All of lore.kernel.org
 help / color / mirror / Atom feed
From: Tejun Heo <tj@kernel.org>
To: syzbot <syzbot+141cc7ede4844354c9c5@syzkaller.appspotmail.com>
Cc: gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org,
	syzkaller-bugs@googlegroups.com
Subject: Re: [syzbot] memory leak in kernfs_fop_open
Date: Wed, 12 Oct 2022 10:36:43 -1000	[thread overview]
Message-ID: <Y0clWyDlLzG+Eqvx@slm.duckdns.org> (raw)
In-Reply-To: <000000000000fe10d805ead95567@google.com>

On Wed, Oct 12, 2022 at 10:00:55AM -0700, syzbot wrote:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    e8bc52cb8df8 Merge tag 'driver-core-6.1-rc1' of git://git...
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=15adbd1c880000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=d97b00ebbd65d751
> dashboard link: https://syzkaller.appspot.com/bug?extid=141cc7ede4844354c9c5
> compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=127fb348880000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=140790e8880000
> 
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/c383c6221def/disk-e8bc52cb.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/212eadb7e8f5/vmlinux-e8bc52cb.xz
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+141cc7ede4844354c9c5@syzkaller.appspotmail.com
> 
> BUG: memory leak
> unreferenced object 0xffff88810bfdeb80 (size 96):
>   comm "udevd", pid 2966, jiffies 4294946369 (age 13.650s)
>   hex dump (first 32 bytes):
>     00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
>     01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
>   backtrace:
>     [<ffffffff816f6911>] kmalloc include/linux/slab.h:600 [inline]
>     [<ffffffff816f6911>] kzalloc include/linux/slab.h:733 [inline]
>     [<ffffffff816f6911>] kernfs_get_open_node fs/kernfs/file.c:568 [inline]
>     [<ffffffff816f6911>] kernfs_fop_open+0x4f1/0x5b0 fs/kernfs/file.c:736
>     [<ffffffff815d909f>] do_dentry_open+0x2ff/0x7c0 fs/open.c:882
>     [<ffffffff815ff9b6>] do_open fs/namei.c:3557 [inline]
>     [<ffffffff815ff9b6>] path_openat+0x1756/0x1be0 fs/namei.c:3691
>     [<ffffffff816026e1>] do_filp_open+0xc1/0x1b0 fs/namei.c:3718
>     [<ffffffff815dca0d>] do_sys_openat2+0xed/0x260 fs/open.c:1310
>     [<ffffffff815dd45f>] do_sys_open fs/open.c:1326 [inline]
>     [<ffffffff815dd45f>] __do_sys_openat fs/open.c:1342 [inline]
>     [<ffffffff815dd45f>] __se_sys_openat fs/open.c:1337 [inline]
>     [<ffffffff815dd45f>] __x64_sys_openat+0x7f/0xe0 fs/open.c:1337
>     [<ffffffff845fc895>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>     [<ffffffff845fc895>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
>     [<ffffffff84800087>] entry_SYSCALL_64_after_hwframe+0x63/0xcd

I tried to reproduce it on my test setup and then qemu running the syz image
but haven't been successful yet. The bug definitely seems plausible but I
haven't been able to spot anything obvious looking at the code yet either.
I'm a bit out of ideas right now. Will keep thinking about it and come back
to it later.

Thanks.

-- 
tejun

      reply	other threads:[~2022-10-12 20:36 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-12 17:00 [syzbot] memory leak in kernfs_fop_open syzbot
2022-10-12 20:36 ` Tejun Heo [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=Y0clWyDlLzG+Eqvx@slm.duckdns.org \
    --to=tj@kernel.org \
    --cc=gregkh@linuxfoundation.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=syzbot+141cc7ede4844354c9c5@syzkaller.appspotmail.com \
    --cc=syzkaller-bugs@googlegroups.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.