KASAN: stack-out-of-bounds Read in debug_check_no_obj_freed (6)

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: bae4e109837b mlxsw: spectrum: Expose discard counters via ..
git tree: net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=10258a47400000
kernel config: https://syzkaller.appspot.com/x/.config?x=d86f24333880b605
dashboard link: https://syzkaller.appspot.com/bug?extid=89bf9105d56addb73b6f
compiler: gcc (GCC) 8.0.1 20180413 (experimental)
CC: [da...@davemloft.net kuz...@ms2.inr.ac.ru
linux-...@vger.kernel.org net...@vger.kernel.org yosh...@linux-ipv6.org]

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

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+89bf91...@syzkaller.appspotmail.com

kernel msg: ebtables bug: please report to author: Valid hook without chain
==================================================================
PANIC: double fault, error_code: 0x0
BUG: KASAN: stack-out-of-bounds in __debug_check_no_obj_freed
lib/debugobjects.c:778 [inline]
BUG: KASAN: stack-out-of-bounds in debug_check_no_obj_freed+0x45f/0x58d
lib/debugobjects.c:818
CPU: 0 PID: 19953 Comm: syz-executor4 Not tainted 4.20.0-rc2+ #303
Read of size 8 at addr ffff8881cc129c40 by task syz-executor5/19943
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011

RIP: 0010:__udp4_lib_err+0x2c/0x1590 net/ipv4/udp.c:682
CPU: 1 PID: 19943 Comm: syz-executor5 Not tainted 4.20.0-rc2+ #303
Code: 89 e5 41 57 48 8d 85 38 ff ff ff 41 56 48 c1 e8 03 41 55 41 54 49 bc
00 00 00 00 00 fc ff df 53 48 89 fb 48 81 ec 20 01 00 00 <48> 89 85 20 ff
ff ff 4c 01 e0 89 b5 f4 fe ff ff 48 89 95 28 ff ff
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
RSP: 0018:ffff8881cba3df18 EFLAGS: 00010286
Call Trace:
RAX: 1ffff11039747bf3 RBX: ffff8881c3f65a40 RCX: ffffc9000de5e000
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x244/0x39d lib/dump_stack.c:113
RDX: ffffffff8a17be20 RSI: 0000000000000000 RDI: ffff8881c3f65a40
RBP: ffff8881cba3e060 R08: ffff8881d933e480 R09: 000000000000000b
R10: 0000000000000000 R11: ffff8881dae2db3b R12: dffffc0000000000
R13: 1ffff11039747c13 R14: ffff8881cba3e0f8 R15: 0000000000000000
print_address_description.cold.7+0x9/0x1ff mm/kasan/report.c:256
FS: 00007fecf1c08700(0000) GS:ffff8881dae00000(0000) knlGS:0000000000000000
kasan_report_error mm/kasan/report.c:354 [inline]
kasan_report.cold.8+0x242/0x309 mm/kasan/report.c:412
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffff8881cba3df08 CR3: 00000001c1738000 CR4: 00000000001406f0
__asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
__debug_check_no_obj_freed lib/debugobjects.c:778 [inline]
debug_check_no_obj_freed+0x45f/0x58d lib/debugobjects.c:818
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
kfree+0xbd/0x230 mm/slab.c:3816


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.