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authorAbhishek Sagar <sagar.abhishek@gmail.com>2008-02-06 01:38:22 -0800
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2008-02-06 10:41:11 -0800
commitf47cd9b553aaada602449204513b5a5b29cba263 (patch)
tree079ddd399b1aa00a8c413ef51f3b8681a19a6e7e /kernel
parent5beec4aa2ac261b0b4992fb41df40a7ab91e4fad (diff)
kprobes: kretprobe user entry-handler
Provide support to add an optional user defined callback to be run at function entry of a kretprobe'd function. Also modify the kprobe smoke tests to include an entry-handler during the kretprobe sanity test. Signed-off-by: Abhishek Sagar <sagar.abhishek@gmail.com> Cc: Prasanna S Panchamukhi <prasanna@in.ibm.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Acked-by: Jim Keniston <jkenisto@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/kprobes.c9
-rw-r--r--kernel/test_kprobes.c16
2 files changed, 22 insertions, 3 deletions
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index d0493eafea3..7a86e643233 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -699,6 +699,12 @@ static int __kprobes pre_handler_kretprobe(struct kprobe *p,
struct kretprobe_instance, uflist);
ri->rp = rp;
ri->task = current;
+
+ if (rp->entry_handler && rp->entry_handler(ri, regs)) {
+ spin_unlock_irqrestore(&kretprobe_lock, flags);
+ return 0;
+ }
+
arch_prepare_kretprobe(ri, regs);
/* XXX(hch): why is there no hlist_move_head? */
@@ -745,7 +751,8 @@ int __kprobes register_kretprobe(struct kretprobe *rp)
INIT_HLIST_HEAD(&rp->used_instances);
INIT_HLIST_HEAD(&rp->free_instances);
for (i = 0; i < rp->maxactive; i++) {
- inst = kmalloc(sizeof(struct kretprobe_instance), GFP_KERNEL);
+ inst = kmalloc(sizeof(struct kretprobe_instance) +
+ rp->data_size, GFP_KERNEL);
if (inst == NULL) {
free_rp_inst(rp);
return -ENOMEM;
diff --git a/kernel/test_kprobes.c b/kernel/test_kprobes.c
index 88cdb109e13..06b6395b45b 100644
--- a/kernel/test_kprobes.c
+++ b/kernel/test_kprobes.c
@@ -135,6 +135,12 @@ static int test_jprobe(void)
#ifdef CONFIG_KRETPROBES
static u32 krph_val;
+static int entry_handler(struct kretprobe_instance *ri, struct pt_regs *regs)
+{
+ krph_val = (rand1 / div_factor);
+ return 0;
+}
+
static int return_handler(struct kretprobe_instance *ri, struct pt_regs *regs)
{
unsigned long ret = regs_return_value(regs);
@@ -144,13 +150,19 @@ static int return_handler(struct kretprobe_instance *ri, struct pt_regs *regs)
printk(KERN_ERR "Kprobe smoke test failed: "
"incorrect value in kretprobe handler\n");
}
+ if (krph_val == 0) {
+ handler_errors++;
+ printk(KERN_ERR "Kprobe smoke test failed: "
+ "call to kretprobe entry handler failed\n");
+ }
- krph_val = (rand1 / div_factor);
+ krph_val = rand1;
return 0;
}
static struct kretprobe rp = {
.handler = return_handler,
+ .entry_handler = entry_handler,
.kp.symbol_name = "kprobe_target"
};
@@ -167,7 +179,7 @@ static int test_kretprobe(void)
ret = kprobe_target(rand1);
unregister_kretprobe(&rp);
- if (krph_val == 0) {
+ if (krph_val != rand1) {
printk(KERN_ERR "Kprobe smoke test failed: "
"kretprobe handler not called\n");
handler_errors++;