* [PATCH -fixes v2] drivers: perf: Fix smp_processor_id() use in preemptible code
@ 2024-08-29 9:00 Alexandre Ghiti
2024-08-30 16:39 ` Atish Patra
2024-09-05 21:55 ` Nam Cao
0 siblings, 2 replies; 3+ messages in thread
From: Alexandre Ghiti @ 2024-08-29 9:00 UTC (permalink / raw)
To: Atish Patra, Anup Patel, Will Deacon, Mark Rutland, Paul Walmsley,
Palmer Dabbelt, Albert Ou, linux-riscv, linux-arm-kernel,
linux-kernel
Cc: Alexandre Ghiti, Andrea Parri, Nam Cao
As reported in [1], the use of smp_processor_id() in
pmu_sbi_device_probe() must be protected by disabling the preemption, so
simply use get_cpu()/put_cpu() instead.
Reported-by: Andrea Parri <parri.andrea@gmail.com>
Reported-by: Nam Cao <namcao@linutronix.de>
Closes: https://lore.kernel.org/linux-riscv/20240820074925.ReMKUPP3@linutronix.de/ [1]
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
---
Changes in v2:
- Do not disable the preemption in static_key_enable() (Will)
drivers/perf/riscv_pmu_sbi.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/perf/riscv_pmu_sbi.c b/drivers/perf/riscv_pmu_sbi.c
index 31a17a56eb3b..febd8e74a72f 100644
--- a/drivers/perf/riscv_pmu_sbi.c
+++ b/drivers/perf/riscv_pmu_sbi.c
@@ -1373,11 +1373,16 @@ static int pmu_sbi_device_probe(struct platform_device *pdev)
/* SBI PMU Snapsphot is only available in SBI v2.0 */
if (sbi_v2_available) {
+ int cpu;
+
ret = pmu_sbi_snapshot_alloc(pmu);
if (ret)
goto out_unregister;
- ret = pmu_sbi_snapshot_setup(pmu, smp_processor_id());
+ cpu = get_cpu();
+ ret = pmu_sbi_snapshot_setup(pmu, cpu);
+ put_cpu();
+
if (ret) {
/* Snapshot is an optional feature. Continue if not available */
pmu_sbi_snapshot_free(pmu);
--
2.39.2
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^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH -fixes v2] drivers: perf: Fix smp_processor_id() use in preemptible code
2024-08-29 9:00 [PATCH -fixes v2] drivers: perf: Fix smp_processor_id() use in preemptible code Alexandre Ghiti
@ 2024-08-30 16:39 ` Atish Patra
2024-09-05 21:55 ` Nam Cao
1 sibling, 0 replies; 3+ messages in thread
From: Atish Patra @ 2024-08-30 16:39 UTC (permalink / raw)
To: Alexandre Ghiti, Atish Patra, Anup Patel, Will Deacon,
Mark Rutland, Paul Walmsley, Palmer Dabbelt, Albert Ou,
linux-riscv, linux-arm-kernel, linux-kernel
Cc: Andrea Parri, Nam Cao
On 8/29/24 2:00 AM, Alexandre Ghiti wrote:
> As reported in [1], the use of smp_processor_id() in
> pmu_sbi_device_probe() must be protected by disabling the preemption, so
> simply use get_cpu()/put_cpu() instead.
>
> Reported-by: Andrea Parri <parri.andrea@gmail.com>
> Reported-by: Nam Cao <namcao@linutronix.de>
> Closes: https://lore.kernel.org/linux-riscv/20240820074925.ReMKUPP3@linutronix.de/ [1]
> Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
> ---
>
> Changes in v2:
> - Do not disable the preemption in static_key_enable() (Will)
>
> drivers/perf/riscv_pmu_sbi.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/perf/riscv_pmu_sbi.c b/drivers/perf/riscv_pmu_sbi.c
> index 31a17a56eb3b..febd8e74a72f 100644
> --- a/drivers/perf/riscv_pmu_sbi.c
> +++ b/drivers/perf/riscv_pmu_sbi.c
> @@ -1373,11 +1373,16 @@ static int pmu_sbi_device_probe(struct platform_device *pdev)
>
> /* SBI PMU Snapsphot is only available in SBI v2.0 */
> if (sbi_v2_available) {
> + int cpu;
> +
> ret = pmu_sbi_snapshot_alloc(pmu);
> if (ret)
> goto out_unregister;
>
> - ret = pmu_sbi_snapshot_setup(pmu, smp_processor_id());
> + cpu = get_cpu();
> + ret = pmu_sbi_snapshot_setup(pmu, cpu);
> + put_cpu();
> +
> if (ret) {
> /* Snapshot is an optional feature. Continue if not available */
> pmu_sbi_snapshot_free(pmu);
Reviewed-by: Atish Patra <atishp@rivosinc.com>
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^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH -fixes v2] drivers: perf: Fix smp_processor_id() use in preemptible code
2024-08-29 9:00 [PATCH -fixes v2] drivers: perf: Fix smp_processor_id() use in preemptible code Alexandre Ghiti
2024-08-30 16:39 ` Atish Patra
@ 2024-09-05 21:55 ` Nam Cao
1 sibling, 0 replies; 3+ messages in thread
From: Nam Cao @ 2024-09-05 21:55 UTC (permalink / raw)
To: Alexandre Ghiti
Cc: Atish Patra, Anup Patel, Will Deacon, Mark Rutland, Paul Walmsley,
Palmer Dabbelt, Albert Ou, linux-riscv, linux-arm-kernel,
linux-kernel, Andrea Parri
On Thu, Aug 29, 2024 at 11:00:34AM +0200, Alexandre Ghiti wrote:
> As reported in [1], the use of smp_processor_id() in
> pmu_sbi_device_probe() must be protected by disabling the preemption, so
> simply use get_cpu()/put_cpu() instead.
>
> Reported-by: Andrea Parri <parri.andrea@gmail.com>
> Reported-by: Nam Cao <namcao@linutronix.de>
> Closes: https://lore.kernel.org/linux-riscv/20240820074925.ReMKUPP3@linutronix.de/ [1]
> Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Tested-by: Nam Cao <namcao@linutronix.de>
Best regards,
Nam
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^ permalink raw reply [flat|nested] 3+ messages in thread
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2024-08-29 9:00 [PATCH -fixes v2] drivers: perf: Fix smp_processor_id() use in preemptible code Alexandre Ghiti
2024-08-30 16:39 ` Atish Patra
2024-09-05 21:55 ` Nam Cao
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