INFO: rcu detected stall in sys

[upstream] INFO: rcu detected stall in sys_sendfile64 (2)
Status: moderation: reported on 2019/01/02 10:31
Reported-by: syzbot+305f4296f090af5a4e2f@syzkaller.appspotmail.com
First: 18d, last: 18d

similar bugs:
Kernel	Title	Repro	Count	Last	Reported	Patched	Status
upstream	INFO: rcu detected stall in sys_sendfile64	C	4	31d	30d		closed as invalid on 2018/12/19 10:12

Sample crash report:

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	(detected by 1, t=10502 jiffies, g=150269, q=38)
rcu: All QSes seen, last rcu_preempt kthread activity 10499 (4295053052-4295042553), jiffies_till_next_fqs=1, root ->qsmask 0x0
syz-executor0   R  running task    21168 16856   8198 0x00000000
Call Trace:
 <IRQ>
 sched_show_task.cold.86+0x2b6/0x30a kernel/sched/core.c:5293
 print_other_cpu_stall.cold.69+0x80e/0x8db kernel/rcu/tree.c:1301
 check_cpu_stall kernel/rcu/tree.c:1429 [inline]
 rcu_pending kernel/rcu/tree.c:3018 [inline]
 rcu_check_callbacks+0xfe8/0x1410 kernel/rcu/tree.c:2521
 update_process_times+0x2d/0x70 kernel/time/timer.c:1635
 tick_sched_handle+0x9f/0x180 kernel/time/tick-sched.c:161
 tick_sched_timer+0x45/0x130 kernel/time/tick-sched.c:1271
 __run_hrtimer kernel/time/hrtimer.c:1389 [inline]
 __hrtimer_run_queues+0x41c/0x10d0 kernel/time/hrtimer.c:1451
 hrtimer_interrupt+0x313/0x780 kernel/time/hrtimer.c:1509
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1035 [inline]
 smp_apic_timer_interrupt+0x1a1/0x760 arch/x86/kernel/apic/apic.c:1060
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807
 </IRQ>
RIP: 0010:check_memory_region+0x1f/0x1b0 mm/kasan/generic.c:190
Code: 00 66 2e 0f 1f 84 00 00 00 00 00 48 85 f6 0f 84 3c 01 00 00 48 b8 ff ff ff ff ff 7f ff ff 55 0f b6 d2 48 39 c7 48 89 e5 41 55 <41> 54 53 0f 86 11 01 00 00 4c 8d 5c 37 ff 48 89 fb 49 b9 00 00 00
RSP: 0018:ffff888096236990 EFLAGS: 00000212 ORIG_RAX: ffffffffffffff13
RAX: ffff7fffffffffff RBX: 0000000000000003 RCX: ffffffff81a03375
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff888096236a28
RBP: ffff888096236998 R08: fffff940003e984f R09: fffff940003e984e
R10: fffff940003e984e R11: ffffea0001f4c277 R12: ffff888096236d48
R13: 0000000000000004 R14: ffffed1012c46d45 R15: dffffc0000000000
 kasan_check_read+0x11/0x20 mm/kasan/common.c:100
 atomic_try_cmpxchg include/asm-generic/atomic-instrumented.h:72 [inline]
 atomic_fetch_add_unless include/linux/atomic.h:580 [inline]
 atomic_add_unless include/linux/atomic.h:597 [inline]
 page_ref_add_unless include/linux/page_ref.h:157 [inline]
 get_page_unless_zero include/linux/mm.h:556 [inline]
 page_cache_get_speculative include/linux/pagemap.h:186 [inline]
 find_get_entry+0x5c5/0x1120 mm/filemap.c:1487
 pagecache_get_page+0x12f/0xf00 mm/filemap.c:1579
 find_get_page include/linux/pagemap.h:272 [inline]
 generic_file_buffered_read mm/filemap.c:2076 [inline]
 generic_file_read_iter+0xa13/0x2d70 mm/filemap.c:2350
 ext4_file_read_iter+0x18b/0x3c0 fs/ext4/file.c:77
 call_read_iter include/linux/fs.h:1856 [inline]
 generic_file_splice_read+0x62c/0xa60 fs/splice.c:308
 do_splice_to+0x12e/0x190 fs/splice.c:880
 splice_direct_to_actor+0x31c/0x9d0 fs/splice.c:957
 do_splice_direct+0x2d4/0x420 fs/splice.c:1066
 do_sendfile+0x62a/0xe50 fs/read_write.c:1439
 __do_sys_sendfile64 fs/read_write.c:1494 [inline]
 __se_sys_sendfile64 fs/read_write.c:1486 [inline]
 __x64_sys_sendfile64+0x15d/0x250 fs/read_write.c:1486
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457ec9
Code: 6d b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 3b b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f835af62c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000000457ec9
RDX: 0000000020000000 RSI: 000000000000000d RDI: 000000000000000d
RBP: 000000000073c180 R08: 0000000000000000 R09: 0000000000000000
R10: 00008080fffffffe R11: 0000000000000246 R12: 00007f835af636d4
R13: 00000000004c4b6b R14: 00000000004d8278 R15: 00000000ffffffff
rcu: rcu_preempt kthread starved for 10499 jiffies! g150269 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
rcu: RCU grace-period kthread stack dump:
rcu_preempt     R  running task    22280    10      2 0x80000000
Call Trace:
 context_switch kernel/sched/core.c:2831 [inline]
 __schedule+0x86c/0x1ed0 kernel/sched/core.c:3472
 schedule+0xef/0x370 kernel/sched/core.c:3516
 schedule_timeout+0x140/0x260 kernel/time/timer.c:1803
 rcu_gp_fqs_loop+0x762/0xa80 kernel/rcu/tree.c:1948
 rcu_gp_kthread+0x341/0xc70 kernel/rcu/tree.c:2105
 kthread+0x35a/0x440 kernel/kthread.c:246
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352
sched: RT throttling activated

All crashes (1):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	Maintainers
ci-upstream-kasan-gce-selinux-root	2018/12/31 02:16	upstream	19530313	2b42fdc8	.config	log	report			akpm@linux-foundation.org, amir73il@gmail.com, darrick.wong@oracle.com, david@fromorbit.com, hannes@cmpxchg.org, hughd@google.com, jrdr.linux@gmail.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, willy@infradead.org