syzbot


KCSAN: data-race in __wb_update_bandwidth / percpu_counter_add_batch (3)

Status: auto-closed as invalid on 2021/01/24 22:24
Subsystems: fs mm
[Documentation on labels]
Reported-by: syzbot+746aebd96e20369a6166@syzkaller.appspotmail.com
First crash: 1233d, last: 1193d
Similar bugs (6)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in __wb_update_bandwidth / percpu_counter_add_batch (7) fs mm 272 6h53m 111d 0/26 moderation: reported on 2023/12/07 10:04
upstream KCSAN: data-race in __wb_update_bandwidth / percpu_counter_add_batch (5) fs mm 3 970d 1004d 0/26 auto-closed as invalid on 2021/09/04 14:56
upstream KCSAN: data-race in __wb_update_bandwidth / percpu_counter_add_batch (4) fs mm 6 1049d 1147d 0/26 auto-closed as invalid on 2021/06/18 08:34
upstream KCSAN: data-race in __wb_update_bandwidth / percpu_counter_add_batch (6) fs mm 17 855d 931d 0/26 auto-closed as invalid on 2021/12/29 06:33
upstream KCSAN: data-race in __wb_update_bandwidth / percpu_counter_add_batch (2) fs mm 3 1270d 1309d 0/26 auto-closed as invalid on 2020/11/08 10:33
upstream KCSAN: data-race in __wb_update_bandwidth / percpu_counter_add_batch fs mm 9 1412d 1571d 0/26 closed as invalid on 2020/06/18 14:24

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

read-write to 0xffff888102693540 of 8 bytes by task 195 on cpu 0:
 percpu_counter_add_batch+0x9b/0x100 lib/percpu_counter.c:91
 __add_wb_stat include/linux/backing-dev.h:70 [inline]
 inc_wb_stat include/linux/backing-dev.h:75 [inline]
 __wb_writeout_inc+0x4e/0x1c0 mm/page-writeback.c:598
 test_clear_page_writeback+0x3a4/0x520 mm/page-writeback.c:2745
 end_page_writeback+0xd7/0x260 mm/filemap.c:1494
 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:2275
 worker_thread+0x635/0xb90 kernel/workqueue.c:2421
 kthread+0x1fd/0x220 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

read to 0xffff888102693540 of 8 bytes by task 8 on cpu 1:
 percpu_counter_read include/linux/percpu_counter.h:72 [inline]
 __wb_update_bandwidth+0xa7/0x5c0 mm/page-writeback.c:1359
 wb_update_bandwidth+0x59/0x80 mm/page-writeback.c:1393
 wb_writeback+0x2a3/0x660 fs/fs-writeback.c:1899
 wb_do_writeback+0x101/0x5d0 fs/fs-writeback.c:2039
 wb_workfn+0xb8/0x410 fs/fs-writeback.c:2080
 process_one_work+0x3e1/0x950 kernel/workqueue.c:2275
 worker_thread+0x635/0xb90 kernel/workqueue.c:2421
 kthread+0x1fd/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-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: writeback wb_workfn (flush-8:0)
==================================================================

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/12/20 22:24 upstream 6a447b0e3151 04201c06 .config console log report info ci2-upstream-kcsan-gce
2020/11/11 08:27 upstream eccc87672492 cca87986 .config console log report info ci2-upstream-kcsan-gce
* Struck through repros no longer work on HEAD.