bisecting fixing commit since fb893de323e2d39f7a1f6df425703a2edbdf56ea
building syzkaller on bc15f7dbbc1c6e2042a7115b3fdacc0ada8c35e7
testing commit fb893de323e2d39f7a1f6df425703a2edbdf56ea
compiler: gcc (GCC) 8.4.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.1
kernel signature: 2bee816e6fc05d6cb4590f5e8ed0dd0b4185585a4fe74e4e09c5420383f2eaf0
run #0: crashed: BUG: soft lockup in rtnl_newlink
run #1: crashed: BUG: soft lockup in do_idle
run #2: crashed: BUG: workqueue lockup
run #3: crashed: BUG: workqueue lockup
run #4: crashed: BUG: soft lockup in do_idle
run #5: crashed: BUG: workqueue lockup
run #6: crashed: BUG: workqueue lockup
run #7: crashed: BUG: workqueue lockup
run #8: crashed: BUG: workqueue lockup
run #9: crashed: BUG: soft lockup in do_idle
run #10: crashed: BUG: soft lockup in do_idle
run #11: crashed: BUG: soft lockup in mutex_spin_on_owner
run #12: crashed: BUG: soft lockup in mutex_spin_on_owner
run #13: crashed: BUG: soft lockup in sys_socket
run #14: crashed: BUG: soft lockup in ipv6_rcv
run #15: crashed: BUG: soft lockup in srcu_reschedule
run #16: crashed: BUG: soft lockup in do_idle
run #17: crashed: BUG: soft lockup in do_idle
run #18: crashed: INFO: rcu detected stall in sys_newfstat
run #19: crashed: INFO: rcu detected stall in do_idle
testing current HEAD c500bee1c5b2f1d59b1081ac879d73268ab0ff17
testing commit c500bee1c5b2f1d59b1081ac879d73268ab0ff17
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.1
kernel signature: f8d5ec53bab2c7fc22def9cd4fbc7121b738da64674467ad9b948cf53d618695
run #0: crashed: BUG: soft lockup in ext4_end_io_rsv_work
run #1: crashed: BUG: workqueue lockup
run #2: crashed: BUG: workqueue lockup
run #3: crashed: INFO: rcu detected stall in do_idle
run #4: crashed: INFO: rcu detected stall in do_idle
run #5: crashed: BUG: workqueue lockup
run #6: crashed: INFO: rcu detected stall in sched_show_task
run #7: crashed: INFO: rcu detected stall in sys_getsockopt
run #8: crashed: INFO: rcu detected stall in dump_cpu_task
run #9: crashed: INFO: rcu detected stall in inet6_rtm_newaddr
revisions tested: 2, total time: 24m45.7309766s (build: 11m17.496036355s, test: 12m39.399214129s)
the crash still happens on HEAD
commit msg: Linux 5.14-rc4
crash: INFO: rcu detected stall in inet6_rtm_newaddr
rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-...!: (2 ticks this GP) idle=e66/1/0x4000000000000000 softirq=8571/8571 fqs=3 
	(t=24178 jiffies g=6513 q=802)
rcu: rcu_preempt kthread starved for 22911 jiffies! g6513 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
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:I stack:29528 pid:   13 ppid:     2 flags:0x00004000
Call Trace:
 context_switch kernel/sched/core.c:4683 [inline]
 __schedule+0x8e8/0x2170 kernel/sched/core.c:5940
 schedule+0xd3/0x270 kernel/sched/core.c:6019
 schedule_timeout+0x11d/0x250 kernel/time/timer.c:1879
 rcu_gp_fqs_loop kernel/rcu/tree.c:1996 [inline]
 rcu_gp_kthread+0xd54/0x18f0 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:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 7388 Comm: kworker/1:4 Not tainted 5.14.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: rcu_gp wait_rcu_exp_gp
RIP: 0010:_compound_head include/linux/page-flags.h:185 [inline]
RIP: 0010:virt_to_head_page include/linux/mm.h:901 [inline]
RIP: 0010:____kasan_slab_free mm/kasan/common.c:344 [inline]
RIP: 0010:__kasan_slab_free+0x32/0xe0 mm/kasan/common.c:374
Code: 41 54 49 89 f4 55 48 89 d5 53 89 cb e8 07 18 89 ff 41 8b 75 14 48 ba 00 00 00 00 00 ea ff ff 48 c1 e8 0c 48 c1 e0 06 48 01 d0 <48> 8b 50 08 48 89 f7 48 8d 4a ff 83 e2 01 48 0f 45 c1 48 8b 48 28
RSP: 0018:ffffc90000378d88 EFLAGS: 00010082
RAX: ffffea000426ff40 RBX: 0000000000000000 RCX: 000000000000002e
RDX: ffffea0000000000 RSI: 0000000000000280 RDI: ffff888109bfd7c0
RBP: ffffffff8362010c R08: 0000000000000000 R09: ffffffff8c730a53
R10: fffffbfff18e614a R11: 0000000000000000 R12: ffff888109bfd7c0
R13: ffff888109b75a00 R14: 0000000000000004 R15: ffff888110db3e60
FS:  0000000000000000(0000) GS:ffff8881f6500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9d0592a000 CR3: 000000011cdaf004 CR4: 00000000001706e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 kasan_slab_free include/linux/kasan.h:230 [inline]
 __cache_free mm/slab.c:3445 [inline]
 kmem_cache_free.part.0+0x72/0x200 mm/slab.c:3740
 __sg_free_table+0x14c/0x270 lib/scatterlist.c:225
 scsi_free_sgtables drivers/scsi/scsi_lib.c:492 [inline]
 scsi_mq_uninit_cmd drivers/scsi/scsi_lib.c:502 [inline]
 scsi_end_request+0x437/0x7a0 drivers/scsi/scsi_lib.c:566
 scsi_io_completion+0x186/0x11b0 drivers/scsi/scsi_lib.c:936
 blk_complete_reqs+0x90/0xc0 block/blk-mq.c:577
 __do_softirq+0x206/0xa19 kernel/softirq.c:558
 invoke_softirq kernel/softirq.c:432 [inline]
 __irq_exit_rcu kernel/softirq.c:636 [inline]
 irq_exit_rcu+0x229/0x270 kernel/softirq.c:648
 common_interrupt+0xa4/0xd0 arch/x86/kernel/irq.c:240
 </IRQ>
 asm_common_interrupt+0x1e/0x40 arch/x86/include/asm/idtentry.h:629
RIP: 0010:arch_local_irq_restore arch/x86/include/asm/irqflags.h:141 [inline]
RIP: 0010:console_trylock_spinning kernel/printk/printk.c:1887 [inline]
RIP: 0010:vprintk_emit+0x42b/0x4c0 kernel/printk/printk.c:2173
Code: 89 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 0f 85 88 00 00 00 48 83 3d 6e 3c 00 08 00 74 10 fb 66 0f 1f 44 00 00 <e9> ee fe ff ff 0f 0b 0f 0b 0f 0b 0f 0b 4c 89 f7 e8 10 98 50 00 e9
RSP: 0018:ffffc90004bb7b10 EFLAGS: 00000286
RAX: 1ffffffff12aea90 RBX: 0000000000000200 RCX: 1ffffffff1849f6a
RDX: dffffc0000000000 RSI: ffffffff87eb6120 RDI: ffffffff8833f160
RBP: ffffc90004bb7b48 R08: 0000000000000001 R09: ffffffff8c242bc7
R10: fffffbfff1848578 R11: fffffffffff9da30 R12: 0000000000000023
R13: ffffffff87ecc260 R14: 1ffffffff12aea8e R15: 0000000000000000
 printk+0xad/0xde kernel/printk/printk.c:2216
 synchronize_rcu_expedited_wait kernel/rcu/tree_exp.h:544 [inline]
 rcu_exp_wait_wake.cold+0x63/0x4df kernel/rcu/tree_exp.h:584
 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
NMI backtrace for cpu 0
CPU: 0 PID: 6131 Comm: syz-executor.1 Not tainted 5.14.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xbd/0xe2 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+0x232/0x360 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+0x36a/0x66e kernel/rcu/tree.c:2641
 update_process_times+0x131/0x1a0 kernel/time/timer.c:1783
 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+0x19e/0xba0 kernel/time/hrtimer.c:1601
 hrtimer_interrupt+0x2ef/0x900 kernel/time/hrtimer.c:1663
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1089 [inline]
 __sysvec_apic_timer_interrupt+0x13e/0x520 arch/x86/kernel/apic/apic.c:1106
 sysvec_apic_timer_interrupt+0x8e/0xc0 arch/x86/kernel/apic/apic.c:1100
 </IRQ>
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638
RIP: 0010:addrconf_verify_rtnl+0x131/0xd30 net/ipv6/addrconf.c:4476
Code: 00 48 81 ed 48 01 00 00 0f 84 9c 01 00 00 48 8b 44 24 28 48 83 c0 02 48 89 04 24 4c 8d 65 6c 4c 89 e0 48 c1 e8 03 0f b6 14 18 <4c> 89 e0 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 6b 08 00 00 f6
RSP: 0018:ffffc900010576c0 EFLAGS: 00000a07
RAX: 1ffff11025d9d68d RBX: dffffc0000000000 RCX: 1ffffffff1250158
RDX: 0000000000000000 RSI: ffffffff8833f0e0 RDI: ffffffff896cdd70
RBP: ffff88812eceb400 R08: 0000000000000001 R09: ffffffff8c242bc7
R10: fffffbfff1848578 R11: 0000000000000000 R12: ffff88812eceb46c
R13: 00000000ffffcf30 R14: ffff888123558c00 R15: ffffc90001057828
 inet6_addr_add+0x402/0x8c0 net/ipv6/addrconf.c:2968
 inet6_rtm_newaddr+0x5d3/0x18c0 net/ipv6/addrconf.c:4871
 rtnetlink_rcv_msg+0x31d/0x8d0 net/core/rtnetlink.c:5574
 netlink_rcv_skb+0x118/0x370 net/netlink/af_netlink.c:2504
 netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline]
 netlink_unicast+0x42e/0x700 net/netlink/af_netlink.c:1340
 netlink_sendmsg+0x704/0xbf0 net/netlink/af_netlink.c:1929
 sock_sendmsg_nosec net/socket.c:703 [inline]
 sock_sendmsg+0xab/0xe0 net/socket.c:723
 __sys_sendto+0x1a4/0x270 net/socket.c:2019
 __do_sys_sendto net/socket.c:2031 [inline]
 __se_sys_sendto net/socket.c:2027 [inline]
 __x64_sys_sendto+0xd8/0x1b0 net/socket.c:2027
 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: 0033:0x417e5c
Code: fa fa ff ff 44 8b 4c 24 2c 4c 8b 44 24 20 89 c5 44 8b 54 24 28 48 8b 54 24 18 b8 2c 00 00 00 48 8b 74 24 10 8b 7c 24 08 0f 05 <48> 3d 00 f0 ff ff 77 34 89 ef 48 89 44 24 08 e8 20 fb ff ff 48 8b
RSP: 002b:00007ffe7eb10360 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 0000000001493720 RCX: 0000000000417e5c
RDX: 0000000000000040 RSI: 0000000001493770 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00007ffe7eb103a4 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000003 R15: 0000000001493770