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authorStephen Boyd <sboyd@codeaurora.org>2013-07-30 23:09:46 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2013-08-01 14:41:39 +0100
commit44424c34049f41123a3a8b4853822f47f4ff03a2 (patch)
tree98e3b4564c5146e0692826f7940be33d2b645c87
parent067e710b9a982a92cc8294d7fa0f1e924c65bba1 (diff)
downloadlinux-44424c34049f41123a3a8b4853822f47f4ff03a2.tar.bz2
ARM: 7803/1: Fix deadlock scenario with smp_send_stop()
If one process calls sys_reboot and that process then stops other CPUs while those CPUs are within a spin_lock() region we can potentially encounter a deadlock scenario like below. CPU 0 CPU 1 ----- ----- spin_lock(my_lock) smp_send_stop() <send IPI> handle_IPI() disable_preemption/irqs while(1); <PREEMPT> spin_lock(my_lock) <--- Waits forever We shouldn't attempt to run any other tasks after we send a stop IPI to a CPU so disable preemption so that this task runs to completion. We use local_irq_disable() here for cross-arch consistency with x86. Reported-by: Sundarajan Srinivasan <sundaraj@codeaurora.com> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
-rw-r--r--arch/arm/kernel/process.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
index d3ca4f6915af..08b47ebd3144 100644
--- a/arch/arm/kernel/process.c
+++ b/arch/arm/kernel/process.c
@@ -197,6 +197,7 @@ void machine_shutdown(void)
*/
void machine_halt(void)
{
+ local_irq_disable();
smp_send_stop();
local_irq_disable();
@@ -211,6 +212,7 @@ void machine_halt(void)
*/
void machine_power_off(void)
{
+ local_irq_disable();
smp_send_stop();
if (pm_power_off)
@@ -230,6 +232,7 @@ void machine_power_off(void)
*/
void machine_restart(char *cmd)
{
+ local_irq_disable();
smp_send_stop();
arm_pm_restart(reboot_mode, cmd);