general protection fault in qdisc_put

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    3b47fd5c Merge tag 'nfs-for-5.3-4' of git://git.linux-nfs...
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10244dd6600000
kernel config:  https://syzkaller.appspot.com/x/.config?x=b89bb446a3faaba4
dashboard link: https://syzkaller.appspot.com/bug?extid=d5870a903591faaca4ae
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=174743fe600000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=11f8c43e600000

The bug was bisected to:

commit e41d58185f1444368873d4d7422f7664a68be61d
Author: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Date:   Wed Jul 12 21:34:35 2017 +0000

    fault-inject: support systematic fault injection

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=13f66bc6600000
final crash:    https://syzkaller.appspot.com/x/report.txt?x=100e6bc6600000
console output: https://syzkaller.appspot.com/x/log.txt?x=17f66bc6600000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+d5870a903591faaca4ae@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: e41d58185f14 ("fault-inject: support systematic fault injection")

RDX: 0000000000000000 RSI: 0000000020000240 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000001bbbbbb
R10: 0000000000000000 R11: 0000000000000246 R12: ffffffffffffffff
R13: 0000000000000005 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
CPU: 1 PID: 9699 Comm: syz-executor169 Not tainted 5.3.0-rc7+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
RIP: 0010:qdisc_put+0x25/0x90 net/sched/sch_generic.c:983
Code: 00 00 00 00 00 55 48 89 e5 41 54 49 89 fc 53 e8 c1 52 bf fb 49 8d 7c  
24 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 04 3c 03 7e 54 41 8b 5c 24 10 31 ff 83 e3 01
RSP: 0018:ffff8880944c7488 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffff8880945c8540 RCX: ffffffff85b49e8a
RDX: 0000000000000002 RSI: ffffffff85b3228f RDI: 0000000000000010
RBP: ffff8880944c7498 R08: ffff888099d50480 R09: ffffed1012898e45
R10: ffffed1012898e44 R11: 0000000000000003 R12: 0000000000000000
R13: ffff8880945c8540 R14: ffff888094894500 R15: ffff8880945c857c
FS:  0000555557553880(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000610 CR3: 000000008c29d000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 sfb_destroy+0x61/0x80 net/sched/sch_sfb.c:468
 qdisc_create+0xbc6/0x1210 net/sched/sch_api.c:1285
 tc_modify_qdisc+0x524/0x1c50 net/sched/sch_api.c:1652
 rtnetlink_rcv_msg+0x463/0xb00 net/core/rtnetlink.c:5223
 netlink_rcv_skb+0x177/0x450 net/netlink/af_netlink.c:2477
 rtnetlink_rcv+0x1d/0x30 net/core/rtnetlink.c:5241
 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline]
 netlink_unicast+0x531/0x710 net/netlink/af_netlink.c:1328
 netlink_sendmsg+0x8a5/0xd60 net/netlink/af_netlink.c:1917
 sock_sendmsg_nosec net/socket.c:637 [inline]
 sock_sendmsg+0xd7/0x130 net/socket.c:657
 ___sys_sendmsg+0x803/0x920 net/socket.c:2311
 __sys_sendmsg+0x105/0x1d0 net/socket.c:2356
 __do_sys_sendmsg net/socket.c:2365 [inline]
 __se_sys_sendmsg net/socket.c:2363 [inline]
 __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2363
 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4424f9
Code: e8 9c 07 03 00 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 3b 0a fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fffed10bed8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000004424f9
RDX: 0000000000000000 RSI: 0000000020000240 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000001bbbbbb
R10: 0000000000000000 R11: 0000000000000246 R12: ffffffffffffffff
R13: 0000000000000005 R14: 0000000000000000 R15: 0000000000000000
Modules linked in:
---[ end trace 97e52c48ae7a3cc1 ]---
RIP: 0010:qdisc_put+0x25/0x90 net/sched/sch_generic.c:983
Code: 00 00 00 00 00 55 48 89 e5 41 54 49 89 fc 53 e8 c1 52 bf fb 49 8d 7c  
24 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 04 3c 03 7e 54 41 8b 5c 24 10 31 ff 83 e3 01
RSP: 0018:ffff8880944c7488 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffff8880945c8540 RCX: ffffffff85b49e8a
RDX: 0000000000000002 RSI: ffffffff85b3228f RDI: 0000000000000010
RBP: ffff8880944c7498 R08: ffff888099d50480 R09: ffffed1012898e45
R10: ffffed1012898e44 R11: 0000000000000003 R12: 0000000000000000
R13: ffff8880945c8540 R14: ffff888094894500 R15: ffff8880945c857c
FS:  0000555557553880(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000610 CR3: 000000008c29d000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


---
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