From: Peter Zijlstra <peterz@infradead.org>
To: Sven Schnelle <svens@linux.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>,
Steven Rostedt <rostedt@goodmis.org>,
Alexander Gordeev <agordeev@linux.ibm.com>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Kees Cook <keescook@chromium.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] ptrace: fix clearing of JOBCTL_TRACED in ptrace_unfreeze_traced()
Date: Wed, 6 Jul 2022 12:44:58 +0200 [thread overview]
Message-ID: <YsVnqtvOa9ImLkmj@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <20220706101625.2100298-1-svens@linux.ibm.com>
On Wed, Jul 06, 2022 at 12:16:25PM +0200, Sven Schnelle wrote:
> CI reported the following splat while running the strace testsuite:
>
> [ 3976.640309] WARNING: CPU: 1 PID: 3570031 at kernel/ptrace.c:272 ptrace_check_attach+0x12e/0x178
> [ 3976.640391] CPU: 1 PID: 3570031 Comm: strace Tainted: G OE 5.19.0-20220624.rc3.git0.ee819a77d4e7.300.fc36.s390x #1
> [ 3976.640410] Hardware name: IBM 3906 M04 704 (z/VM 7.1.0)
> [ 3976.640452] Call Trace:
> [ 3976.640454] [<00000000ab4b645a>] ptrace_check_attach+0x132/0x178
> [ 3976.640457] ([<00000000ab4b6450>] ptrace_check_attach+0x128/0x178)
> [ 3976.640460] [<00000000ab4b6cde>] __s390x_sys_ptrace+0x86/0x160
> [ 3976.640463] [<00000000ac03fcec>] __do_syscall+0x1d4/0x200
> [ 3976.640468] [<00000000ac04e312>] system_call+0x82/0xb0
> [ 3976.640470] Last Breaking-Event-Address:
> [ 3976.640471] [<00000000ab4ea3c8>] wait_task_inactive+0x98/0x190
>
> This is because JOBCTL_TRACED is set, but the task is not in TASK_TRACED
> state. Caused by ptrace_unfreeze_traced() which does:
>
> task->jobctl &= ~TASK_TRACED
>
> but it should be:
>
> task->jobctl &= ~JOBCTL_TRACED
>
> Fixes: 31cae1eaae4f ("sched,signal,ptrace: Rework TASK_TRACED, TASK_STOPPED state")
> Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> ---
> kernel/ptrace.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/ptrace.c b/kernel/ptrace.c
> index 156a99283b11..1893d909e45c 100644
> --- a/kernel/ptrace.c
> +++ b/kernel/ptrace.c
> @@ -222,7 +222,7 @@ static void ptrace_unfreeze_traced(struct task_struct *task)
> if (lock_task_sighand(task, &flags)) {
> task->jobctl &= ~JOBCTL_PTRACE_FROZEN;
> if (__fatal_signal_pending(task)) {
> - task->jobctl &= ~TASK_TRACED;
> + task->jobctl &= ~JOBCTL_TRACED;
> wake_up_state(task, __TASK_TRACED);
> }
> unlock_task_sighand(task, &flags);
> --
> 2.34.1
>
next prev parent reply other threads:[~2022-07-06 10:45 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-06 10:16 [PATCH] ptrace: fix clearing of JOBCTL_TRACED in ptrace_unfreeze_traced() Sven Schnelle
2022-07-06 10:44 ` Peter Zijlstra [this message]
2022-07-06 11:04 ` Oleg Nesterov
2022-07-06 11:13 ` Peter Zijlstra
2022-07-06 12:48 ` Alexander Gordeev
2022-07-06 21:15 ` Eric W. Biederman
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=YsVnqtvOa9ImLkmj@worktop.programming.kicks-ass.net \
--to=peterz@infradead.org \
--cc=agordeev@linux.ibm.com \
--cc=ebiederm@xmission.com \
--cc=keescook@chromium.org \
--cc=linux-kernel@vger.kernel.org \
--cc=oleg@redhat.com \
--cc=rostedt@goodmis.org \
--cc=svens@linux.ibm.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.