syzbot


KCSAN: data-race in fprop_new_period / fprop_reflect_period_percpu (2)

Status: auto-closed as invalid on 2020/12/23 11:14
Subsystems: fs mm
[Documentation on labels]
Reported-by: syzbot+7a110c0628ede1f0e1b0@syzkaller.appspotmail.com
First crash: 1194d, last: 1193d
Similar bugs (9)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in fprop_new_period / fprop_reflect_period_percpu (7) fs mm 5 610d 690d 0/26 auto-closed as invalid on 2022/07/28 18:16
upstream KCSAN: data-race in fprop_new_period / fprop_reflect_period_percpu (5) fs mm 2 938d 939d 0/26 auto-closed as invalid on 2021/09/04 07:15
upstream KCSAN: data-race in fprop_new_period / fprop_reflect_period_percpu (3) fs mm 2 1115d 1147d 0/26 auto-closed as invalid on 2021/03/11 15:36
upstream KCSAN: data-race in fprop_new_period / fprop_reflect_period_percpu (6) fs mm 1 729d 729d 0/26 auto-closed as invalid on 2022/04/01 06:25
upstream KCSAN: data-race in fprop_new_period / fprop_reflect_period_percpu (9) fs mm 8 199d 281d 0/26 auto-obsoleted due to no activity on 2023/09/13 06:09
upstream KCSAN: data-race in fprop_new_period / fprop_reflect_period_percpu (8) fs mm 20 325d 525d 0/26 auto-obsoleted due to no activity on 2023/05/10 03:18
upstream KCSAN: data-race in fprop_new_period / fprop_reflect_period_percpu fs mm 1 1262d 1262d 0/26 auto-closed as invalid on 2020/10/15 13:11
upstream KCSAN: data-race in fprop_new_period / fprop_reflect_period_percpu (4) fs mm 3 1002d 1070d 0/26 auto-closed as invalid on 2021/07/02 00:21
upstream KCSAN: data-race in fprop_new_period / fprop_reflect_period_percpu (10) fs mm 26 12d 76d 0/26 moderation: reported on 2023/12/10 00:01

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

read-write to 0xffffffff8830b820 of 4 bytes by interrupt on cpu 0:
 fprop_new_period+0xd7/0x130 lib/flex_proportions.c:83
 writeout_period+0x55/0xe0 mm/page-writeback.c:628
 call_timer_fn+0x2e/0x240 kernel/time/timer.c:1410
 expire_timers+0x116/0x260 kernel/time/timer.c:1455
 __run_timers+0x338/0x3d0 kernel/time/timer.c:1747
 run_timer_softirq+0x2d/0x30 kernel/time/timer.c:1762
 __do_softirq+0x12c/0x2b1 kernel/softirq.c:298
 run_ksoftirqd+0x13/0x20 kernel/softirq.c:653
 smpboot_thread_fn+0x34f/0x520 kernel/smpboot.c:165
 kthread+0x1fa/0x220 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

read to 0xffffffff8830b820 of 4 bytes by task 8 on cpu 1:
 fprop_reflect_period_percpu+0x22/0x1a0 lib/flex_proportions.c:192
 __fprop_inc_percpu+0x1a/0x80 lib/flex_proportions.c:222
 __fprop_inc_percpu_max+0x3f/0x190 lib/flex_proportions.c:271
 wb_domain_writeout_inc mm/page-writeback.c:575 [inline]
 __wb_writeout_inc+0x54/0x1a0 mm/page-writeback.c:599
 test_clear_page_writeback+0x2fa/0x450 mm/page-writeback.c:2745
 end_page_writeback+0xa7/0x110 mm/filemap.c:1487
 ext4_finish_bio+0x429/0x490 fs/ext4/page-io.c:146
 ext4_release_io_end+0x98/0x200 fs/ext4/page-io.c:161
 ext4_end_io_end fs/ext4/page-io.c:195 [inline]
 ext4_do_flush_completed_IO fs/ext4/page-io.c:260 [inline]
 ext4_end_io_rsv_work+0x306/0x360 fs/ext4/page-io.c:274
 process_one_work+0x3e1/0x950 kernel/workqueue.c:2272
 worker_thread+0x635/0xb90 kernel/workqueue.c:2418
 kthread+0x1fa/0x220 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 8 Comm: kworker/u4:0 Not tainted 5.10.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: ext4-rsv-conversion ext4_end_io_rsv_work
==================================================================

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/11/18 11:13 upstream 0fa8ee0d9ab9 09323409 .config console log report info ci2-upstream-kcsan-gce
2020/11/17 09:37 upstream 9c87c9f41245 bd2a760b .config console log report info ci2-upstream-kcsan-gce
* Struck through repros no longer work on HEAD.