Subject: BUG: unable to handle kernel paging request in fl_dump_key

From: syzbot <[email-masked]>
Date: Fri, 15 May 2020 06:53:14 -0700

Hello,

syzbot found the following crash on:

HEAD commit:    99addbe3 net: broadcom: Select BROADCOM_PHY for BCMGENET
git tree:       net
console output: https://syzkaller.appspot.com/x/log.txt?x=173e568c100000
kernel config:  https://syzkaller.appspot.com/x/.config?x=b0212dbee046bc1f
dashboard link: https://syzkaller.appspot.com/bug?extid=9c1be56e9317b795e874
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: [email-masked]

BUG: unable to handle page fault for address: fffffbfff4a9538a
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 21ffe5067 P4D 21ffe5067 PUD 21ffe4067 PMD 0 
Oops: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 5831 Comm: syz-executor.3 Not tainted 5.7.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:fl_dump_key+0x8c/0x1980 net/sched/cls_flower.c:2514
Code: 04 f2 04 f2 c7 40 0c 04 f3 f3 f3 65 48 8b 04 25 28 00 00 00 48 89 84 24 b0 00 00 00 31 c0 e8 3b 0d 20 fb 48 89 e8 48 c1 e8 03 <42> 0f b6 04 30 84 c0 74 08 3c 03 0f 8e 6f 17 00 00 44 8b 75 00 31
RSP: 0018:ffffc900019672d8 EFLAGS: 00010a03
RAX: 1ffffffff4a9538a RBX: ffffffffa54a9a8f RCX: ffffc9000f733000
RDX: 000000000000080f RSI: ffffffff86532275 RDI: ffff88808f68b800
RBP: ffffffffa54a9c57 R08: ffff888096266200 R09: ffff888097a5603c
R10: ffff888097a56036 R11: ffffed1012f4ac06 R12: ffff88808f68b800
R13: ffff88806780a100 R14: dffffc0000000000 R15: ffff88806780a100
FS:  00007f0a86395700(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffffbfff4a9538a CR3: 0000000099de6000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 fl_tmplt_dump+0xcf/0x250 net/sched/cls_flower.c:2784
 tc_chain_fill_node+0x48e/0x7c0 net/sched/cls_api.c:2707
 tc_chain_notify+0x189/0x2e0 net/sched/cls_api.c:2733
 tc_ctl_chain+0xb82/0x1080 net/sched/cls_api.c:2919
 rtnetlink_rcv_msg+0x44e/0xad0 net/core/rtnetlink.c:5454
 netlink_rcv_skb+0x15a/0x410 net/netlink/af_netlink.c:2469
 netlink_unicast_kernel net/netlink/af_netlink.c:1303 [inline]
 netlink_unicast+0x537/0x740 net/netlink/af_netlink.c:1329
 netlink_sendmsg+0x882/0xe10 net/netlink/af_netlink.c:1918
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:672
 ____sys_sendmsg+0x6bf/0x7e0 net/socket.c:2362
 ___sys_sendmsg+0x100/0x170 net/socket.c:2416
 __sys_sendmsg+0xec/0x1b0 net/socket.c:2449
 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x49/0xb3
RIP: 0033:0x45c829
Code: 0d b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 db b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f0a86394c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000500d20 RCX: 000000000045c829
RDX: 0000000000000000 RSI: 00000000200001c0 RDI: 0000000000000003
RBP: 000000000078c040 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000a05 R14: 00000000004ccbdd R15: 00007f0a863956d4
Modules linked in:
CR2: fffffbfff4a9538a
---[ end trace da47bdc433f8d794 ]---
RIP: 0010:fl_dump_key+0x8c/0x1980 net/sched/cls_flower.c:2514
Code: 04 f2 04 f2 c7 40 0c 04 f3 f3 f3 65 48 8b 04 25 28 00 00 00 48 89 84 24 b0 00 00 00 31 c0 e8 3b 0d 20 fb 48 89 e8 48 c1 e8 03 <42> 0f b6 04 30 84 c0 74 08 3c 03 0f 8e 6f 17 00 00 44 8b 75 00 31
RSP: 0018:ffffc900019672d8 EFLAGS: 00010a03
RAX: 1ffffffff4a9538a RBX: ffffffffa54a9a8f RCX: ffffc9000f733000
RDX: 000000000000080f RSI: ffffffff86532275 RDI: ffff88808f68b800
RBP: ffffffffa54a9c57 R08: ffff888096266200 R09: ffff888097a5603c
R10: ffff888097a56036 R11: ffffed1012f4ac06 R12: ffff88808f68b800
R13: ffff88806780a100 R14: dffffc0000000000 R15: ffff88806780a100
FS:  00007f0a86395700(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffffbfff4a9538a CR3: 0000000099de6000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

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