Call kprobe_target indirectly. This prevents gcc to unroll
a noinline function in caller function.
Signed-off-by: Masami Hiramatsu <[email protected]>
CC: Ananth N Mavinakayanahalli <[email protected]>
CC: Jim Keniston <[email protected]>
CC: David Miller <[email protected]>
---
I ported patches which had been discussed on
http://sources.redhat.com/bugzilla/show_bug.cgi?id=3542
tests/test_kprobes.c | 21 ++++++---------------
1 file changed, 6 insertions(+), 15 deletions(-)
Index: 2.6.26-rc2-mm1/tests/test_kprobes.c
===================================================================
--- 2.6.26-rc2-mm1.orig/tests/test_kprobes.c
+++ 2.6.26-rc2-mm1/tests/test_kprobes.c
@@ -22,21 +22,10 @@
static u32 rand1, preh_val, posth_val, jph_val;
static int errors, handler_errors, num_tests;
+static u32 (*target)(u32 value);
static noinline u32 kprobe_target(u32 value)
{
- /*
- * gcc ignores noinline on some architectures unless we stuff
- * sufficient lard into the function. The get_kprobe() here is
- * just for that.
- *
- * NOTE: We aren't concerned about the correctness of get_kprobe()
- * here; hence, this call is neither under !preempt nor with the
- * kprobe_mutex held. This is fine(tm)
- */
- if (get_kprobe((void *)0xdeadbeef))
- printk(KERN_INFO "Kprobe smoke test: probe on 0xdeadbeef!\n");
-
return (value / div_factor);
}
@@ -74,7 +63,7 @@ static int test_kprobe(void)
return ret;
}
- ret = kprobe_target(rand1);
+ ret = target(rand1);
unregister_kprobe(&kp);
if (preh_val == 0) {
@@ -121,7 +110,7 @@ static int test_jprobe(void)
return ret;
}
- ret = kprobe_target(rand1);
+ ret = target(rand1);
unregister_jprobe(&jp);
if (jph_val == 0) {
printk(KERN_ERR "Kprobe smoke test failed: "
@@ -177,7 +166,7 @@ static int test_kretprobe(void)
return ret;
}
- ret = kprobe_target(rand1);
+ ret = target(rand1);
unregister_kretprobe(&rp);
if (krph_val != rand1) {
printk(KERN_ERR "Kprobe smoke test failed: "
@@ -193,6 +182,8 @@ int init_test_probes(void)
{
int ret;
+ target = kprobe_target;
+
do {
rand1 = random32();
} while (rand1 <= div_factor);
--
Masami Hiramatsu
Software Engineer
Hitachi Computer Products (America) Inc.
Software Solutions Division
e-mail: [email protected]
On Fri, Jun 06, 2008 at 10:08:08AM -0400, Masami Hiramatsu wrote:
> Call kprobe_target indirectly. This prevents gcc to unroll
> a noinline function in caller function.
>
> Signed-off-by: Masami Hiramatsu <[email protected]>
Acked-by: Ananth N Mavinakayanahalli <[email protected]>