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KCSAN: data-race in fprop_new_period / fprop_reflect_period_percpu (11)

Status: moderation: reported on 2024/06/30 03:47
Subsystems: mm fs
[Documentation on labels]
Reported-by: syzbot+d775c6bb22ea9b8e2b9a@syzkaller.appspotmail.com
First crash: 19d, last: 19d
Similar bugs (10)
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 757d 836d 0/27 auto-closed as invalid on 2022/07/28 18:16
upstream KCSAN: data-race in fprop_new_period / fprop_reflect_period_percpu (2) fs mm 2 1339d 1320d 0/27 auto-closed as invalid on 2020/12/23 11:14
upstream KCSAN: data-race in fprop_new_period / fprop_reflect_period_percpu (5) fs mm 2 1084d 1085d 0/27 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 1261d 1293d 0/27 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 875d 875d 0/27 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 345d 427d 0/27 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 471d 671d 0/27 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 1408d 1408d 0/27 auto-closed as invalid on 2020/10/15 13:11
upstream KCSAN: data-race in fprop_new_period / fprop_reflect_period_percpu (4) mm fs 3 1148d 1216d 0/27 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 31 62d 222d 0/27 auto-obsoleted due to no activity on 2024/06/22 10:03

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

read-write to 0xffffffff8841e0e8 of 4 bytes by interrupt on cpu 1:
 fprop_new_period+0xaa/0xe0 lib/flex_proportions.c:79
 writeout_period+0x59/0xe0 mm/page-writeback.c:613
 call_timer_fn+0x3a/0x300 kernel/time/timer.c:1792
 expire_timers kernel/time/timer.c:1843 [inline]
 __run_timers kernel/time/timer.c:2417 [inline]
 __run_timer_base+0x417/0x640 kernel/time/timer.c:2428
 run_timer_base kernel/time/timer.c:2437 [inline]
 run_timer_softirq+0x45/0x70 kernel/time/timer.c:2448
 handle_softirqs+0xc3/0x280 kernel/softirq.c:554
 __do_softirq kernel/softirq.c:588 [inline]
 invoke_softirq kernel/softirq.c:428 [inline]
 __irq_exit_rcu kernel/softirq.c:637 [inline]
 irq_exit_rcu+0x3e/0x90 kernel/softirq.c:649
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline]
 sysvec_apic_timer_interrupt+0x73/0x80 arch/x86/kernel/apic/apic.c:1043
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
 kcsan_setup_watchpoint+0x404/0x410 kernel/kcsan/core.c:705
 mpage_prepare_extent_to_map+0x369/0xb80 fs/ext4/inode.c:2408
 ext4_do_writepages+0xa20/0x2110 fs/ext4/inode.c:2677
 ext4_writepages+0x159/0x2e0 fs/ext4/inode.c:2768
 do_writepages+0x1d8/0x480 mm/page-writeback.c:2634
 filemap_fdatawrite_wbc+0xdb/0x100 mm/filemap.c:397
 __filemap_fdatawrite_range mm/filemap.c:430 [inline]
 __filemap_fdatawrite mm/filemap.c:436 [inline]
 filemap_flush+0x61/0x90 mm/filemap.c:463
 ext4_alloc_da_blocks+0x50/0x130 fs/ext4/inode.c:3069
 ext4_release_file+0x5f/0x1c0 fs/ext4/file.c:169
 __fput+0x2c2/0x660 fs/file_table.c:422
 ____fput+0x15/0x20 fs/file_table.c:450
 task_work_run+0x13a/0x1a0 kernel/task_work.c:180
 exit_task_work include/linux/task_work.h:38 [inline]
 do_exit+0x5d5/0x1710 kernel/exit.c:874
 do_group_exit+0x102/0x150 kernel/exit.c:1023
 get_signal+0xf2f/0x1080 kernel/signal.c:2909
 arch_do_signal_or_restart+0x95/0x4b0 arch/x86/kernel/signal.c:310
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 irqentry_exit_to_user_mode+0x94/0x130 kernel/entry/common.c:231
 irqentry_exit+0x12/0x50 kernel/entry/common.c:334
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623

read to 0xffffffff8841e0e8 of 4 bytes by task 5591 on cpu 0:
 fprop_reflect_period_percpu+0x22/0x1a0 lib/flex_proportions.c:111
 __fprop_add_percpu lib/flex_proportions.c:142 [inline]
 __fprop_add_percpu_max+0x58/0x180 lib/flex_proportions.c:200
 wb_domain_writeout_add mm/page-writeback.c:560 [inline]
 __wb_writeout_add+0x77/0x1d0 mm/page-writeback.c:584
 __folio_end_writeback+0x215/0x4a0 mm/page-writeback.c:3042
 folio_end_writeback+0x74/0x1f0 mm/filemap.c:1632
 ext4_finish_bio+0x476/0x8e0 fs/ext4/page-io.c:144
 ext4_release_io_end+0x8c/0x1f0 fs/ext4/page-io.c:159
 ext4_end_io_end fs/ext4/page-io.c:193 [inline]
 ext4_do_flush_completed_IO fs/ext4/page-io.c:258 [inline]
 ext4_end_io_rsv_work+0x2d3/0x370 fs/ext4/page-io.c:272
 process_one_work kernel/workqueue.c:3248 [inline]
 process_scheduled_works+0x483/0x9a0 kernel/workqueue.c:3329
 worker_thread+0x526/0x720 kernel/workqueue.c:3409
 kthread+0x1d1/0x210 kernel/kthread.c:389
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

value changed: 0x00000025 -> 0x00000026

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 5591 Comm: kworker/u8:12 Tainted: G        W          6.10.0-rc5-syzkaller-00280-g27b31deb900d #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
Workqueue: ext4-rsv-conversion ext4_end_io_rsv_work
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/06/30 03:46 upstream 27b31deb900d 757f06b1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in fprop_new_period / fprop_reflect_period_percpu
* Struck through repros no longer work on HEAD.