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Date:   Fri, 24 Jan 2020 11:57:10 -0800
From:   syzbot <>
Subject: INFO: rcu detected stall in ip_set_udel


syzbot found the following crash on:

HEAD commit:    4703d911 Merge tag 'xarray-5.5' of git://
git tree:       upstream
console output:
kernel config:
dashboard link:
compiler:       clang version 10.0.0 ( c2443155a0fb245c8f17f2c1c72b6ea391e86e81)
syz repro:
C reproducer:

IMPORTANT: if you fix the bug, please add the following tag to the commit:

rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-....: (10500 ticks this GP) idle=b52/1/0x4000000000000002 softirq=13996/13996 fqs=5248 
	(t=10502 jiffies g=7337 q=2939)
NMI backtrace for cpu 1
CPU: 1 PID: 8895 Comm: syz-executor098 Not tainted 5.5.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1fb/0x318 lib/dump_stack.c:118
 nmi_cpu_backtrace+0xaa/0x190 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x16f/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:2827 [inline]
 rcu_sched_clock_irq+0x1521/0x1ab0 kernel/rcu/tree.c:2271
 update_process_times+0x12d/0x180 kernel/time/timer.c:1726
 tick_sched_handle kernel/time/tick-sched.c:171 [inline]
 tick_sched_timer+0x263/0x420 kernel/time/tick-sched.c:1314
 __run_hrtimer kernel/time/hrtimer.c:1517 [inline]
 __hrtimer_run_queues+0x3f3/0x840 kernel/time/hrtimer.c:1579
 hrtimer_interrupt+0x37c/0xda0 kernel/time/hrtimer.c:1641
 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:829
RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:752 [inline]
RIP: 0010:lock_is_held_type+0x25c/0x2b0 kernel/locking/lockdep.c:4523
Code: 28 91 0a 89 48 c1 e8 03 42 80 3c 30 00 74 0c 48 c7 c7 28 91 0a 89 e8 c3 2b 57 00 48 83 3d 63 fe ae 07 00 74 56 4c 89 e7 57 9d <0f> 1f 44 00 00 89 d8 48 83 c4 28 5b 41 5c 41 5d 41 5e 41 5f 5d c3
RSP: 0018:ffffc90002077120 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13
RAX: 1ffffffff1215225 RBX: 0000000000000001 RCX: 0000000000000000
RDX: 00000000ffffffff RSI: ffff88809fa54638 RDI: 0000000000000282
RBP: ffffc90002077170 R08: ffffffff86a708bc R09: ffffffff83b538c7
R10: ffff8880a861c1c0 R11: 0000000000000004 R12: 0000000000000282
R13: ffff8880a861ca54 R14: dffffc0000000000 R15: 1ffff110150c394a
 lock_is_held include/linux/lockdep.h:361 [inline]
 hash_ip4_del+0xa5/0xb50 net/netfilter/ipset/ip_set_hash_gen.h:847
 hash_ip4_uadt+0x589/0x810 net/netfilter/ipset/ip_set_hash_ip.c:151
 call_ad+0x10a/0x5b0 net/netfilter/ipset/ip_set_core.c:1716
 ip_set_ad+0x6a9/0x860 net/netfilter/ipset/ip_set_core.c:1804
 ip_set_udel+0x3a/0x50 net/netfilter/ipset/ip_set_core.c:1838
 nfnetlink_rcv_msg+0x9ae/0xcd0 net/netfilter/nfnetlink.c:229
 netlink_rcv_skb+0x19e/0x3e0 net/netlink/af_netlink.c:2477
 nfnetlink_rcv+0x1e0/0x1e50 net/netfilter/nfnetlink.c:563
 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline]
 netlink_unicast+0x767/0x920 net/netlink/af_netlink.c:1328
 netlink_sendmsg+0xa2c/0xd50 net/netlink/af_netlink.c:1917
 sock_sendmsg_nosec net/socket.c:639 [inline]
 sock_sendmsg net/socket.c:659 [inline]
 ____sys_sendmsg+0x4f7/0x7f0 net/socket.c:2330
 ___sys_sendmsg net/socket.c:2384 [inline]
 __sys_sendmsg+0x1ed/0x290 net/socket.c:2417
 __do_sys_sendmsg net/socket.c:2426 [inline]
 __se_sys_sendmsg net/socket.c:2424 [inline]
 __x64_sys_sendmsg+0x7f/0x90 net/socket.c:2424
 do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294
RIP: 0033:0x440509
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 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 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffd23b04ed8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440509
RDX: 0000000000000040 RSI: 0000000020000080 RDI: 0000000000000004
RBP: 00000000006ca018 R08: 0000000000000018 R09: 00000000004002c8
R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000401d90
R13: 0000000000401e20 R14: 0000000000000000 R15: 0000000000000000

This bug is generated by a bot. It may contain errors.
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