bisecting fixing commit since 4fa640dc52302b5e62b01b05c755b055549633ae building syzkaller on d88894e6773ab63ac8b3f4b2edbae88290aaf0d6 testing commit 4fa640dc52302b5e62b01b05c755b055549633ae with gcc (GCC) 8.4.1 20210217 kernel signature: 01ec0811025845132e25eee53b8aad732d2001a20ac9fec49e0d1dea11407386 run #0: crashed: BUG: soft lockup in do_idle run #1: crashed: BUG: workqueue lockup run #2: crashed: BUG: soft lockup in do_idle run #3: crashed: BUG: soft lockup in do_idle run #4: crashed: BUG: soft lockup in do_idle run #5: crashed: BUG: soft lockup in wb_workfn run #6: crashed: BUG: workqueue lockup run #7: crashed: BUG: soft lockup in do_idle 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 do_idle run #12: crashed: BUG: soft lockup in do_idle run #13: crashed: BUG: soft lockup in do_idle run #14: crashed: BUG: soft lockup in do_idle run #15: crashed: BUG: soft lockup in do_idle run #16: crashed: BUG: soft lockup in do_idle run #17: crashed: BUG: soft lockup in do_idle run #18: crashed: BUG: soft lockup in addrconf_dad_work run #19: crashed: BUG: soft lockup in do_idle testing current HEAD 17ae69aba89dbfa2139b7f8024b757ab3cc42f59 testing commit 17ae69aba89dbfa2139b7f8024b757ab3cc42f59 with gcc (GCC) 10.2.1 20210217 kernel signature: 320c308bf99803fc4e255ba831f93f96b7a53bd43ad57d130390672058d38af9 run #0: crashed: BUG: soft lockup in security_file_ioctl run #1: crashed: BUG: soft lockup in do_idle run #2: crashed: BUG: soft lockup in do_idle run #3: crashed: BUG: soft lockup in do_idle run #4: crashed: BUG: soft lockup in do_idle run #5: crashed: BUG: soft lockup in do_idle run #6: crashed: BUG: soft lockup in ext4_end_io_rsv_work run #7: crashed: INFO: rcu detected stall in do_idle run #8: crashed: BUG: soft lockup in do_idle run #9: crashed: BUG: soft lockup in batadv_dat_purge revisions tested: 2, total time: 23m33.062820048s (build: 12m19.883098183s, test: 10m13.526873001s) the crash still happens on HEAD commit msg: Merge tag 'landlock_v34' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security crash: BUG: soft lockup in batadv_dat_purge watchdog: BUG: soft lockup - CPU#0 stuck for 103s! [kworker/u4:2:27] Modules linked in: irq event stamp: 1068869 hardirqs last enabled at (1068867): [] __local_bh_enable_ip+0x11f/0x220 kernel/softirq.c:389 hardirqs last disabled at (1068869): [] sysvec_apic_timer_interrupt+0xb/0xc0 arch/x86/kernel/apic/apic.c:1100 softirqs last enabled at (1068866): [] spin_unlock_bh include/linux/spinlock.h:399 [inline] softirqs last enabled at (1068866): [] __batadv_dat_purge.part.0+0x20b/0x330 net/batman-adv/distributed-arp-table.c:184 softirqs last disabled at (1068868): [] spin_lock_bh include/linux/spinlock.h:359 [inline] softirqs last disabled at (1068868): [] __batadv_dat_purge.part.0+0xed/0x330 net/batman-adv/distributed-arp-table.c:172 CPU: 0 PID: 27 Comm: kworker/u4:2 Not tainted 5.12.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: bat_events batadv_dat_purge RIP: 0010:arch_local_irq_enable+0x2c/0x40 arch/x86/include/asm/paravirt.h:694 Code: c0 80 41 37 89 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 75 14 48 83 3d 9d d3 e3 07 00 74 08 fb 66 0f 1f 44 00 00 0f 0b 48 c7 c7 80 41 37 89 e8 d5 e4 51 00 eb de 0f 1f 00 48 b8 RSP: 0018:ffffc900001d7b78 EFLAGS: 00000282 RAX: 1ffffffff126e830 RBX: 0000000000000003 RCX: 0000000000000001 RDX: dffffc0000000000 RSI: ffffffff87cb4900 RDI: ffffffff88132660 RBP: ffffffff894c8300 R08: 0000000000000000 R09: ffffffff8a441017 R10: fffffbfff1488202 R11: 0000000000000001 R12: ffff888100b181c0 R13: 0000000000000000 R14: 00000000ffffffff R15: ffff888100b18bb0 FS: 0000000000000000(0000) GS:ffff8881f6400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f4c0ec3c06c CR3: 0000000124c18001 CR4: 00000000001706f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: arch_local_irq_restore arch/x86/include/asm/irqflags.h:140 [inline] lock_is_held_type+0xfa/0x130 kernel/locking/lockdep.c:5557 lock_is_held include/linux/lockdep.h:283 [inline] rcu_read_lock_sched_held+0x3a/0xb0 kernel/rcu/update.c:125 trace_lock_release include/trace/events/lock.h:58 [inline] lock_release+0x60e/0x7e0 kernel/locking/lockdep.c:5523 __raw_spin_unlock_bh include/linux/spinlock_api_smp.h:174 [inline] _raw_spin_unlock_bh+0x12/0x30 kernel/locking/spinlock.c:207 spin_unlock_bh include/linux/spinlock.h:399 [inline] __batadv_dat_purge.part.0+0x20b/0x330 net/batman-adv/distributed-arp-table.c:184 __batadv_dat_purge net/batman-adv/distributed-arp-table.c:165 [inline] batadv_dat_purge+0x3d/0x50 net/batman-adv/distributed-arp-table.c:203 process_one_work+0x84c/0x13b0 kernel/workqueue.c:2275 worker_thread+0x598/0xf80 kernel/workqueue.c:2421 kthread+0x36f/0x450 kernel/kthread.c:313 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294