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From: David Hildenbrand <david@redhat.com>
To: Edward Adam Davis <eadavis@qq.com>, kees@kernel.org
Cc: mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com,
	vincent.guittot@linaro.org, dietmar.eggemann@arm.com,
	rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de,
	vschneid@redhat.com, akpm@linux-foundation.org,
	lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com,
	vbabka@suse.cz, rppt@kernel.org, surenb@google.com,
	mhocko@suse.com, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH Next] copy_process(): Fixed jump logic error
Date: Wed, 24 Sep 2025 14:29:00 +0200	[thread overview]
Message-ID: <2dcffe42-141b-40fc-9bc1-b61a1ed7d74f@redhat.com> (raw)
In-Reply-To: <tencent_5E4F978D9525A58D97925ADDBADDB2193107@qq.com>

On 24.09.25 14:06, Edward Adam Davis wrote:
> After futex_hash_allocate_default() fails, the logic should jump to
> bad_fork_cancel_cgroup, not bad_fork_core_free.
> 
> Jumping to bad_fork_core_free would cause a siglock imbalance.
> 
> Signed-off-by: Edward Adam Davis <eadavis@qq.com>

If it's still only in -next (which I assume when looking at the Next 
tag), into which patch should this fixup get squashed?

Or is this already upstream and we want actually Fixes: and CC stable?

(staring at current master, this seems to be an upstream problem?)

> ---
>   kernel/fork.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/kernel/fork.c b/kernel/fork.c
> index e9a7fb5c3e49..a0b8eeeb1d27 100644
> --- a/kernel/fork.c
> +++ b/kernel/fork.c
> @@ -2349,7 +2349,7 @@ __latent_entropy struct task_struct *copy_process(
>   	if (need_futex_hash_allocate_default(clone_flags)) {
>   		retval = futex_hash_allocate_default();
>   		if (retval)
> -			goto bad_fork_core_free;
> +			goto bad_fork_cancel_cgroup;
>   		/*
>   		 * If we fail beyond this point we don't free the allocated
>   		 * futex hash map. We assume that another thread will be created

Makes me wonder whether we would have to undo anything the 
sched_cgroup_fork() did, or if that cleanup is implied in 
bad_fork_cancel_cgroup. Without digging too deep into the code, I assume 
the latter.

-- 
Cheers

David / dhildenb



  reply	other threads:[~2025-09-24 12:29 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-09-24 12:06 Edward Adam Davis
2025-09-24 12:29 ` David Hildenbrand [this message]
2025-09-26 15:11 ` Vlastimil Babka
2025-09-26 15:21   ` Sebastian Andrzej Siewior

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