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From:   Xiu Jianfeng <xiujianfeng@huawei.com>
To:     <jgross@suse.com>, <boris.ostrovsky@oracle.com>,
        <tglx@linutronix.de>, <mingo@redhat.com>, <bp@alien8.de>,
        <dave.hansen@linux.intel.com>, <hpa@zytor.com>, <jeremy@goop.org>
CC:     <x86@kernel.org>, <xen-devel@lists.xenproject.org>,
        <linux-kernel@vger.kernel.org>
Subject: [PATCH v2 1/2] x86/xen: Fix memory leak in xen_smp_intr_init{_pv}()
Date:   Wed, 23 Nov 2022 23:58:57 +0800
Message-ID: <20221123155858.11382-2-xiujianfeng@huawei.com>
In-Reply-To: <20221123155858.11382-1-xiujianfeng@huawei.com>
References: <20221123155858.11382-1-xiujianfeng@huawei.com>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

These local variables @{resched|pmu|callfunc...}_name saves the new
string allocated by kasprintf(), and when bind_{v}ipi_to_irqhandler()
fails, it goes to the @fail tag, and calls xen_smp_intr_free{_pv}() to
free resource, however the new string is not saved, which cause a memory
leak issue. fix it.

Fixes: 9702785a747a ("i386: move xen")
Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
---
 arch/x86/xen/smp.c    | 24 ++++++++++++------------
 arch/x86/xen/smp_pv.c | 12 ++++++------
 2 files changed, 18 insertions(+), 18 deletions(-)

diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
index c3e1f9a7d43a..4b0d6fff88de 100644
--- a/arch/x86/xen/smp.c
+++ b/arch/x86/xen/smp.c
@@ -32,30 +32,30 @@ static irqreturn_t xen_reschedule_interrupt(int irq, void *dev_id)
 
 void xen_smp_intr_free(unsigned int cpu)
 {
+	kfree(per_cpu(xen_resched_irq, cpu).name);
+	per_cpu(xen_resched_irq, cpu).name = NULL;
 	if (per_cpu(xen_resched_irq, cpu).irq >= 0) {
 		unbind_from_irqhandler(per_cpu(xen_resched_irq, cpu).irq, NULL);
 		per_cpu(xen_resched_irq, cpu).irq = -1;
-		kfree(per_cpu(xen_resched_irq, cpu).name);
-		per_cpu(xen_resched_irq, cpu).name = NULL;
 	}
+	kfree(per_cpu(xen_callfunc_irq, cpu).name);
+	per_cpu(xen_callfunc_irq, cpu).name = NULL;
 	if (per_cpu(xen_callfunc_irq, cpu).irq >= 0) {
 		unbind_from_irqhandler(per_cpu(xen_callfunc_irq, cpu).irq, NULL);
 		per_cpu(xen_callfunc_irq, cpu).irq = -1;
-		kfree(per_cpu(xen_callfunc_irq, cpu).name);
-		per_cpu(xen_callfunc_irq, cpu).name = NULL;
 	}
+	kfree(per_cpu(xen_debug_irq, cpu).name);
+	per_cpu(xen_debug_irq, cpu).name = NULL;
 	if (per_cpu(xen_debug_irq, cpu).irq >= 0) {
 		unbind_from_irqhandler(per_cpu(xen_debug_irq, cpu).irq, NULL);
 		per_cpu(xen_debug_irq, cpu).irq = -1;
-		kfree(per_cpu(xen_debug_irq, cpu).name);
-		per_cpu(xen_debug_irq, cpu).name = NULL;
 	}
+	kfree(per_cpu(xen_callfuncsingle_irq, cpu).name);
+	per_cpu(xen_callfuncsingle_irq, cpu).name = NULL;
 	if (per_cpu(xen_callfuncsingle_irq, cpu).irq >= 0) {
 		unbind_from_irqhandler(per_cpu(xen_callfuncsingle_irq, cpu).irq,
 				       NULL);
 		per_cpu(xen_callfuncsingle_irq, cpu).irq = -1;
-		kfree(per_cpu(xen_callfuncsingle_irq, cpu).name);
-		per_cpu(xen_callfuncsingle_irq, cpu).name = NULL;
 	}
 }
 
@@ -65,6 +65,7 @@ int xen_smp_intr_init(unsigned int cpu)
 	char *resched_name, *callfunc_name, *debug_name;
 
 	resched_name = kasprintf(GFP_KERNEL, "resched%d", cpu);
+	per_cpu(xen_resched_irq, cpu).name = resched_name;
 	rc = bind_ipi_to_irqhandler(XEN_RESCHEDULE_VECTOR,
 				    cpu,
 				    xen_reschedule_interrupt,
@@ -74,9 +75,9 @@ int xen_smp_intr_init(unsigned int cpu)
 	if (rc < 0)
 		goto fail;
 	per_cpu(xen_resched_irq, cpu).irq = rc;
-	per_cpu(xen_resched_irq, cpu).name = resched_name;
 
 	callfunc_name = kasprintf(GFP_KERNEL, "callfunc%d", cpu);
+	per_cpu(xen_callfunc_irq, cpu).name = callfunc_name;
 	rc = bind_ipi_to_irqhandler(XEN_CALL_FUNCTION_VECTOR,
 				    cpu,
 				    xen_call_function_interrupt,
@@ -86,10 +87,10 @@ int xen_smp_intr_init(unsigned int cpu)
 	if (rc < 0)
 		goto fail;
 	per_cpu(xen_callfunc_irq, cpu).irq = rc;
-	per_cpu(xen_callfunc_irq, cpu).name = callfunc_name;
 
 	if (!xen_fifo_events) {
 		debug_name = kasprintf(GFP_KERNEL, "debug%d", cpu);
+		per_cpu(xen_debug_irq, cpu).name = debug_name;
 		rc = bind_virq_to_irqhandler(VIRQ_DEBUG, cpu,
 					     xen_debug_interrupt,
 					     IRQF_PERCPU | IRQF_NOBALANCING,
@@ -97,10 +98,10 @@ int xen_smp_intr_init(unsigned int cpu)
 		if (rc < 0)
 			goto fail;
 		per_cpu(xen_debug_irq, cpu).irq = rc;
-		per_cpu(xen_debug_irq, cpu).name = debug_name;
 	}
 
 	callfunc_name = kasprintf(GFP_KERNEL, "callfuncsingle%d", cpu);
+	per_cpu(xen_callfuncsingle_irq, cpu).name = callfunc_name;
 	rc = bind_ipi_to_irqhandler(XEN_CALL_FUNCTION_SINGLE_VECTOR,
 				    cpu,
 				    xen_call_function_single_interrupt,
@@ -110,7 +111,6 @@ int xen_smp_intr_init(unsigned int cpu)
 	if (rc < 0)
 		goto fail;
 	per_cpu(xen_callfuncsingle_irq, cpu).irq = rc;
-	per_cpu(xen_callfuncsingle_irq, cpu).name = callfunc_name;
 
 	return 0;
 
diff --git a/arch/x86/xen/smp_pv.c b/arch/x86/xen/smp_pv.c
index 480be82e9b7b..6175f2c5c822 100644
--- a/arch/x86/xen/smp_pv.c
+++ b/arch/x86/xen/smp_pv.c
@@ -97,18 +97,18 @@ asmlinkage __visible void cpu_bringup_and_idle(void)
 
 void xen_smp_intr_free_pv(unsigned int cpu)
 {
+	kfree(per_cpu(xen_irq_work, cpu).name);
+	per_cpu(xen_irq_work, cpu).name = NULL;
 	if (per_cpu(xen_irq_work, cpu).irq >= 0) {
 		unbind_from_irqhandler(per_cpu(xen_irq_work, cpu).irq, NULL);
 		per_cpu(xen_irq_work, cpu).irq = -1;
-		kfree(per_cpu(xen_irq_work, cpu).name);
-		per_cpu(xen_irq_work, cpu).name = NULL;
 	}
 
+	kfree(per_cpu(xen_pmu_irq, cpu).name);
+	per_cpu(xen_pmu_irq, cpu).name = NULL;
 	if (per_cpu(xen_pmu_irq, cpu).irq >= 0) {
 		unbind_from_irqhandler(per_cpu(xen_pmu_irq, cpu).irq, NULL);
 		per_cpu(xen_pmu_irq, cpu).irq = -1;
-		kfree(per_cpu(xen_pmu_irq, cpu).name);
-		per_cpu(xen_pmu_irq, cpu).name = NULL;
 	}
 }
 
@@ -118,6 +118,7 @@ int xen_smp_intr_init_pv(unsigned int cpu)
 	char *callfunc_name, *pmu_name;
 
 	callfunc_name = kasprintf(GFP_KERNEL, "irqwork%d", cpu);
+	per_cpu(xen_irq_work, cpu).name = callfunc_name;
 	rc = bind_ipi_to_irqhandler(XEN_IRQ_WORK_VECTOR,
 				    cpu,
 				    xen_irq_work_interrupt,
@@ -127,10 +128,10 @@ int xen_smp_intr_init_pv(unsigned int cpu)
 	if (rc < 0)
 		goto fail;
 	per_cpu(xen_irq_work, cpu).irq = rc;
-	per_cpu(xen_irq_work, cpu).name = callfunc_name;
 
 	if (is_xen_pmu) {
 		pmu_name = kasprintf(GFP_KERNEL, "pmu%d", cpu);
+		per_cpu(xen_pmu_irq, cpu).name = pmu_name;
 		rc = bind_virq_to_irqhandler(VIRQ_XENPMU, cpu,
 					     xen_pmu_irq_handler,
 					     IRQF_PERCPU|IRQF_NOBALANCING,
@@ -138,7 +139,6 @@ int xen_smp_intr_init_pv(unsigned int cpu)
 		if (rc < 0)
 			goto fail;
 		per_cpu(xen_pmu_irq, cpu).irq = rc;
-		per_cpu(xen_pmu_irq, cpu).name = pmu_name;
 	}
 
 	return 0;
-- 
2.17.1