linux-kernel - [syzbot ci] Re: slab: clear OBJEXTS_ALLOC

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Message-ID: <68efec35.050a0220.91a22.02cb.GAE@google.com>
Date: Wed, 15 Oct 2025 11:47:17 -0700
From: syzbot ci <syzbot+cib7b0db858ede4f18@...kaller.appspotmail.com>
To: akpm@...ux-foundation.org, ast@...nel.org, cl@...two.org, gehao@...inos.cn, 
	hao.ge@...ux.dev, harry.yoo@...cle.com, linux-kernel@...r.kernel.org, 
	linux-mm@...ck.org, rientjes@...gle.com, roman.gushchin@...ux.dev, 
	shakeel.butt@...ux.dev, surenb@...gle.com, vbabka@...e.cz
Cc: syzbot@...ts.linux.dev, syzkaller-bugs@...glegroups.com
Subject: [syzbot ci] Re: slab: clear OBJEXTS_ALLOC_FAIL when freeing a slab

syzbot ci has tested the following series

[v4] slab: clear OBJEXTS_ALLOC_FAIL when freeing a slab
https://lore.kernel.org/all/20251015125945.481950-1-hao.ge@linux.dev
* [PATCH v4] slab: clear OBJEXTS_ALLOC_FAIL when freeing a slab

and found the following issue:
kernel BUG in __free_slab

Full report is available here:
https://ci.syzbot.org/series/61ff4fe1-2e84-410d-ad85-42ead772d9c8

***

kernel BUG in __free_slab

tree:      torvalds
URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux
base:      3a8660878839faadb4f1a6dd72c3179c1df56787
arch:      amd64
compiler:  Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
config:    https://ci.syzbot.org/builds/e5875084-ea86-418c-979d-5b00cded86ca/config
syz repro: https://ci.syzbot.org/findings/1f8913d8-6d9a-448a-9419-90b758c82c3b/syz_repro

 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2684
 __sys_sendmsg net/socket.c:2716 [inline]
 __do_sys_sendmsg net/socket.c:2721 [inline]
 __se_sys_sendmsg net/socket.c:2719 [inline]
 __x64_sys_sendmsg+0x19b/0x260 net/socket.c:2719
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
------------[ cut here ]------------
kernel BUG at mm/slab.h:544!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 15 Comm: ksoftirqd/0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:slab_obj_exts mm/slab.h:543 [inline]
RIP: 0010:free_slab_obj_exts mm/slub.c:2178 [inline]
RIP: 0010:unaccount_slab mm/slub.c:3186 [inline]
RIP: 0010:__free_slab+0x1b8/0x1e0 mm/slub.c:3286
Code: e8 2d 8a 0c ff 90 0f 0b 48 89 df 48 c7 c6 18 ad 91 8d e8 1b 8a 0c ff 90 0f 0b 48 89 df 48 c7 c6 9d 66 95 8d e8 09 8a 0c ff 90 <0f> 0b 48 89 df 48 c7 c6 18 ad 91 8d e8 f7 89 0c ff 90 0f 0b 48 89
RSP: 0000:ffffc900001478b0 EFLAGS: 00010246
RAX: 680205e52e87ff00 RBX: ffffea00044c3c80 RCX: 680205e52e87ff00
RDX: 0000000000000000 RSI: ffffffff8d7e835a RDI: ffffffff8bc076e0
RBP: 0000000000000001 R08: ffffffff8f9e1177 R09: 1ffffffff1f3c22e
R10: dffffc0000000000 R11: fffffbfff1f3c22f R12: ffffffff821b61b0
R13: ffffffff81a82877 R14: ffff888160415a00 R15: ffffea00044c3c98
FS:  0000000000000000(0000) GS:ffff88818e70c000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fef42bb12f8 CR3: 000000000df38000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 rcu_do_batch kernel/rcu/tree.c:2605 [inline]
 rcu_core+0xcab/0x1770 kernel/rcu/tree.c:2861
 handle_softirqs+0x286/0x870 kernel/softirq.c:622
 run_ksoftirqd+0x9b/0x100 kernel/softirq.c:1063
 smpboot_thread_fn+0x542/0xa60 kernel/smpboot.c:160
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:slab_obj_exts mm/slab.h:543 [inline]
RIP: 0010:free_slab_obj_exts mm/slub.c:2178 [inline]
RIP: 0010:unaccount_slab mm/slub.c:3186 [inline]
RIP: 0010:__free_slab+0x1b8/0x1e0 mm/slub.c:3286
Code: e8 2d 8a 0c ff 90 0f 0b 48 89 df 48 c7 c6 18 ad 91 8d e8 1b 8a 0c ff 90 0f 0b 48 89 df 48 c7 c6 9d 66 95 8d e8 09 8a 0c ff 90 <0f> 0b 48 89 df 48 c7 c6 18 ad 91 8d e8 f7 89 0c ff 90 0f 0b 48 89
RSP: 0000:ffffc900001478b0 EFLAGS: 00010246
RAX: 680205e52e87ff00 RBX: ffffea00044c3c80 RCX: 680205e52e87ff00
RDX: 0000000000000000 RSI: ffffffff8d7e835a RDI: ffffffff8bc076e0
RBP: 0000000000000001 R08: ffffffff8f9e1177 R09: 1ffffffff1f3c22e
R10: dffffc0000000000 R11: fffffbfff1f3c22f R12: ffffffff821b61b0
R13: ffffffff81a82877 R14: ffff888160415a00 R15: ffffea00044c3c98
FS:  0000000000000000(0000) GS:ffff88818e70c000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fef42bb12f8 CR3: 000000000df38000 CR4: 00000000000006f0


***

If these findings have caused you to resend the series or submit a
separate fix, please add the following tag to your commit message:
  Tested-by: syzbot@...kaller.appspotmail.com

---
This report is generated by a bot. It may contain errors.
syzbot ci engineers can be reached at syzkaller@...glegroups.com.