path: root/arch/avr32/mm
diff options
authorDavid Hildenbrand <>2015-05-11 17:52:11 +0200
committerIngo Molnar <>2015-05-19 08:39:15 +0200
commit70ffdb9393a7264a069265edded729078dcf0425 (patch)
tree9f93a018845ab2b02be1ee7cba83ae77f5191022 /arch/avr32/mm
parentce01948eb85da733558fa77c2a554144a57ab0fb (diff)
mm/fault, arch: Use pagefault_disable() to check for disabled pagefaults in the handler
Introduce faulthandler_disabled() and use it to check for irq context and disabled pagefaults (via pagefault_disable()) in the pagefault handlers. Please note that we keep the in_atomic() checks in place - to detect whether in irq context (in which case preemption is always properly disabled). In contrast, preempt_disable() should never be used to disable pagefaults. With !CONFIG_PREEMPT_COUNT, preempt_disable() doesn't modify the preempt counter, and therefore the result of in_atomic() differs. We validate that condition by using might_fault() checks when calling might_sleep(). Therefore, add a comment to faulthandler_disabled(), describing why this is needed. faulthandler_disabled() and pagefault_disable() are defined in linux/uaccess.h, so let's properly add that include to all relevant files. This patch is based on a patch from Thomas Gleixner. Reviewed-and-tested-by: Thomas Gleixner <> Signed-off-by: David Hildenbrand <> Signed-off-by: Peter Zijlstra (Intel) <> Cc: David.Laight@ACULAB.COM Cc: Linus Torvalds <> Cc: Peter Zijlstra <> Cc: Thomas Gleixner <> Cc: Cc: Cc: Cc: Cc: Cc: Cc: Cc: Cc: Cc: Cc: Cc: Cc: Cc: Cc: Link: Signed-off-by: Ingo Molnar <>
Diffstat (limited to 'arch/avr32/mm')
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/avr32/mm/fault.c b/arch/avr32/mm/fault.c
index d223a8b..c035339 100644
--- a/arch/avr32/mm/fault.c
+++ b/arch/avr32/mm/fault.c
@@ -14,11 +14,11 @@
#include <linux/pagemap.h>
#include <linux/kdebug.h>
#include <linux/kprobes.h>
+#include <linux/uaccess.h>
#include <asm/mmu_context.h>
#include <asm/sysreg.h>
#include <asm/tlb.h>
-#include <asm/uaccess.h>
static inline int notify_page_fault(struct pt_regs *regs, int trap)
@@ -81,7 +81,7 @@ asmlinkage void do_page_fault(unsigned long ecr, struct pt_regs *regs)
* If we're in an interrupt or have no user context, we must
* not take the fault...
- if (in_atomic() || !mm || regs->sr & SYSREG_BIT(GM))
+ if (faulthandler_disabled() || !mm || regs->sr & SYSREG_BIT(GM))
goto no_context;