[v5.15] WARNING in fib6_add

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: f67653019430 Linux 5.15.118
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=117c69e0a80000
kernel config: https://syzkaller.appspot.com/x/.config?x=c6daef03436a2bc5
dashboard link: https://syzkaller.appspot.com/bug?extid=e5389639a271451d71c8
compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2
userspace arch: arm64

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/600ef9372d32/disk-f6765301.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/46dca37198b3/vmlinux-f6765301.xz
kernel image: https://storage.googleapis.com/syzbot-assets/7ae4a35a0a6d/Image-f6765301.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e53896...@syzkaller.appspotmail.com

el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:596
el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:614
el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584
------------[ cut here ]------------
WARNING: CPU: 1 PID: 20848 at net/ipv6/ip6_fib.c:1506 fib6_add+0x26fc/0x3400
Modules linked in:
CPU: 1 PID: 20848 Comm: syz-executor.1 Not tainted 5.15.118-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : fib6_add+0x26fc/0x3400
lr : fib6_add+0x26fc/0x3400
sp : ffff80001ec57500
x29: ffff80001ec576e0 x28: ffff000123a6d800 x27: ffff80001ec57850
x26: 00000000ffffffff x25: ffff700003d8aec4 x24: ffff0000cfffb200
x23: 0000000000000000 x22: 0000000000000002 x21: ffff0000cb994620
x20: dfff800000000000 x19: 0000000000000000 x18: 0000000000000202
x17: ff80800008335ea8 x16: ffff8000084c316c x15: ffff800008335ea8
x14: 00000000ffffffff x13: ffffffffffffffff x12: 0000000000040000
x11: 000000000000dd81 x10: ffff80001e68a000 x9 : ffff8000108e5500
x8 : 000000000000dd82 x7 : 0000000000000000 x6 : 0000000000000001
x5 : ffff80001ec56858 x4 : 0000000000000100 x3 : ffff8000108e50b4
x2 : ffff0000cb994600 x1 : 0000000000000001 x0 : 0000000000000000
Call trace:
fib6_add+0x26fc/0x3400
__ip6_ins_rt net/ipv6/route.c:1302 [inline]
ip6_route_add+0x94/0x17c net/ipv6/route.c:3872
ipv6_route_ioctl+0x3fc/0x670 net/ipv6/route.c:4492
inet6_ioctl+0x2f8/0x380 net/ipv6/af_inet6.c:580
sock_do_ioctl+0x134/0x2dc net/socket.c:1121
sock_ioctl+0x4f0/0x8ac net/socket.c:1238
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
__se_sys_ioctl fs/ioctl.c:860 [inline]
__arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:860
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:596
el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:614
el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584
irq event stamp: 695
hardirqs last enabled at (694): [<ffff800011952c58>] __exit_to_kernel_mode arch/arm64/kernel/entry-common.c:81 [inline]
hardirqs last enabled at (694): [<ffff800011952c58>] exit_to_kernel_mode+0x100/0x178 arch/arm64/kernel/entry-common.c:91
hardirqs last disabled at (695): [<ffff80001194fe58>] el1_dbg+0x24/0x80 arch/arm64/kernel/entry-common.c:387
softirqs last enabled at (600): [<ffff8000080300b4>] local_bh_enable+0x10/0x34 include/linux/bottom_half.h:31
softirqs last disabled at (680): [<ffff8000108c5920>] spin_lock_bh include/linux/spinlock.h:368 [inline]
softirqs last disabled at (680): [<ffff8000108c5920>] __ip6_ins_rt net/ipv6/route.c:1301 [inline]
softirqs last disabled at (680): [<ffff8000108c5920>] ip6_route_add+0x80/0x17c net/ipv6/route.c:3872
---[ end trace 0a3010e590ca5df0 ]---


---
This report is generated by a bot. It may contain errors.
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syzbot will keep track of this issue. See:
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If the bug is a duplicate of another bug, reply with:
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If you want to undo deduplication, reply with:
#syz undup

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: f67653019430 Linux 5.15.118
git tree: linux-5.15.y

console output: https://syzkaller.appspot.com/x/log.txt?x=10b48280a80000

kernel config: https://syzkaller.appspot.com/x/.config?x=c6daef03436a2bc5
dashboard link: https://syzkaller.appspot.com/bug?extid=e5389639a271451d71c8
compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2
userspace arch: arm64

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16819cd7280000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=123fa4d7280000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/600ef9372d32/disk-f6765301.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/46dca37198b3/vmlinux-f6765301.xz
kernel image: https://storage.googleapis.com/syzbot-assets/7ae4a35a0a6d/Image-f6765301.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e53896...@syzkaller.appspotmail.com

el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:596
el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:614
el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584
------------[ cut here ]------------

WARNING: CPU: 0 PID: 3969 at net/ipv6/ip6_fib.c:1506 fib6_add+0x26fc/0x3400
Modules linked in:
CPU: 0 PID: 3969 Comm: syz-executor416 Not tainted 5.15.118-syzkaller #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : fib6_add+0x26fc/0x3400
lr : fib6_add+0x26fc/0x3400

sp : ffff80001cc67500
x29: ffff80001cc676e0 x28: ffff0000d9e3bc00 x27: ffff80001cc67850
x26: 00000000ffffffff x25: ffff70000398cec4 x24: ffff0000d2061880
x23: 0000000000000000 x22: 0000000000000002 x21: ffff0000d2061720

x20: dfff800000000000 x19: 0000000000000000 x18: 0000000000000202
x17: ff80800008335ea8 x16: ffff8000084c316c x15: ffff800008335ea8

x14: 00000000ffffffff x13: ffffffffffffffff x12: 0000000000000000
x11: ff808000108e5500 x10: 0000000000000000 x9 : ffff8000108e5500
x8 : ffff0000dbc651c0 x7 : 0000000000000000 x6 : 0000000000000001
x5 : ffff80001cc66858 x4 : 0000000000000100 x3 : ffff8000108e50b4
x2 : ffff0000d2061700 x1 : 0000000000000001 x0 : 0000000000000000

Call trace:
fib6_add+0x26fc/0x3400
__ip6_ins_rt net/ipv6/route.c:1302 [inline]
ip6_route_add+0x94/0x17c net/ipv6/route.c:3872
ipv6_route_ioctl+0x3fc/0x670 net/ipv6/route.c:4492
inet6_ioctl+0x2f8/0x380 net/ipv6/af_inet6.c:580
sock_do_ioctl+0x134/0x2dc net/socket.c:1121
sock_ioctl+0x4f0/0x8ac net/socket.c:1238
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
__se_sys_ioctl fs/ioctl.c:860 [inline]
__arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:860
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:596
el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:614
el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

irq event stamp: 128213
hardirqs last enabled at (128212): [<ffff800011952c58>] __exit_to_kernel_mode arch/arm64/kernel/entry-common.c:81 [inline]
hardirqs last enabled at (128212): [<ffff800011952c58>] exit_to_kernel_mode+0x100/0x178 arch/arm64/kernel/entry-common.c:91
hardirqs last disabled at (128213): [<ffff80001194fe58>] el1_dbg+0x24/0x80 arch/arm64/kernel/entry-common.c:387
softirqs last enabled at (128098): [<ffff800008020ccc>] softirq_handle_end kernel/softirq.c:401 [inline]
softirqs last enabled at (128098): [<ffff800008020ccc>] __do_softirq+0xb5c/0xe20 kernel/softirq.c:587
softirqs last disabled at (128198): [<ffff8000108c5920>] spin_lock_bh include/linux/spinlock.h:368 [inline]
softirqs last disabled at (128198): [<ffff8000108c5920>] __ip6_ins_rt net/ipv6/route.c:1301 [inline]
softirqs last disabled at (128198): [<ffff8000108c5920>] ip6_route_add+0x80/0x17c net/ipv6/route.c:3872
---[ end trace 3fe0652f2c203844 ]---


---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: e84a4e368abe Linux 6.1.35
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=154269e0a80000
kernel config: https://syzkaller.appspot.com/x/.config?x=f77b603a569f81a7
dashboard link: https://syzkaller.appspot.com/bug?extid=48e882067aaab477fdfe

compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2
userspace arch: arm64

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12ab218f280000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15e2f180a80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/30886a06f234/disk-e84a4e36.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/84ab10f3c74b/vmlinux-e84a4e36.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ea73248cc405/Image-e84a4e36.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:

Reported-by: syzbot+48e882...@syzkaller.appspotmail.com

el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206
el0_svc+0x58/0x168 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:581
------------[ cut here ]------------
WARNING: CPU: 0 PID: 4218 at net/ipv6/ip6_fib.c:1507 fib6_add+0x26a0/0x32f4
Modules linked in:
CPU: 0 PID: 4218 Comm: syz-executor235 Not tainted 6.1.35-syzkaller #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)

pc : fib6_add+0x26a0/0x32f4
lr : fib6_add+0x26a0/0x32f4
sp : ffff80001e027520
x29: ffff80001e027700 x28: ffff0000dd9a0400 x27: ffff80001e027870
x26: 00000000ffffffff x25: ffff700003c04ec8 x24: ffff0000d798cf00
x23: 0000000000000000 x22: 0000000000000002 x21: ffff0000d798cda0
x20: dfff800000000000 x19: 0000000000000000 x18: ffff80001e0267e0
x17: 0000000000000000 x16: ffff8000084fa400 x15: 0000000000000000
x14: 0000000000000000 x13: 0000000000000001 x12: 0000000000000001
x11: ff80800010f82814 x10: 0000000000000000 x9 : ffff800010f82814
x8 : ffff0000db168000 x7 : 0000000000000001 x6 : 0000000000000001
x5 : 00000000ffffffff x4 : 0000000000000b20 x3 : ffff800010f823f0
x2 : ffff0000d798cd80 x1 : 0000000000000001 x0 : 0000000000000000
Call trace:
fib6_add+0x26a0/0x32f4
__ip6_ins_rt net/ipv6/route.c:1302 [inline]
ip6_route_add+0x94/0x168 net/ipv6/route.c:3847
ipv6_route_ioctl+0x3fc/0x670 net/ipv6/route.c:4467
inet6_ioctl+0x2d0/0x358 net/ipv6/af_inet6.c:585
sock_do_ioctl+0x134/0x2dc net/socket.c:1174
sock_ioctl+0x4ec/0x858 net/socket.c:1291
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl fs/ioctl.c:856 [inline]
__arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:856
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x64/0x218 arch/arm64/kernel/syscall.c:206
el0_svc+0x58/0x168 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:581
irq event stamp: 132167
hardirqs last enabled at (132166): [<ffff8000121047b0>] __exit_to_kernel_mode arch/arm64/kernel/entry-common.c:84 [inline]
hardirqs last enabled at (132166): [<ffff8000121047b0>] exit_to_kernel_mode+0xe8/0x118 arch/arm64/kernel/entry-common.c:94
hardirqs last disabled at (132167): [<ffff80001210239c>] el1_dbg+0x24/0x80 arch/arm64/kernel/entry-common.c:405
softirqs last enabled at (132032): [<ffff800011628774>] l2tp_ip6_hash+0x124/0x180 net/l2tp/l2tp_ip6.c:217
softirqs last disabled at (132146): [<ffff800010f62d64>] spin_lock_bh include/linux/spinlock.h:355 [inline]
softirqs last disabled at (132146): [<ffff800010f62d64>] __ip6_ins_rt net/ipv6/route.c:1301 [inline]
softirqs last disabled at (132146): [<ffff800010f62d64>] ip6_route_add+0x80/0x168 net/ipv6/route.c:3847
---[ end trace 0000000000000000 ]---

---
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 bug is already fixed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

[syzbot]

syzbot suspects this issue was fixed by commit:

commit a3f5de10b5cfd39328d76e73a88dc1daa22ed50f
Author: Eric Dumazet <edum...@google.com>
Date: Wed Nov 29 16:06:30 2023 +0000

ipv6: fix potential NULL deref in fib6_add()

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=17149733e80000
start commit: ecda77b46871 Linux 6.1.56
git tree: linux-6.1.y
kernel config: https://syzkaller.appspot.com/x/.config?x=e82fa6f6f9ab7d72
dashboard link: https://syzkaller.appspot.com/bug?extid=48e882067aaab477fdfe
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=158e4111680000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17f0d0de680000

If the result looks correct, please mark the issue as fixed by replying with:

#syz fix: ipv6: fix potential NULL deref in fib6_add()

For information about bisection process see: https://goo.gl/tpsmEJ#bisection

[syzbot]

Auto-closing this bug as obsolete.
No recent activity, existing reproducers are no longer triggering the issue.