INFO: rcu detected stall in sys

INFO: rcu detected stall in sys_sendfile64 (2)
Status: upstream: reported C repro on 2019/01/19 11:32
Reported-by: syzbot+1505c80c74256c6118a5@syzkaller.appspotmail.com
First crash: 861d, last: 331d

Cause bisection: introduced by (bisect log) :
commit 34e07e42c55aeaa78e93b057a6664e2ecde3fadb
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date: Thu Feb 8 10:54:48 2018 +0000

drm/i915: Add missing kerneldoc for 'ent' in i915_driver_init_early

Crash: INFO: rcu detected stall in do_iter_write (log)
Repro: C syz .config

Fix bisection: failed (bisect log)

similar bugs (3):
Kernel	Title	Repro	Count	Last	Reported	Patched	Status
upstream	INFO: rcu detected stall in sys_sendfile64	C	4	873d	873d	0/22	closed as invalid on 2018/12/19 10:12
linux-4.19	INFO: rcu detected stall in sys_sendfile64 (2)		3	418d	470d	0/1	auto-closed as invalid on 2020/07/16 06:45
linux-4.19	INFO: rcu detected stall in sys_sendfile64		1	752d	752d	0/1	auto-closed as invalid on 2019/10/16 04:09

Sample crash report:

hrtimer: interrupt took 41724 ns
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
	(detected by 0, t=10502 jiffies, g=9509, q=0)
rcu: All QSes seen, last rcu_preempt kthread activity 10503 (4295059083-4295048580), jiffies_till_next_fqs=1, root ->qsmask 0x0
syz-executor914 R  running task    25720  9581   9578 0x00004000
Call Trace:
 <IRQ>
 sched_show_task kernel/sched/core.c:5954 [inline]
 sched_show_task.cold+0x2ee/0x35d kernel/sched/core.c:5929
 print_other_cpu_stall kernel/rcu/tree_stall.h:410 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:538 [inline]
 rcu_pending kernel/rcu/tree.c:2827 [inline]
 rcu_sched_clock_irq.cold+0xaf4/0xc0d kernel/rcu/tree.c:2271
 update_process_times+0x2d/0x70 kernel/time/timer.c:1726
 tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:171
 tick_sched_timer+0x53/0x140 kernel/time/tick-sched.c:1314
 __run_hrtimer kernel/time/hrtimer.c:1517 [inline]
 __hrtimer_run_queues+0x364/0xe40 kernel/time/hrtimer.c:1579
 hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1641
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1110 [inline]
 smp_apic_timer_interrupt+0x160/0x610 arch/x86/kernel/apic/apic.c:1135
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829
 </IRQ>
RIP: 0010:unwind_next_frame.part.0+0x0/0xa20 arch/x86/kernel/unwind_frame.c:260
Code: 00 00 48 8b 45 d0 65 48 33 04 25 28 00 00 00 75 12 48 81 c4 e0 00 00 00 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 02 77 12 00 66 90 <55> 4c 8d 4f 58 48 b8 00 00 00 00 00 fc ff df 48 89 e5 41 57 41 56
RSP: 0018:ffffc900020d74f0 EFLAGS: 00000202 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000000 RBX: ffffffff8163c730 RCX: ffffffff8163c852
RDX: 0000000000000001 RSI: ffffffff8163c85e RDI: ffffc900020d7510
RBP: ffffc900020d7500 R08: ffff888097218040 R09: ffffc900020d7568
R10: ffffc900020d7538 R11: ffffc900020d7548 R12: ffffc900020d75c8
R13: 0000000000000000 R14: ffff888097218040 R15: ffff8880aa4008c0
 arch_stack_walk+0x81/0xf0 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0xac/0xe0 kernel/stacktrace.c:123
 save_stack+0x23/0x90 mm/kasan/common.c:72
 set_track mm/kasan/common.c:80 [inline]
 __kasan_kmalloc mm/kasan/common.c:513 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:486
 kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:521
 slab_post_alloc_hook mm/slab.h:584 [inline]
 slab_alloc mm/slab.c:3320 [inline]
 __do_kmalloc mm/slab.c:3654 [inline]
 __kmalloc+0x14c/0x770 mm/slab.c:3665
 kmalloc_array include/linux/slab.h:598 [inline]
 kcalloc include/linux/slab.h:609 [inline]
 iter_file_splice_write+0x16e/0xc10 fs/splice.c:702
 do_splice_from fs/splice.c:863 [inline]
 direct_splice_actor+0x123/0x190 fs/splice.c:1037
 splice_direct_to_actor+0x3b4/0xa30 fs/splice.c:992
 do_splice_direct+0x1da/0x2a0 fs/splice.c:1080
 do_sendfile+0x597/0xd00 fs/read_write.c:1464
 __do_sys_sendfile64 fs/read_write.c:1525 [inline]
 __se_sys_sendfile64 fs/read_write.c:1511 [inline]
 __x64_sys_sendfile64+0x1dd/0x220 fs/read_write.c:1511
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x441a09
Code: e8 7c e7 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 bb 07 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffc00736e88 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007ffc00737030 RCX: 0000000000441a09
RDX: 0000000000000000 RSI: 0000000000000005 RDI: 0000000000000004
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 00008000fffffffe R11: 0000000000000246 R12: 0000000000000000
R13: 00000000004026e0 R14: 0000000000000000 R15: 0000000000000000
rcu: rcu_preempt kthread starved for 10562 jiffies! g9509 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: RCU grace-period kthread stack dump:
rcu_preempt     R  running task    29264    10      2 0x80004000
Call Trace:
 context_switch kernel/sched/core.c:3385 [inline]
 __schedule+0x934/0x1f90 kernel/sched/core.c:4081
 schedule+0xdc/0x2b0 kernel/sched/core.c:4155
 schedule_timeout+0x486/0xc50 kernel/time/timer.c:1895
 rcu_gp_fqs_loop kernel/rcu/tree.c:1661 [inline]
 rcu_gp_kthread+0x9b2/0x18d0 kernel/rcu/tree.c:1821
 kthread+0x361/0x430 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Crashes (93):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro
ci-upstream-kasan-gce-root	2020/01/24 19:12	upstream	4703d911	2e95ab33	.config	log	report	syz	C
ci-upstream-kasan-gce-root	2019/06/06 12:31	upstream	156c0591	a547defc	.config	log	report	syz	C
ci-upstream-kasan-gce-selinux-root	2019/05/03 14:43	upstream	ea986679	1bfa09b9	.config	log	report	syz	C
ci-upstream-kasan-gce-selinux-root	2019/04/23 07:48	upstream	085b7755	53199d6e	.config	log	report	syz	C
ci-upstream-kasan-gce-smack-root	2019/04/23 07:46	upstream	085b7755	53199d6e	.config	log	report	syz	C
ci-upstream-kasan-gce-root	2019/02/19 13:36	upstream	b5372fe5	59f36113	.config	log	report	syz	C
ci-upstream-kasan-gce-selinux-root	2019/01/19 11:06	upstream	2339e91d	2103a236	.config	log	report	syz	C
ci-upstream-linux-next-kasan-gce-root	2019/04/23 07:50	linux-next	3f018f4a	53199d6e	.config	log	report	syz	C
ci-upstream-kasan-gce-selinux-root	2020/05/24 17:22	upstream	caffb99b	bd28eb9d	.config	log	report
ci-upstream-kasan-gce-root	2020/05/08 15:49	upstream	79dede78	2b98fdbc	.config	log	report
ci-upstream-kasan-gce-selinux-root	2020/05/02 18:35	upstream	690e2aba	58da4c35	.config	log	report
ci-upstream-kasan-gce-selinux-root	2020/04/12 10:08	upstream	b032227c	a8c6a3f8	.config	log	report
ci-upstream-kasan-gce-selinux-root	2020/04/07 07:01	upstream	7e634208	99a96044	.config	log	report
ci-upstream-kasan-gce-root	2020/03/13 14:48	upstream	3cc6e2c5	d850e9d0	.config	log	report
ci-upstream-kasan-gce-root	2020/03/12 15:54	upstream	e6e6ec48	d850e9d0	.config	log	report
ci-upstream-kasan-gce-root	2020/03/10 02:02	upstream	30bb5572	35f53e45	.config	log	report
ci-upstream-kasan-gce-root	2020/02/26 11:16	upstream	f8788d86	59b57593	.config	log	report
ci-upstream-kasan-gce-selinux-root	2020/02/20 20:07	upstream	ca7e1fd1	bd2a74a3	.config	log	report
ci-upstream-kasan-gce-smack-root	2020/02/15 02:02	upstream	2019fc96	5d7b90f1	.config	log	report
ci-upstream-kasan-gce-selinux-root	2020/02/12 03:14	upstream	359c92c0	a75b198c	.config	log	report
ci-upstream-kasan-gce-selinux-root	2020/02/10 20:19	upstream	bb6d3fb3	18847f55	.config	log	report
ci-upstream-kasan-gce-selinux-root	2020/02/07 05:17	upstream	90568ecf	06150bf1	.config	log	report
ci-upstream-kasan-gce-root	2020/01/12 10:20	upstream	ac61145a	4c04afaa	.config	log	report
ci-upstream-kasan-gce-selinux-root	2019/12/24 14:01	upstream	46cf053e	be5c2c81	.config	log	report
ci-upstream-kasan-gce-selinux-root	2019/11/16 04:32	upstream	eb70e26c	cdac920b	.config	log	report
ci-upstream-kasan-gce-selinux-root	2019/08/23 05:44	upstream	59c36bc8	ca6f3cfa	.config	log	report
ci-upstream-kasan-gce-root	2019/07/22 14:40	upstream	c6dd78fc	b3c615f5	.config	log	report
ci-upstream-kasan-gce-smack-root	2019/06/20 07:04	upstream	abf02e29	34bf9440	.config	log	report
ci-upstream-kasan-gce-smack-root	2019/06/17 15:30	upstream	9e0babf2	442206d7	.config	log	report
ci-upstream-kasan-gce-selinux-root	2019/06/13 12:00	upstream	b076173a	3f4e812b	.config	log	report
ci-upstream-kasan-gce-smack-root	2019/06/13 09:59	upstream	b076173a	3f4e812b	.config	log	report
ci-upstream-kasan-gce-root	2019/06/12 12:28	upstream	aa723548	794a1ad7	.config	log	report
ci-upstream-kasan-gce-root	2019/06/07 07:45	upstream	01047631	698773cb	.config	log	report
ci-upstream-kasan-gce-smack-root	2019/06/06 19:18	upstream	156c0591	698773cb	.config	log	report
ci-upstream-kasan-gce-root	2019/06/05 22:41	upstream	156c0591	bfb4a51e	.config	log	report
ci-upstream-kasan-gce-smack-root	2019/06/04 22:25	upstream	788a0249	e41a20c5	.config	log	report
ci-upstream-kasan-gce-root	2019/06/04 22:22	upstream	788a0249	e41a20c5	.config	log	report
ci-upstream-kasan-gce-selinux-root	2018/12/31 02:16	upstream	19530313	2b42fdc8	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/06/13 06:22	linux-next	e7b08814	f4724dd3	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/06/12 07:56	linux-next	e7b08814	58802067	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/04/27 12:27	linux-next	ac935d22	0ce7569e	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/04/18 22:41	linux-next	ac935d22	365fba24	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/03/28 13:20	linux-next	770fbb32	f1ebdfba	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/02/18 07:05	linux-next	c25a951c	1ce142dc	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/02/03 22:53	linux-next	2747d5fd	93e5e335	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2019/12/26 08:34	linux-next	7ddd09fc	be5c2c81	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2019/07/02 08:45	linux-next	48a8a5f9	cccc4302	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2019/07/01 20:25	linux-next	48a8a5f9	907bf746	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2019/06/23 14:17	linux-next	e2d28c40	3efccdd2	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2019/06/23 05:59	linux-next	dc636f5d	34bf9440	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2019/06/18 13:24	linux-next	1c6b4050	e3f76baa	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2019/06/17 14:25	linux-next	a125097c	442206d7	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2019/06/08 20:42	linux-next	3f310e51	0159583c	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2019/06/05 14:53	linux-next	b2924447	bfb4a51e	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2019/06/05 14:50	linux-next	b2924447	bfb4a51e	.config	log	report