From: Dmitry Vyukov <dvyukov@google.com>
To: syzbot <syzbot+b7c3ba8cdc2f6cf83c21@syzkaller.appspotmail.com>
Cc: gregkh@linuxfoundation.org, jirislaby@kernel.org,
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com
Subject: Re: [syzbot] [kernel?] KCSAN: data-race in __fput / __tty_hangup (4)
Date: Fri, 21 Apr 2023 10:21:31 +0200 [thread overview]
Message-ID: <CACT4Y+bj7jCOjGV5jCUPzN5zjgdHxRn9vkwQEBuPWVzMbMCnXw@mail.gmail.com> (raw)
In-Reply-To: <00000000000013aaac05f9d44e7a@google.com>
On Fri, 21 Apr 2023 at 10:18, syzbot
<syzbot+b7c3ba8cdc2f6cf83c21@syzkaller.appspotmail.com> wrote:
>
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: fcd476ea6a88 Merge tag 'urgent-rcu.2023.03.28a' of git://g..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=146618b9c80000
> kernel config: https://syzkaller.appspot.com/x/.config?x=f7350c77b8056a38
> dashboard link: https://syzkaller.appspot.com/bug?extid=b7c3ba8cdc2f6cf83c21
> compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2
>
> Unfortunately, I don't have any reproducer for this issue yet.
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/f3d8ce4faab0/disk-fcd476ea.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/fc53d9dee279/vmlinux-fcd476ea.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/22ad755d39b2/bzImage-fcd476ea.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+b7c3ba8cdc2f6cf83c21@syzkaller.appspotmail.com
If I am reading this correctly, this race can lead to NULL derefs
among other things.
hung_up_tty_fops does not have splice_read, while other fops have.
So the following code in splice can execute NULL callback:
if (unlikely(!in->f_op->splice_read))
return warn_unsupported(in, "read");
return in->f_op->splice_read(in, ppos, pipe, len, flags);
> ==================================================================
> BUG: KCSAN: data-race in __fput / __tty_hangup
>
> write to 0xffff88813b31e828 of 8 bytes by task 17702 on cpu 0:
> __tty_hangup+0x1e2/0x510 drivers/tty/tty_io.c:622
> tty_vhangup+0x17/0x20 drivers/tty/tty_io.c:701
> pty_close+0x262/0x280 drivers/tty/pty.c:79
> tty_release+0x204/0x930 drivers/tty/tty_io.c:1753
> __fput+0x245/0x570 fs/file_table.c:321
> ____fput+0x15/0x20 fs/file_table.c:349
> task_work_run+0x123/0x160 kernel/task_work.c:179
> get_signal+0xe5c/0xfe0 kernel/signal.c:2635
> arch_do_signal_or_restart+0x89/0x2b0 arch/x86/kernel/signal.c:306
> exit_to_user_mode_loop+0x6d/0xe0 kernel/entry/common.c:168
> exit_to_user_mode_prepare+0x6a/0xa0 kernel/entry/common.c:204
> __syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline]
> syscall_exit_to_user_mode+0x26/0x140 kernel/entry/common.c:297
> do_syscall_64+0x4d/0xc0 arch/x86/entry/common.c:86
> entry_SYSCALL_64_after_hwframe+0x63/0xcd
>
> read to 0xffff88813b31e828 of 8 bytes by task 17705 on cpu 1:
> __fput+0x21c/0x570 fs/file_table.c:320
> ____fput+0x15/0x20 fs/file_table.c:349
> task_work_run+0x123/0x160 kernel/task_work.c:179
> get_signal+0xe5c/0xfe0 kernel/signal.c:2635
> arch_do_signal_or_restart+0x89/0x2b0 arch/x86/kernel/signal.c:306
> exit_to_user_mode_loop+0x6d/0xe0 kernel/entry/common.c:168
> exit_to_user_mode_prepare+0x6a/0xa0 kernel/entry/common.c:204
> __syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline]
> syscall_exit_to_user_mode+0x26/0x140 kernel/entry/common.c:297
> do_syscall_64+0x4d/0xc0 arch/x86/entry/common.c:86
> entry_SYSCALL_64_after_hwframe+0x63/0xcd
>
> value changed: 0xffffffff84e91ed0 -> 0xffffffff84e91dc0
>
> Reported by Kernel Concurrency Sanitizer on:
> CPU: 1 PID: 17705 Comm: syz-executor.0 Not tainted 6.3.0-rc4-syzkaller-00034-gfcd476ea6a88 #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/17/2023
> ==================================================================
>
>
> ---
> This report is generated by a bot. It may contain errors.
> See https://goo.gl/tpsmEJ for more information about syzbot.
> syzbot engineers can be reached at syzkaller@googlegroups.com.
>
> syzbot will keep track of this issue. See:
> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
next prev parent reply other threads:[~2023-04-21 8:22 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-21 8:18 [syzbot] [kernel?] KCSAN: data-race in __fput / __tty_hangup (4) syzbot
2023-04-21 8:21 ` Dmitry Vyukov [this message]
2023-04-21 15:12 ` Tetsuo Handa
2023-04-21 16:02 ` Tetsuo Handa
2023-04-23 23:34 ` Al Viro
2023-04-23 23:55 ` Tetsuo Handa
2023-04-24 0:44 ` Al Viro
2023-04-24 1:09 ` Tetsuo Handa
2023-04-25 14:47 ` Tetsuo Handa
2023-04-25 16:03 ` Al Viro
2023-04-25 22:09 ` Tetsuo Handa
2023-04-26 11:05 ` [PATCH] tty: tty_io: remove hung_up_tty_fops Tetsuo Handa
2023-04-28 16:27 ` Nathan Chancellor
2023-04-28 16:41 ` Tetsuo Handa
2023-04-28 17:11 ` Al Viro
2023-04-29 10:43 ` Tetsuo Handa
2023-04-28 17:31 ` Greg Kroah-Hartman
2023-04-29 15:21 ` Guenter Roeck
2023-05-01 18:42 ` Geert Uytterhoeven
2023-05-14 1:02 ` [PATCH v2] " Tetsuo Handa
2023-05-30 10:44 ` Greg Kroah-Hartman
2023-05-30 11:57 ` Tetsuo Handa
2023-05-30 12:51 ` Greg Kroah-Hartman
2024-04-27 6:20 ` [PATCH v3] " Tetsuo Handa
2024-04-27 19:02 ` Linus Torvalds
2024-04-28 10:19 ` Tetsuo Handa
2024-04-28 18:50 ` Linus Torvalds
2024-04-29 13:55 ` Marco Elver
2024-04-29 15:38 ` Linus Torvalds
2024-05-01 18:45 ` Paul E. McKenney
2024-05-01 18:56 ` Linus Torvalds
2024-05-01 19:02 ` Paul E. McKenney
2024-05-01 20:14 ` Marco Elver
2024-05-01 21:06 ` Linus Torvalds
2024-05-01 21:20 ` Linus Torvalds
2024-05-01 21:49 ` Paul E. McKenney
2024-05-01 22:32 ` Paul E. McKenney
2024-05-02 16:37 ` Boqun Feng
2024-05-03 23:59 ` Paul E. McKenney
2024-05-04 0:14 ` Linus Torvalds
2024-05-04 5:08 ` Paul E. McKenney
2024-05-04 17:50 ` Linus Torvalds
2024-05-04 18:18 ` Paul E. McKenney
2024-05-04 19:11 ` Linus Torvalds
2024-05-04 19:25 ` Linus Torvalds
2024-05-04 22:17 ` Paul E. McKenney
2024-05-04 22:04 ` Paul E. McKenney
2024-05-02 14:14 ` Marco Elver
2024-05-02 16:42 ` Tetsuo Handa
2024-05-02 17:20 ` Marco Elver
2024-05-02 17:29 ` Linus Torvalds
2024-05-02 18:14 ` Al Viro
2024-05-02 19:29 ` Marco Elver
2024-05-02 23:54 ` Tetsuo Handa
2024-05-03 1:12 ` Linus Torvalds
2023-04-23 13:28 ` [syzbot] [kernel?] KCSAN: data-race in __fput / __tty_hangup (4) Tetsuo Handa
2023-04-23 14:00 ` Greg Kroah-Hartman
2023-04-23 14:03 ` Greg Kroah-Hartman
2023-04-23 14:17 ` Tetsuo Handa
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=CACT4Y+bj7jCOjGV5jCUPzN5zjgdHxRn9vkwQEBuPWVzMbMCnXw@mail.gmail.com \
--to=dvyukov@google.com \
--cc=gregkh@linuxfoundation.org \
--cc=jirislaby@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=syzbot+b7c3ba8cdc2f6cf83c21@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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).