syzbot


WARNING in ip_rt_bug

Status: upstream: reported on 2025/12/25 15:31
Reported-by: syzbot+9ddd779b5859d2975072@syzkaller.appspotmail.com
First crash: 6d19h, last: 6d19h
Similar bugs (9)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 WARNING in ip_rt_bug -1 C error 2 1550d 2098d 0/1 upstream: reported C repro on 2020/04/03 11:53
linux-4.14 WARNING in ip_rt_bug -1 C inconclusive 1 2027d 2087d 0/1 upstream: reported C repro on 2020/04/15 03:43
linux-6.1 WARNING in ip_rt_bug (2) -1 1 637d 637d 0/3 auto-obsoleted due to no activity on 2024/07/13 04:22
linux-6.1 WARNING in ip_rt_bug -1 1 868d 868d 0/3 auto-obsoleted due to no activity on 2023/11/25 06:32
upstream WARNING in ip_rt_bug (2) net -1 C done error 506 4d12h 1176d 0/29 upstream: reported C repro on 2022/10/12 18:26
linux-5.15 WARNING in ip_rt_bug -1 7 240d 360d 0/3 auto-obsoleted due to no activity on 2025/08/13 17:11
upstream WARNING in ip_rt_bug net -1 1 2832d 2824d 0/29 auto-closed as invalid on 2019/02/22 10:34
linux-6.1 WARNING in ip_rt_bug (4) origin:upstream -1 C error 1 78d 115d 0/3 upstream: reported C repro on 2025/09/08 02:20
linux-6.1 WARNING in ip_rt_bug (3) -1 26 208d 376d 0/3 auto-obsoleted due to no activity on 2025/09/07 04:48

Sample crash report:
------------[ cut here ]------------
WARNING: CPU: 0 PID: 7737 at net/ipv4/route.c:1283 kfree_skb include/linux/skbuff.h:1232 [inline]
WARNING: CPU: 0 PID: 7737 at net/ipv4/route.c:1283 ip_rt_bug+0x29/0x100 net/ipv4/route.c:1282
Modules linked in:
CPU: 0 PID: 7737 Comm: syz.4.347 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:ip_rt_bug+0x29/0x100 net/ipv4/route.c:1283
Code: 90 f3 0f 1e fa 41 57 41 56 41 55 41 54 53 48 89 d3 e8 9b c0 a3 f8 66 90 e8 94 c0 a3 f8 48 89 df be 02 00 00 00 e8 97 86 7a ff <0f> 0b 31 c0 5b 41 5c 41 5d 41 5e 41 5f c3 f3 0f 1e fa 49 bd 00 00
RSP: 0000:ffffc90000007678 EFLAGS: 00010296
RAX: 3512b860b81f0d00 RBX: ffff8880244cdb40 RCX: 3512b860b81f0d00
RDX: dffffc0000000000 RSI: ffffffff8aaabce0 RDI: ffffffff8afc6f80
RBP: ffff88807a041f00 R08: ffffffff90d9459f R09: 1ffffffff21b28b3
R10: dffffc0000000000 R11: fffffbfff21b28b4 R12: ffff88807a041f30
R13: ffff8880244cdb98 R14: ffff8880244cdb40 R15: ffff8881416a0d00
FS:  00007ff1428206c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffffffffffffe70 CR3: 0000000075c0a000 CR4: 00000000003506f0
Call Trace:
 <IRQ>
 dst_output include/net/dst.h:467 [inline]
 ip_local_out net/ipv4/ip_output.c:129 [inline]
 ip_send_skb+0x12f/0x1d0 net/ipv4/ip_output.c:1491
 __icmp_send+0xfc1/0x1320 net/ipv4/icmp.c:785
 ipv4_send_dest_unreach net/ipv4/route.c:1263 [inline]
 ipv4_link_failure+0x64f/0xa20 net/ipv4/route.c:1270
 dst_link_failure include/net/dst.h:437 [inline]
 arp_error_report+0x112/0x160 net/ipv4/arp.c:296
 neigh_invalidate+0x22c/0x450 net/core/neighbour.c:1064
 neigh_timer_handler+0x914/0xff0 net/core/neighbour.c:1151
 call_timer_fn+0x16e/0x530 kernel/time/timer.c:1701
 expire_timers kernel/time/timer.c:1752 [inline]
 __run_timers+0x52d/0x7d0 kernel/time/timer.c:2023
 run_timer_softirq+0x67/0xf0 kernel/time/timer.c:2036
 handle_softirqs+0x280/0x820 kernel/softirq.c:578
 __do_softirq kernel/softirq.c:612 [inline]
 invoke_softirq kernel/softirq.c:452 [inline]
 __irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661
 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
 sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:cap_vm_enough_memory+0x0/0x240 security/commoncap.c:1401
Code: ff e8 24 f0 ac fd be 01 00 00 00 48 c7 c7 e0 79 34 8d 4c 89 f2 e8 c0 64 79 00 e9 cc fc ff ff 66 2e 0f 1f 84 00 00 00 00 00 90 <f3> 0f 1e fa 55 41 57 41 56 41 55 41 54 53 50 49 bd 00 00 00 00 00
RSP: 0000:ffffc90003946de8 EFLAGS: 00000246
RAX: 1ffffffff18f931c RBX: 0000000000000001 RCX: ffff888029305a00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff88807d4c7200
RBP: 0000000000000001 R08: ffff888029305a00 R09: 0000000000000003
R10: 0000000000000003 R11: 0000000000000000 R12: ffffffff8c7c98e0
R13: dffffc0000000000 R14: ffff88807d4c7200 R15: ffffffff8c7c98c8
 security_vm_enough_memory_mm+0x6b/0xa0 security/security.c:1035
 shmem_acct_block mm/shmem.c:199 [inline]
 shmem_inode_acct_block+0xd8/0x460 mm/shmem.c:215
 shmem_alloc_and_acct_folio+0xb2/0x630 mm/shmem.c:1697
 shmem_get_folio_gfp+0xcde/0x2ac0 mm/shmem.c:2041
 shmem_get_folio mm/shmem.c:2164 [inline]
 shmem_write_begin+0xf2/0x420 mm/shmem.c:2706
 generic_perform_write+0x2fb/0x5b0 mm/filemap.c:4031
 shmem_file_write_iter+0xfb/0x120 mm/shmem.c:2883
 __kernel_write_iter+0x274/0x670 fs/read_write.c:517
 dump_emit_page fs/coredump.c:957 [inline]
 dump_user_range+0x3f6/0x800 fs/coredump.c:984
 elf_core_dump+0x3114/0x36e0 fs/binfmt_elf.c:2184
 do_coredump+0x1755/0x2480 fs/coredump.c:833
 get_signal+0x1133/0x1400 kernel/signal.c:2888
 arch_do_signal_or_restart+0x9c/0x7b0 arch/x86/kernel/signal.c:310
 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0xf6/0x180 kernel/entry/common.c:210
 irqentry_exit_to_user_mode+0x9/0x40 kernel/entry/common.c:315
 exc_page_fault+0x8f/0x110 arch/x86/mm/fault.c:1524
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:608
RIP: 0033:0x7ff14198f751
Code: 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 83 c8 ff c3 66 2e 0f 1f
RSP: 002b:fffffffffffffe70 EFLAGS: 00010217
RAX: 0000000000000000 RBX: 00007ff141be6090 RCX: 00007ff14198f749
RDX: 0000000000000000 RSI: fffffffffffffe70 RDI: 0000000000008000
RBP: 00007ff141a13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007ff141be6128 R14: 00007ff141be6090 R15: 00007ffef4762628
 </TASK>
----------------
Code disassembly (best guess), 1 bytes skipped:
   0:	e8 24 f0 ac fd       	call   0xfdacf029
   5:	be 01 00 00 00       	mov    $0x1,%esi
   a:	48 c7 c7 e0 79 34 8d 	mov    $0xffffffff8d3479e0,%rdi
  11:	4c 89 f2             	mov    %r14,%rdx
  14:	e8 c0 64 79 00       	call   0x7964d9
  19:	e9 cc fc ff ff       	jmp    0xfffffcea
  1e:	66 2e 0f 1f 84 00 00 	cs nopw 0x0(%rax,%rax,1)
  25:	00 00 00
  28:	90                   	nop
* 29:	f3 0f 1e fa          	endbr64 <-- trapping instruction
  2d:	55                   	push   %rbp
  2e:	41 57                	push   %r15
  30:	41 56                	push   %r14
  32:	41 55                	push   %r13
  34:	41 54                	push   %r12
  36:	53                   	push   %rbx
  37:	50                   	push   %rax
  38:	49                   	rex.WB
  39:	bd 00 00 00 00       	mov    $0x0,%ebp

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/12/25 15:30 linux-6.6.y 5fa4793a2d2d d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in ip_rt_bug
* Struck through repros no longer work on HEAD.