This is a note to let you know that I've just added the patch titled
drivers: perf: Fix smp_processor_id() use in preemptible code
to the 6.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drivers-perf-fix-smp_processor_id-use-in-preemptible.patch
and it can be found in the queue-6.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit e7e913873b300d0c5e12ad65ff58502315ff6b60
Author: Alexandre Ghiti <alexghiti@xxxxxxxxxxxx>
Date: Mon Aug 26 18:52:10 2024 +0200
drivers: perf: Fix smp_processor_id() use in preemptible code
[ Upstream commit 2840dadf0dde92638d13b97998026c5fcddbdceb ]
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@xxxxxxxxxxxxx>
Closes: https://lore.kernel.org/linux-riscv/20240820074925.ReMKUPP3@xxxxxxxxxxxxx/ [1]
Signed-off-by: Alexandre Ghiti <alexghiti@xxxxxxxxxxxx>
Reviewed-by: Anup Patel <anup@xxxxxxxxxxxxxx>
Tested-by: Nam Cao <namcao@xxxxxxxxxxxxx>
Fixes: a8625217a054 ("drivers/perf: riscv: Implement SBI PMU snapshot function")
Reported-by: Andrea Parri <parri.andrea@xxxxxxxxx>
Tested-by: Andrea Parri <parri.andrea@xxxxxxxxx>
Link: https://lore.kernel.org/r/20240826165210.124696-1-alexghiti@xxxxxxxxxxxx
Signed-off-by: Palmer Dabbelt <palmer@xxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/perf/riscv_pmu_sbi.c b/drivers/perf/riscv_pmu_sbi.c
index 11c7c85047ed..765bda7924f7 100644
--- a/drivers/perf/riscv_pmu_sbi.c
+++ b/drivers/perf/riscv_pmu_sbi.c
@@ -1368,11 +1368,15 @@ 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);
if (ret) {
/* Snapshot is an optional feature. Continue if not available */
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);
}
+ put_cpu();
}
register_sysctl("kernel", sbi_pmu_sysctl_table);
