summaryrefslogtreecommitdiff
path: root/drivers/parisc
diff options
context:
space:
mode:
authorGuilherme G. Piccoli <gpiccoli@igalia.com>2023-02-21 00:11:05 +0300
committerHelge Deller <deller@gmx.de>2023-05-03 18:43:26 +0300
commit829632dae8321787525ee37dc4828bbe6edafdae (patch)
treeed3c7d2bf77f2ad379e8655759ba18a3c24f0d60 /drivers/parisc
parente0838a99289e013d17496ed9464c3cf71d49b977 (diff)
downloadlinux-829632dae8321787525ee37dc4828bbe6edafdae.tar.xz
parisc: Replace regular spinlock with spin_trylock on panic path
The panic notifiers' callbacks execute in an atomic context, with interrupts/preemption disabled, and all CPUs not running the panic function are off, so it's very dangerous to wait on a regular spinlock, there's a risk of deadlock. Refactor the panic notifier of parisc/power driver to make use of spin_trylock - for that, we've added a second version of the soft-power function. Also, some comments were reorganized and trailing white spaces, useless header inclusion and blank lines were removed. Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com> Cc: Jeroen Roovers <jer@xs4all.nl> Acked-by: Helge Deller <deller@gmx.de> # parisc Signed-off-by: Guilherme G. Piccoli <gpiccoli@igalia.com> Signed-off-by: Helge Deller <deller@gmx.de>
Diffstat (limited to 'drivers/parisc')
-rw-r--r--drivers/parisc/power.c16
1 files changed, 10 insertions, 6 deletions
diff --git a/drivers/parisc/power.c b/drivers/parisc/power.c
index 456776bd8ee6..6f5e5f0230d3 100644
--- a/drivers/parisc/power.c
+++ b/drivers/parisc/power.c
@@ -37,7 +37,6 @@
#include <linux/module.h>
#include <linux/init.h>
#include <linux/kernel.h>
-#include <linux/notifier.h>
#include <linux/panic_notifier.h>
#include <linux/reboot.h>
#include <linux/sched/signal.h>
@@ -175,16 +174,21 @@ static void powerfail_interrupt(int code, void *x)
-/* parisc_panic_event() is called by the panic handler.
- * As soon as a panic occurs, our tasklets above will not be
- * executed any longer. This function then re-enables the
- * soft-power switch and allows the user to switch off the system
+/*
+ * parisc_panic_event() is called by the panic handler.
+ *
+ * As soon as a panic occurs, our tasklets above will not
+ * be executed any longer. This function then re-enables
+ * the soft-power switch and allows the user to switch off
+ * the system. We rely in pdc_soft_power_button_panic()
+ * since this version spin_trylocks (instead of regular
+ * spinlock), preventing deadlocks on panic path.
*/
static int parisc_panic_event(struct notifier_block *this,
unsigned long event, void *ptr)
{
/* re-enable the soft-power switch */
- pdc_soft_power_button(0);
+ pdc_soft_power_button_panic(0);
return NOTIFY_DONE;
}