From: Andrea Righi <righiandr@users.sourceforge.net>

Limit the rate of the kernel logging for the segfaults of user
applications, to avoid potential message floods or denial-of-service
attacks.

Signed-off-by: Andrea Righi <a.righi@cineca.it>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 arch/x86_64/mm/fault.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletion(-)

diff -puN arch/avr32/mm/fault.c~x86_64-ratelimit-segfault-reporting-rate arch/avr32/mm/fault.c
diff -puN arch/x86_64/mm/fault.c~x86_64-ratelimit-segfault-reporting-rate arch/x86_64/mm/fault.c
--- a/arch/x86_64/mm/fault.c~x86_64-ratelimit-segfault-reporting-rate
+++ a/arch/x86_64/mm/fault.c
@@ -489,7 +489,8 @@ bad_area_nosemaphore:
 		    (address >> 32))
 			return;
 
-		if (exception_trace && unhandled_signal(tsk, SIGSEGV)) {
+		if (exception_trace && unhandled_signal(tsk, SIGSEGV) &&
+		    printk_ratelimit()) {
 			printk(
 		       "%s%s[%d]: segfault at %016lx rip %016lx rsp %016lx error %lx\n",
 					tsk->pid > 1 ? KERN_INFO : KERN_EMERG,
_