x237/0x4d0 fs/namei.c:4587
 __do_sys_unlink fs/namei.c:4635 [inline]
 __se_sys_unlink fs/namei.c:4633 [inline]
 __x64_sys_unlink+0x2e/0x40 fs/namei.c:4633
 x64_sys_call+0x2329/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:88
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888104d4cc94 of 4 bytes by task 3934 on cpu 1:
 inode_get_mtime_nsec include/linux/fs.h:1634 [inline]
 inode_get_mtime include/linux/fs.h:1640 [inline]
 fill_mg_cmtime+0x58/0x280 fs/stat.c:55
 generic_fillattr+0x241/0x330 fs/stat.c:99
 shmem_getattr+0x17b/0x200 mm/shmem.c:1177
 vfs_getattr_nosec fs/stat.c:208 [inline]
 vfs_getattr fs/stat.c:246 [inline]
 vfs_statx_path+0x171/0x2d0 fs/stat.c:283
 vfs_statx+0xe1/0x170 fs/stat.c:347
 vfs_fstatat fs/stat.c:366 [inline]
 __do_sys_newfstatat fs/stat.c:530 [inline]
 __se_sys_newfstatat+0xdc/0x300 fs/stat.c:524
 __x64_sys_newfstatat+0x55/0x70 fs/stat.c:524
 x64_sys_call+0x236d/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:263
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x1be6e1bb -> 0x1bf9ab0c

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3934 Comm: udevd Not tainted 6.12.0-syzkaller-09567-g7eef7e306d3c #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/11/26 10:55 upstream 7eef7e306d3c e9a9a9f2 .config console log report [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce upstream test error: KCSAN: data-race in fill_mg_cmtime / shmem_unlink
* Struck through repros no longer work on HEAD.