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| author | Arun KS <arunks.linux@gmail.com> | 2014-05-07 02:41:23 +0100 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2014-05-16 18:03:33 +0100 |
| commit | b9acc49ee9464f8f8232a790045d057eb158e869 (patch) | |
| tree | e99259f1dfa0e90effebcf3f41da03775bf615ef | |
| parent | 90f51a09ef83703b6c2e0434e0384b61b59699d3 (diff) | |
| download | op-kernel-dev-b9acc49ee9464f8f8232a790045d057eb158e869.zip op-kernel-dev-b9acc49ee9464f8f8232a790045d057eb158e869.tar.gz | |
arm64: 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.
Based-on-work-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Arun KS <getarunks@gmail.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
| -rw-r--r-- | arch/arm64/kernel/process.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index ed37c36..43b7c34 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -135,6 +135,7 @@ void machine_shutdown(void) */ void machine_halt(void) { + local_irq_disable(); smp_send_stop(); while (1); } @@ -147,6 +148,7 @@ void machine_halt(void) */ void machine_power_off(void) { + local_irq_disable(); smp_send_stop(); if (pm_power_off) pm_power_off(); @@ -165,10 +167,9 @@ void machine_power_off(void) */ void machine_restart(char *cmd) { - smp_send_stop(); - /* Disable interrupts first */ local_irq_disable(); + smp_send_stop(); /* Now call the architecture specific reboot code. */ if (arm_pm_restart) |
