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| author | Stephen Boyd <sboyd@codeaurora.org> | 2013-07-30 23:09:46 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2013-08-01 14:41:39 +0100 |
| commit | 44424c34049f41123a3a8b4853822f47f4ff03a2 (patch) | |
| tree | 98e3b4564c5146e0692826f7940be33d2b645c87 /arch | |
| parent | 067e710b9a982a92cc8294d7fa0f1e924c65bba1 (diff) | |
| download | linux-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>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm/kernel/process.c | 3 |
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); |