Re: WARNING in mark_lock

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer still triggered  
crash:
KASAN: use-after-free Read in class_equal

==================================================================
BUG: KASAN: use-after-free in class_equal+0x40/0x50  
kernel/locking/lockdep.c:1527
Read of size 8 at addr ffff88808a268ba0 by task syz-executor.1/9270

CPU: 0 PID: 9270 Comm: syz-executor.1 Not tainted 5.2.0-rc3+ #1
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Call Trace:

Allocated by task 2647419968:
BUG: unable to handle page fault for address: ffffffff8c00b020
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 8a70067 P4D 8a70067 PUD 8a71063 PMD 0
Thread overran stack, or stack corrupted
Oops: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 9270 Comm: syz-executor.1 Not tainted 5.2.0-rc3+ #1
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
RIP: 0010:stack_depot_fetch+0x10/0x30 lib/stackdepot.c:203
Code: e9 7b fd ff ff 4c 89 ff e8 8d b4 62 fe e9 e6 fd ff ff 90 90 90 90 90  
90 90 90 89 f8 c1 ef 11 25 ff ff 1f 00 81 e7 f0 3f 00 00 <48> 03 3c c5 20  
6c 04 8b 48 8d 47 18 48 89 06 8b 47 0c c3 0f 1f 00
RSP: 0018:ffff88808a2688e8 EFLAGS: 00010006
RAX: 00000000001f8880 RBX: ffff88808a269304 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffff88808a2688f0 RDI: 0000000000003ff0
RBP: ffff88808a268908 R08: 0000000000000020 R09: ffffed1015d044fa
R10: ffffed1015d044f9 R11: ffff8880ae8227cf R12: ffffea0002289a00
R13: ffff88808a268ba0 R14: ffff8880aa58ec40 R15: ffff88808a269300
FS:  00005555570ba940(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffff8c00b020 CR3: 000000008dd00000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
Modules linked in:
CR2: ffffffff8c00b020
---[ end trace 4acfe4b59fbc9cdb ]---
RIP: 0010:stack_depot_fetch+0x10/0x30 lib/stackdepot.c:203
Code: e9 7b fd ff ff 4c 89 ff e8 8d b4 62 fe e9 e6 fd ff ff 90 90 90 90 90  
90 90 90 89 f8 c1 ef 11 25 ff ff 1f 00 81 e7 f0 3f 00 00 <48> 03 3c c5 20  
6c 04 8b 48 8d 47 18 48 89 06 8b 47 0c c3 0f 1f 00
RSP: 0018:ffff88808a2688e8 EFLAGS: 00010006
RAX: 00000000001f8880 RBX: ffff88808a269304 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffff88808a2688f0 RDI: 0000000000003ff0
RBP: ffff88808a268908 R08: 0000000000000020 R09: ffffed1015d044fa
R10: ffffed1015d044f9 R11: ffff8880ae8227cf R12: ffffea0002289a00
R13: ffff88808a268ba0 R14: ffff8880aa58ec40 R15: ffff88808a269300
FS:  00005555570ba940(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffff8c00b020 CR3: 000000008dd00000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


Tested on:

commit:         0b58d013 bpf: tls, implement unhash to avoid transition ou..
git tree:       git://github.com/cilium/linux ktls-unhash
console output: https://syzkaller.appspot.com/x/log.txt?x=153368a3a00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=2cc918d28ebd06b4
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)