x86: Fix NULL pointer dereference on CPU hotplug after disabling irqs

PATCH In review Tomoki Sekiyama 1 participant 2 messages May 28, 2012 – Jun 6, 2012 x86

Share & tools

Tomoki Sekiyama

author

2012-05-28 09:30 UTC #0 lore raw

PATCH 1/1 x86: Fix NULL pointer dereference on CPU hotplug after disabling irqs

In current Linux, percpu variable `vector_irq' is not cleared on offlined cpus while disabling devices' irqs. If the cpu that has the disabled irqs in vector_irq is hotplugged, __setup_vector_irq() hits invalid irq vector and may crash.

This bug can be reproduced as following;

 # echo 0 > /sys/devices/system/cpu/cpu7/online
 # modprobe -r some_driver_using_interrupts      # vector_irq@cpu7 uncleared
 # echo 1 > /sys/devices/system/cpu/cpu7/online  # kernel may crash

This patch fixes this bug by clearing vector_irq in __clear_irq_vector() even if the cpu is offlined.

Signed-off-by Tomoki Sekiyama <[email protected]>

Cc Thomas Gleixner <[email protected]>

Cc Ingo Molnar <[email protected]>

Cc "H. Peter Anvin" <[email protected]>

Cc [email protected]

---
 arch/x86/kernel/apic/io_apic.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

arch/x86/kernel/apic/io_apic.c +2 -2

index ac96561..5f0ff59 100644
@@ -1195,7 +1195,7 @@ static void __clear_irq_vector(int irq, struct irq_cfg *cfg)
 	BUG_ON(!cfg->vector);
  	vector = cfg->vector;
-	for_each_cpu_and(cpu, cfg->domain, cpu_online_mask)
+	for_each_cpu(cpu, cfg->domain)
 		per_cpu(vector_irq, cpu)[vector] = -1;
  	cfg->vector = 0;

@@ -1203,7 +1203,7 @@ static void __clear_irq_vector(int irq, struct irq_cfg *cfg)
  	if (likely(!cfg->move_in_progress))
 		return;
-	for_each_cpu_and(cpu, cfg->old_domain, cpu_online_mask) {
+	for_each_cpu(cpu, cfg->old_domain) {
 		for (vector = FIRST_EXTERNAL_VECTOR; vector < NR_VECTORS;
 								vector++) {
 			if (per_cpu(vector_irq, cpu)[vector] != irq)

Signature · 1 line

1.7.7.6

tip-bot for Tomoki Sekiyama

author

2012-06-06 15:20 UTC #1 lore raw

[tip:x86/urgent] x86/ioapic: Fix NULL pointer dereference on CPU hotplug after disabling irqs

Commit-ID:  f6175f5bfb4c9f2ed32758c95f765b529b1a7f15
Gitweb:     http://git.kernel.org/tip/f6175f5bfb4c9f2ed32758c95f765b529b1a7f15
Author:     Tomoki Sekiyama <[email protected]>
AuthorDate: Mon, 28 May 2012 18:09:18 +0900
Committer:  Ingo Molnar <[email protected]>
CommitDate: Wed, 6 Jun 2012 12:03:25 +0200

x86/ioapic: Fix NULL pointer dereference on CPU hotplug after disabling irqs

This bug can be reproduced as following;

  # echo 0 > /sys/devices/system/cpu/cpu7/online
  # modprobe -r some_driver_using_interrupts      # vector_irq@cpu7 uncleared
  # echo 1 > /sys/devices/system/cpu/cpu7/online  # kernel may crash

This patch fixes this bug by clearing vector_irq in __clear_irq_vector() even if the cpu is offlined.

Signed-off-by Tomoki Sekiyama <[email protected]>

Acked-by Thomas Gleixner <[email protected]>

Cc [email protected]

Cc Suresh Siddha <[email protected]>

Cc Yinghai Lu <[email protected]>

Cc Alexander Gordeev <[email protected]>

Link http://lkml.kernel.org/r/[email protected] open here

Signed-off-by Ingo Molnar <[email protected]>

---
 arch/x86/kernel/apic/io_apic.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

arch/x86/kernel/apic/io_apic.c +2 -2

index ac96561..5f0ff59 100644
@@ -1195,7 +1195,7 @@ static void __clear_irq_vector(int irq, struct irq_cfg *cfg)
 	BUG_ON(!cfg->vector);
 
 	vector = cfg->vector;
-	for_each_cpu_and(cpu, cfg->domain, cpu_online_mask)
+	for_each_cpu(cpu, cfg->domain)
 		per_cpu(vector_irq, cpu)[vector] = -1;
 
 	cfg->vector = 0;

@@ -1203,7 +1203,7 @@ static void __clear_irq_vector(int irq, struct irq_cfg *cfg)
 
 	if (likely(!cfg->move_in_progress))
 		return;
-	for_each_cpu_and(cpu, cfg->old_domain, cpu_online_mask) {
+	for_each_cpu(cpu, cfg->old_domain) {
 		for (vector = FIRST_EXTERNAL_VECTOR; vector < NR_VECTORS;
 								vector++) {
 			if (per_cpu(vector_irq, cpu)[vector] != irq)