KCSAN: data-race in rq_depth_scale_up / wbt_inflight

KCSAN: data-race in rq_depth_scale_up / wbt_inflight_cb (2)
Status: moderation: reported on 2020/12/07 12:02
Reported-by: syzbot+7017e2e7267e5dd9ddd0@syzkaller.appspotmail.com
First crash: 67d, last: 3d01h

similar bugs (1):
Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in rq_depth_scale_up / wbt_inflight_cb				3	175d	219d	0/17	auto-closed as invalid on 2020/09/06 13:38

Sample crash report:

==================================================================
BUG: KCSAN: data-race in rq_depth_scale_up / wbt_inflight_cb

write to 0xffff8881028025e0 of 4 bytes by interrupt on cpu 0:
 rq_depth_calc_max_depth block/blk-rq-qos.c:157 [inline]
 rq_depth_scale_up+0x156/0x180 block/blk-rq-qos.c:174
 scale_up block/blk-wbt.c:311 [inline]
 wb_timer_fn+0x155/0xa00 block/blk-wbt.c:382
 blk_stat_timer_fn+0x3f4/0x410 block/blk-stat.c:99
 call_timer_fn+0x2e/0x240 kernel/time/timer.c:1417
 expire_timers+0x116/0x260 kernel/time/timer.c:1462
 __run_timers+0x338/0x3d0 kernel/time/timer.c:1731
 run_timer_softirq+0x19/0x30 kernel/time/timer.c:1744
 __do_softirq+0x13c/0x2c3 kernel/softirq.c:343
 asm_call_irq_on_stack+0xf/0x20
 __run_on_irqstack arch/x86/include/asm/irq_stack.h:26 [inline]
 run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:77 [inline]
 do_softirq_own_stack+0x32/0x40 arch/x86/kernel/irq_64.c:77
 invoke_softirq kernel/softirq.c:226 [inline]
 __irq_exit_rcu+0xb4/0xc0 kernel/softirq.c:420
 sysvec_apic_timer_interrupt+0x74/0x90 arch/x86/kernel/apic/apic.c:1096
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:628
 is_atomic kernel/kcsan/core.c:249 [inline]
 should_watch kernel/kcsan/core.c:262 [inline]
 check_access kernel/kcsan/core.c:631 [inline]
 __tsan_read1+0x134/0x180 kernel/kcsan/core.c:839
 tomoyo_check_acl+0x6a/0x200 security/tomoyo/domain.c:173
 tomoyo_path_permission security/tomoyo/file.c:586 [inline]
 tomoyo_path_perm+0x22f/0x330 security/tomoyo/file.c:838
 tomoyo_inode_getattr+0x18/0x20 security/tomoyo/tomoyo.c:123
 security_inode_getattr+0x7f/0xd0 security/security.c:1280
 vfs_getattr fs/stat.c:121 [inline]
 vfs_statx+0xf8/0x270 fs/stat.c:189
 vfs_fstatat fs/stat.c:207 [inline]
 vfs_lstat include/linux/fs.h:3122 [inline]
 __do_sys_newlstat fs/stat.c:362 [inline]
 __se_sys_newlstat+0x46/0x250 fs/stat.c:356
 __x64_sys_newlstat+0x2d/0x40 fs/stat.c:356
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8881028025e0 of 4 bytes by task 24387 on cpu 1:
 get_limit block/blk-wbt.c:473 [inline]
 wbt_inflight_cb+0xc6/0x220 block/blk-wbt.c:495
 rq_qos_wait+0xac/0x210 block/blk-rq-qos.c:266
 __wbt_wait block/blk-wbt.c:518 [inline]
 wbt_wait+0x1bb/0x2b0 block/blk-wbt.c:583
 __rq_qos_throttle+0x39/0x70 block/blk-rq-qos.c:72
 rq_qos_throttle block/blk-rq-qos.h:182 [inline]
 blk_mq_submit_bio+0x229/0x1000 block/blk-mq.c:2158
 __submit_bio_noacct_mq block/blk-core.c:1028 [inline]
 submit_bio_noacct+0x75d/0x910 block/blk-core.c:1061
 submit_bio+0x1f3/0x350 block/blk-core.c:1131
 submit_bh_wbc+0x392/0x3d0 fs/buffer.c:3054
 submit_bh fs/buffer.c:3060 [inline]
 __sync_dirty_buffer+0x12c/0x1d0 fs/buffer.c:3155
 sync_dirty_buffer+0x16/0x20 fs/buffer.c:3168
 __fat_write_inode+0x492/0x4d0 fs/fat/inode.c:898
 fat_write_inode+0xb9/0xd0 fs/fat/inode.c:914
 write_inode+0x8c/0x1f0 fs/fs-writeback.c:1320
 __writeback_single_inode+0x2a7/0x500 fs/fs-writeback.c:1518
 writeback_single_inode+0x126/0x580 fs/fs-writeback.c:1572
 sync_inode fs/fs-writeback.c:2604 [inline]
 sync_inode_metadata+0x52/0x70 fs/fs-writeback.c:2624
 __generic_file_fsync+0xf5/0x140 fs/libfs.c:1087
 fat_file_fsync+0x48/0x100 fs/fat/file.c:190
 vfs_fsync_range+0x107/0x120 fs/sync.c:200
 generic_write_sync include/linux/fs.h:2737 [inline]
 generic_file_write_iter+0x103/0x130 mm/filemap.c:3573
 call_write_iter include/linux/fs.h:1901 [inline]
 do_iter_readv_writev+0x2cb/0x360 fs/read_write.c:740
 do_iter_write+0x112/0x4b0 fs/read_write.c:866
 vfs_iter_write+0x4c/0x70 fs/read_write.c:907
 iter_file_splice_write+0x42a/0x780 fs/splice.c:686
 do_splice_from fs/splice.c:764 [inline]
 direct_splice_actor+0x80/0xa0 fs/splice.c:933
 splice_direct_to_actor+0x345/0x650 fs/splice.c:888
 do_splice_direct+0xf5/0x170 fs/splice.c:976
 do_sendfile+0x5db/0xca0 fs/read_write.c:1257
 __do_sys_sendfile64 fs/read_write.c:1318 [inline]
 __se_sys_sendfile64 fs/read_write.c:1304 [inline]
 __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1304
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 24387 Comm: syz-executor.5 Not tainted 5.11.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (3):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	VM info	Maintainers
ci2-upstream-kcsan-gce	2021/01/22 05:00	upstream	83d09ad4	d4f4eca5	.config	log	report	info	axboe@kernel.dk, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2020/12/19 05:15	upstream	3644e2d2	04201c06	.config	log	report	info	axboe@kernel.dk, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2020/11/18 23:10	upstream	c2e7554e	0767f13f	.config	log	report	info	axboe@kernel.dk, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org