* [PATCH] perf core: Replace offsetof() with struct_size()
@ 2025-09-02 3:43 Xichao Zhao
2025-09-02 7:25 ` Peter Zijlstra
0 siblings, 1 reply; 2+ messages in thread
From: Xichao Zhao @ 2025-09-02 3:43 UTC (permalink / raw)
To: peterz, mingo, acme, namhyung
Cc: mark.rutland, alexander.shishkin, jolsa, irogers, adrian.hunter,
kan.liang, linux-perf-users, linux-kernel, Xichao Zhao
When dealing with structures containing flexible arrays, struct_size()
provides additional compile-time checks compared to offsetof(). This
enhances code robustness and reduces the risk of potential errors.
Signed-off-by: Xichao Zhao <zhao.xichao@vivo.com>
---
kernel/events/callchain.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/events/callchain.c b/kernel/events/callchain.c
index 6c83ad674d01..0f88e44af664 100644
--- a/kernel/events/callchain.c
+++ b/kernel/events/callchain.c
@@ -80,7 +80,7 @@ static int alloc_callchain_buffers(void)
* accessed from NMI. Use a temporary manual per cpu allocation
* until that gets sorted out.
*/
- size = offsetof(struct callchain_cpus_entries, cpu_entries[nr_cpu_ids]);
+ size = struct_size(entries, cpu_entries, nr_cpu_ids);
entries = kzalloc(size, GFP_KERNEL);
if (!entries)
--
2.34.1
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] perf core: Replace offsetof() with struct_size()
2025-09-02 3:43 [PATCH] perf core: Replace offsetof() with struct_size() Xichao Zhao
@ 2025-09-02 7:25 ` Peter Zijlstra
0 siblings, 0 replies; 2+ messages in thread
From: Peter Zijlstra @ 2025-09-02 7:25 UTC (permalink / raw)
To: Xichao Zhao
Cc: mingo, acme, namhyung, mark.rutland, alexander.shishkin, jolsa,
irogers, adrian.hunter, kan.liang, linux-perf-users,
linux-kernel
On Tue, Sep 02, 2025 at 11:43:49AM +0800, Xichao Zhao wrote:
> When dealing with structures containing flexible arrays, struct_size()
> provides additional compile-time checks compared to offsetof(). This
> enhances code robustness and reduces the risk of potential errors.
>
> Signed-off-by: Xichao Zhao <zhao.xichao@vivo.com>
> ---
> kernel/events/callchain.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/events/callchain.c b/kernel/events/callchain.c
> index 6c83ad674d01..0f88e44af664 100644
> --- a/kernel/events/callchain.c
> +++ b/kernel/events/callchain.c
> @@ -80,7 +80,7 @@ static int alloc_callchain_buffers(void)
> * accessed from NMI. Use a temporary manual per cpu allocation
> * until that gets sorted out.
> */
> - size = offsetof(struct callchain_cpus_entries, cpu_entries[nr_cpu_ids]);
> + size = struct_size(entries, cpu_entries, nr_cpu_ids);
None of this code is needed anymore; that issue with NMI not being able
to access vmalloc memory should be long fixed.
^ permalink raw reply [flat|nested] 2+ messages in thread
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