bisecting fixing commit since 4fa640dc52302b5e62b01b05c755b055549633ae
building syzkaller on d88894e6773ab63ac8b3f4b2edbae88290aaf0d6
testing commit 4fa640dc52302b5e62b01b05c755b055549633ae
compiler: gcc (GCC) 8.4.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2
kernel signature: 36c63fda3960456ba6291ae4a5e7feed0e590a268e9065c5df75bcd021e52baa
run #0: crashed: BUG: soft lockup in do_idle
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 do_idle
run #7: crashed: BUG: soft lockup in do_idle
run #8: crashed: BUG: soft lockup in do_idle
run #9: crashed: BUG: soft lockup in rtnl_newlink
run #10: crashed: BUG: soft lockup in do_idle
run #11: crashed: BUG: soft lockup in rtnl_newlink
run #12: crashed: BUG: soft lockup in khugepaged
run #13: crashed: BUG: soft lockup in wg_ratelimiter_gc_entries
run #14: crashed: BUG: soft lockup in addrconf_dad_work
run #15: crashed: BUG: soft lockup in do_idle
run #16: crashed: BUG: soft lockup in addrconf_dad_work
run #17: crashed: BUG: soft lockup in rtnl_newlink
run #18: crashed: BUG: workqueue lockup
run #19: crashed: BUG: soft lockup in iterate_cleanup_work
testing current HEAD 58e1100fdc5990b0cc0d4beaf2562a92e621ac7d
testing commit 58e1100fdc5990b0cc0d4beaf2562a92e621ac7d
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2
kernel signature: 8c2eab59c2ee904ac522a4273f85ca0725bf8900c9de442bec5177104ab6e950
run #0: crashed: BUG: soft lockup in process_srcu
run #1: crashed: BUG: soft lockup in do_idle
run #2: crashed: BUG: soft lockup in ext4_end_io_rsv_work
run #3: crashed: BUG: workqueue lockup
run #4: crashed: BUG: soft lockup in linkwatch_event
run #5: crashed: BUG: soft lockup in sys_lsetxattr
run #6: crashed: BUG: soft lockup in rtnl_newlink
run #7: crashed: BUG: soft lockup in ext4_end_io_rsv_work
run #8: crashed: BUG: soft lockup in rtnl_newlink
run #9: crashed: BUG: soft lockup in queue_delayed_work_on
revisions tested: 2, total time: 22m27.16609159s (build: 11m21.726160409s, test: 10m16.273060071s)
the crash still happens on HEAD
commit msg: MAINTAINERS: co-maintain random.c
crash: BUG: soft lockup in queue_delayed_work_on
watchdog: BUG: soft lockup - CPU#0 stuck for 82s! [kworker/u4:1:38]
Modules linked in:
irq event stamp: 944468
hardirqs last  enabled at (944467): [<ffffffff81471d10>] queue_delayed_work_on+0xc0/0x160 kernel/workqueue.c:1707
hardirqs last disabled at (944468): [<ffffffff879fe10b>] sysvec_apic_timer_interrupt+0xb/0xc0 arch/x86/kernel/apic/apic.c:1097
softirqs last  enabled at (944460): [<ffffffff8759823b>] spin_unlock_bh include/linux/spinlock.h:394 [inline]
softirqs last  enabled at (944460): [<ffffffff8759823b>] __batadv_dat_purge.part.0+0x20b/0x330 net/batman-adv/distributed-arp-table.c:187
softirqs last disabled at (944458): [<ffffffff8759811d>] spin_lock_bh include/linux/spinlock.h:354 [inline]
softirqs last disabled at (944458): [<ffffffff8759811d>] __batadv_dat_purge.part.0+0xed/0x330 net/batman-adv/distributed-arp-table.c:175
CPU: 0 PID: 38 Comm: kworker/u4:1 Not tainted 5.16.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: bat_events batadv_dat_purge
RIP: 0010:queue_delayed_work_on+0xec/0x160 kernel/workqueue.c:1709
Code: c0 40 8d 77 89 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 75 69 48 83 3d 0d 70 30 08 00 74 3b fb 66 0f 1f 44 00 00 <5b> 44 89 f8 5d 41 5c 41 5d 41 5e 41 5f c3 4c 89 f1 4c 89 e2 4c 89
RSP: 0018:ffffc90000497cf0 EFLAGS: 00000282
RAX: 1ffffffff12ef1a8 RBX: 0000000000000200 RCX: 1ffffffff18a4a16
RDX: dffffc0000000000 RSI: ffffffff880b8b60 RDI: ffffffff885541e0
RBP: 0000000000000040 R08: 0000000000000001 R09: ffffffff8c4c1d4f
R10: fffffbfff18983a9 R11: 1ffffffff1809b3d R12: ffff88816c7c94b0
R13: ffff8881100b5800 R14: 00000000000003e8 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff8881f6400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055a17eb2e0e8 CR3: 000000010c25f005 CR4: 00000000003706f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 process_one_work+0x87f/0x1450 kernel/workqueue.c:2298
 worker_thread+0x598/0x1040 kernel/workqueue.c:2445
 kthread+0x3ab/0x480 kernel/kthread.c:327
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
----------------
Code disassembly (best guess), 1 bytes skipped:
   0:	40 8d 77 89          	rex lea -0x77(%rdi),%esi
   4:	48 ba 00 00 00 00 00 	movabs $0xdffffc0000000000,%rdx
   b:	fc ff df
   e:	48 c1 e8 03          	shr    $0x3,%rax
  12:	80 3c 10 00          	cmpb   $0x0,(%rax,%rdx,1)
  16:	75 69                	jne    0x81
  18:	48 83 3d 0d 70 30 08 	cmpq   $0x0,0x830700d(%rip)        # 0x830702d
  1f:	00
  20:	74 3b                	je     0x5d
  22:	fb                   	sti
  23:	66 0f 1f 44 00 00    	nopw   0x0(%rax,%rax,1)
* 29:	5b                   	pop    %rbx <-- trapping instruction
  2a:	44 89 f8             	mov    %r15d,%eax
  2d:	5d                   	pop    %rbp
  2e:	41 5c                	pop    %r12
  30:	41 5d                	pop    %r13
  32:	41 5e                	pop    %r14
  34:	41 5f                	pop    %r15
  36:	c3                   	retq
  37:	4c 89 f1             	mov    %r14,%rcx
  3a:	4c 89 e2             	mov    %r12,%rdx
  3d:	4c                   	rex.WR
  3e:	89                   	.byte 0x89