INFO: rcu detected stall in discover_timer (2)

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 54ecb8f7 Linux 5.4-rc1
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13285c33600000
kernel config: https://syzkaller.appspot.com/x/.config?x=fb0b431ccdf08c1c
dashboard link: https://syzkaller.appspot.com/bug?extid=e0e13ba47ef9333eab70
compiler: clang version 9.0.0 (/home/glider/llvm/clang
80fee25776c2fb61e74c1ecb1a523375c2500b69)
CC: [b...@alien8.de gre...@linuxfoundation.org h...@zytor.com
ja...@google.com jpoi...@redhat.com linux-...@vger.kernel.org
mhir...@kernel.org mi...@redhat.com pet...@infradead.org
tg...@linutronix.de x...@kernel.org]

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+e0e13b...@syzkaller.appspotmail.com

protocol 88fb is buggy, dev hsr_slave_0
protocol 88fb is buggy, dev hsr_slave_1
protocol 88fb is buggy, dev hsr_slave_0
protocol 88fb is buggy, dev hsr_slave_1
rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 0-...!: (1 GPs behind) idle=96e/1/0x4000000000000004
softirq=113072/113073 fqs=0
(t=10500 jiffies g=170997 q=107)
rcu: rcu_preempt kthread starved for 10500 jiffies! g170997 f0x0
RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
rcu: RCU grace-period kthread stack dump:
rcu_preempt R running task 28952 10 2 0x80004000
Call Trace:
context_switch kernel/sched/core.c:3384 [inline]
__schedule+0x74b/0xb80 kernel/sched/core.c:4069
schedule+0x131/0x1e0 kernel/sched/core.c:4136
schedule_timeout+0x14f/0x240 kernel/time/timer.c:1895
rcu_gp_fqs_loop kernel/rcu/tree.c:1639 [inline]
rcu_gp_kthread+0xed8/0x1770 kernel/rcu/tree.c:1799
kthread+0x332/0x350 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
NMI backtrace for cpu 0
CPU: 0 PID: 22163 Comm: syz-executor.3 Not tainted 5.4.0-rc1 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x1d8/0x2f8 lib/dump_stack.c:113
nmi_cpu_backtrace+0xaf/0x1a0 lib/nmi_backtrace.c:101
nmi_trigger_cpumask_backtrace+0x174/0x290 lib/nmi_backtrace.c:62
arch_trigger_cpumask_backtrace+0x10/0x20 arch/x86/kernel/apic/hw_nmi.c:38
trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]
rcu_dump_cpu_stacks+0x15a/0x220 kernel/rcu/tree_stall.h:254
print_cpu_stall kernel/rcu/tree_stall.h:455 [inline]
check_cpu_stall kernel/rcu/tree_stall.h:529 [inline]
rcu_pending kernel/rcu/tree.c:2795 [inline]
rcu_sched_clock_irq+0xe22/0x1ae0 kernel/rcu/tree.c:2244
update_process_times+0x12d/0x180 kernel/time/timer.c:1726
tick_sched_handle kernel/time/tick-sched.c:167 [inline]
tick_sched_timer+0x263/0x420 kernel/time/tick-sched.c:1299
__run_hrtimer kernel/time/hrtimer.c:1514 [inline]
__hrtimer_run_queues+0x403/0x840 kernel/time/hrtimer.c:1576
hrtimer_interrupt+0x38c/0xda0 kernel/time/hrtimer.c:1638
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1110 [inline]
smp_apic_timer_interrupt+0x109/0x280 arch/x86/kernel/apic/apic.c:1135
apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:830
RIP: 0010:unwind_next_frame+0xa6/0x7a0 arch/x86/kernel/unwind_frame.c:269
Code: 00 4c 89 f0 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 80 3c 08 00 74
08 4c 89 f7 e8 04 fd 77 00 41 f6 06 03 0f 85 75 05 00 00 <48> 89 5d b8 4d
8d 75 38 4c 89 f0 48 c1 e8 03 48 bb 00 00 00 00 00
RSP: 0018:ffff8880aea09738 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: 1ffff11015d41307 RBX: 0000000000000000 RCX: ffff888043c16440
RDX: 0000000000000101 RSI: 0000000000000001 RDI: ffff8880aea097e0
RBP: ffff8880aea097d0 R08: ffffffff816251d5 R09: ffff8880aea097e0
R10: ffffed1015d41308 R11: 0000000000000000 R12: ffff888043c16440
R13: ffff8880aea097e0 R14: dffffc0000000000 R15: ffff8880aea09838
arch_stack_walk+0xb4/0xe0 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0xb6/0x150 kernel/stacktrace.c:123
save_stack mm/kasan/common.c:69 [inline]
set_track mm/kasan/common.c:77 [inline]
__kasan_kmalloc+0x11c/0x1b0 mm/kasan/common.c:510
kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:518
slab_post_alloc_hook mm/slab.h:584 [inline]
slab_alloc_node mm/slab.c:3262 [inline]
kmem_cache_alloc_node_trace+0x225/0x2d0 mm/slab.c:3592
__do_kmalloc_node mm/slab.c:3614 [inline]
__kmalloc_node_track_caller+0x3c/0x60 mm/slab.c:3629
__kmalloc_reserve net/core/skbuff.c:141 [inline]
__alloc_skb+0xe8/0x500 net/core/skbuff.c:209
alloc_skb include/linux/skbuff.h:1049 [inline]
new_skb drivers/block/aoe/aoecmd.c:67 [inline]
aoecmd_cfg_pkts drivers/block/aoe/aoecmd.c:426 [inline]
aoecmd_cfg+0x1d6/0x7f0 drivers/block/aoe/aoecmd.c:1372
discover_timer+0x57/0x60 drivers/block/aoe/aoemain.c:24
call_timer_fn+0x95/0x170 kernel/time/timer.c:1404
expire_timers kernel/time/timer.c:1449 [inline]
__run_timers+0x7b6/0x990 kernel/time/timer.c:1773
run_timer_softirq+0x4a/0x90 kernel/time/timer.c:1786
__do_softirq+0x333/0x7c4 arch/x86/include/asm/paravirt.h:766
invoke_softirq kernel/softirq.c:373 [inline]
irq_exit+0x227/0x230 kernel/softirq.c:413
exiting_irq arch/x86/include/asm/apic.h:536 [inline]
smp_apic_timer_interrupt+0x113/0x280 arch/x86/kernel/apic/apic.c:1137
apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:830
</IRQ>
RIP: 0010:__find_get_block_slow fs/buffer.c:217 [inline]
RIP: 0010:__find_get_block+0x4b7/0x10b0 fs/buffer.c:1296
Code: e8 de a0 e8 ff 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 80
3c 08 00 74 08 48 89 df e8 7f cf e8 ff 49 89 dc 48 8b 1b <48> 89 de 48 83
e6 20 31 ff e8 fb 9a af ff 48 83 e3 20 75 15 e8 c0
RSP: 0018:ffff88802d7cf858 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: 1ffff11012c61c15 RBX: 000000000000c02b RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff88809630e0a8
RBP: ffff88802d7cf8b8 R08: dffffc0000000000 R09: ffffed1012c61c16
R10: ffffed1012c61c16 R11: 0000000000000000 R12: ffff88809630e0a8
R13: 0000000000000001 R14: ffff88809630e0a8 R15: 1ffff1101452f07b
sb_find_get_block include/linux/buffer_head.h:338 [inline]
recently_deleted fs/ext4/ialloc.c:682 [inline]
find_inode_bit+0x283/0x510 fs/ext4/ialloc.c:722
__ext4_new_inode+0x11ab/0x5650 fs/ext4/ialloc.c:914
ext4_create+0x232/0x5a0 fs/ext4/namei.c:2587
lookup_open fs/namei.c:3224 [inline]
do_last fs/namei.c:3314 [inline]
path_openat+0x2236/0x4420 fs/namei.c:3525
do_filp_open+0x192/0x3d0 fs/namei.c:3555
do_sys_open+0x29f/0x560 fs/open.c:1097
__do_sys_openat fs/open.c:1124 [inline]
__se_sys_openat fs/open.c:1118 [inline]
__x64_sys_openat+0xa2/0xb0 fs/open.c:1118
do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x459a29
Code: fd 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 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f1d98c42c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000000459a29
RDX: 00000000000026e1 RSI: 0000000020000200 RDI: ffffffffffffff9c
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f1d98c436d4
R13: 00000000004c6288 R14: 00000000004db1e8 R15: 00000000ffffffff
net_ratelimit: 14 callbacks suppressed
protocol 88fb is buggy, dev hsr_slave_0
protocol 88fb is buggy, dev hsr_slave_1
protocol 88fb is buggy, dev hsr_slave_0
protocol 88fb is buggy, dev hsr_slave_1
protocol 88fb is buggy, dev hsr_slave_0
protocol 88fb is buggy, dev hsr_slave_1
protocol 88fb is buggy, dev hsr_slave_0
protocol 88fb is buggy, dev hsr_slave_1


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.