bisecting fixing commit since 7b6ae471e5415bc2bf4384a83ccb4c21de7824c0
building syzkaller on 29c3f20f99b6befe0395fe8e474b1e24240cac95
testing commit 7b6ae471e5415bc2bf4384a83ccb4c21de7824c0
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.1
kernel signature: fee7c686ec8ca778ee736c50e14e5674227bf77a3808fab0b41ee84fcdda16f5
run #0: crashed: INFO: rcu detected stall in ieee80211_iface_work
run #1: crashed: INFO: rcu detected stall in mac80211_hwsim_beacon
run #2: crashed: INFO: rcu detected stall in ieee80211_tasklet_handler
run #3: crashed: INFO: rcu detected stall in tasklet_action_common
run #4: crashed: INFO: rcu detected stall in addrconf_rs_timer
run #5: crashed: INFO: rcu detected stall in mac80211_hwsim_beacon
run #6: crashed: INFO: rcu detected stall in smp_call_function
run #7: crashed: INFO: rcu detected stall in mac80211_hwsim_beacon
run #8: crashed: INFO: rcu detected stall in mac80211_hwsim_beacon
run #9: crashed: INFO: rcu detected stall in mac80211_hwsim_beacon
run #10: crashed: INFO: rcu detected stall in mac80211_hwsim_beacon
run #11: crashed: BUG: soft lockup in addrconf_rs_timer
run #12: crashed: INFO: rcu detected stall in smp_call_function
run #13: crashed: INFO: rcu detected stall in mld_dad_work
run #14: crashed: BUG: soft lockup in smp_call_function
run #15: crashed: INFO: rcu detected stall in mac80211_hwsim_beacon
run #16: crashed: INFO: rcu detected stall in batadv_purge_orig
run #17: crashed: INFO: rcu detected stall in mac80211_hwsim_beacon
run #18: crashed: INFO: rcu detected stall in mac80211_hwsim_beacon
run #19: crashed: INFO: rcu detected stall in addrconf_rs_timer
testing current HEAD 002c0aef109067168ae68ee69b5ce67edc2e63c1
testing commit 002c0aef109067168ae68ee69b5ce67edc2e63c1
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.1
kernel signature: 6716b6e02431fcff7207f9ce2f0a522598136fb426cde93fe7b3ef7b80633303
run #0: crashed: INFO: rcu detected stall in __hrtimer_run_queues
run #1: crashed: INFO: rcu detected stall in mac80211_hwsim_beacon
run #2: crashed: INFO: rcu detected stall in mac80211_hwsim_beacon
run #3: crashed: INFO: rcu detected stall in smp_call_function
run #4: crashed: INFO: rcu detected stall in mac80211_hwsim_beacon
run #5: crashed: INFO: rcu detected stall in ieee80211_iface_work
run #6: crashed: INFO: rcu detected stall in smp_call_function
run #7: crashed: INFO: rcu detected stall in neigh_periodic_work
run #8: crashed: INFO: rcu detected stall in smp_call_function
run #9: crashed: INFO: rcu detected stall in ipv6_rcv
revisions tested: 2, total time: 27m39.227481649s (build: 13m18.825954689s, test: 13m48.359588828s)
the crash still happens on HEAD
commit msg: Merge tag 'block-5.14-2021-08-20' of git://git.kernel.dk/linux-block
crash: INFO: rcu detected stall in ipv6_rcv
rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 0-...!: (6 ticks this GP) idle=da6/1/0x4000000000000000 softirq=12362/12362 fqs=0
(t=12718 jiffies g=10157 q=943)
rcu: rcu_preempt kthread starved for 12718 jiffies! g10157 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt state:R running task stack:29104 pid: 14 ppid: 2 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:4681 [inline]
__schedule+0x907/0x26b0 kernel/sched/core.c:5938
schedule+0xd3/0x270 kernel/sched/core.c:6017
schedule_timeout+0x11d/0x250 kernel/time/timer.c:1881
rcu_gp_fqs_loop kernel/rcu/tree.c:1996 [inline]
rcu_gp_kthread+0xd34/0x1980 kernel/rcu/tree.c:2169
kthread+0x38b/0x460 kernel/kthread.c:319
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
rcu: Stack dump where RCU GP kthread last ran:
NMI backtrace for cpu 0
CPU: 0 PID: 4946 Comm: systemd-timesyn Not tainted 5.14.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x57/0x7d lib/dump_stack.c:105
nmi_cpu_backtrace.cold+0x30/0x99 lib/nmi_backtrace.c:105
nmi_trigger_cpumask_backtrace+0x11f/0x170 lib/nmi_backtrace.c:62
trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]
rcu_check_gp_kthread_starvation.cold+0x1d1/0x1d6 kernel/rcu/tree_stall.h:479
print_cpu_stall kernel/rcu/tree_stall.h:623 [inline]
check_cpu_stall kernel/rcu/tree_stall.h:700 [inline]
rcu_pending kernel/rcu/tree.c:3922 [inline]
rcu_sched_clock_irq.cold+0x9a/0x747 kernel/rcu/tree.c:2641
update_process_times+0x13b/0x1c0 kernel/time/timer.c:1785
tick_sched_handle+0x6f/0x130 kernel/time/tick-sched.c:226
tick_sched_timer+0x132/0x210 kernel/time/tick-sched.c:1421
__run_hrtimer kernel/time/hrtimer.c:1537 [inline]
__hrtimer_run_queues+0x18a/0xb00 kernel/time/hrtimer.c:1601
hrtimer_interrupt+0x2f9/0x920 kernel/time/hrtimer.c:1663
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1089 [inline]
__sysvec_apic_timer_interrupt+0x146/0x530 arch/x86/kernel/apic/apic.c:1106
sysvec_apic_timer_interrupt+0x40/0xc0 arch/x86/kernel/apic/apic.c:1100
asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638
RIP: 0010:find_match.part.0+0x149/0xb10 net/ipv6/route.c:761
Code: c1 ea 03 0f b6 14 02 4c 89 f0 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 61 03 00 00 45 39 3e 7c 13 31 c0 48 8d 65 d0 5b 41 5a <41> 5c 41 5d 41 5e 41 5f 5d c3 48 b8 00 00 00 00 00 fc ff df 48 8b
RSP: 0018:ffffc90000007680 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffff88804ca54ca0 RCX: 0000000000000003
RDX: 000000000000000f RSI: 0000000000000001 RDI: ffff88801dfa80d0
RBP: ffffc900000076a0 R08: 1ffff11003bf501a R09: ffffc90000007880
R10: fffffbfff1dbab1c R11: ffff88804cb48d40 R12: 0000000000000003
R13: 0000000000000000 R14: ffffc90000007890 R15: 00000000fffffffd
find_match net/ipv6/route.c:824 [inline]
__find_rr_leaf+0x14f/0xa40 net/ipv6/route.c:825
find_rr_leaf net/ipv6/route.c:846 [inline]
rt6_select net/ipv6/route.c:890 [inline]
fib6_table_lookup+0x496/0x840 net/ipv6/route.c:2174
ip6_pol_route+0x17d/0xe10 net/ipv6/route.c:2210
pol_lookup_func include/net/ip6_fib.h:579 [inline]
fib6_rule_lookup+0xfb/0x630 net/ipv6/fib6_rules.c:115
ip6_route_input_lookup net/ipv6/route.c:2280 [inline]
ip6_route_input+0x56a/0x980 net/ipv6/route.c:2576
ip6_rcv_finish net/ipv6/ip6_input.c:74 [inline]
NF_HOOK include/linux/netfilter.h:307 [inline]
NF_HOOK include/linux/netfilter.h:301 [inline]
ipv6_rcv+0x1c5/0x330 net/ipv6/ip6_input.c:297
__netif_receive_skb_one_core+0x104/0x180 net/core/dev.c:5498
process_backlog+0x22a/0x610 net/core/dev.c:6492
__napi_poll+0x94/0x350 net/core/dev.c:7047
napi_poll net/core/dev.c:7114 [inline]
net_rx_action+0x6fc/0xa50 net/core/dev.c:7201
__do_softirq+0x29b/0x9c2 kernel/softirq.c:558
do_softirq.part.0+0xde/0x130 kernel/softirq.c:459
do_softirq kernel/softirq.c:451 [inline]
__local_bh_enable_ip+0x102/0x120 kernel/softirq.c:383
local_bh_enable include/linux/bottom_half.h:32 [inline]
unix_create1+0x476/0x540 net/unix/af_unix.c:823
unix_create+0xb7/0x1d0 net/unix/af_unix.c:857
__sock_create+0x23e/0x590 net/socket.c:1450
sock_create net/socket.c:1501 [inline]
__sys_socket+0xd6/0x1a0 net/socket.c:1543
__do_sys_socket net/socket.c:1552 [inline]
__se_sys_socket net/socket.c:1550 [inline]
__x64_sys_socket+0x6a/0xb0 net/socket.c:1550
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f93acb7bf17
Code: 73 01 c3 48 8b 0d 81 ef 2a 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 29 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 51 ef 2a 00 f7 d8 64 89 01 48
RSP: 002b:00007fff4ed71d68 EFLAGS: 00000246 ORIG_RAX: 0000000000000029
RAX: ffffffffffffffda RBX: 00007f93ad48dc05 RCX: 00007f93acb7bf17
RDX: 0000000000000000 RSI: 0000000000080002 RDI: 0000000000000001
RBP: 00007fff4ed71ea0 R08: 0000000000000000 R09: 00007fff4ed77080
R10: 00007fff4ed72f55 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 00007fff4ed71da0
NMI backtrace for cpu 0
CPU: 0 PID: 4946 Comm: systemd-timesyn Not tainted 5.14.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x57/0x7d lib/dump_stack.c:105
nmi_cpu_backtrace.cold+0x30/0x99 lib/nmi_backtrace.c:105
nmi_trigger_cpumask_backtrace+0x11f/0x170 lib/nmi_backtrace.c:62
trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]
rcu_dump_cpu_stacks+0x25e/0x3f0 kernel/rcu/tree_stall.h:342
print_cpu_stall kernel/rcu/tree_stall.h:625 [inline]
check_cpu_stall kernel/rcu/tree_stall.h:700 [inline]
rcu_pending kernel/rcu/tree.c:3922 [inline]
rcu_sched_clock_irq.cold+0x9f/0x747 kernel/rcu/tree.c:2641
update_process_times+0x13b/0x1c0 kernel/time/timer.c:1785
tick_sched_handle+0x6f/0x130 kernel/time/tick-sched.c:226
tick_sched_timer+0x132/0x210 kernel/time/tick-sched.c:1421
__run_hrtimer kernel/time/hrtimer.c:1537 [inline]
__hrtimer_run_queues+0x18a/0xb00 kernel/time/hrtimer.c:1601
hrtimer_interrupt+0x2f9/0x920 kernel/time/hrtimer.c:1663
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1089 [inline]
__sysvec_apic_timer_interrupt+0x146/0x530 arch/x86/kernel/apic/apic.c:1106
sysvec_apic_timer_interrupt+0x40/0xc0 arch/x86/kernel/apic/apic.c:1100
asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638
RIP: 0010:find_match.part.0+0x149/0xb10 net/ipv6/route.c:761
Code: c1 ea 03 0f b6 14 02 4c 89 f0 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 61 03 00 00 45 39 3e 7c 13 31 c0 48 8d 65 d0 5b 41 5a <41> 5c 41 5d 41 5e 41 5f 5d c3 48 b8 00 00 00 00 00 fc ff df 48 8b
RSP: 0018:ffffc90000007680 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffff88804ca54ca0 RCX: 0000000000000003
RDX: 000000000000000f RSI: 0000000000000001 RDI: ffff88801dfa80d0
RBP: ffffc900000076a0 R08: 1ffff11003bf501a R09: ffffc90000007880
R10: fffffbfff1dbab1c R11: ffff88804cb48d40 R12: 0000000000000003
R13: 0000000000000000 R14: ffffc90000007890 R15: 00000000fffffffd
find_match net/ipv6/route.c:824 [inline]
__find_rr_leaf+0x14f/0xa40 net/ipv6/route.c:825
find_rr_leaf net/ipv6/route.c:846 [inline]
rt6_select net/ipv6/route.c:890 [inline]
fib6_table_lookup+0x496/0x840 net/ipv6/route.c:2174
ip6_pol_route+0x17d/0xe10 net/ipv6/route.c:2210
pol_lookup_func include/net/ip6_fib.h:579 [inline]
fib6_rule_lookup+0xfb/0x630 net/ipv6/fib6_rules.c:115
ip6_route_input_lookup net/ipv6/route.c:2280 [inline]
ip6_route_input+0x56a/0x980 net/ipv6/route.c:2576
ip6_rcv_finish net/ipv6/ip6_input.c:74 [inline]
NF_HOOK include/linux/netfilter.h:307 [inline]
NF_HOOK include/linux/netfilter.h:301 [inline]
ipv6_rcv+0x1c5/0x330 net/ipv6/ip6_input.c:297
__netif_receive_skb_one_core+0x104/0x180 net/core/dev.c:5498
process_backlog+0x22a/0x610 net/core/dev.c:6492
__napi_poll+0x94/0x350 net/core/dev.c:7047
napi_poll net/core/dev.c:7114 [inline]
net_rx_action+0x6fc/0xa50 net/core/dev.c:7201
__do_softirq+0x29b/0x9c2 kernel/softirq.c:558
do_softirq.part.0+0xde/0x130 kernel/softirq.c:459
do_softirq kernel/softirq.c:451 [inline]
__local_bh_enable_ip+0x102/0x120 kernel/softirq.c:383
local_bh_enable include/linux/bottom_half.h:32 [inline]
unix_create1+0x476/0x540 net/unix/af_unix.c:823
unix_create+0xb7/0x1d0 net/unix/af_unix.c:857
__sock_create+0x23e/0x590 net/socket.c:1450
sock_create net/socket.c:1501 [inline]
__sys_socket+0xd6/0x1a0 net/socket.c:1543
__do_sys_socket net/socket.c:1552 [inline]
__se_sys_socket net/socket.c:1550 [inline]
__x64_sys_socket+0x6a/0xb0 net/socket.c:1550
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f93acb7bf17
Code: 73 01 c3 48 8b 0d 81 ef 2a 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 29 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 51 ef 2a 00 f7 d8 64 89 01 48
RSP: 002b:00007fff4ed71d68 EFLAGS: 00000246 ORIG_RAX: 0000000000000029
RAX: ffffffffffffffda RBX: 00007f93ad48dc05 RCX: 00007f93acb7bf17
RDX: 0000000000000000 RSI: 0000000000080002 RDI: 0000000000000001
RBP: 00007fff4ed71ea0 R08: 0000000000000000 R09: 00007fff4ed77080
R10: 00007fff4ed72f55 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 00007fff4ed71da0
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 10092 Comm: kworker/1:6 Not tainted 5.14.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events_power_efficient gc_worker
RIP: 0010:__lock_acquire+0x149/0x5410 kernel/locking/lockdep.c:4918
Code: 48 89 f1 48 89 34 24 48 c1 e9 03 0f b6 14 11 84 d2 74 09 80 fa 03 0f 8e b6 13 00 00 48 c7 c1 a0 37 32 8f 41 8b b5 e8 09 00 00 <48> ba 00 00 00 00 00 fc ff df 48 c1 e9 03 0f b6 0c 11 48 c7 c2 a0
RSP: 0018:ffffc90000fd8b98 EFLAGS: 00000046
RAX: ffffffff8edd7f80 RBX: ffffffff8ab70140 RCX: ffffffff8f3237a0
RDX: 0000000000000000 RSI: 0000000000000003 RDI: ffffffff8ab70148
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000000
R13: ffff8880372cc180 R14: 0000000000000002 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff8880b9f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055d22559b9e0 CR3: 000000002a6a7000 CR4: 00000000001506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
lock_acquire kernel/locking/lockdep.c:5625 [inline]
lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5590
rcu_lock_acquire include/linux/rcupdate.h:267 [inline]
rcu_read_lock include/linux/rcupdate.h:687 [inline]
advance_sched+0x3e5/0x920 net/sched/sch_taprio.c:763
__run_hrtimer kernel/time/hrtimer.c:1537 [inline]
__hrtimer_run_queues+0x4d7/0xb00 kernel/time/hrtimer.c:1601
hrtimer_interrupt+0x2f9/0x920 kernel/time/hrtimer.c:1663
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1089 [inline]
__sysvec_apic_timer_interrupt+0x146/0x530 arch/x86/kernel/apic/apic.c:1106
sysvec_apic_timer_interrupt+0x8e/0xc0 arch/x86/kernel/apic/apic.c:1100
asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638
RIP: 0010:lock_acquire+0x1ef/0x510 kernel/locking/lockdep.c:5593
Code: cc af 7e 83 f8 01 0f 85 b4 02 00 00 9c 58 f6 c4 02 0f 85 9f 02 00 00 48 83 7c 24 08 00 74 01 fb 48 b8 00 00 00 00 00 fc ff df <48> 01 c3 48 c7 03 00 00 00 00 48 c7 43 08 00 00 00 00 48 8b 84 24
RSP: 0018:ffffc9000ac57bc0 EFLAGS: 00000206
RAX: dffffc0000000000 RBX: 1ffff9200158af7a RCX: efcc8a4881e63037
RDX: 1ffff11006e5996d RSI: ffffffff88cb1c00 RDI: ffffffff891f61c0
RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff8edd58e7
R10: fffffbfff1dbab1c R11: 000000000007a088 R12: 0000000000000002
R13: 0000000000000000 R14: ffffffff8ab70140 R15: 0000000000000000
rcu_lock_acquire include/linux/rcupdate.h:267 [inline]
rcu_read_lock include/linux/rcupdate.h:687 [inline]
gc_worker+0x125/0xbf0 net/netfilter/nf_conntrack_core.c:1377
process_one_work+0x84c/0x13d0 kernel/workqueue.c:2276
worker_thread+0x598/0x1040 kernel/workqueue.c:2422
kthread+0x38b/0x460 kernel/kthread.c:319
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
----------------
Code disassembly (best guess):
0: c1 ea 03 shr $0x3,%edx
3: 0f b6 14 02 movzbl (%rdx,%rax,1),%edx
7: 4c 89 f0 mov %r14,%rax
a: 83 e0 07 and $0x7,%eax
d: 83 c0 03 add $0x3,%eax
10: 38 d0 cmp %dl,%al
12: 7c 08 jl 0x1c
14: 84 d2 test %dl,%dl
16: 0f 85 61 03 00 00 jne 0x37d
1c: 45 39 3e cmp %r15d,(%r14)
1f: 7c 13 jl 0x34
21: 31 c0 xor %eax,%eax
23: 48 8d 65 d0 lea -0x30(%rbp),%rsp
27: 5b pop %rbx
28: 41 5a pop %r10
* 2a: 41 5c pop %r12 <-- trapping instruction
2c: 41 5d pop %r13
2e: 41 5e pop %r14
30: 41 5f pop %r15
32: 5d pop %rbp
33: c3 retq
34: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
3b: fc ff df
3e: 48 rex.W
3f: 8b .byte 0x8b