syzbot


BUG: unable to handle kernel paging request in ip_route_output_key_hash_rcu

Status: upstream: reported C repro on 2025/10/13 20:16
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+132e7f07cb8a05d72f21@syzkaller.appspotmail.com
First crash: 113d, last: 30m
Fix bisection: failed (error log, bisect log)
  
Bug presence (2)
Date Name Commit Repro Result
2025/10/20 upstream (ToT) 211ddde0823f C [report] BUG: unable to handle kernel paging request in ip_route_output_key_hash_rcu
2026/01/24 upstream (ToT) 62085877ae65 C Failed due to an error; will retry later
Similar bugs (7)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KMSAN: uninit-value in ip_route_output_key_hash_rcu (4) net 7 2 1828d 1847d 0/29 auto-closed as invalid on 2021/06/01 04:17
upstream KMSAN: kernel-infoleak in copyout (2) net 17 C 6723 971d 2140d 22/29 fixed on 2023/06/08 14:41
upstream KMSAN: uninit-value in ip_route_output_key_hash_rcu (5) net 7 1 1526d 1526d 0/29 auto-closed as invalid on 2022/02/28 08:56
upstream general protection fault in ip_route_output_key_hash_rcu (2) net 2 2 613d 624d 0/29 closed as invalid on 2024/07/26 12:16
upstream general protection fault in ip_route_output_key_hash_rcu (3) net 7 4 342d 368d 28/29 fixed on 2025/06/10 16:19
upstream KMSAN: kernel-infoleak in _copy_to_iter (7) net 23 C 138977 1075d 1427d 22/29 fixed on 2023/02/24 13:50
upstream KMSAN: uninit-value in IP6_ECN_decapsulate net 7 C 981 777d 2693d 25/29 fixed on 2023/12/21 03:45

Sample crash report:
Unable to handle kernel paging request at virtual address ffff700031480000
KASAN: maybe wild-memory-access in range [0xffff80018a400000-0xffff80018a400007]
Mem abort info:
  ESR = 0x0000000096000006
  EC = 0x25: DABT (current EL), IL = 32 bits
  SET = 0, FnV = 0
  EA = 0, S1PTW = 0
  FSC = 0x06: level 2 translation fault
Data abort info:
  ISV = 0, ISS = 0x00000006
  CM = 0, WnR = 0
swapper pgtable: 4k pages, 48-bit VAs, pgdp=000000020dfa8000
[ffff700031480000] pgd=000000023ea48003, p4d=000000023ea48003, pud=000000023ea47003, pmd=0000000000000000
Internal error: Oops: 0000000096000006 [#1] PREEMPT SMP
Modules linked in:
CPU: 0 PID: 4514 Comm: syz.0.18 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/03/2025
pstate: 82400005 (Nzcv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--)
pc : __mkroute_output net/ipv4/route.c:2622 [inline]
pc : ip_route_output_key_hash_rcu+0xe38/0x1e38 net/ipv4/route.c:2850
lr : __mkroute_output net/ipv4/route.c:2613 [inline]
lr : ip_route_output_key_hash_rcu+0xdb8/0x1e38 net/ipv4/route.c:2850
sp : ffff800021307310
x29: ffff800021307360 x28: dfff800000000000 x27: 0000000000000001
x26: 0000000080000000 x25: ffff0000d3a6cc00 x24: ffff0000d9aa7620
x23: 0000000000000000 x22: ffff80018a400000 x21: ffff0000cbe2e000
x20: 0000000000000000 x19: 0000000000000000 x18: 000000007a1e01bb
x17: dfff800000000000 x16: ffff8000082d7e60 x15: 0000000000000000
x14: 0000000000000005 x13: 0000000000ff0100 x12: 0000000000ff0100
x11: ff00800010481b38 x10: 0000000000000000 x9 : ffff80018a400000
x8 : 1ffff00031480000 x7 : ffff8000105cc7c4 x6 : 0000000000000000
x5 : 0000000000000000 x4 : 0000000000000000 x3 : 0000000000000002
x2 : 0000000000000008 x1 : 0000000000000000 x0 : 0000000000000000
Call trace:
 __mkroute_output net/ipv4/route.c:2622 [inline]
 ip_route_output_key_hash_rcu+0xe38/0x1e38 net/ipv4/route.c:2850
 ip_route_output_key_hash+0x1b0/0x300 net/ipv4/route.c:2679
 __ip_route_output_key include/net/route.h:137 [inline]
 ip_route_output_flow+0x3c/0x160 net/ipv4/route.c:2909
 ip_route_output_key include/net/route.h:153 [inline]
 sctp_v4_get_dst+0x27c/0xda4 net/sctp/protocol.c:448
 sctp_transport_route+0xe8/0x258 net/sctp/transport.c:457
 sctp_assoc_add_peer+0x4e0/0x1560 net/sctp/associola.c:665
 sctp_connect_new_asoc+0x2f8/0x630 net/sctp/socket.c:1098
 sctp_sendmsg_new_asoc net/sctp/socket.c:1690 [inline]
 sctp_sendmsg+0x10d4/0x20b4 net/sctp/socket.c:2001
 inet_sendmsg+0x154/0x284 net/ipv4/af_inet.c:841
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg net/socket.c:730 [inline]
 __sys_sendto+0x324/0x440 net/socket.c:2152
 __do_sys_sendto net/socket.c:2164 [inline]
 __se_sys_sendto net/socket.c:2160 [inline]
 __arm64_sys_sendto+0xd8/0xf8 net/socket.c:2160
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585
Code: d538d089 8b080136 d343fec8 aa1703f4 (387c6908) 
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
   0:	d538d089 	mrs	x9, tpidr_el1
   4:	8b080136 	add	x22, x9, x8
   8:	d343fec8 	lsr	x8, x22, #3
   c:	aa1703f4 	mov	x20, x23
* 10:	387c6908 	ldrb	w8, [x8, x28] <-- trapping instruction

Crashes (26):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/01/30 18:56 linux-6.1.y cd9b81672742 ae7dc18c .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 BUG: unable to handle kernel paging request in ip_route_output_key_hash_rcu
2025/10/20 06:08 linux-6.1.y 8e6e2188d949 1c8c8cd8 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 BUG: unable to handle kernel paging request in ip_route_output_key_hash_rcu
2026/02/04 01:19 linux-6.1.y cd9b81672742 42b01fab .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 BUG: unable to handle kernel paging request in ip_route_output_key_hash_rcu
2026/02/04 01:18 linux-6.1.y cd9b81672742 42b01fab .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 BUG: unable to handle kernel paging request in ip_route_output_key_hash_rcu
2026/02/03 13:41 linux-6.1.y cd9b81672742 6df4c87a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 BUG: unable to handle kernel paging request in ip_route_output_key_hash_rcu
2026/02/02 16:36 linux-6.1.y cd9b81672742 018ebef2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 BUG: unable to handle kernel paging request in ip_route_output_key_hash_rcu
2026/02/02 16:35 linux-6.1.y cd9b81672742 018ebef2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 BUG: unable to handle kernel paging request in ip_route_output_key_hash_rcu
2026/01/30 21:06 linux-6.1.y cd9b81672742 ae7dc18c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 BUG: unable to handle kernel paging request in ip_route_output_key_hash_rcu
2026/01/30 17:39 linux-6.1.y cd9b81672742 ae7dc18c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 BUG: unable to handle kernel paging request in ip_route_output_key_hash_rcu
2026/01/30 16:50 linux-6.1.y cd9b81672742 ae7dc18c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 BUG: unable to handle kernel paging request in ip_route_output_key_hash_rcu
2026/01/27 16:44 linux-6.1.y cd9b81672742 9a514c2f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 BUG: unable to handle kernel paging request in ip_route_output_key_hash_rcu
2026/01/27 16:30 linux-6.1.y cd9b81672742 9a514c2f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 BUG: unable to handle kernel paging request in ip_route_output_key_hash_rcu
2026/01/27 15:34 linux-6.1.y cd9b81672742 9a514c2f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 BUG: unable to handle kernel paging request in ip_route_output_key_hash_rcu
2026/01/27 15:34 linux-6.1.y cd9b81672742 9a514c2f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 BUG: unable to handle kernel paging request in ip_route_output_key_hash_rcu
2026/01/27 15:31 linux-6.1.y cd9b81672742 9a514c2f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 BUG: unable to handle kernel paging request in ip_route_output_key_hash_rcu
2026/01/27 04:55 linux-6.1.y cd9b81672742 efb3e894 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 BUG: unable to handle kernel paging request in ip_route_output_key_hash_rcu
2026/01/27 04:55 linux-6.1.y cd9b81672742 efb3e894 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 BUG: unable to handle kernel paging request in ip_route_output_key_hash_rcu
2026/01/26 15:31 linux-6.1.y cd9b81672742 a4c52dd6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 BUG: unable to handle kernel paging request in ip_route_output_key_hash_rcu
2026/01/26 15:31 linux-6.1.y cd9b81672742 a4c52dd6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 BUG: unable to handle kernel paging request in ip_route_output_key_hash_rcu
2026/01/26 15:23 linux-6.1.y cd9b81672742 a4c52dd6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 BUG: unable to handle kernel paging request in ip_route_output_key_hash_rcu
2026/01/22 12:18 linux-6.1.y cd9b81672742 a16aed1d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 BUG: unable to handle kernel paging request in ip_route_output_key_hash_rcu
2026/01/20 20:35 linux-6.1.y cd9b81672742 06648d9c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 BUG: unable to handle kernel paging request in ip_route_output_key_hash_rcu
2026/01/20 20:33 linux-6.1.y cd9b81672742 06648d9c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 BUG: unable to handle kernel paging request in ip_route_output_key_hash_rcu
2026/01/14 02:11 linux-6.1.y bec0e10ee67e d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 BUG: unable to handle kernel paging request in ip_route_output_key_hash_rcu
2025/10/20 03:20 linux-6.1.y 8e6e2188d949 1c8c8cd8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 BUG: unable to handle kernel paging request in ip_route_output_key_hash_rcu
2025/10/13 20:15 linux-6.1.y 882efbdd9d34 b6605ba8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 BUG: unable to handle kernel paging request in ip_route_output_key_hash_rcu
* Struck through repros no longer work on HEAD.