BUG: unable to handle kernel paging request in tcf_action_dump_terse

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 307eea32 dt-bindings: net: renesas,ravb: Add support for r..
git tree: net
console output: https://syzkaller.appspot.com/x/log.txt?x=13b7e29d900000
kernel config: https://syzkaller.appspot.com/x/.config?x=240e2ebab67245c7
dashboard link: https://syzkaller.appspot.com/bug?extid=5f66662adc70969940fd
compiler: gcc (GCC) 10.1.0-syz 20200507

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

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+5f6666...@syzkaller.appspotmail.com

netlink: 8 bytes leftover after parsing attributes in process `syz-executor.5'.
BUG: unable to handle page fault for address: fffffffffffffff0
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 9e90067 P4D 9e90067 PUD 9e92067 PMD 0
Oops: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 9876 Comm: syz-executor.5 Not tainted 5.9.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:tcf_action_dump_terse+0x8c/0x4e0 net/sched/act_api.c:766
Code: 3c 03 0f 8e 0a 03 00 00 48 89 da 44 8b ad b8 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 80 3c 02 00 0f 85 10 04 00 00 <48> 8b 03 4c 8d 60 10 4c 89 e7 e8 d5 2b 4e fd 4c 89 e1 be 01 00 00
RSP: 0018:ffffc9001604f170 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: fffffffffffffff0 RCX: ffffc900137c6000
RDX: 1ffffffffffffffe RSI: ffffffff868ac439 RDI: ffff88808f9dfdf8
RBP: ffff88808f9dfd40 R08: 0000000000000000 R09: ffff88805dd4a024
R10: 0000000000000000 R11: 0000000000000000 R12: fffffffffffffff0
R13: 0000000000000024 R14: ffff88805dd4a000 R15: ffff88808f9dfe00
FS: 00007ffbf7f0d700(0000) GS:ffff8880ae500000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffffffffffffff0 CR3: 00000000a6cea000 CR4: 00000000001506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
tcf_action_dump_1+0xd2/0x5a0 net/sched/act_api.c:795
tcf_dump_walker net/sched/act_api.c:249 [inline]
tcf_generic_walker+0x207/0xba0 net/sched/act_api.c:343
tc_dump_action+0x6d5/0xe60 net/sched/act_api.c:1623
netlink_dump+0x4cd/0xf60 net/netlink/af_netlink.c:2246
__netlink_dump_start+0x643/0x900 net/netlink/af_netlink.c:2354
netlink_dump_start include/linux/netlink.h:246 [inline]
rtnetlink_rcv_msg+0x70f/0xad0 net/core/rtnetlink.c:5526
netlink_rcv_skb+0x15a/0x430 net/netlink/af_netlink.c:2470
netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline]
netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1330
netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1919
sock_sendmsg_nosec net/socket.c:651 [inline]
sock_sendmsg+0xcf/0x120 net/socket.c:671
____sys_sendmsg+0x331/0x810 net/socket.c:2353
___sys_sendmsg+0xf3/0x170 net/socket.c:2407
__sys_sendmmsg+0x195/0x480 net/socket.c:2497
__do_sys_sendmmsg net/socket.c:2526 [inline]
__se_sys_sendmmsg net/socket.c:2523 [inline]
__x64_sys_sendmmsg+0x99/0x100 net/socket.c:2523
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45e179
Code: 3d b2 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 0b b2 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffbf7f0cc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 0000000000027f40 RCX: 000000000045e179
RDX: 0492492492492805 RSI: 0000000020000140 RDI: 0000000000000003
RBP: 000000000118cf88 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cf4c
R13: 00007ffc4024440f R14: 00007ffbf7f0d9c0 R15: 000000000118cf4c
Modules linked in:
CR2: fffffffffffffff0
---[ end trace 8426deb8202e61ba ]---
RIP: 0010:tcf_action_dump_terse+0x8c/0x4e0 net/sched/act_api.c:766
Code: 3c 03 0f 8e 0a 03 00 00 48 89 da 44 8b ad b8 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 80 3c 02 00 0f 85 10 04 00 00 <48> 8b 03 4c 8d 60 10 4c 89 e7 e8 d5 2b 4e fd 4c 89 e1 be 01 00 00
RSP: 0018:ffffc9001604f170 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: fffffffffffffff0 RCX: ffffc900137c6000
RDX: 1ffffffffffffffe RSI: ffffffff868ac439 RDI: ffff88808f9dfdf8
RBP: ffff88808f9dfd40 R08: 0000000000000000 R09: ffff88805dd4a024
R10: 0000000000000000 R11: 0000000000000000 R12: fffffffffffffff0
R13: 0000000000000024 R14: ffff88805dd4a000 R15: ffff88808f9dfe00
FS: 00007ffbf7f0d700(0000) GS:ffff8880ae500000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffffffffffffff0 CR3: 00000000a6cea000 CR4: 00000000001506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


---
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.

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: 2172e358 Add linux-next specific files for 20201002
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=12ba75ff900000
kernel config: https://syzkaller.appspot.com/x/.config?x=70698f530a7e856f

dashboard link: https://syzkaller.appspot.com/bug?extid=5f66662adc70969940fd
compiler: gcc (GCC) 10.1.0-syz 20200507

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=142fd4af900000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16ffcdeb900000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+5f6666...@syzkaller.appspotmail.com

BUG: unable to handle page fault for address: fffffffffffffff0
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page

PGD a291067 P4D a291067 PUD a293067 PMD 0

Oops: 0000 [#1] PREEMPT SMP KASAN

CPU: 1 PID: 8162 Comm: syz-executor344 Not tainted 5.9.0-rc7-next-20201002-syzkaller #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011

RIP: 0010:tcf_action_dump_terse+0x8c/0x4e0 net/sched/act_api.c:759
Code: 3c 03 0f 8e 0a 03 00 00 48 89 da 44 8b ad b8 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 80 3c 02 00 0f 85 10 04 00 00 <48> 8b 03 4c 8d 60 10 4c 89 e7 e8 55 5b 58 fd 4c 89 e1 be 01 00 00
RSP: 0018:ffffc90009bff178 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: fffffffffffffff0 RCX: 0000000000000000
RDX: 1ffffffffffffffe RSI: ffffffff867eb859 RDI: ffff888097102eb8
RBP: ffff888097102e00 R08: 0000000000000000 R09: ffff88809ea92024

R10: 0000000000000000 R11: 0000000000000000 R12: fffffffffffffff0

R13: 0000000000000024 R14: ffff88809ea92000 R15: ffff888097102ec0
FS: 00007f6bfe65f700(0000) GS:ffff8880ae500000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: fffffffffffffff0 CR3: 0000000096ec4000 CR4: 00000000001506e0

DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:

tcf_action_dump_1+0xd2/0x5a0 net/sched/act_api.c:788

tcf_dump_walker net/sched/act_api.c:249 [inline]
tcf_generic_walker+0x207/0xba0 net/sched/act_api.c:343

tc_dump_action+0x6d5/0xe60 net/sched/act_api.c:1610
netlink_dump+0x4df/0xba0 net/netlink/af_netlink.c:2268
__netlink_dump_start+0x643/0x900 net/netlink/af_netlink.c:2373

netlink_dump_start include/linux/netlink.h:246 [inline]
rtnetlink_rcv_msg+0x70f/0xad0 net/core/rtnetlink.c:5526

netlink_rcv_skb+0x15a/0x430 net/netlink/af_netlink.c:2489

netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline]
netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1330
netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1919
sock_sendmsg_nosec net/socket.c:651 [inline]
sock_sendmsg+0xcf/0x120 net/socket.c:671

____sys_sendmsg+0x331/0x810 net/socket.c:2362
___sys_sendmsg+0xf3/0x170 net/socket.c:2416
__sys_sendmmsg+0x196/0x4b0 net/socket.c:2506
__do_sys_sendmmsg net/socket.c:2535 [inline]
__se_sys_sendmmsg net/socket.c:2532 [inline]
__x64_sys_sendmmsg+0x99/0x100 net/socket.c:2532
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x44a569
Code: e8 8c e7 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 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 0f 83 5b 05 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f6bfe65ed98 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00000000006dfc48 RCX: 000000000044a569
RDX: 010efe10675dec16 RSI: 0000000020000200 RDI: 0000000000000003
RBP: 00000000006dfc40 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dfc4c
R13: 0000000000000005 R14: 00a3a20740000000 R15: 0507002400000038

Modules linked in:
CR2: fffffffffffffff0

---[ end trace c7fd3dfeaf54c122 ]---
RIP: 0010:tcf_action_dump_terse+0x8c/0x4e0 net/sched/act_api.c:759
Code: 3c 03 0f 8e 0a 03 00 00 48 89 da 44 8b ad b8 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 80 3c 02 00 0f 85 10 04 00 00 <48> 8b 03 4c 8d 60 10 4c 89 e7 e8 55 5b 58 fd 4c 89 e1 be 01 00 00
RSP: 0018:ffffc90009bff178 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: fffffffffffffff0 RCX: 0000000000000000
RDX: 1ffffffffffffffe RSI: ffffffff867eb859 RDI: ffff888097102eb8
RBP: ffff888097102e00 R08: 0000000000000000 R09: ffff88809ea92024

R10: 0000000000000000 R11: 0000000000000000 R12: fffffffffffffff0

R13: 0000000000000024 R14: ffff88809ea92000 R15: ffff888097102ec0
FS: 00007f6bfe65f700(0000) GS:ffff8880ae500000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: fffffffffffffff0 CR3: 0000000096ec4000 CR4: 00000000001506e0

[Hillf Danton]

Sun, 04 Oct 2020 01:48:22 -0700

Skip place holders in idr.

--- a/net/sched/act_api.c
+++ b/net/sched/act_api.c
@@ -235,6 +235,8 @@ static int tcf_dump_walker(struct tcf_id
index++;
if (index < s_i)
continue;
+ if (IS_ERR(p))
+ continue;

if (jiffy_since &&
time_after(jiffy_since,

[syzbot]

syzbot has bisected this issue to:

commit 0fedc63fadf0404a729e73a35349481c8009c02f
Author: Cong Wang <xiyou.w...@gmail.com>
Date: Wed Sep 23 03:56:24 2020 +0000

net_sched: commit action insertions together

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=12c20657900000
start commit: 2172e358 Add linux-next specific files for 20201002
git tree: linux-next
final oops: https://syzkaller.appspot.com/x/report.txt?x=11c20657900000
console output: https://syzkaller.appspot.com/x/log.txt?x=16c20657900000

kernel config: https://syzkaller.appspot.com/x/.config?x=70698f530a7e856f
dashboard link: https://syzkaller.appspot.com/bug?extid=5f66662adc70969940fd

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=142fd4af900000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16ffcdeb900000

Reported-by: syzbot+5f6666...@syzkaller.appspotmail.com
Fixes: 0fedc63fadf0 ("net_sched: commit action insertions together")

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

[Cong Wang]

#syz fix: net_sched: check error pointer in tcf_dump_walker()