From: Kees Cook <keescook@chromium.org>
To: Erick Archer <erick.archer@outlook.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Namhyung Kim <namhyung@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@kernel.org>, Ian Rogers <irogers@google.com>,
Adrian Hunter <adrian.hunter@intel.com>,
"Liang, Kan" <kan.liang@linux.intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Christophe JAILLET <christophe.jaillet@wanadoo.fr>,
"Gustavo A. R. Silva" <gustavoars@kernel.org>,
Justin Stitt <justinstitt@google.com>,
x86@kernel.org, linux-perf-users@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org
Subject: Re: [PATCH] perf/x86/amd/uncore: Add flex array to struct amd_uncore_ctx
Date: Sat, 11 May 2024 13:04:51 -0700 [thread overview]
Message-ID: <202405111304.6A390B9D@keescook> (raw)
In-Reply-To: <AS8PR02MB7237E4848B44A5226BD3551C8BE02@AS8PR02MB7237.eurprd02.prod.outlook.com>
On Sat, May 11, 2024 at 04:51:54PM +0200, Erick Archer wrote:
> This is an effort to get rid of all multiplications from allocation
> functions in order to prevent integer overflows [1][2].
>
> The "struct amd_uncore_ctx" can be refactored to use a flex array for
> the "events" member. This way, the allocation/freeing of the memory can
> be simplified.
>
> Specifically, as the "curr" variable is a pointer to the amd_uncore_ctx
> structure and it now ends up in a flexible array:
>
> struct amd_uncore_ctx {
> [...]
> struct perf_event *events[];
> };
>
> the two-step allocation can be simplifief by using just one kzalloc_node
> function and the struct_size() helper to do the arithmetic calculation
> for the memory to be allocated.
>
> This way, the code is more readable and safer.
>
> Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments [1]
> Link: https://github.com/KSPP/linux/issues/160 [2]
> Suggested-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
> Signed-off-by: Erick Archer <erick.archer@outlook.com>
> ---
> Hi,
>
> This patch can be considered v4 of this other one [1]. However, since
> the patch has completely changed due to the addition of the flex array,
> I have decided to make a new series and remove the "Reviewed-by:" tag
> by Gustavo A. R. Silva and Kees cook.
>
> [1] https://lore.kernel.org/linux-hardening/PAXPR02MB7248F46DEFA47E79677481B18B152@PAXPR02MB7248.eurprd02.prod.outlook.com/
>
> Thanks,
> Erick
> ---
> arch/x86/events/amd/uncore.c | 18 +++++-------------
> 1 file changed, 5 insertions(+), 13 deletions(-)
My favorite kind of patch: fewer lines, clearer code.
Reviewed-by: Kees Cook <keescook@chromium.org>
-Kees
--
Kees Cook
prev parent reply other threads:[~2024-05-11 20:04 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-11 14:51 [PATCH] perf/x86/amd/uncore: Add flex array to struct amd_uncore_ctx Erick Archer
2024-05-11 20:04 ` Kees Cook [this message]
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