------------[ cut here ]------------
WARNING: net/ipv4/ipmr.c:2302 at ip_mr_output+0xbb1/0xe70 net/ipv4/ipmr.c:2302, CPU#1: syz.2.782/9503
Modules linked in:
CPU: 1 UID: 0 PID: 9503 Comm: syz.2.782 Not tainted 6.16.0-rc3-next-20250627-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:ip_mr_output+0xbb1/0xe70 net/ipv4/ipmr.c:2302
Code: df e9 63 f6 ff ff e8 1e 18 be f7 48 8b 74 24 18 45 31 f6 31 ff ba 02 00 00 00 e8 0a fe 4b ff e9 45 f6 ff ff e8 00 18 be f7 90 <0f> 0b 90 e9 94 f5 ff ff e8 f2 17 be f7 90 0f 0b 90 42 80 3c 2b 00
RSP: 0018:ffffc90000a08900 EFLAGS: 00010246
RAX: ffffffff8a01ba60 RBX: ffff88805d1003c0 RCX: ffff88807cb25a00
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90000a08a10 R08: ffff88807cb25a00 R09: 0000000000000004
R10: 0000000000000003 R11: ffffffff8a01aeb0 R12: 0000000000000010
R13: dffffc0000000000 R14: ffff888051151c00 R15: 0000000000000000
FS:  0000555587b6e500(0000) GS:ffff888125d1e000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fecba7edbf8 CR3: 0000000024782000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 igmp_send_report+0x89e/0xdb0 net/ipv4/igmp.c:799
 igmp_timer_expire+0x204/0x510 net/ipv4/igmp.c:-1
 call_timer_fn+0x17b/0x5f0 kernel/time/timer.c:1747
 expire_timers kernel/time/timer.c:1798 [inline]
 __run_timers kernel/time/timer.c:2372 [inline]
 __run_timer_base+0x61a/0x860 kernel/time/timer.c:2384
 run_timer_base kernel/time/timer.c:2393 [inline]
 run_timer_softirq+0xb7/0x180 kernel/time/timer.c:2403
 handle_softirqs+0x286/0x870 kernel/softirq.c:579
 __do_softirq kernel/softirq.c:613 [inline]
 invoke_softirq kernel/softirq.c:453 [inline]
 __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:680
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:696
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1050
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:finish_task_switch+0x26b/0x950 kernel/sched/core.c:5181
Code: 0f 84 3c 01 00 00 48 85 db 0f 85 63 01 00 00 e9 27 05 00 00 4c 8b 75 d0 4c 89 e7 e8 1f 40 e0 09 e8 8a 12 36 00 fb 4c 8b 65 c0 <49> 8d bc 24 18 16 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 28 84 c0
RSP: 0018:ffffc90003f4f758 EFLAGS: 00000282
RAX: de82e89a76d95e00 RBX: 0000000000000000 RCX: de82e89a76d95e00
RDX: 0000000000000000 RSI: ffffffff8d992a42 RDI: ffffffff8be31f80
RBP: ffffc90003f4f7b0 R08: ffffffff8fa18937 R09: 1ffffffff1f43126
R10: dffffc0000000000 R11: fffffbfff1f43127 R12: ffff88807cb25a00
R13: dffffc0000000000 R14: ffff88802583da00 R15: ffff8880b873ab18
 context_switch kernel/sched/core.c:5316 [inline]
 __schedule+0x16fd/0x4d00 kernel/sched/core.c:6696
 __schedule_loop kernel/sched/core.c:6774 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6789
 futex_do_wait kernel/futex/waitwake.c:358 [inline]
 __futex_wait+0x1c3/0x3e0 kernel/futex/waitwake.c:687
 futex_wait+0x104/0x360 kernel/futex/waitwake.c:715
 do_futex+0x333/0x420 kernel/futex/syscalls.c:102
 __do_sys_futex kernel/futex/syscalls.c:179 [inline]
 __se_sys_futex+0x36f/0x400 kernel/futex/syscalls.c:160
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7846d8e929
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff68413368 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 0000000000058ac4 RCX: 00007f7846d8e929
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f7846fb5fac
RBP: 0000000000000226 R08: 7fffffffffffffff R09: 000000026841365f
R10: 00007fff68413460 R11: 0000000000000246 R12: 00007f7846fb5fac
R13: 00007fff68413460 R14: 0000000000058cea R15: 00007fff68413480
 </TASK>
----------------
Code disassembly (best guess):
   0:	0f 84 3c 01 00 00    	je     0x142
   6:	48 85 db             	test   %rbx,%rbx
   9:	0f 85 63 01 00 00    	jne    0x172
   f:	e9 27 05 00 00       	jmp    0x53b
  14:	4c 8b 75 d0          	mov    -0x30(%rbp),%r14
  18:	4c 89 e7             	mov    %r12,%rdi
  1b:	e8 1f 40 e0 09       	call   0x9e0403f
  20:	e8 8a 12 36 00       	call   0x3612af
  25:	fb                   	sti
  26:	4c 8b 65 c0          	mov    -0x40(%rbp),%r12
* 2a:	49 8d bc 24 18 16 00 	lea    0x1618(%r12),%rdi <-- trapping instruction
  31:	00
  32:	48 89 f8             	mov    %rdi,%rax
  35:	48 c1 e8 03          	shr    $0x3,%rax
  39:	42 0f b6 04 28       	movzbl (%rax,%r13,1),%eax
  3e:	84 c0                	test   %al,%al