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From: Julien Grall <julien.grall@arm.com>
To: will.deacon@arm.com, mark.rutland@arm.com
Cc: linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	Julien Grall <julien.grall@arm.com>
Subject: [PATCH 2/3] drivers/perf: arm_pmu: Defer the setting of __oprofile_cpu_pmu
Date: Tue, 31 May 2016 12:41:22 +0100	[thread overview]
Message-ID: <1464694883-26298-3-git-send-email-julien.grall@arm.com> (raw)
In-Reply-To: <1464694883-26298-1-git-send-email-julien.grall@arm.com>

The global variable __oprofile_cpu_pmu is set before the PMU is fully
initialized. If an error occurs before the end of the initialization,
the PMU will be freed and the variable will contain an invalid pointer.

This will result in a kernel crash when perf will be used.

Fix it by moving the setting of __oprofile_cpu_pmu when the PMU is fully
initialized (i.e when it is no longer possible to fail).

Signed-off-by: Julien Grall <julien.grall@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
---
 drivers/perf/arm_pmu.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
index 6401f0c..95614d2 100644
--- a/drivers/perf/arm_pmu.c
+++ b/drivers/perf/arm_pmu.c
@@ -992,9 +992,6 @@ int arm_pmu_device_probe(struct platform_device *pdev,
 
 	armpmu_init(pmu);
 
-	if (!__oprofile_cpu_pmu)
-		__oprofile_cpu_pmu = pmu;
-
 	pmu->plat_device = pdev;
 
 	if (node && (of_id = of_match_node(of_table, pdev->dev.of_node))) {
@@ -1030,6 +1027,9 @@ int arm_pmu_device_probe(struct platform_device *pdev,
 	if (ret)
 		goto out_destroy;
 
+	if (!__oprofile_cpu_pmu)
+		__oprofile_cpu_pmu = pmu;
+
 	pr_info("enabled with %s PMU driver, %d counters available\n",
 			pmu->name, pmu->num_events);
 
-- 
1.9.1

  parent reply	other threads:[~2016-05-31 11:42 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-05-31 11:41 [PATCH 0/3] drivers/perf: arm_pmu: Small bug fixes in the driver Julien Grall
2016-05-31 11:41 ` [PATCH 1/3] drivers/perf: arm_pmu: Fix reference count of a device_node in of_pmu_irq_cfg Julien Grall
2016-05-31 11:41 ` Julien Grall [this message]
2016-05-31 16:28   ` [PATCH 2/3] drivers/perf: arm_pmu: Defer the setting of __oprofile_cpu_pmu Will Deacon
2016-05-31 17:29     ` Mark Rutland
2016-05-31 11:41 ` [PATCH 3/3] drivers/perf: arm_pmu: Avoid leaking pmu->irq_affinity on error Julien Grall

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