5 files changed, 65 insertions, 56 deletions

diff --git a/arch/i386/kernel/kprobes.c b/arch/i386/kernel/kprobes.c
index 6345b430b105..fd35039859e6 100644
--- a/arch/i386/kernel/kprobes.c
+++ b/arch/i386/kernel/kprobes.c
@@ -158,8 +158,6 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
         kprobe_opcode_t *addr = NULL;
         unsigned long *lp;
 
-        /* We're in an interrupt, but this is clear and BUG()-safe. */
-        preempt_disable();
         /* Check if the application is using LDT entry for its code segment and
          * calculate the address by reading the base address from the LDT entry.
          */
@@ -232,6 +230,11 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
                 goto no_kprobe;
         }
 
+        /*
+         * This preempt_disable() matches the preempt_enable_no_resched()
+         * in post_kprobe_handler()
+         */
+        preempt_disable();
         kprobe_status = KPROBE_HIT_ACTIVE;
         set_current_kprobe(p, regs);
 
@@ -245,7 +248,6 @@ ss_probe:
         return 1;
 
 no_kprobe:
-        preempt_enable_no_resched();
         return ret;
 }
 
@@ -313,11 +315,11 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
         unlock_kprobes();
         preempt_enable_no_resched();
 
-        /*
-         * By returning a non-zero value, we are telling
-         * kprobe_handler() that we have handled unlocking
-         * and re-enabling preemption.
-         */
+        /*
+         * By returning a non-zero value, we are telling
+         * kprobe_handler() that we have handled unlocking
+         * and re-enabling preemption
+         */
         return 1;
 }
 
@@ -453,29 +455,29 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
                                        unsigned long val, void *data)
 {
         struct die_args *args = (struct die_args *)data;
+        int ret = NOTIFY_DONE;
+
+        preempt_disable();
         switch (val) {
         case DIE_INT3:
                 if (kprobe_handler(args->regs))
-                        return NOTIFY_STOP;
+                        ret = NOTIFY_STOP;
                 break;
         case DIE_DEBUG:
                 if (post_kprobe_handler(args->regs))
-                        return NOTIFY_STOP;
+                        ret = NOTIFY_STOP;
                 break;
         case DIE_GPF:
-                if (kprobe_running() &&
-                    kprobe_fault_handler(args->regs, args->trapnr))
-                        return NOTIFY_STOP;
-                break;
         case DIE_PAGE_FAULT:
                 if (kprobe_running() &&
                     kprobe_fault_handler(args->regs, args->trapnr))
-                        return NOTIFY_STOP;
+                        ret = NOTIFY_STOP;
                 break;
         default:
                 break;
         }
-        return NOTIFY_DONE;
+        preempt_enable();
+        return ret;
 }
 
 int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
@@ -502,7 +504,6 @@ int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
 
 void __kprobes jprobe_return(void)
 {
-        preempt_enable_no_resched();
         asm volatile ("       xchgl   %%ebx,%%esp     \n"
                       "       int3                      \n"
                       "       .globl jprobe_return_end  \n"
diff --git a/arch/ia64/kernel/kprobes.c b/arch/ia64/kernel/kprobes.c
index 471086b808a4..1e80ec80dd21 100644
--- a/arch/ia64/kernel/kprobes.c
+++ b/arch/ia64/kernel/kprobes.c
@@ -395,7 +395,7 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
         /*
          * By returning a non-zero value, we are telling
          * kprobe_handler() that we have handled unlocking
-         * and re-enabling preemption.
+         * and re-enabling preemption
          */
         return 1;
 }
@@ -607,8 +607,6 @@ static int __kprobes pre_kprobes_handler(struct die_args *args)
         struct pt_regs *regs = args->regs;
         kprobe_opcode_t *addr = (kprobe_opcode_t *)instruction_pointer(regs);
 
-        preempt_disable();
-
         /* Handle recursion cases */
         if (kprobe_running()) {
                 p = get_kprobe(addr);
@@ -665,6 +663,11 @@ static int __kprobes pre_kprobes_handler(struct die_args *args)
                 goto no_kprobe;
         }
 
+        /*
+         * This preempt_disable() matches the preempt_enable_no_resched()
+         * in post_kprobes_handler()
+         */
+        preempt_disable();
         kprobe_status = KPROBE_HIT_ACTIVE;
         set_current_kprobe(p);
 
@@ -682,7 +685,6 @@ ss_probe:
         return 1;
 
 no_kprobe:
-        preempt_enable_no_resched();
         return ret;
 }
 
@@ -733,22 +735,26 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
                                        unsigned long val, void *data)
 {
         struct die_args *args = (struct die_args *)data;
+        int ret = NOTIFY_DONE;
+
+        preempt_disable();
         switch(val) {
         case DIE_BREAK:
                 if (pre_kprobes_handler(args))
-                        return NOTIFY_STOP;
+                        ret = NOTIFY_STOP;
                 break;
         case DIE_SS:
                 if (post_kprobes_handler(args->regs))
-                        return NOTIFY_STOP;
+                        ret = NOTIFY_STOP;
                 break;
         case DIE_PAGE_FAULT:
                 if (kprobes_fault_handler(args->regs, args->trapnr))
-                        return NOTIFY_STOP;
+                        ret = NOTIFY_STOP;
         default:
                 break;
         }
-        return NOTIFY_DONE;
+        preempt_enable();
+        return ret;
 }
 
 int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
diff --git a/arch/ppc64/kernel/kprobes.c b/arch/ppc64/kernel/kprobes.c
index ed876a5178ae..6071ee99f5cb 100644
--- a/arch/ppc64/kernel/kprobes.c
+++ b/arch/ppc64/kernel/kprobes.c
@@ -209,6 +209,11 @@ static inline int kprobe_handler(struct pt_regs *regs)
                 goto no_kprobe;
         }
 
+        /*
+         * This preempt_disable() matches the preempt_enable_no_resched()
+         * in post_kprobe_handler().
+         */
+        preempt_disable();
         kprobe_status = KPROBE_HIT_ACTIVE;
         current_kprobe = p;
         kprobe_saved_msr = regs->msr;
@@ -219,11 +224,6 @@ static inline int kprobe_handler(struct pt_regs *regs)
 ss_probe:
         prepare_singlestep(p, regs);
         kprobe_status = KPROBE_HIT_SS;
-        /*
-         * This preempt_disable() matches the preempt_enable_no_resched()
-         * in post_kprobe_handler().
-         */
-        preempt_disable();
         return 1;
 
 no_kprobe:
@@ -293,6 +293,7 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
         regs->nip = orig_ret_address;
 
         unlock_kprobes();
+        preempt_enable_no_resched();
 
         /*
          * By returning a non-zero value, we are telling
diff --git a/arch/sparc64/kernel/kprobes.c b/arch/sparc64/kernel/kprobes.c
index 0d66d07c8c6e..755a0d7d887f 100644
--- a/arch/sparc64/kernel/kprobes.c
+++ b/arch/sparc64/kernel/kprobes.c
@@ -118,8 +118,6 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
         void *addr = (void *) regs->tpc;
         int ret = 0;
 
-        preempt_disable();
-
         if (kprobe_running()) {
                 /* We *are* holding lock here, so this is safe.
                  * Disarm the probe we just hit, and ignore it.
@@ -171,6 +169,11 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
                 goto no_kprobe;
         }
 
+        /*
+         * This preempt_disable() matches the preempt_enable_no_resched()
+         * in post_kprobes_handler()
+         */
+        preempt_disable();
         set_current_kprobe(p, regs);
         kprobe_status = KPROBE_HIT_ACTIVE;
         if (p->pre_handler && p->pre_handler(p, regs))
@@ -182,7 +185,6 @@ ss_probe:
         return 1;
 
 no_kprobe:
-        preempt_enable_no_resched();
         return ret;
 }
 
@@ -322,29 +324,29 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
                                        unsigned long val, void *data)
 {
         struct die_args *args = (struct die_args *)data;
+        int ret = NOTIFY_DONE;
+
+        preempt_disable();
         switch (val) {
         case DIE_DEBUG:
                 if (kprobe_handler(args->regs))
-                        return NOTIFY_STOP;
+                        ret = NOTIFY_STOP;
                 break;
         case DIE_DEBUG_2:
                 if (post_kprobe_handler(args->regs))
-                        return NOTIFY_STOP;
+                        ret = NOTIFY_STOP;
                 break;
         case DIE_GPF:
-                if (kprobe_running() &&
-                    kprobe_fault_handler(args->regs, args->trapnr))
-                        return NOTIFY_STOP;
-                break;
         case DIE_PAGE_FAULT:
                 if (kprobe_running() &&
                     kprobe_fault_handler(args->regs, args->trapnr))
-                        return NOTIFY_STOP;
+                        ret = NOTIFY_STOP;
                 break;
         default:
                 break;
         }
-        return NOTIFY_DONE;
+        preempt_enable();
+        return ret;
 }
 
 asmlinkage void __kprobes kprobe_trap(unsigned long trap_level,
@@ -396,7 +398,6 @@ int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
 
 void __kprobes jprobe_return(void)
 {
-        preempt_enable_no_resched();
         __asm__ __volatile__(
                 ".globl jprobe_return_trap_instruction\n"
 "jprobe_return_trap_instruction:\n\t"
diff --git a/arch/x86_64/kernel/kprobes.c b/arch/x86_64/kernel/kprobes.c
index 76a28b007be9..ebfa2c9241ca 100644
--- a/arch/x86_64/kernel/kprobes.c
+++ b/arch/x86_64/kernel/kprobes.c
@@ -302,9 +302,6 @@ int __kprobes kprobe_handler(struct pt_regs *regs)
         int ret = 0;
         kprobe_opcode_t *addr = (kprobe_opcode_t *)(regs->rip - sizeof(kprobe_opcode_t));
 
-        /* We're in an interrupt, but this is clear and BUG()-safe. */
-        preempt_disable();
-
         /* Check we're not actually recursing */
         if (kprobe_running()) {
                 /* We *are* holding lock here, so this is safe.
@@ -372,6 +369,11 @@ int __kprobes kprobe_handler(struct pt_regs *regs)
                 goto no_kprobe;
         }
 
+        /*
+         * This preempt_disable() matches the preempt_enable_no_resched()
+         * in post_kprobe_handler()
+         */
+        preempt_disable();
         kprobe_status = KPROBE_HIT_ACTIVE;
         set_current_kprobe(p, regs);
 
@@ -385,7 +387,6 @@ ss_probe:
         return 1;
 
 no_kprobe:
-        preempt_enable_no_resched();
         return ret;
 }
 
@@ -456,7 +457,7 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
         /*
          * By returning a non-zero value, we are telling
          * kprobe_handler() that we have handled unlocking
-         * and re-enabling preemption.
+         * and re-enabling preemption
          */
         return 1;
 }
@@ -599,29 +600,29 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
                                        unsigned long val, void *data)
 {
         struct die_args *args = (struct die_args *)data;
+        int ret = NOTIFY_DONE;
+
+        preempt_disable();
         switch (val) {
         case DIE_INT3:
                 if (kprobe_handler(args->regs))
-                        return NOTIFY_STOP;
+                        ret = NOTIFY_STOP;
                 break;
         case DIE_DEBUG:
                 if (post_kprobe_handler(args->regs))
-                        return NOTIFY_STOP;
+                        ret = NOTIFY_STOP;
                 break;
         case DIE_GPF:
-                if (kprobe_running() &&
-                    kprobe_fault_handler(args->regs, args->trapnr))
-                        return NOTIFY_STOP;
-                break;
         case DIE_PAGE_FAULT:
                 if (kprobe_running() &&
                     kprobe_fault_handler(args->regs, args->trapnr))
-                        return NOTIFY_STOP;
+                        ret = NOTIFY_STOP;
                 break;
         default:
                 break;
         }
-        return NOTIFY_DONE;
+        preempt_enable();
+        return ret;
 }
 
 int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
@@ -647,7 +648,6 @@ int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
 
 void __kprobes jprobe_return(void)
 {
-        preempt_enable_no_resched();
         asm volatile ("       xchg   %%rbx,%%rsp     \n"
                       "       int3                      \n"
                       "       .globl jprobe_return_end  \n"