From: Erick Archer <erick.archer@outlook.com>
To: 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>,
Kees Cook <keescook@chromium.org>,
"Gustavo A. R. Silva" <gustavoars@kernel.org>,
Justin Stitt <justinstitt@google.com>
Cc: Erick Archer <erick.archer@outlook.com>,
x86@kernel.org, linux-perf-users@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org
Subject: [PATCH] perf/x86/amd/uncore: Add flex array to struct amd_uncore_ctx
Date: Sat, 11 May 2024 16:51:54 +0200 [thread overview]
Message-ID: <AS8PR02MB7237E4848B44A5226BD3551C8BE02@AS8PR02MB7237.eurprd02.prod.outlook.com> (raw)
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(-)
diff --git a/arch/x86/events/amd/uncore.c b/arch/x86/events/amd/uncore.c
index 4ccb8fa483e6..86755d16a3b2 100644
--- a/arch/x86/events/amd/uncore.c
+++ b/arch/x86/events/amd/uncore.c
@@ -37,8 +37,8 @@ static int pmu_version;
struct amd_uncore_ctx {
int refcnt;
int cpu;
- struct perf_event **events;
struct hlist_node node;
+ struct perf_event *events[];
};
struct amd_uncore_pmu {
@@ -426,10 +426,8 @@ static void amd_uncore_ctx_free(struct amd_uncore *uncore, unsigned int cpu)
if (cpu == ctx->cpu)
cpumask_clear_cpu(cpu, &pmu->active_mask);
- if (!--ctx->refcnt) {
- kfree(ctx->events);
+ if (!--ctx->refcnt)
kfree(ctx);
- }
*per_cpu_ptr(pmu->ctx, cpu) = NULL;
}
@@ -474,19 +472,13 @@ static int amd_uncore_ctx_init(struct amd_uncore *uncore, unsigned int cpu)
/* Allocate context if sibling does not exist */
if (!curr) {
node = cpu_to_node(cpu);
- curr = kzalloc_node(sizeof(*curr), GFP_KERNEL, node);
+ curr = kzalloc_node(struct_size(curr, events,
+ pmu->num_counters),
+ GFP_KERNEL, node);
if (!curr)
goto fail;
curr->cpu = cpu;
- curr->events = kzalloc_node(sizeof(*curr->events) *
- pmu->num_counters,
- GFP_KERNEL, node);
- if (!curr->events) {
- kfree(curr);
- goto fail;
- }
-
cpumask_set_cpu(cpu, &pmu->active_mask);
}
--
2.25.1
next reply other threads:[~2024-05-11 14:52 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-11 14:51 Erick Archer [this message]
2024-05-11 20:04 ` [PATCH] perf/x86/amd/uncore: Add flex array to struct amd_uncore_ctx Kees Cook
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