general protection fault in ip_route_output_key_hash_rcu

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: b3060a1a Linux 4.19.64
git tree: linux-4.19.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1461442c600000
kernel config: https://syzkaller.appspot.com/x/.config?x=40e496d2d42c10d5
dashboard link: https://syzkaller.appspot.com/bug?extid=d6c1d54d8dc9fc24fb50
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

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

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+d6c1d5...@syzkaller.appspotmail.com

9pnet: p9_fd_create_tcp (30343): problem connecting socket to 127.0.0.1
9pnet: p9_fd_create_tcp (30343): problem connecting socket to 127.0.0.1
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 7921 Comm: kworker/0:3 Not tainted 4.19.64 #38
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Workqueue: krxrpcd rxrpc_peer_keepalive_worker
RIP: 0010:__read_once_size include/linux/compiler.h:193 [inline]
RIP: 0010:__in_dev_get_rcu include/linux/inetdevice.h:218 [inline]
RIP: 0010:__mkroute_output net/ipv4/route.c:2236 [inline]
RIP: 0010:ip_route_output_key_hash_rcu+0x460/0x30e0 net/ipv4/route.c:2541
Code: 00 0f 85 64 28 00 00 48 8b 85 70 ff ff ff 4c 89 f2 48 c1 ea 03 48 8b
40 10 48 89 85 30 ff ff ff 48 b8 00 00 00 00 00 fc ff df <80> 3c 02 00 0f
85 09 28 00 00 48 8b 85 68 ff ff ff 4c 8b b8 28 03
RSP: 0018:ffff88805e887550 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: ffff88805e8878d0 RCX: 0000000000000000
RDX: 0000000000000065 RSI: ffffffff85c8493e RDI: ffff88805e887676
RBP: ffff88805e887628 R08: ffff88805e87e040 R09: ffffed1015d04733
R10: ffffed1015d04732 R11: ffff8880ae823993 R12: ffff88806217c140
R13: 0000000000000000 R14: 0000000000000328 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000606ed8 CR3: 000000008ecf9000 CR4: 00000000001426f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
ip_route_output_key_hash+0x212/0x380 net/ipv4/route.c:2370
__ip_route_output_key include/net/route.h:124 [inline]
ip_route_output_flow+0x28/0xc0 net/ipv4/route.c:2625
udp_sendmsg+0x1adb/0x25e0 net/ipv4/udp.c:1094
inet_sendmsg+0x141/0x5d0 net/ipv4/af_inet.c:798
sock_sendmsg_nosec net/socket.c:622 [inline]
sock_sendmsg+0xd7/0x130 net/socket.c:632
kernel_sendmsg+0x44/0x50 net/socket.c:640
rxrpc_send_keepalive+0x1ff/0x8e0 net/rxrpc/output.c:658
rxrpc_peer_keepalive_dispatch net/rxrpc/peer_event.c:366 [inline]
rxrpc_peer_keepalive_worker+0x7be/0xd02 net/rxrpc/peer_event.c:427
process_one_work+0x989/0x1750 kernel/workqueue.c:2153
worker_thread+0x98/0xe40 kernel/workqueue.c:2296
kthread+0x354/0x420 kernel/kthread.c:246
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415
Modules linked in:
---[ end trace 009ab2e060adbc82 ]---
RIP: 0010:__read_once_size include/linux/compiler.h:193 [inline]
RIP: 0010:__in_dev_get_rcu include/linux/inetdevice.h:218 [inline]
RIP: 0010:__mkroute_output net/ipv4/route.c:2236 [inline]
RIP: 0010:ip_route_output_key_hash_rcu+0x460/0x30e0 net/ipv4/route.c:2541
Code: 00 0f 85 64 28 00 00 48 8b 85 70 ff ff ff 4c 89 f2 48 c1 ea 03 48 8b
40 10 48 89 85 30 ff ff ff 48 b8 00 00 00 00 00 fc ff df <80> 3c 02 00 0f
85 09 28 00 00 48 8b 85 68 ff ff ff 4c 8b b8 28 03
RSP: 0018:ffff88805e887550 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: ffff88805e8878d0 RCX: 0000000000000000
RDX: 0000000000000065 RSI: ffffffff85c8493e RDI: ffff88805e887676
RBP: ffff88805e887628 R08: ffff88805e87e040 R09: ffffed1015d04733
R10: ffffed1015d04732 R11: ffff8880ae823993 R12: ffff88806217c140
R13: 0000000000000000 R14: 0000000000000328 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f0661ad9570 CR3: 00000000874fd000 CR4: 00000000001426f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.