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drivers: perf: Fix smp_processor_id() use in preemptible code

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[ Upstream commit 2840dadf0d ]

As reported in [1], the use of smp_processor_id() in
pmu_sbi_device_probe() must be protected by disabling the preemption, so
simple use get_cpu()/put_cpu() instead.

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>
Reviewed-by: Anup Patel <anup@brainfault.org>
Tested-by: Nam Cao <namcao@linutronix.de>
Fixes: a8625217a0 ("drivers/perf: riscv: Implement SBI PMU snapshot function")
Reported-by: Andrea Parri <parri.andrea@gmail.com>
Tested-by: Andrea Parri <parri.andrea@gmail.com>
Link: https://lore.kernel.org/r/20240826165210.124696-1-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Alexandre Ghiti
2024-08-26 18:52:10 +02:00
committed by Greg Kroah-Hartman
parent 176b6a0675
commit edcab8d5bc
1 changed files with 6 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files
drivers/perf/riscv_pmu_sbi.c
+6 -1
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@@ -1368,11 +1368,15 @@ static int pmu_sbi_device_probe(struct platform_device *pdev)
/* SBI PMU Snapsphot is only available in SBI v2.0 */ /* SBI PMU Snapsphot is only available in SBI v2.0 */
if (sbi_v2_available) { if (sbi_v2_available) {
int cpu;
ret = pmu_sbi_snapshot_alloc(pmu); ret = pmu_sbi_snapshot_alloc(pmu);
if (ret) if (ret)
goto out_unregister; goto out_unregister;
ret = pmu_sbi_snapshot_setup(pmu, smp_processor_id()); cpu = get_cpu();
ret = pmu_sbi_snapshot_setup(pmu, cpu);
if (ret) { if (ret) {
/* Snapshot is an optional feature. Continue if not available */ /* Snapshot is an optional feature. Continue if not available */
pmu_sbi_snapshot_free(pmu); pmu_sbi_snapshot_free(pmu);
@@ -1386,6 +1390,7 @@ static int pmu_sbi_device_probe(struct platform_device *pdev)
*/ */
static_branch_enable(&sbi_pmu_snapshot_available); static_branch_enable(&sbi_pmu_snapshot_available);
} }
put_cpu();
} }
register_sysctl("kernel", sbi_pmu_sysctl_table); register_sysctl("kernel", sbi_pmu_sysctl_table);