From: Denis V. Lunev <den@openvz.org>
Date: Tue, 7 Aug 2007 09:13:18 +0000 (+0400)
Subject: PCI: pci_get_device call from interrupt in reboot fixups
X-Git-Tag: v2.6.24-rc1~1393^2~22
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3d034aecd8b70d34388a4e40ca50af0d014223e1;p=linux-2.6

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 03e1cce58f..139eb03490 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 @@ void mach_reboot_fixups(void)
 	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);