5 files changed, 27 insertions, 74 deletions

diff --git a/arch/i386/kernel/kprobes.c b/arch/i386/kernel/kprobes.c
index 99565a66915d..ad469299267a 100644
--- a/arch/i386/kernel/kprobes.c
+++ b/arch/i386/kernel/kprobes.c
@@ -31,7 +31,6 @@
 #include <linux/config.h>
 #include <linux/kprobes.h>
 #include <linux/ptrace.h>
-#include <linux/spinlock.h>
 #include <linux/preempt.h>
 #include <asm/cacheflush.h>
 #include <asm/kdebug.h>
@@ -123,6 +122,7 @@ static inline void prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
                 regs->eip = (unsigned long)&p->ainsn.insn;
 }
 
+/* Called with kretprobe_lock held */
 void __kprobes arch_prepare_kretprobe(struct kretprobe *rp,
                                       struct pt_regs *regs)
 {
@@ -168,15 +168,12 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
         }
         /* Check we're not actually recursing */
         if (kprobe_running()) {
-                /* We *are* holding lock here, so this is safe.
-                   Disarm the probe we just hit, and ignore it. */
                 p = get_kprobe(addr);
                 if (p) {
                         if (kcb->kprobe_status == KPROBE_HIT_SS &&
                                 *p->ainsn.insn == BREAKPOINT_INSTRUCTION) {
                                 regs->eflags &= ~TF_MASK;
                                 regs->eflags |= kcb->kprobe_saved_eflags;
-                                unlock_kprobes();
                                 goto no_kprobe;
                         }
                         /* We have reentered the kprobe_handler(), since
@@ -197,14 +194,11 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
                                 goto ss_probe;
                         }
                 }
-                /* If it's not ours, can't be delete race, (we hold lock). */
                 goto no_kprobe;
         }
 
-        lock_kprobes();
         p = get_kprobe(addr);
         if (!p) {
-                unlock_kprobes();
                 if (regs->eflags & VM_MASK) {
                         /* We are in virtual-8086 mode. Return 0 */
                         goto no_kprobe;
@@ -268,9 +262,10 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
         struct kretprobe_instance *ri = NULL;
         struct hlist_head *head;
         struct hlist_node *node, *tmp;
-        unsigned long orig_ret_address = 0;
+        unsigned long flags, orig_ret_address = 0;
         unsigned long trampoline_address =(unsigned long)&kretprobe_trampoline;
 
+        spin_lock_irqsave(&kretprobe_lock, flags);
         head = kretprobe_inst_table_head(current);
 
         /*
@@ -310,7 +305,7 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
         regs->eip = orig_ret_address;
 
         reset_current_kprobe();
-        unlock_kprobes();
+        spin_unlock_irqrestore(&kretprobe_lock, flags);
         preempt_enable_no_resched();
 
         /*
@@ -395,7 +390,7 @@ static void __kprobes resume_execution(struct kprobe *p,
 
 /*
  * Interrupts are disabled on entry as trap1 is an interrupt gate and they
- * remain disabled thoroughout this function.  And we hold kprobe lock.
+ * remain disabled thoroughout this function.
  */
 static inline int post_kprobe_handler(struct pt_regs *regs)
 {
@@ -419,7 +414,6 @@ static inline int post_kprobe_handler(struct pt_regs *regs)
                 goto out;
         }
         reset_current_kprobe();
-        unlock_kprobes();
 out:
         preempt_enable_no_resched();
 
@@ -434,7 +428,6 @@ out:
         return 1;
 }
 
-/* Interrupts disabled, kprobe_lock held. */
 static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
 {
         struct kprobe *cur = kprobe_running();
@@ -448,7 +441,6 @@ static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
                 regs->eflags |= kcb->kprobe_old_eflags;
 
                 reset_current_kprobe();
-                unlock_kprobes();
                 preempt_enable_no_resched();
         }
         return 0;
@@ -463,7 +455,7 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
         struct die_args *args = (struct die_args *)data;
         int ret = NOTIFY_DONE;
 
-        preempt_disable();
+        rcu_read_lock();
         switch (val) {
         case DIE_INT3:
                 if (kprobe_handler(args->regs))
@@ -482,7 +474,7 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
         default:
                 break;
         }
-        preempt_enable();
+        rcu_read_unlock();
         return ret;
 }
 
diff --git a/arch/ia64/kernel/kprobes.c b/arch/ia64/kernel/kprobes.c
index 17e70b1b8d79..fddbac32d44a 100644
--- a/arch/ia64/kernel/kprobes.c
+++ b/arch/ia64/kernel/kprobes.c
@@ -26,7 +26,6 @@
 #include <linux/config.h>
 #include <linux/kprobes.h>
 #include <linux/ptrace.h>
-#include <linux/spinlock.h>
 #include <linux/string.h>
 #include <linux/slab.h>
 #include <linux/preempt.h>
@@ -343,10 +342,11 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
         struct kretprobe_instance *ri = NULL;
         struct hlist_head *head;
         struct hlist_node *node, *tmp;
-        unsigned long orig_ret_address = 0;
+        unsigned long flags, orig_ret_address = 0;
         unsigned long trampoline_address =
                 ((struct fnptr *)kretprobe_trampoline)->ip;
 
+        spin_lock_irqsave(&kretprobe_lock, flags);
         head = kretprobe_inst_table_head(current);
 
         /*
@@ -386,7 +386,7 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
         regs->cr_iip = orig_ret_address;
 
         reset_current_kprobe();
-        unlock_kprobes();
+        spin_unlock_irqrestore(&kretprobe_lock, flags);
         preempt_enable_no_resched();
 
         /*
@@ -397,6 +397,7 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
         return 1;
 }
 
+/* Called with kretprobe_lock held */
 void __kprobes arch_prepare_kretprobe(struct kretprobe *rp,
                                       struct pt_regs *regs)
 {
@@ -612,7 +613,6 @@ static int __kprobes pre_kprobes_handler(struct die_args *args)
                         if ((kcb->kprobe_status == KPROBE_HIT_SS) &&
                              (p->ainsn.inst_flag == INST_FLAG_BREAK_INST)) {
                                 ia64_psr(regs)->ss = 0;
-                                unlock_kprobes();
                                 goto no_kprobe;
                         }
                         /* We have reentered the pre_kprobe_handler(), since
@@ -641,10 +641,8 @@ static int __kprobes pre_kprobes_handler(struct die_args *args)
                 }
         }
 
-        lock_kprobes();
         p = get_kprobe(addr);
         if (!p) {
-                unlock_kprobes();
                 if (!is_ia64_break_inst(regs)) {
                         /*
                          * The breakpoint instruction was removed right
@@ -707,7 +705,6 @@ static int __kprobes post_kprobes_handler(struct pt_regs *regs)
                 goto out;
         }
         reset_current_kprobe();
-        unlock_kprobes();
 
 out:
         preempt_enable_no_resched();
@@ -728,7 +725,6 @@ static int __kprobes kprobes_fault_handler(struct pt_regs *regs, int trapnr)
         if (kcb->kprobe_status & KPROBE_HIT_SS) {
                 resume_execution(cur, regs);
                 reset_current_kprobe();
-                unlock_kprobes();
                 preempt_enable_no_resched();
         }
 
@@ -741,7 +737,7 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
         struct die_args *args = (struct die_args *)data;
         int ret = NOTIFY_DONE;
 
-        preempt_disable();
+        rcu_read_lock();
         switch(val) {
         case DIE_BREAK:
                 if (pre_kprobes_handler(args))
@@ -757,7 +753,7 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
         default:
                 break;
         }
-        preempt_enable();
+        rcu_read_unlock();
         return ret;
 }
 
diff --git a/arch/ppc64/kernel/kprobes.c b/arch/ppc64/kernel/kprobes.c
index 3f89f3e5584a..e0a25b35437f 100644
--- a/arch/ppc64/kernel/kprobes.c
+++ b/arch/ppc64/kernel/kprobes.c
@@ -30,7 +30,6 @@
 #include <linux/config.h>
 #include <linux/kprobes.h>
 #include <linux/ptrace.h>
-#include <linux/spinlock.h>
 #include <linux/preempt.h>
 #include <asm/cacheflush.h>
 #include <asm/kdebug.h>
@@ -125,6 +124,7 @@ static inline void set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
         kcb->kprobe_saved_msr = regs->msr;
 }
 
+/* Called with kretprobe_lock held */
 void __kprobes arch_prepare_kretprobe(struct kretprobe *rp,
                                       struct pt_regs *regs)
 {
@@ -152,8 +152,6 @@ static inline int kprobe_handler(struct pt_regs *regs)
 
         /* Check we're not actually recursing */
         if (kprobe_running()) {
-                /* We *are* holding lock here, so this is safe.
-                   Disarm the probe we just hit, and ignore it. */
                 p = get_kprobe(addr);
                 if (p) {
                         kprobe_opcode_t insn = *p->ainsn.insn;
@@ -161,7 +159,6 @@ static inline int kprobe_handler(struct pt_regs *regs)
                                         is_trap(insn)) {
                                 regs->msr &= ~MSR_SE;
                                 regs->msr |= kcb->kprobe_saved_msr;
-                                unlock_kprobes();
                                 goto no_kprobe;
                         }
                         /* We have reentered the kprobe_handler(), since
@@ -183,14 +180,11 @@ static inline int kprobe_handler(struct pt_regs *regs)
                                 goto ss_probe;
                         }
                 }
-                /* If it's not ours, can't be delete race, (we hold lock). */
                 goto no_kprobe;
         }
 
-        lock_kprobes();
         p = get_kprobe(addr);
         if (!p) {
-                unlock_kprobes();
                 if (*addr != BREAKPOINT_INSTRUCTION) {
                         /*
                          * PowerPC has multiple variants of the "trap"
@@ -254,9 +248,10 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
         struct kretprobe_instance *ri = NULL;
         struct hlist_head *head;
         struct hlist_node *node, *tmp;
-        unsigned long orig_ret_address = 0;
+        unsigned long flags, orig_ret_address = 0;
         unsigned long trampoline_address =(unsigned long)&kretprobe_trampoline;
 
+        spin_lock_irqsave(&kretprobe_lock, flags);
         head = kretprobe_inst_table_head(current);
 
         /*
@@ -296,7 +291,7 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
         regs->nip = orig_ret_address;
 
         reset_current_kprobe();
-        unlock_kprobes();
+        spin_unlock_irqrestore(&kretprobe_lock, flags);
         preempt_enable_no_resched();
 
         /*
@@ -348,7 +343,6 @@ static inline int post_kprobe_handler(struct pt_regs *regs)
                 goto out;
         }
         reset_current_kprobe();
-        unlock_kprobes();
 out:
         preempt_enable_no_resched();
 
@@ -363,7 +357,6 @@ out:
         return 1;
 }
 
-/* Interrupts disabled, kprobe_lock held. */
 static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
 {
         struct kprobe *cur = kprobe_running();
@@ -378,7 +371,6 @@ static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
                 regs->msr |= kcb->kprobe_saved_msr;
 
                 reset_current_kprobe();
-                unlock_kprobes();
                 preempt_enable_no_resched();
         }
         return 0;
@@ -393,11 +385,7 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
         struct die_args *args = (struct die_args *)data;
         int ret = NOTIFY_DONE;
 
-        /*
-         * Interrupts are not disabled here.  We need to disable
-         * preemption, because kprobe_running() uses smp_processor_id().
-         */
-        preempt_disable();
+        rcu_read_lock();
         switch (val) {
         case DIE_BPT:
                 if (kprobe_handler(args->regs))
@@ -415,7 +403,7 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
         default:
                 break;
         }
-        preempt_enable_no_resched();
+        rcu_read_unlock();
         return ret;
 }
 
diff --git a/arch/sparc64/kernel/kprobes.c b/arch/sparc64/kernel/kprobes.c
index b95984154dba..58a815e90373 100644
--- a/arch/sparc64/kernel/kprobes.c
+++ b/arch/sparc64/kernel/kprobes.c
@@ -116,15 +116,11 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
         struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
 
         if (kprobe_running()) {
-                /* We *are* holding lock here, so this is safe.
-                 * Disarm the probe we just hit, and ignore it.
-                 */
                 p = get_kprobe(addr);
                 if (p) {
                         if (kcb->kprobe_status == KPROBE_HIT_SS) {
                                 regs->tstate = ((regs->tstate & ~TSTATE_PIL) |
                                         kcb->kprobe_orig_tstate_pil);
-                                unlock_kprobes();
                                 goto no_kprobe;
                         }
                         /* We have reentered the kprobe_handler(), since
@@ -144,14 +140,11 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
                         if (p->break_handler && p->break_handler(p, regs))
                                 goto ss_probe;
                 }
-                /* If it's not ours, can't be delete race, (we hold lock). */
                 goto no_kprobe;
         }
 
-        lock_kprobes();
         p = get_kprobe(addr);
         if (!p) {
-                unlock_kprobes();
                 if (*(u32 *)addr != BREAKPOINT_INSTRUCTION) {
                         /*
                          * The breakpoint instruction was removed right
@@ -296,14 +289,12 @@ static inline int post_kprobe_handler(struct pt_regs *regs)
                 goto out;
         }
         reset_current_kprobe();
-        unlock_kprobes();
 out:
         preempt_enable_no_resched();
 
         return 1;
 }
 
-/* Interrupts disabled, kprobe_lock held. */
 static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
 {
         struct kprobe *cur = kprobe_running();
@@ -316,7 +307,6 @@ static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
                 resume_execution(cur, regs, kcb);
 
                 reset_current_kprobe();
-                unlock_kprobes();
                 preempt_enable_no_resched();
         }
         return 0;
@@ -331,7 +321,7 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
         struct die_args *args = (struct die_args *)data;
         int ret = NOTIFY_DONE;
 
-        preempt_disable();
+        rcu_read_lock();
         switch (val) {
         case DIE_DEBUG:
                 if (kprobe_handler(args->regs))
@@ -350,7 +340,7 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
         default:
                 break;
         }
-        preempt_enable();
+        rcu_read_unlock();
         return ret;
 }
 
diff --git a/arch/x86_64/kernel/kprobes.c b/arch/x86_64/kernel/kprobes.c
index 6cb40d133b7c..9bef2c8dc12c 100644
--- a/arch/x86_64/kernel/kprobes.c
+++ b/arch/x86_64/kernel/kprobes.c
@@ -34,7 +34,6 @@
 #include <linux/config.h>
 #include <linux/kprobes.h>
 #include <linux/ptrace.h>
-#include <linux/spinlock.h>
 #include <linux/string.h>
 #include <linux/slab.h>
 #include <linux/preempt.h>
@@ -266,6 +265,7 @@ static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
                 regs->rip = (unsigned long)p->ainsn.insn;
 }
 
+/* Called with kretprobe_lock held */
 void __kprobes arch_prepare_kretprobe(struct kretprobe *rp,
                                       struct pt_regs *regs)
 {
@@ -299,15 +299,12 @@ int __kprobes kprobe_handler(struct pt_regs *regs)
 
         /* Check we're not actually recursing */
         if (kprobe_running()) {
-                /* We *are* holding lock here, so this is safe.
-                   Disarm the probe we just hit, and ignore it. */
                 p = get_kprobe(addr);
                 if (p) {
                         if (kcb->kprobe_status == KPROBE_HIT_SS &&
                                 *p->ainsn.insn == BREAKPOINT_INSTRUCTION) {
                                 regs->eflags &= ~TF_MASK;
                                 regs->eflags |= kcb->kprobe_saved_rflags;
-                                unlock_kprobes();
                                 goto no_kprobe;
                         } else if (kcb->kprobe_status == KPROBE_HIT_SSDONE) {
                                 /* TODO: Provide re-entrancy from
@@ -340,14 +337,11 @@ int __kprobes kprobe_handler(struct pt_regs *regs)
                                 goto ss_probe;
                         }
                 }
-                /* If it's not ours, can't be delete race, (we hold lock). */
                 goto no_kprobe;
         }
 
-        lock_kprobes();
         p = get_kprobe(addr);
         if (!p) {
-                unlock_kprobes();
                 if (*addr != BREAKPOINT_INSTRUCTION) {
                         /*
                          * The breakpoint instruction was removed right
@@ -406,9 +400,10 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
         struct kretprobe_instance *ri = NULL;
         struct hlist_head *head;
         struct hlist_node *node, *tmp;
-        unsigned long orig_ret_address = 0;
+        unsigned long flags, orig_ret_address = 0;
         unsigned long trampoline_address =(unsigned long)&kretprobe_trampoline;
 
+        spin_lock_irqsave(&kretprobe_lock, flags);
         head = kretprobe_inst_table_head(current);
 
         /*
@@ -448,7 +443,7 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
         regs->rip = orig_ret_address;
 
         reset_current_kprobe();
-        unlock_kprobes();
+        spin_unlock_irqrestore(&kretprobe_lock, flags);
         preempt_enable_no_resched();
 
         /*
@@ -536,10 +531,6 @@ static void __kprobes resume_execution(struct kprobe *p,
         }
 }
 
-/*
- * Interrupts are disabled on entry as trap1 is an interrupt gate and they
- * remain disabled thoroughout this function.  And we hold kprobe lock.
- */
 int __kprobes post_kprobe_handler(struct pt_regs *regs)
 {
         struct kprobe *cur = kprobe_running();
@@ -560,8 +551,6 @@ int __kprobes post_kprobe_handler(struct pt_regs *regs)
         if (kcb->kprobe_status == KPROBE_REENTER) {
                 restore_previous_kprobe(kcb);
                 goto out;
-        } else {
-                unlock_kprobes();
         }
         reset_current_kprobe();
 out:
@@ -578,7 +567,6 @@ out:
         return 1;
 }
 
-/* Interrupts disabled, kprobe_lock held. */
 int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
 {
         struct kprobe *cur = kprobe_running();
@@ -592,7 +580,6 @@ int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
                 regs->eflags |= kcb->kprobe_old_rflags;
 
                 reset_current_kprobe();
-                unlock_kprobes();
                 preempt_enable_no_resched();
         }
         return 0;
@@ -607,7 +594,7 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
         struct die_args *args = (struct die_args *)data;
         int ret = NOTIFY_DONE;
 
-        preempt_disable();
+        rcu_read_lock();
         switch (val) {
         case DIE_INT3:
                 if (kprobe_handler(args->regs))
@@ -626,7 +613,7 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
         default:
                 break;
         }
-        preempt_enable();
+        rcu_read_unlock();
         return ret;
 }