Re: [syzbot] [net?] WARNING in NUM

[Paolo Abeni <pabeni@redhat.com>]

On 12/7/24 06:10, syzbot wrote:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    cdd30ebb1b9f module: Convert symbol namespace to string li..
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=146c8330580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=6851fe4f61792030
> dashboard link: https://syzkaller.appspot.com/bug?extid=3f059ffbdd539a3f6bc9
> compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
> 
> Unfortunately, I don't have any reproducer for this issue yet.
> 
> Downloadable assets:
> disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7feb34a89c2a/non_bootable_disk-cdd30ebb.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/35bb9b3cd157/vmlinux-cdd30ebb.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/9c6bbf481907/bzImage-cdd30ebb.xz
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+3f059ffbdd539a3f6bc9@syzkaller.appspotmail.com
> 
> Dec  3 05:04:02 syzkaller daemon.info dhcpcd[5653]: eth3: IAID d8:df:c9:55
> Dec  3 05:04:02 syzkaller daemon.info dhcpcd[5653]: eth3: adding address fe80::7[   49.690919][ T6466] ------------[ cut here ]------------
> f27:c3e8:bb45:52[   49.693207][ T6466] WARNING: CPU: 3 PID: 6466 at net/ipv6/ip6mr.c:419 ip6mr_free_table+0xbd/0x120 net/ipv6/ip6mr.c:419
> df
> Dec  3 05:04:02 [   49.710042][ T6466] Code: 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 75 58 49 83 bc 24 c0 0e 00 00 00 74 09 e8 c4 c5 af f7 90 <0f> 0b 90 e8 bb c5 af f7 48 8d 7b 38 e8 22 86 9c f7 48 89 df be 0f
> syzkaller kern.w[   49.717312][ T6466] RSP: 0018:ffffc90003487bd8 EFLAGS: 00010293
> arn kernel: [   [   49.719598][ T6466] RAX: 0000000000000000 RBX: ffff888108508000 RCX: ffffffff89ea4014
> 49.690919][ T646[   49.725534][ T6466] RBP: 0000000000000001 R08: 0000000000000005 R09: 0000000000000000
> 6] ------------[[   49.725548][ T6466] R10: 0000000000000001 R11: 0000000000000001 R12: ffff88804e965ac0
>  cut here ]-----[   49.725561][ T6466] R13: ffff888108508000 R14: ffff888108508008 R15: dead000000000100
> -------
> Dec  3 05:04:02 [   49.739536][ T6466] CR2: 00007f4fd5157580 CR3: 0000000035ea8000 CR4: 0000000000352ef0
> syzkaller kern.w[   49.742428][ T6466] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> arn kernel: [   [   49.746956][ T6466] Call Trace:
> 49.693207][ T646[   49.748809][ T6466]  ? __warn+0xea/0x3c0 kernel/panic.c:746
> 6] WARNING: CPU:[   49.750217][ T6466]  ? ip6mr_free_table+0xbd/0x120 net/ipv6/ip6mr.c:419
>  3 PID: 6466 at [   49.751877][ T6466]  ? __report_bug lib/bug.c:199 [inline]
>  3 PID: 6466 at [   49.751877][ T6466]  ? report_bug+0x3c0/0x580 lib/bug.c:219
> net/ipv6/ip6mr.c[   49.751908][ T6466]  ? exc_invalid_op+0x17/0x50 arch/x86/kernel/traps.c:309
> :419 ip6mr_free_[   49.751922][ T6466]  ? asm_exc_invalid_op+0x1a/0x20 arch/x86/include/asm/idtentry.h:621
> table+0xbd/0x120[   49.759463][ T6466]  ? ip6mr_free_table+0xbc/0x120 net/ipv6/ip6mr.c:419
> 
> Dec  3 05:04:02 syzkaller kern[   49.762545][ T6466]  ? ip6mr_free_table+0xbc/0x120 net/ipv6/ip6mr.c:419
> .warn kernel: [ [   49.765091][ T6466]  ip6mr_rules_exit+0x176/0x2d0 net/ipv6/ip6mr.c:283
>   49.696818][ T6[   49.767196][ T6466]  ip6mr_net_exit_batch+0x53/0xa0 net/ipv6/ip6mr.c:1388
> 466] Modules lin[   49.768971][ T6466]  ? __pfx_ip6mr_net_exit_batch+0x10/0x10 net/ipv6/ip6mr.c:285
> ked in:
> Dec  3 05:04:02 [   49.769038][ T6466]  setup_net+0x4fe/0x860 net/core/net_namespace.c:394
> syzkaller kern.w[   49.769059][ T6466]  ? __pfx_setup_net+0x10/0x10 net/core/net_namespace.c:185
> arn kernel: [   [   49.778049][ T6466]  ? __down_read_common kernel/locking/rwsem.c:1255 [inline]
> arn kernel: [   [   49.778049][ T6466]  ? __down_read_killable kernel/locking/rwsem.c:1271 [inline]
> arn kernel: [   [   49.778049][ T6466]  ? down_read_killable+0xcc/0x380 kernel/locking/rwsem.c:1549
> 49.699801][ T646[   49.781754][ T6466]  ? lockdep_init_map_waits include/linux/lockdep.h:135 [inline]
> 49.699801][ T646[   49.781754][ T6466]  ? lockdep_init_map_wait include/linux/lockdep.h:142 [inline]
> 49.699801][ T646[   49.781754][ T6466]  ? __raw_spin_lock_init+0x3a/0x110 kernel/locking/spinlock_debug.c:25
> 6] CPU: 3 UID: 0 PID: 6466 Comm: syz.2.106 Not tainted 6.13.0-rc1-syzkaller-00002-gcdd30ebb1b9f #0

#syz fix: ipmr: tune the ipmr_can_free_table() checks.