------------[ cut here ]------------
WARNING: net/ipv4/ipmr.c:2302 at ip_mr_output+0xbb1/0xe70 net/ipv4/ipmr.c:2302, CPU#0: syz.6.7976/1872
Modules linked in:
CPU: 0 UID: 0 PID: 1872 Comm: syz.6.7976 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:ffffc90000007900 EFLAGS: 00010246
RAX: ffffffff8a01ba60 RBX: ffff88805d7d3b40 RCX: ffff888025293c00
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90000007a10 R08: ffff888025293c00 R09: 0000000000000004
R10: 0000000000000003 R11: ffffffff8a01aeb0 R12: 0000000000000010
R13: dffffc0000000000 R14: ffff88805bb6ca00 R15: 0000000000000000
FS:  00007f7b028956c0(0000) GS:ffff888125c1e000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7af75ff000 CR3: 0000000027d4e000 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:lock_acquire+0x175/0x360 kernel/locking/lockdep.c:5875
Code: 00 00 00 00 9c 8f 44 24 30 f7 44 24 30 00 02 00 00 0f 85 cd 00 00 00 f7 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 5b 83 02 11 <48> 3b 44 24 58 0f 85 f2 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e
RSP: 0018:ffffc9000cf3f658 EFLAGS: 00000206
RAX: 0b3445cc4b42f100 RBX: 0000000000000000 RCX: 0b3445cc4b42f100
RDX: 0000000000000000 RSI: ffffffff8db80736 RDI: ffffffff8be31f80
RBP: ffffffff8235ef68 R08: 0000000000000000 R09: ffffffff8235ef68
R10: dffffc0000000000 R11: fffffbfff1f43206 R12: 0000000000000000
R13: ffff8880329549f0 R14: 0000000000000001 R15: 0000000000000246
 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
 _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
 spin_lock include/linux/spinlock.h:351 [inline]
 inode_add_bytes+0x38/0x140 fs/stat.c:931
 __dquot_alloc_space+0x285/0xea0 fs/quota/dquot.c:1695
 dquot_alloc_space_nodirty include/linux/quotaops.h:299 [inline]
 dquot_alloc_block_nodirty include/linux/quotaops.h:326 [inline]
 shmem_inode_acct_blocks+0x2a5/0x470 mm/shmem.c:243
 shmem_alloc_and_add_folio+0x8bc/0xf60 mm/shmem.c:1940
 shmem_get_folio_gfp+0x59d/0x1660 mm/shmem.c:2537
 shmem_get_folio mm/shmem.c:2643 [inline]
 shmem_write_begin+0xf7/0x2b0 mm/shmem.c:3293
 generic_perform_write+0x2c7/0x910 mm/filemap.c:4175
 shmem_file_write_iter+0xf8/0x120 mm/shmem.c:3468
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0x548/0xa90 fs/read_write.c:686
 ksys_write+0x145/0x250 fs/read_write.c:738
 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: 0033:0x7f7b0198d3df
Code: 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 f9 92 02 00 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 48 89 44 24 08 e8 4c 93 02 00 48
RSP: 002b:00007f7b02894df0 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000400000 RCX: 00007f7b0198d3df
RDX: 0000000000400000 RSI: 00007f7af7200000 RDI: 0000000000000008
RBP: 0000000000000000 R08: 0000000000000000 R09: 00000000000011eb
R10: 0000000000000002 R11: 0000000000000293 R12: 0000000000000008
R13: 00007f7b02894ef0 R14: 00007f7b02894eb0 R15: 00007f7af7200000
 </TASK>
----------------
Code disassembly (best guess):
   0:	00 00                	add    %al,(%rax)
   2:	00 00                	add    %al,(%rax)
   4:	9c                   	pushf
   5:	8f 44 24 30          	pop    0x30(%rsp)
   9:	f7 44 24 30 00 02 00 	testl  $0x200,0x30(%rsp)
  10:	00
  11:	0f 85 cd 00 00 00    	jne    0xe4
  17:	f7 44 24 08 00 02 00 	testl  $0x200,0x8(%rsp)
  1e:	00
  1f:	74 01                	je     0x22
  21:	fb                   	sti
  22:	65 48 8b 05 5b 83 02 	mov    %gs:0x1102835b(%rip),%rax        # 0x11028385
  29:	11
* 2a:	48 3b 44 24 58       	cmp    0x58(%rsp),%rax <-- trapping instruction
  2f:	0f 85 f2 00 00 00    	jne    0x127
  35:	48 83 c4 60          	add    $0x60,%rsp
  39:	5b                   	pop    %rbx
  3a:	41 5c                	pop    %r12
  3c:	41 5d                	pop    %r13
  3e:	41 5e                	pop    %r14