From: Qing Wang <wangqing7171@gmail.com>
To: oleg@redhat.com
Cc: thaumy.love@gmail.com, Liam.Howlett@oracle.com,
akpm@linux-foundation.org, brauner@kernel.org,
bsegall@google.com, jack@suse.cz, joel.granados@kernel.org,
juri.lelli@redhat.com, linux-kernel@vger.kernel.org,
lorenzo.stoakes@oracle.com, mingo@redhat.com, mjguzik@gmail.com,
peterz@infradead.org, rostedt@goodmis.org, rppt@kernel.org,
syzbot+e0378d4f4fe57aa2bdd0@syzkaller.appspotmail.com,
wangqing7171@gmail.com
Subject: Re: [PATCH] fork/pid: Fix use-after-free in __task_pid_nr_ns
Date: Wed, 7 Jan 2026 17:40:58 +0800 [thread overview]
Message-ID: <20260107094058.3753465-1-wangqing7171@gmail.com> (raw)
In-Reply-To: <aV0FL-GKYaCQmiBs@redhat.com>
On Tue, 06 Jan 2026 at 20:50, Oleg Nesterov <oleg@redhat.com> wrote:
> On a second thought...
>
> sched_fork() is called before perf_event_init_task(). So perhaps
> sync_child_event() could also check task->__state != TASK_NEW before
> perf_event_read_event() ?
>
> Not sure, I know nothing about perf. Would be nice if perf experts can
> take a look.
>
> Oleg.
I agree with your idea. But we don't need to fix this issue anymore,
because after reviewing the current mainline code, I found that it has
already been resolved(c418d8b4d7a4 "perf/core: Fix missing read event
generation on task exit") by moving sync_child_event() from
perf_child_detach() into perf_event_exit_event().
Here https://patch.msgid.link/20251209041600.963586-1-thaumy.love@gmail.com
As a result, perf_event_read_event() no longer occurs on the problematic
path reported (i.e., the close()->perf_release() path).
Qing.
next prev parent reply other threads:[~2026-01-07 9:41 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-05 4:36 Qing Wang
2026-01-05 22:46 ` Andrew Morton
2026-01-06 7:07 ` Qing Wang
2026-01-06 9:04 ` Oleg Nesterov
2026-01-06 10:06 ` Qing Wang
2026-01-06 10:26 ` Qing Wang
2026-01-06 10:58 ` Oleg Nesterov
2026-01-06 10:58 ` Qing Wang
2026-01-06 11:19 ` Oleg Nesterov
2026-01-07 2:43 ` Qing Wang
2026-01-06 12:50 ` Oleg Nesterov
2026-01-07 9:40 ` Qing Wang [this message]
2026-01-07 14:54 ` Oleg Nesterov
2026-01-07 9:43 ` Oleg Nesterov
[not found] <20260105045609.1764387-1-wangqing7171@gmail.com>
2026-01-07 20:39 ` Kees Cook
2026-01-08 2:15 ` Qing Wang
2026-01-08 3:44 ` Qing Wang
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