syzbot


KCSAN: data-race in touch_atime / touch_atime (3)

Status: moderation: reported on 2024/05/27 01:15
Subsystems: ext4
[Documentation on labels]
Reported-by: syzbot+d339c673f459c1a220ea@syzkaller.appspotmail.com
First crash: 19d, last: 7d14h
Similar bugs (2)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in touch_atime / touch_atime (2) ext4 51 54d 135d 0/27 auto-obsoleted due to no activity on 2024/05/19 09:43
upstream KCSAN: data-race in touch_atime / touch_atime ext4 21 268d 290d 0/27 auto-obsoleted due to no activity on 2023/10/18 23:00

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

write to 0xffff888106861858 of 8 bytes by task 24819 on cpu 1:
 inode_set_atime_to_ts include/linux/fs.h:1557 [inline]
 inode_update_timestamps fs/inode.c:1878 [inline]
 generic_update_time fs/inode.c:1900 [inline]
 inode_update_time fs/inode.c:1920 [inline]
 touch_atime+0x1f3/0x350 fs/inode.c:1992
 file_accessed include/linux/fs.h:2458 [inline]
 splice_direct_to_actor+0x521/0x670 fs/splice.c:1126
 do_splice_direct_actor fs/splice.c:1207 [inline]
 do_splice_direct+0xd7/0x150 fs/splice.c:1233
 do_sendfile+0x3ab/0x960 fs/read_write.c:1295
 __do_sys_sendfile64 fs/read_write.c:1362 [inline]
 __se_sys_sendfile64 fs/read_write.c:1348 [inline]
 __x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1348
 x64_sys_call+0x2c9f/0x2d70 arch/x86/include/generated/asm/syscalls_64.h:41
 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 0xffff888106861858 of 8 bytes by task 24829 on cpu 0:
 inode_get_atime include/linux/fs.h:1551 [inline]
 inode_update_timestamps fs/inode.c:1875 [inline]
 generic_update_time fs/inode.c:1900 [inline]
 inode_update_time fs/inode.c:1920 [inline]
 touch_atime+0x1a0/0x350 fs/inode.c:1992
 file_accessed include/linux/fs.h:2458 [inline]
 filemap_splice_read+0x8b0/0x920 mm/filemap.c:2950
 ext4_file_splice_read+0x95/0xc0 fs/ext4/file.c:158
 do_splice_read fs/splice.c:985 [inline]
 splice_direct_to_actor+0x26c/0x670 fs/splice.c:1089
 do_splice_direct_actor fs/splice.c:1207 [inline]
 do_splice_direct+0xd7/0x150 fs/splice.c:1233
 do_sendfile+0x3ab/0x960 fs/read_write.c:1295
 __do_sys_sendfile64 fs/read_write.c:1362 [inline]
 __se_sys_sendfile64 fs/read_write.c:1348 [inline]
 __x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1348
 x64_sys_call+0x2c9f/0x2d70 arch/x86/include/generated/asm/syscalls_64.h:41
 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: 0x000000002e7dd9a6 -> 0x000000002f167026

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 24829 Comm: syz-executor.2 Tainted: G        W          6.10.0-rc2-syzkaller-00235-g8a92980606e3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
==================================================================

Crashes (6):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/06/07 14:03 upstream 8a92980606e3 121701b6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in touch_atime / touch_atime
2024/06/06 07:52 upstream 2df0193e62cf 121701b6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in touch_atime / touch_atime
2024/06/06 00:59 upstream 71d7b52cc33b 5aa1a7c9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in touch_atime / touch_atime
2024/06/01 07:57 upstream d8ec19857b09 3113787f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in touch_atime / touch_atime
2024/05/31 09:03 upstream 4a4be1ad3a6e 34889ee3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in touch_atime / touch_atime
2024/05/27 01:14 upstream 1613e604df0c a10a183e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in touch_atime / touch_atime
* Struck through repros no longer work on HEAD.