From: "Arnd Bergmann" <arnd@arndb.de>
To: "Lorenzo Stoakes" <lorenzo.stoakes@oracle.com>,
"Shakeel Butt" <shakeel.butt@linux.dev>
Cc: "Andrew Morton" <akpm@linux-foundation.org>,
"Vlastimil Babka" <vbabka@suse.cz>,
"Liam R. Howlett" <Liam.Howlett@oracle.com>,
"Suren Baghdasaryan" <surenb@google.com>,
linux-api@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, "Minchan Kim" <minchan@kernel.org>
Subject: Re: [PATCH 1/2] mm/madvise: introduce PR_MADV_SELF flag to process_madvise()
Date: Mon, 23 Sep 2024 21:49:43 +0000 [thread overview]
Message-ID: <337e4359-37e0-4ed7-894d-6c88b3498a42@app.fastmail.com> (raw)
In-Reply-To: <c44d373d-d72b-4e62-a613-a746a2c290e7@lucifer.local>
On Mon, Sep 23, 2024, at 19:34, Lorenzo Stoakes wrote:
> On Mon, Sep 23, 2024 at 11:56:06AM GMT, Shakeel Butt wrote:
>
> + /* Require PTRACE_MODE_READ to avoid leaking ASLR metadata. */
> + mm = mm_access(task, PTRACE_MODE_READ_FSCREDS);
> + if (IS_ERR_OR_NULL(mm)) {
> + ret = IS_ERR(mm) ? PTR_ERR(mm) : -ESRCH;
> + goto release_task;
> + }
Any chance we can fix mm_access() to not be able to return
a NULL pointer and an error pointer? IS_ERR_OR_NULL() is
usually an indication of a confusing API, and this is
clearly one of them, given that only one of the
callers actually wants the NULL value instead of -ESRCH.
Arnd
next prev parent reply other threads:[~2024-09-23 21:50 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-09-23 16:03 [PATCH 0/2] unrestrict process_madvise() for current process Lorenzo Stoakes
2024-09-23 16:03 ` [PATCH 1/2] mm/madvise: introduce PR_MADV_SELF flag to process_madvise() Lorenzo Stoakes
2024-09-23 18:56 ` Shakeel Butt
2024-09-23 19:34 ` Lorenzo Stoakes
2024-09-23 21:49 ` Arnd Bergmann [this message]
2024-09-24 7:49 ` Lorenzo Stoakes
2024-09-23 21:20 ` kernel test robot
2024-09-23 21:30 ` kernel test robot
2024-09-24 3:15 ` kernel test robot
2024-09-24 8:47 ` Lorenzo Stoakes
2024-09-23 16:03 ` [PATCH 2/2] selftests/mm: add test for process_madvise PR_MADV_SELF flag use Lorenzo Stoakes
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