syzbot


general protection fault in qdisc_destroy
Status: fixed on 2019/12/09 13:28
Reported-by: syzbot+3cf1f0cc076c816106a2@syzkaller.appspotmail.com
Fix commit: e0f600b69df3 net_sched: let qdisc_put() accept NULL pointer
First crash: 979d, last: 974d

Fix bisection: fixed by (bisect log) :
commit e0f600b69df33b5ef69c2821ac69fafa96baab98
Author: Cong Wang <xiyou.wangcong@gmail.com>
Date: Thu Sep 12 17:22:30 2019 +0000

  net_sched: let qdisc_put() accept NULL pointer

similar bugs (1):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 general protection fault in qdisc_destroy C done 9 974d 984d 1/1 fixed on 2019/12/09 13:28

Sample crash report:
RBP: 00007ffe42bc60a0 R08: 0000000000000001 R09: 00000000bb1414ac
R10: 0000000000000000 R11: 0000000000000246 R12: ffffffffffffffff
R13: 0000000000000006 R14: 0000000000000000 R15: 0000000000000000
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
Modules linked in:
CPU: 0 PID: 6795 Comm: syz-executor191 Not tainted 4.14.145 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff88808d36c100 task.stack: ffff88809bda8000
RIP: 0010:qdisc_destroy+0x26/0x320 net/sched/sch_generic.c:708
RSP: 0018:ffff88809bdaf590 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 1ffff11011a6d934
RDX: 0000000000000002 RSI: ffff88808d36c980 RDI: 0000000000000010
RBP: ffff88809bdaf5a8 R08: ffff88808d36c100 R09: ffff88808d36c9a0
R10: 0000000000000000 R11: 0000000000000000 R12: ffff888089f7a0c0
R13: ffffffff84eaeb60 R14: 00000000fffffff4 R15: ffff888094ac7ce4
FS:  0000000001462880(0000) GS:ffff8880aee00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 00000000a5760000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 sfb_destroy+0x61/0x80 net/sched/sch_sfb.c:471
 qdisc_create+0x9e0/0xe60 net/sched/sch_api.c:1113
 tc_modify_qdisc+0x494/0x1270 net/sched/sch_api.c:1434
 rtnetlink_rcv_msg+0x3eb/0xb70 net/core/rtnetlink.c:4285
 netlink_rcv_skb+0x14f/0x3c0 net/netlink/af_netlink.c:2432
 rtnetlink_rcv+0x1d/0x30 net/core/rtnetlink.c:4297
 netlink_unicast_kernel net/netlink/af_netlink.c:1286 [inline]
 netlink_unicast+0x45d/0x640 net/netlink/af_netlink.c:1312
 netlink_sendmsg+0x7c4/0xc60 net/netlink/af_netlink.c:1877
 sock_sendmsg_nosec net/socket.c:646 [inline]
 sock_sendmsg+0xce/0x110 net/socket.c:656
 ___sys_sendmsg+0x70a/0x840 net/socket.c:2062
 __sys_sendmsg+0xb9/0x140 net/socket.c:2096
 SYSC_sendmsg net/socket.c:2107 [inline]
 SyS_sendmsg+0x2d/0x50 net/socket.c:2103
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x441669
RSP: 002b:00007ffe42bc6028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441669
RDX: 0000000000000000 RSI: 0000000020000240 RDI: 0000000000000003
RBP: 00007ffe42bc60a0 R08: 0000000000000001 R09: 00000000bb1414ac
R10: 0000000000000000 R11: 0000000000000246 R12: ffffffffffffffff
R13: 0000000000000006 R14: 0000000000000000 R15: 0000000000000000
Code: 0f 1f 44 00 00 55 48 89 e5 41 55 41 54 53 48 89 fb e8 2f f4 79 fc 48 8d 7b 10 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e 70 02 00 00 f6 43 10 01 74 
RIP: qdisc_destroy+0x26/0x320 net/sched/sch_generic.c:708 RSP: ffff88809bdaf590
---[ end trace 47d4e85bb3c07596 ]---

Crashes (4):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-linux-4-14 2019/09/20 12:59 linux-4.14.y b10ab5e2c476 d96e88f3 .config log report syz C
ci2-linux-4-14 2019/09/20 20:15 linux-4.14.y b10ab5e2c476 d96e88f3 .config log report
ci2-linux-4-14 2019/09/20 12:26 linux-4.14.y b10ab5e2c476 d96e88f3 .config log report
ci2-linux-4-14 2019/09/16 04:28 linux-4.14.y e2cd24b62938 32d59357 .config log report