[v5.15] general protection fault in find_match
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syzbot
Sep 7, 2025, 9:45:29 AM (10 days ago) Sep 7
to syzkaller...@googlegroups.com
Hello,
syzbot found the following issue on:
HEAD commit: 7a6c2d093c45 Linux 5.15.191
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1355b312580000
kernel config: https://syzkaller.appspot.com/x/.config?x=4aee9f779ad20a6a
dashboard link: https://syzkaller.appspot.com/bug?extid=e8c6624ed4f30e2c7a6f
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/5ab7658d1be2/disk-7a6c2d09.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/dc30f611bdaa/vmlinux-7a6c2d09.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ba4ba285539e/bzImage-7a6c2d09.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e8c662...@syzkaller.appspotmail.com
netlink: 12 bytes leftover after parsing attributes in process `syz.4.158'.
tipc: Started in network mode
tipc: Node identity 00000000000000000000000000000001, cluster identity 4711
general protection fault, probably for non-canonical address 0xdffffc000000006c: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000360-0x0000000000000367]
CPU: 1 PID: 5142 Comm: syz.4.158 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:__in6_dev_get include/net/addrconf.h:321 [inline]
RIP: 0010:ip6_ignore_linkdown include/net/addrconf.h:412 [inline]
RIP: 0010:find_match+0xa3/0xc30 net/ipv6/route.c:744
Code: 00 00 00 00 00 fc ff df 42 80 7c 25 00 00 74 08 48 89 df e8 df f5 2a f9 48 89 d8 bb 60 03 00 00 48 03 18 48 89 d8 48 c1 e8 03 <42> 80 3c 20 00 74 08 48 89 df e8 be f5 2a f9 48 8b 1b e8 66 b8 17
RSP: 0018:ffffc900031967d8 EFLAGS: 00010206
RAX: 000000000000006c RBX: 0000000000000360 RCX: ffff888021300000
RDX: 0000000000000002 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 1ffff110048c9ca4 R08: ffffc90003196b60 R09: ffffc90003196b70
R10: fffff52000632d3a R11: 1ffff92000632d38 R12: dffffc0000000000
R13: 0000000000000003 R14: 1ffff110048c9ca5 R15: ffff88802464e52f
FS: 00007fb75a1496c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffec0000 CR3: 0000000021ed3000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
rt6_nh_find_match+0xd5/0x140 net/ipv6/route.c:784
nexthop_for_each_fib6_nh+0x1be/0x3e0 net/ipv4/nexthop.c:1242
__find_rr_leaf+0x45e/0x6c0 net/ipv6/route.c:825
find_rr_leaf net/ipv6/route.c:853 [inline]
rt6_select net/ipv6/route.c:897 [inline]
fib6_table_lookup+0x39c/0xa70 net/ipv6/route.c:2183
ip6_pol_route+0x209/0x1290 net/ipv6/route.c:2219
pol_lookup_func include/net/ip6_fib.h:582 [inline]
fib6_rule_lookup+0x2fc/0x570 net/ipv6/fib6_rules.c:120
ip6_route_output_flags+0xbf/0x300 net/ipv6/route.c:2640
ip6_dst_lookup_tail+0x251/0x1200 net/ipv6/ip6_output.c:1128
ip6_dst_lookup_flow+0x44/0xd0 net/ipv6/ip6_output.c:1231
tipc_udp_xmit+0x2ff/0xa50 net/tipc/udp_media.c:210
tipc_bearer_xmit_skb+0x292/0x3c0 net/tipc/bearer.c:577
tipc_enable_bearer net/tipc/bearer.c:368 [inline]
__tipc_nl_bearer_enable+0xed3/0x11f0 net/tipc/bearer.c:1049
tipc_nl_bearer_enable+0x1e/0x30 net/tipc/bearer.c:1058
genl_family_rcv_msg_doit net/netlink/genetlink.c:731 [inline]
genl_family_rcv_msg net/netlink/genetlink.c:775 [inline]
genl_rcv_msg+0xbc6/0xf40 net/netlink/genetlink.c:792
netlink_rcv_skb+0x1e0/0x430 net/netlink/af_netlink.c:2507
genl_rcv+0x24/0x40 net/netlink/genetlink.c:803
netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
netlink_unicast+0x774/0x920 net/netlink/af_netlink.c:1344
netlink_sendmsg+0x8ab/0xbc0 net/netlink/af_netlink.c:1918
sock_sendmsg_nosec net/socket.c:704 [inline]
__sock_sendmsg net/socket.c:716 [inline]
____sys_sendmsg+0x5a2/0x8c0 net/socket.c:2436
___sys_sendmsg+0x1f0/0x260 net/socket.c:2490
__sys_sendmsg net/socket.c:2519 [inline]
__do_sys_sendmsg net/socket.c:2528 [inline]
__se_sys_sendmsg+0x190/0x250 net/socket.c:2526
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fb75bee1be9
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:00007fb75a149038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fb75c118fa0 RCX: 00007fb75bee1be9
RDX: 0000000000000000 RSI: 00002000000010c0 RDI: 0000000000000006
RBP: 00007fb75bf64e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb75c119038 R14: 00007fb75c118fa0 R15: 00007ffd78b19318
</TASK>
Modules linked in:
---[ end trace 2fc07f6c8ae78d8e ]---
RIP: 0010:__in6_dev_get include/net/addrconf.h:321 [inline]
RIP: 0010:ip6_ignore_linkdown include/net/addrconf.h:412 [inline]
RIP: 0010:find_match+0xa3/0xc30 net/ipv6/route.c:744
Code: 00 00 00 00 00 fc ff df 42 80 7c 25 00 00 74 08 48 89 df e8 df f5 2a f9 48 89 d8 bb 60 03 00 00 48 03 18 48 89 d8 48 c1 e8 03 <42> 80 3c 20 00 74 08 48 89 df e8 be f5 2a f9 48 8b 1b e8 66 b8 17
RSP: 0018:ffffc900031967d8 EFLAGS: 00010206
RAX: 000000000000006c RBX: 0000000000000360 RCX: ffff888021300000
RDX: 0000000000000002 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 1ffff110048c9ca4 R08: ffffc90003196b60 R09: ffffc90003196b70
R10: fffff52000632d3a R11: 1ffff92000632d38 R12: dffffc0000000000
R13: 0000000000000003 R14: 1ffff110048c9ca5 R15: ffff88802464e52f
FS: 00007fb75a1496c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffec0000 CR3: 0000000021ed3000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess), 7 bytes skipped:
0: df 42 80 filds -0x80(%rdx)
3: 7c 25 jl 0x2a
5: 00 00 add %al,(%rax)
7: 74 08 je 0x11
9: 48 89 df mov %rbx,%rdi
c: e8 df f5 2a f9 call 0xf92af5f0
11: 48 89 d8 mov %rbx,%rax
14: bb 60 03 00 00 mov $0x360,%ebx
19: 48 03 18 add (%rax),%rbx
1c: 48 89 d8 mov %rbx,%rax
1f: 48 c1 e8 03 shr $0x3,%rax
* 23: 42 80 3c 20 00 cmpb $0x0,(%rax,%r12,1) <-- trapping instruction
28: 74 08 je 0x32
2a: 48 89 df mov %rbx,%rdi
2d: e8 be f5 2a f9 call 0xf92af5f0
32: 48 8b 1b mov (%rbx),%rbx
35: e8 .byte 0xe8
36: 66 data16
37: b8 .byte 0xb8
38: 17 (bad)
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title
If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)
If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report
If you want to undo deduplication, reply with:
#syz undup
syzbot found the following issue on:
HEAD commit: 7a6c2d093c45 Linux 5.15.191
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1355b312580000
kernel config: https://syzkaller.appspot.com/x/.config?x=4aee9f779ad20a6a
dashboard link: https://syzkaller.appspot.com/bug?extid=e8c6624ed4f30e2c7a6f
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/5ab7658d1be2/disk-7a6c2d09.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/dc30f611bdaa/vmlinux-7a6c2d09.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ba4ba285539e/bzImage-7a6c2d09.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e8c662...@syzkaller.appspotmail.com
netlink: 12 bytes leftover after parsing attributes in process `syz.4.158'.
tipc: Started in network mode
tipc: Node identity 00000000000000000000000000000001, cluster identity 4711
general protection fault, probably for non-canonical address 0xdffffc000000006c: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000360-0x0000000000000367]
CPU: 1 PID: 5142 Comm: syz.4.158 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:__in6_dev_get include/net/addrconf.h:321 [inline]
RIP: 0010:ip6_ignore_linkdown include/net/addrconf.h:412 [inline]
RIP: 0010:find_match+0xa3/0xc30 net/ipv6/route.c:744
Code: 00 00 00 00 00 fc ff df 42 80 7c 25 00 00 74 08 48 89 df e8 df f5 2a f9 48 89 d8 bb 60 03 00 00 48 03 18 48 89 d8 48 c1 e8 03 <42> 80 3c 20 00 74 08 48 89 df e8 be f5 2a f9 48 8b 1b e8 66 b8 17
RSP: 0018:ffffc900031967d8 EFLAGS: 00010206
RAX: 000000000000006c RBX: 0000000000000360 RCX: ffff888021300000
RDX: 0000000000000002 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 1ffff110048c9ca4 R08: ffffc90003196b60 R09: ffffc90003196b70
R10: fffff52000632d3a R11: 1ffff92000632d38 R12: dffffc0000000000
R13: 0000000000000003 R14: 1ffff110048c9ca5 R15: ffff88802464e52f
FS: 00007fb75a1496c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffec0000 CR3: 0000000021ed3000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
rt6_nh_find_match+0xd5/0x140 net/ipv6/route.c:784
nexthop_for_each_fib6_nh+0x1be/0x3e0 net/ipv4/nexthop.c:1242
__find_rr_leaf+0x45e/0x6c0 net/ipv6/route.c:825
find_rr_leaf net/ipv6/route.c:853 [inline]
rt6_select net/ipv6/route.c:897 [inline]
fib6_table_lookup+0x39c/0xa70 net/ipv6/route.c:2183
ip6_pol_route+0x209/0x1290 net/ipv6/route.c:2219
pol_lookup_func include/net/ip6_fib.h:582 [inline]
fib6_rule_lookup+0x2fc/0x570 net/ipv6/fib6_rules.c:120
ip6_route_output_flags+0xbf/0x300 net/ipv6/route.c:2640
ip6_dst_lookup_tail+0x251/0x1200 net/ipv6/ip6_output.c:1128
ip6_dst_lookup_flow+0x44/0xd0 net/ipv6/ip6_output.c:1231
tipc_udp_xmit+0x2ff/0xa50 net/tipc/udp_media.c:210
tipc_bearer_xmit_skb+0x292/0x3c0 net/tipc/bearer.c:577
tipc_enable_bearer net/tipc/bearer.c:368 [inline]
__tipc_nl_bearer_enable+0xed3/0x11f0 net/tipc/bearer.c:1049
tipc_nl_bearer_enable+0x1e/0x30 net/tipc/bearer.c:1058
genl_family_rcv_msg_doit net/netlink/genetlink.c:731 [inline]
genl_family_rcv_msg net/netlink/genetlink.c:775 [inline]
genl_rcv_msg+0xbc6/0xf40 net/netlink/genetlink.c:792
netlink_rcv_skb+0x1e0/0x430 net/netlink/af_netlink.c:2507
genl_rcv+0x24/0x40 net/netlink/genetlink.c:803
netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
netlink_unicast+0x774/0x920 net/netlink/af_netlink.c:1344
netlink_sendmsg+0x8ab/0xbc0 net/netlink/af_netlink.c:1918
sock_sendmsg_nosec net/socket.c:704 [inline]
__sock_sendmsg net/socket.c:716 [inline]
____sys_sendmsg+0x5a2/0x8c0 net/socket.c:2436
___sys_sendmsg+0x1f0/0x260 net/socket.c:2490
__sys_sendmsg net/socket.c:2519 [inline]
__do_sys_sendmsg net/socket.c:2528 [inline]
__se_sys_sendmsg+0x190/0x250 net/socket.c:2526
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fb75bee1be9
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:00007fb75a149038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fb75c118fa0 RCX: 00007fb75bee1be9
RDX: 0000000000000000 RSI: 00002000000010c0 RDI: 0000000000000006
RBP: 00007fb75bf64e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb75c119038 R14: 00007fb75c118fa0 R15: 00007ffd78b19318
</TASK>
Modules linked in:
---[ end trace 2fc07f6c8ae78d8e ]---
RIP: 0010:__in6_dev_get include/net/addrconf.h:321 [inline]
RIP: 0010:ip6_ignore_linkdown include/net/addrconf.h:412 [inline]
RIP: 0010:find_match+0xa3/0xc30 net/ipv6/route.c:744
Code: 00 00 00 00 00 fc ff df 42 80 7c 25 00 00 74 08 48 89 df e8 df f5 2a f9 48 89 d8 bb 60 03 00 00 48 03 18 48 89 d8 48 c1 e8 03 <42> 80 3c 20 00 74 08 48 89 df e8 be f5 2a f9 48 8b 1b e8 66 b8 17
RSP: 0018:ffffc900031967d8 EFLAGS: 00010206
RAX: 000000000000006c RBX: 0000000000000360 RCX: ffff888021300000
RDX: 0000000000000002 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 1ffff110048c9ca4 R08: ffffc90003196b60 R09: ffffc90003196b70
R10: fffff52000632d3a R11: 1ffff92000632d38 R12: dffffc0000000000
R13: 0000000000000003 R14: 1ffff110048c9ca5 R15: ffff88802464e52f
FS: 00007fb75a1496c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffec0000 CR3: 0000000021ed3000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess), 7 bytes skipped:
0: df 42 80 filds -0x80(%rdx)
3: 7c 25 jl 0x2a
5: 00 00 add %al,(%rax)
7: 74 08 je 0x11
9: 48 89 df mov %rbx,%rdi
c: e8 df f5 2a f9 call 0xf92af5f0
11: 48 89 d8 mov %rbx,%rax
14: bb 60 03 00 00 mov $0x360,%ebx
19: 48 03 18 add (%rax),%rbx
1c: 48 89 d8 mov %rbx,%rax
1f: 48 c1 e8 03 shr $0x3,%rax
* 23: 42 80 3c 20 00 cmpb $0x0,(%rax,%r12,1) <-- trapping instruction
28: 74 08 je 0x32
2a: 48 89 df mov %rbx,%rdi
2d: e8 be f5 2a f9 call 0xf92af5f0
32: 48 8b 1b mov (%rbx),%rbx
35: e8 .byte 0xe8
36: 66 data16
37: b8 .byte 0xb8
38: 17 (bad)
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title
If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)
If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report
If you want to undo deduplication, reply with:
#syz undup
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