parisc: ratelimit userspace segfault printing
Ratelimit printing of userspace segfaults and make it runtime
configurable via the /proc/sys/debug/exception-trace variable. This
should resolve syslog from growing way too fast and thus prevents
possible system service attacks.
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: stable@vger.kernel.org # 3.13+
diff --git a/arch/parisc/mm/fault.c b/arch/parisc/mm/fault.c
index 9d08c71..d72197f 100644
--- a/arch/parisc/mm/fault.c
+++ b/arch/parisc/mm/fault.c
@@ -19,10 +19,6 @@
#include <asm/uaccess.h>
#include <asm/traps.h>
-#define PRINT_USER_FAULTS /* (turn this on if you want user faults to be */
- /* dumped to the console via printk) */
-
-
/* Various important other fields */
#define bit22set(x) (x & 0x00000200)
#define bits23_25set(x) (x & 0x000001c0)
@@ -34,6 +30,8 @@
DEFINE_PER_CPU(struct exception_data, exception_data);
+int show_unhandled_signals = 1;
+
/*
* parisc_acctyp(unsigned int inst) --
* Given a PA-RISC memory access instruction, determine if the
@@ -173,6 +171,32 @@
return 0;
}
+/*
+ * Print out info about fatal segfaults, if the show_unhandled_signals
+ * sysctl is set:
+ */
+static inline void
+show_signal_msg(struct pt_regs *regs, unsigned long code,
+ unsigned long address, struct task_struct *tsk,
+ struct vm_area_struct *vma)
+{
+ if (!unhandled_signal(tsk, SIGSEGV))
+ return;
+
+ if (!printk_ratelimit())
+ return;
+
+ pr_warn("\n");
+ pr_warn("do_page_fault() command='%s' type=%lu address=0x%08lx",
+ tsk->comm, code, address);
+ print_vma_addr(KERN_CONT " in ", regs->iaoq[0]);
+ if (vma)
+ pr_warn(" vm_start = 0x%08lx, vm_end = 0x%08lx\n",
+ vma->vm_start, vma->vm_end);
+
+ show_regs(regs);
+}
+
void do_page_fault(struct pt_regs *regs, unsigned long code,
unsigned long address)
{
@@ -270,16 +294,8 @@
if (user_mode(regs)) {
struct siginfo si;
-#ifdef PRINT_USER_FAULTS
- printk(KERN_DEBUG "\n");
- printk(KERN_DEBUG "do_page_fault() pid=%d command='%s' type=%lu address=0x%08lx\n",
- task_pid_nr(tsk), tsk->comm, code, address);
- if (vma) {
- printk(KERN_DEBUG "vm_start = 0x%08lx, vm_end = 0x%08lx\n",
- vma->vm_start, vma->vm_end);
- }
- show_regs(regs);
-#endif
+ show_signal_msg(regs, code, address, tsk, vma);
+
switch (code) {
case 15: /* Data TLB miss fault/Data page fault */
/* send SIGSEGV when outside of vma */