* [PATCH -fixes] drivers: perf: Fix wrong put_cpu() placement
@ 2024-11-12 11:34 Alexandre Ghiti
2024-11-12 19:06 ` Atish Kumar Patra
2024-11-12 22:53 ` patchwork-bot+linux-riscv
0 siblings, 2 replies; 3+ messages in thread
From: Alexandre Ghiti @ 2024-11-12 11:34 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, Atish Patra
Unfortunately, the wrong patch version was merged which places the
put_cpu() after enabling a static key, which is not safe as pointed by
Will [1], so move put_cpu() before to avoid this.
Fixes: 2840dadf0dde ("drivers: perf: Fix smp_processor_id() use in preemptible code")
Reported-by: Atish Patra <atishp@rivosinc.com>
Link: https://lore.kernel.org/all/20240827125335.GD4772@willie-the-truck/ [1]
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
---
drivers/perf/riscv_pmu_sbi.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/perf/riscv_pmu_sbi.c b/drivers/perf/riscv_pmu_sbi.c
index 391ca1422cae..1aa303f76cc7 100644
--- a/drivers/perf/riscv_pmu_sbi.c
+++ b/drivers/perf/riscv_pmu_sbi.c
@@ -1393,8 +1393,9 @@ static int pmu_sbi_device_probe(struct platform_device *pdev)
goto out_unregister;
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);
@@ -1408,7 +1409,6 @@ static int pmu_sbi_device_probe(struct platform_device *pdev)
*/
static_branch_enable(&sbi_pmu_snapshot_available);
}
- put_cpu();
}
register_sysctl("kernel", sbi_pmu_sysctl_table);
--
2.39.2
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH -fixes] drivers: perf: Fix wrong put_cpu() placement
2024-11-12 11:34 [PATCH -fixes] drivers: perf: Fix wrong put_cpu() placement Alexandre Ghiti
@ 2024-11-12 19:06 ` Atish Kumar Patra
2024-11-12 22:53 ` patchwork-bot+linux-riscv
1 sibling, 0 replies; 3+ messages in thread
From: Atish Kumar Patra @ 2024-11-12 19:06 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
On Tue, Nov 12, 2024 at 3:34 AM Alexandre Ghiti <alexghiti@rivosinc.com> wrote:
>
> Unfortunately, the wrong patch version was merged which places the
> put_cpu() after enabling a static key, which is not safe as pointed by
> Will [1], so move put_cpu() before to avoid this.
>
> Fixes: 2840dadf0dde ("drivers: perf: Fix smp_processor_id() use in preemptible code")
> Reported-by: Atish Patra <atishp@rivosinc.com>
> Link: https://lore.kernel.org/all/20240827125335.GD4772@willie-the-truck/ [1]
> Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
> ---
> drivers/perf/riscv_pmu_sbi.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/perf/riscv_pmu_sbi.c b/drivers/perf/riscv_pmu_sbi.c
> index 391ca1422cae..1aa303f76cc7 100644
> --- a/drivers/perf/riscv_pmu_sbi.c
> +++ b/drivers/perf/riscv_pmu_sbi.c
> @@ -1393,8 +1393,9 @@ static int pmu_sbi_device_probe(struct platform_device *pdev)
> goto out_unregister;
>
> 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);
> @@ -1408,7 +1409,6 @@ static int pmu_sbi_device_probe(struct platform_device *pdev)
> */
> static_branch_enable(&sbi_pmu_snapshot_available);
> }
> - put_cpu();
> }
>
> register_sysctl("kernel", sbi_pmu_sysctl_table);
> --
> 2.39.2
>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Tested-by: Atish Patra <atishp@rivosinc.com>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH -fixes] drivers: perf: Fix wrong put_cpu() placement
2024-11-12 11:34 [PATCH -fixes] drivers: perf: Fix wrong put_cpu() placement Alexandre Ghiti
2024-11-12 19:06 ` Atish Kumar Patra
@ 2024-11-12 22:53 ` patchwork-bot+linux-riscv
1 sibling, 0 replies; 3+ messages in thread
From: patchwork-bot+linux-riscv @ 2024-11-12 22:53 UTC (permalink / raw)
To: Alexandre Ghiti
Cc: linux-riscv, atishp, anup, will, mark.rutland, paul.walmsley,
palmer, aou, linux-arm-kernel, linux-kernel, atishp
Hello:
This patch was applied to riscv/linux.git (fixes)
by Palmer Dabbelt <palmer@rivosinc.com>:
On Tue, 12 Nov 2024 12:34:22 +0100 you wrote:
> Unfortunately, the wrong patch version was merged which places the
> put_cpu() after enabling a static key, which is not safe as pointed by
> Will [1], so move put_cpu() before to avoid this.
>
> Fixes: 2840dadf0dde ("drivers: perf: Fix smp_processor_id() use in preemptible code")
> Reported-by: Atish Patra <atishp@rivosinc.com>
> Link: https://lore.kernel.org/all/20240827125335.GD4772@willie-the-truck/ [1]
> Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
>
> [...]
Here is the summary with links:
- [-fixes] drivers: perf: Fix wrong put_cpu() placement
https://git.kernel.org/riscv/c/57f7c7dc78cd
You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html
^ permalink raw reply [flat|nested] 3+ messages in thread
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2024-11-12 11:34 [PATCH -fixes] drivers: perf: Fix wrong put_cpu() placement Alexandre Ghiti
2024-11-12 19:06 ` Atish Kumar Patra
2024-11-12 22:53 ` patchwork-bot+linux-riscv
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