PCI: pci_get_device call from interrupt in reboot fixups
The following calltrace is possible now:
handle_sysrq
machine_emergency_restart
mach_reboot_fixups
pci_get_device
pci_get_subsys
down_read
The patch skips reboot fixup if called from sysrq-B code.
Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/arch/x86/kernel/reboot_fixups_32.c b/arch/x86/kernel/reboot_fixups_32.c
index 03e1cce..139eb03 100644
--- a/arch/x86/kernel/reboot_fixups_32.c
+++ b/arch/x86/kernel/reboot_fixups_32.c
@@ -11,6 +11,7 @@
#include <asm/delay.h>
#include <linux/pci.h>
+#include <linux/interrupt.h>
#include <asm/reboot_fixups.h>
#include <asm/msr.h>
@@ -56,6 +57,11 @@
struct pci_dev *dev;
int i;
+ /* we can be called from sysrq-B code. In such a case it is
+ * prohibited to dig PCI */
+ if (in_interrupt())
+ return;
+
for (i=0; i < ARRAY_SIZE(fixups_table); i++) {
cur = &(fixups_table[i]);
dev = pci_get_device(cur->vendor, cur->device, NULL);
