From: David Hildenbrand <david@redhat.com>
To: Jeongjun Park <aha310510@gmail.com>, akpm@linux-foundation.org
Cc: andrii@kernel.org, osalvador@suse.de, Liam.Howlett@Oracle.com,
surenb@google.com, christophe.leroy@csgroup.eu,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
syzbot+6246a83e7bd9f8a3e239@syzkaller.appspotmail.com
Subject: Re: [PATCH next] mm/maps: move kmalloc() call location in do_procmap_query() out of RCU critical section
Date: Wed, 2 Jul 2025 16:44:01 +0200 [thread overview]
Message-ID: <693725d9-a293-414f-a706-f77446e335b1@redhat.com> (raw)
In-Reply-To: <20250702135332.291866-1-aha310510@gmail.com>
On 02.07.25 15:53, Jeongjun Park wrote:
> In do_procmap_query(), we are allocating name_buf as much as name_buf_sz
> with kmalloc().
>
> However, due to the previous commit eff061546ca5
> ("mm/maps: execute PROCMAP_QUERY ioctl under per-vma locks"),
> the location of kmalloc() is located inside the RCU critical section.
>
> This causes might_sleep_if() to be called inside the RCU critical section,
> so we need to move the call location of kmalloc() outside the RCU critical
> section to prevent this.
>
> Reported-by: syzbot+6246a83e7bd9f8a3e239@syzkaller.appspotmail.com
> Closes: https://syzkaller.appspot.com/bug?extid=6246a83e7bd9f8a3e239
> Fixes: eff061546ca5 ("mm/maps: execute PROCMAP_QUERY ioctl under per-vma locks")
That commit is not upstream yet (and the commit id is not stable), so it
should be squashed into the problematic commit.
As a side note: the patch subject of this and the original patch should
start with "fs/proc/task_mmu", not "mm/maps".
--
Cheers,
David / dhildenb
next prev parent reply other threads:[~2025-07-02 14:44 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-07-02 13:53 [PATCH next] mm/maps: move kmalloc() call location in do_procmap_query() out of RCU critical section Jeongjun Park
2025-07-02 14:44 ` David Hildenbrand [this message]
2025-07-02 23:34 ` Suren Baghdasaryan
2025-07-04 6:11 ` Suren Baghdasaryan
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