------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 1 PID: 15497 at lib/refcount.c:28 refcount_warn_saturate+0x1d1/0x1e0 lib/refcount.c:28
Modules linked in:
CPU: 1 PID: 15497 Comm: syz-executor.1 Not tainted 5.16.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:refcount_warn_saturate+0x1d1/0x1e0 lib/refcount.c:28
Code: e9 db fe ff ff 48 89 df e8 3c ff e1 fd e9 8a fe ff ff e8 82 c4 9b fd 48 c7 c7 00 5c 04 8a c6 05 cf 9a a1 09 01 e8 35 57 25 05 <0f> 0b e9 af fe ff ff 0f 1f 84 00 00 00 00 00 41 56 41 55 41 54 55
RSP: 0018:ffffc90000fd8d00 EFLAGS: 00010282
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: ffff88802e8f00c0 RSI: ffffffff815e3a18 RDI: fffff520001fb192
RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000001
R10: ffffffff815dd7be R11: 0000000000000000 R12: ffff88801438c820
R13: 1ffff920001fb1a8 R14: ffffffff886228c0 R15: 0000000000000000
FS:  00007f5c4c703700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fcef311f180 CR3: 000000007516d000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 __refcount_sub_and_test include/linux/refcount.h:283 [inline]
 __refcount_dec_and_test include/linux/refcount.h:315 [inline]
 refcount_dec_and_test include/linux/refcount.h:333 [inline]
 sctp_transport_put+0x138/0x180 net/sctp/transport.c:486
 call_timer_fn+0x1a5/0x6b0 kernel/time/timer.c:1421
 expire_timers kernel/time/timer.c:1466 [inline]
 __run_timers.part.0+0x67c/0xa30 kernel/time/timer.c:1734
 __run_timers kernel/time/timer.c:1715 [inline]
 run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1747
 __do_softirq+0x29b/0x9c2 kernel/softirq.c:558
 invoke_softirq kernel/softirq.c:432 [inline]
 __irq_exit_rcu+0x123/0x180 kernel/softirq.c:637
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:649
 sysvec_apic_timer_interrupt+0x93/0xc0 arch/x86/kernel/apic/apic.c:1097
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638
RIP: 0010:lock_acquire+0x1ef/0x510 kernel/locking/lockdep.c:5605
Code: 96 a6 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:ffffc900051ffd10 EFLAGS: 00000206
RAX: dffffc0000000000 RBX: 1ffff92000a3ffa4 RCX: 7e8285bf9ccb5258
RDX: 1ffff11005d1e163 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff8ff7aa07
R10: fffffbfff1fef540 R11: 0000000000000000 R12: 0000000000000002
R13: 0000000000000000 R14: ffffffff8bb812a0 R15: 0000000000000000
 rcu_lock_acquire include/linux/rcupdate.h:268 [inline]
 rcu_read_lock include/linux/rcupdate.h:688 [inline]
 __fget_files+0x4c/0x470 fs/file.c:904
 __fget fs/file.c:914 [inline]
 __fget_light fs/file.c:1009 [inline]
 __fget_light+0xd4/0x280 fs/file.c:998
 fdget include/linux/file.h:65 [inline]
 ksys_pwrite64 fs/read_write.c:693 [inline]
 __do_sys_pwrite64 fs/read_write.c:707 [inline]
 __se_sys_pwrite64 fs/read_write.c:704 [inline]
 __x64_sys_pwrite64+0x10f/0x250 fs/read_write.c:704
 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: 0033:0x7f5c4dd40e67
Code: 08 89 3c 24 48 89 4c 24 18 e8 e5 f8 ff ff 4c 8b 54 24 18 48 8b 54 24 10 41 89 c0 48 8b 74 24 08 8b 3c 24 b8 12 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 48 89 04 24 e8 15 f9 ff ff 48 8b
RSP: 002b:00007f5c4c702f00 EFLAGS: 00000293 ORIG_RAX: 0000000000000012
RAX: ffffffffffffffda RBX: 00007f5c4ddd79c8 RCX: 00007f5c4dd40e67
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 0000000000003c02 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003
R13: 0000000000000003 R14: 000000002002f5d0 R15: 0000000000001f7e
 </TASK>
----------------
Code disassembly (best guess):
   0:	96                   	xchg   %eax,%esi
   1:	a6                   	cmpsb  %es:(%rdi),%ds:(%rsi)
   2:	7e 83                	jle    0xffffff87
   4:	f8                   	clc
   5:	01 0f                	add    %ecx,(%rdi)
   7:	85 b4 02 00 00 9c 58 	test   %esi,0x589c0000(%rdx,%rax,1)
   e:	f6 c4 02             	test   $0x2,%ah
  11:	0f 85 9f 02 00 00    	jne    0x2b6
  17:	48 83 7c 24 08 00    	cmpq   $0x0,0x8(%rsp)
  1d:	74 01                	je     0x20
  1f:	fb                   	sti
  20:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  27:	fc ff df
* 2a:	48 01 c3             	add    %rax,%rbx <-- trapping instruction
  2d:	48 c7 03 00 00 00 00 	movq   $0x0,(%rbx)
  34:	48 c7 43 08 00 00 00 	movq   $0x0,0x8(%rbx)
  3b:	00
  3c:	48                   	rex.W
  3d:	8b                   	.byte 0x8b
  3e:	84                   	.byte 0x84
  3f:	24                   	.byte 0x24