[moderation/CI] Re: coredump/fcntl: Add FD_CLOBCOR flag to close fd before dumping core

[syzbot ci <syzbot+ci5e0a64dea7cd43ee@syzkaller.appspotmail.com>]

syzbot ci has tested the following series

[v1] coredump/fcntl: Add FD_CLOBCOR flag to close fd before dumping core
https://lore.kernel.org/all/20260618030700.2511668-1-jackzxcui1989@163.com
* [PATCH] coredump/fcntl: Add FD_CLOBCOR flag to close fd before dumping core

and found the following issue:
WARNING: suspicious RCU usage in exit_files_before_core

Full report is available here:
https://ci.syzbot.org/series/bda032a0-64d8-4226-8ad1-6a4c99514d61

***

WARNING: suspicious RCU usage in exit_files_before_core

tree:      torvalds
URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux
base:      2a706d98d50a28dd635b3d028531d839c1f5f19a
arch:      amd64
compiler:  Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
config:    https://ci.syzbot.org/builds/e0dd4cce-02a0-415c-9720-8816ca17346d/config

=============================
WARNING: suspicious RCU usage
syzkaller #0 Not tainted
-----------------------------
./include/linux/fdtable.h:104 suspicious rcu_dereference_check() usage!

other info that might help us debug this:


rcu_scheduler_active = 2, debug_locks = 1
no locks held by syz.2.65/5687.

stack backtrace:
CPU: 0 UID: 0 PID: 5687 Comm: syz.2.65 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
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150
 lockdep_rcu_suspicious+0x13f/0x1d0
 exit_files_before_core+0x35a/0x410
 vfs_coredump+0xa52/0x4550
 get_signal+0x1107/0x1330
 arch_do_signal_or_restart+0xbc/0x830
 irqentry_exit+0x2a4/0x860
 asm_exc_page_fault+0x26/0x30
RIP: 0033:0x0
Code: Unable to access opcode bytes at 0xffffffffffffffd6.
RSP: 002b:0000200000000008 EFLAGS: 00010217
RAX: 0000000000000000 RBX: 00007f3125415fa0 RCX: 00007f312519ce59
RDX: 0000200000000000 RSI: 0000200000000000 RDI: 0000000000000000
RBP: 00007f3125232d6f R08: 0000200000000000 R09: 0000000000000000
R10: 0000200000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3125415fac R14: 00007f3125415fa0 R15: 00007f3125415fa0
 </TASK>


***

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@syzkaller.appspotmail.com

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

To test a patch for this bug, please reply with `#syz test`
(should be on a separate line).

The patch should be attached to the email.
Note: arguments like custom git repos and branches are not supported.

The email will later be sent to:
[alex.aring@gmail.com allen.lkml@gmail.com arnd@arndb.de brauner@kernel.org chuck.lever@oracle.com ebiederm@xmission.com j.granados@samsung.com jack@suse.cz jackzxcui1989@163.com jlayton@kernel.org keescook@chromium.org linux-arch@vger.kernel.org linux-fsdevel@vger.kernel.org linux-kernel@vger.kernel.org mcgrof@kernel.org viro@zeniv.linux.org.uk]

If the report looks fine to you, reply with:
#syz upstream

If the report is a false positive, reply with
#syz invalid