KCSAN: data-race in hrtimer_interrupt / print

KCSAN: data-race in hrtimer_interrupt / print_cpu (2)
Status: auto-closed as invalid on 2020/11/19 01:50
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 485d, last: 370d

similar bugs (2):
Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in hrtimer_interrupt / print_cpu (3)				13	241d	311d	0/22	auto-closed as invalid on 2021/03/28 05:11
upstream	KCSAN: data-race in hrtimer_interrupt / print_cpu				18	498d	644d	0/22	closed as invalid on 2020/06/18 14:24

Sample crash report:

==================================================================
BUG: KCSAN: data-race in hrtimer_interrupt / print_cpu

write to 0xffff88812c11ec20 of 8 bytes by interrupt on cpu 1:
 hrtimer_interrupt+0x1fa/0xa40 kernel/time/hrtimer.c:1642
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1080 [inline]
 __sysvec_apic_timer_interrupt+0xa3/0x240 arch/x86/kernel/apic/apic.c:1097
 asm_call_irq_on_stack+0xf/0x20
 __run_sysvec_on_irqstack arch/x86/include/asm/irq_stack.h:37 [inline]
 run_sysvec_on_irqstack_cond arch/x86/include/asm/irq_stack.h:89 [inline]
 sysvec_apic_timer_interrupt+0x80/0xd0 arch/x86/kernel/apic/apic.c:1091
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:631
 format_decode+0xff/0x8a0 lib/vsprintf.c:2353
 vsnprintf+0xcd/0xed0 lib/vsprintf.c:2570
 seq_vprintf+0x71/0xd0 fs/seq_file.c:379
 SEQ_printf+0x76/0xb0 kernel/time/timer_list.c:38
 print_timer kernel/time/timer_list.c:63 [inline]
 print_active_timers kernel/time/timer_list.c:104 [inline]
 print_base kernel/time/timer_list.c:127 [inline]
 print_cpu+0x218/0x7f0 kernel/time/timer_list.c:138
 timer_list_show+0x114/0x180 kernel/time/timer_list.c:311
 seq_read+0x2ee/0x900 fs/seq_file.c:208
 pde_read fs/proc/inode.c:306 [inline]
 proc_reg_read+0x116/0x1a0 fs/proc/inode.c:318
 do_loop_readv_writev fs/read_write.c:742 [inline]
 do_iter_read+0x2df/0x4b0 fs/read_write.c:784
 vfs_readv+0xa0/0xe0 fs/read_write.c:902
 kernel_readv fs/splice.c:354 [inline]
 default_file_splice_read+0x3b7/0x640 fs/splice.c:411
 do_splice_to fs/splice.c:890 [inline]
 splice_direct_to_actor+0x2c7/0x660 fs/splice.c:969
 do_splice_direct+0xf2/0x170 fs/splice.c:1078
 do_sendfile+0x56a/0xba0 fs/read_write.c:1238
 __do_sys_sendfile64 fs/read_write.c:1299 [inline]
 __se_sys_sendfile64 fs/read_write.c:1285 [inline]
 __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1285
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88812c11ec20 of 8 bytes by task 23452 on cpu 0:
 print_cpu+0x479/0x7f0 kernel/time/timer_list.c:148
 timer_list_show+0x114/0x180 kernel/time/timer_list.c:311
 seq_read+0x2ee/0x900 fs/seq_file.c:208
 pde_read fs/proc/inode.c:306 [inline]
 proc_reg_read+0x116/0x1a0 fs/proc/inode.c:318
 do_loop_readv_writev fs/read_write.c:742 [inline]
 do_iter_read+0x3d2/0x4b0 fs/read_write.c:784
 vfs_readv+0xa0/0xe0 fs/read_write.c:902
 kernel_readv fs/splice.c:354 [inline]
 default_file_splice_read+0x3b7/0x640 fs/splice.c:411
 do_splice_to fs/splice.c:890 [inline]
 splice_direct_to_actor+0x2c7/0x660 fs/splice.c:969
 do_splice_direct+0xf2/0x170 fs/splice.c:1078
 do_sendfile+0x56a/0xba0 fs/read_write.c:1238
 __do_sys_sendfile64 fs/read_write.c:1299 [inline]
 __se_sys_sendfile64 fs/read_write.c:1285 [inline]
 __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1285
 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: 0 PID: 23452 Comm: syz-executor.2 Not tainted 5.9.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (7):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	VM info
ci2-upstream-kcsan-gce	2020/10/15 01:41	upstream	3e4fb4346c78	fc7735a2	.config	log	report	info
ci2-upstream-kcsan-gce	2020/10/11 21:49	upstream	3dd0130f2430	4a77ae0b	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/11 02:32	upstream	581cb3a26baf	ac7ca78e	.config	log	report
ci2-upstream-kcsan-gce	2020/08/25 20:11	upstream	abb3438d69fb	344da168	.config	log	report
ci2-upstream-kcsan-gce	2020/07/25 18:36	upstream	23ee3e4e5bd2	1f7cc1ca	.config	log	report
ci2-upstream-kcsan-gce	2020/07/06 14:40	upstream	dcb7fd82c75e	ac5a135b	.config	log	report
ci2-upstream-kcsan-gce	2020/06/22 02:42	upstream	64677779e896	4f2acff9	.config	log	report