From: Breno Leitao <leitao@debian.org>
To: Igor Putko <igorpetindev@gmail.com>
Cc: Andreas Hindborg <a.hindborg@kernel.org>,
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com,
syzbot+6b16e3d085833cbf3e25@syzkaller.appspotmail.com
Subject: Re: [PATCH] configfs: fix slab-use-after-free in configfs_get_config_item()
Date: Thu, 30 Jul 2026 07:20:37 -0700 [thread overview]
Message-ID: <amtdX2pfOpz10IMg@gmail.com> (raw)
In-Reply-To: <20260730092502.5913-1-igorpetindev@gmail.com>
On Thu, Jul 30, 2026 at 12:25:02PM +0300, Igor Putko wrote:
> Fix this by taking configfs_dirent_lock inside configfs_get_config_item()
> and checking if the CONFIGFS_USET_DROPPING flag is set before taking a
> reference on the config_item.
How was this tested?
With this applied, a plain rmdir of any configfs item oopses, because
configfs_rmdir() itself calls this helper on the dentry it is removing,
after it has already set CONFIGFS_USET_DROPPING.
BUG: kernel NULL pointer dereference, address: 0000000000000040
RIP: 0010:configfs_rmdir+0x23d/0x3a0
Call Trace:
vfs_rmdir+0xbb/0x200
__x64_sys_rmdir+0x29/0x90
next prev parent reply other threads:[~2026-07-30 14:20 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-30 9:25 [PATCH] configfs: fix slab-use-after-free in configfs_get_config_item() Igor Putko
2026-07-30 14:20 ` Breno Leitao [this message]
2026-07-30 14:43 ` Igor Putko
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