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general protection fault in fib_dump_info (2)

Status: fixed on 2020/09/16 22:51
Subsystems: net
[Documentation on labels]
Reported-by: syzbot+a61aa19b0c14c8770bd9@syzkaller.appspotmail.com
Fix commit: eeaac3634ee0 net: nexthop: don't allow empty NHA_GROUP
First crash: 1348d, last: 1334d
Cause bisection: introduced by (bisect log) :
commit 0b5e2e39739e861fa5fc84ab27a35dbe62a15330
Author: David Ahern <dsahern@gmail.com>
Date: Tue May 26 18:56:16 2020 +0000

  nexthop: Expand nexthop_is_multipath in a few places

Crash: general protection fault in fib_dump_info (log)
Repro: C syz .config
  
▶ ▼ Duplicate bugs (1)
duplicates (1):
Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
general protection fault in fib_check_nexthop net 2 1339d 1336d 0/26 closed as dup on 2020/08/22 14:22
▶ ▼ Discussions (5)
Title Replies (including bot) Last reply
[PATCH 5.4 000/214] 5.4.62-rc1 review 219 (219) 2020/09/02 07:24
[PATCH 5.7 00/15] 5.7.19-rc1 review 20 (20) 2020/08/27 08:09
[PATCH 5.8 00/16] 5.8.5-rc1 review 20 (20) 2020/08/27 07:59
[PATCH net] net: nexthop: don't allow empty NHA_GROUP 4 (4) 2020/08/22 19:42
general protection fault in fib_dump_info (2) 2 (3) 2020/08/21 16:05
▶ ▼ Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream general protection fault in fib_dump_info C 428 2431d 2442d 3/26 fixed on 2017/10/24 06:54

Sample crash report:
general protection fault, probably for non-canonical address 0xdffffc0000000010: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000080-0x0000000000000087]
CPU: 0 PID: 6874 Comm: syz-executor185 Not tainted 5.9.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:nexthop_is_blackhole include/net/nexthop.h:240 [inline]
RIP: 0010:fib_dump_info+0x893/0x1f00 net/ipv4/fib_semantics.c:1781
Code: 3c 02 00 0f 85 83 15 00 00 4d 8b 6d 10 e8 e5 a3 ab fa 49 8d bd 80 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 62 15 00 00 4d 8b ad 80 00 00 00 e8 97 e4 2a 01
RSP: 0018:ffffc90000f07260 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffff8880a66b5a00 RCX: ffffffff86c89af3
RDX: 0000000000000010 RSI: ffffffff86c89b2b RDI: 0000000000000080
RBP: ffff88809a6a6817 R08: 0000000000000001 R09: ffff88809a6a682b
R10: 0000000000000001 R11: 0000000000000000 R12: ffff88809a6a6800
R13: 0000000000000000 R14: 0000000000000000 R15: ffff8880922158c0
FS:  0000000001024880(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000004 CR3: 00000000a216b000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 rtmsg_fib+0x318/0xdf0 net/ipv4/fib_semantics.c:524
 fib_table_insert+0x1383/0x1af0 net/ipv4/fib_trie.c:1284
 inet_rtm_newroute+0x109/0x1e0 net/ipv4/fib_frontend.c:883
 rtnetlink_rcv_msg+0x44e/0xad0 net/core/rtnetlink.c:5563
 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+0x6e8/0x810 net/socket.c:2353
 ___sys_sendmsg+0xf3/0x170 net/socket.c:2407
 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2440
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x440549
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 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 7b 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffd84f061e8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440549
RDX: 0000000000000000 RSI: 0000000020000580 RDI: 0000000000000004
RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8
R10: 00000000004002c8 R11: 0000000000000246 R12: 0000000000401d50
R13: 0000000000401de0 R14: 0000000000000000 R15: 0000000000000000
Modules linked in:
---[ end trace 8f6c443d607ba182 ]---
RIP: 0010:nexthop_is_blackhole include/net/nexthop.h:240 [inline]
RIP: 0010:fib_dump_info+0x893/0x1f00 net/ipv4/fib_semantics.c:1781
Code: 3c 02 00 0f 85 83 15 00 00 4d 8b 6d 10 e8 e5 a3 ab fa 49 8d bd 80 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 62 15 00 00 4d 8b ad 80 00 00 00 e8 97 e4 2a 01
RSP: 0018:ffffc90000f07260 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffff8880a66b5a00 RCX: ffffffff86c89af3
RDX: 0000000000000010 RSI: ffffffff86c89b2b RDI: 0000000000000080
RBP: ffff88809a6a6817 R08: 0000000000000001 R09: ffff88809a6a682b
R10: 0000000000000001 R11: 0000000000000000 R12: ffff88809a6a6800
R13: 0000000000000000 R14: 0000000000000000 R15: ffff8880922158c0
FS:  0000000001024880(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000004 CR3: 00000000a216b000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Crashes (16):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/08/23 20:32 upstream c3d8f220d012 cef5ae68 .config console log report syz C ci-upstream-kasan-gce
2020/08/22 06:00 upstream cd02217a5d81 6436ce4b .config console log report syz C ci-upstream-kasan-gce-root
2020/08/21 07:30 upstream da2968ff879b 1d75fe45 .config console log report syz C ci-upstream-kasan-gce-smack-root
2020/08/21 05:57 upstream da2968ff879b 1d75fe45 .config console log report syz C ci-upstream-kasan-gce-386
2020/08/21 06:26 net-old cf96d977381d 1d75fe45 .config console log report syz C ci-upstream-net-this-kasan-gce
2020/08/21 06:17 net-next-old 1e76a2ff317d 1d75fe45 .config console log report syz C ci-upstream-net-kasan-gce
2020/08/23 07:47 linux-next 494d311a82bb 1da71ab0 .config console log report syz C ci-upstream-linux-next-kasan-gce-root
2020/08/20 02:08 upstream 18445bf405cb 94b45706 .config console log report ci-upstream-kasan-gce
2020/08/23 14:17 upstream c3d8f220d012 cef5ae68 .config console log report ci-upstream-kasan-gce-386
2020/08/20 23:59 upstream da2968ff879b 1d75fe45 .config console log report ci-upstream-kasan-gce-386
2020/08/20 21:27 upstream 7eac66d0456f 1d75fe45 .config console log report ci-upstream-kasan-gce-386
2020/08/18 06:01 net-old bf2bcd6f1a88 424dd8e7 .config console log report ci-upstream-net-this-kasan-gce
2020/08/13 18:42 net-old 9643609423c7 54ce1ed6 .config console log report ci-upstream-net-this-kasan-gce
2020/08/12 18:42 net-old 633f5b6bca9b bc15f7db .config console log report ci-upstream-net-this-kasan-gce
2020/08/09 05:52 net-old 7c7ab580db49 f721e4a0 .config console log report ci-upstream-net-this-kasan-gce
2020/08/18 05:11 net-next-old 7fca4dee610d 424dd8e7 .config console log report ci-upstream-net-kasan-gce
* Struck through repros no longer work on HEAD.