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Subject[PATCH 11/20] kprobes: Return -ENOENT if probe point doesnt exist
From: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>

Return -ENOENT if probe point doesn't exist, but still returns
-EINVAL if both of kprobe->addr and kprobe->symbol_name are
specified or both are not specified.

Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Link: http://lkml.kernel.org/r/20110627072650.6528.67329.stgit@fedora15
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
kernel/kprobes.c | 33 +++++++++++++++++++++++----------
1 files changed, 23 insertions(+), 10 deletions(-)
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 7798181..b30fd54 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1255,19 +1255,29 @@ static int __kprobes in_kprobes_functions(unsigned long addr)
/*
* If we have a symbol_name argument, look it up and add the offset field
* to it. This way, we can specify a relative address to a symbol.
+ * This returns encoded errors if it fails to look up symbol or invalid
+ * combination of parameters.
*/
static kprobe_opcode_t __kprobes *kprobe_addr(struct kprobe *p)
{
kprobe_opcode_t *addr = p->addr;
+
+ if ((p->symbol_name && p->addr) ||
+ (!p->symbol_name && !p->addr))
+ goto invalid;
+
if (p->symbol_name) {
- if (addr)
- return NULL;
kprobe_lookup_name(p->symbol_name, addr);
+ if (!addr)
+ return ERR_PTR(-ENOENT);
}

- if (!addr)
- return NULL;
- return (kprobe_opcode_t *)(((char *)addr) + p->offset);
+ addr = (kprobe_opcode_t *)(((char *)addr) + p->offset);
+ if (addr)
+ return addr;
+
+invalid:
+ return ERR_PTR(-EINVAL);
}

/* Check passed kprobe is valid and return kprobe in kprobe_table. */
@@ -1311,8 +1321,8 @@ int __kprobes register_kprobe(struct kprobe *p)
kprobe_opcode_t *addr;

addr = kprobe_addr(p);
- if (!addr)
- return -EINVAL;
+ if (IS_ERR(addr))
+ return PTR_ERR(addr);
p->addr = addr;

ret = check_kprobe_rereg(p);
@@ -1335,6 +1345,8 @@ int __kprobes register_kprobe(struct kprobe *p)
*/
probed_mod = __module_text_address((unsigned long) p->addr);
if (probed_mod) {
+ /* Return -ENOENT if fail. */
+ ret = -ENOENT;
/*
* We must hold a refcount of the probed module while updating
* its code to prohibit unexpected unloading.
@@ -1351,6 +1363,7 @@ int __kprobes register_kprobe(struct kprobe *p)
module_put(probed_mod);
goto fail_with_jump_label;
}
+ /* ret will be updated by following code */
}
preempt_enable();
jump_label_unlock();
@@ -1399,7 +1412,7 @@ out:
fail_with_jump_label:
preempt_enable();
jump_label_unlock();
- return -EINVAL;
+ return ret;
}
EXPORT_SYMBOL_GPL(register_kprobe);

@@ -1686,8 +1699,8 @@ int __kprobes register_kretprobe(struct kretprobe *rp)

if (kretprobe_blacklist_size) {
addr = kprobe_addr(&rp->kp);
- if (!addr)
- return -EINVAL;
+ if (IS_ERR(addr))
+ return PTR_ERR(addr);

for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
if (kretprobe_blacklist[i].addr == addr)
--
1.7.5.4



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