From 8e1144050e49dd4ef19c117dc5626f212cfe73cf Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Tue, 6 Jan 2009 14:41:47 -0800 Subject: [PATCH] kprobes: indirectly call kprobe_target Call kprobe_target indirectly. This prevents gcc to unroll a noinline function in caller function. I ported patches which had been discussed on http://sources.redhat.com/bugzilla/show_bug.cgi?id=3542 Signed-off-by: Masami Hiramatsu Acked-by: Ananth N Mavinakayanahalli Cc: Jim Keniston Cc: David Miller Cc: Anil S Keshavamurthy Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/test_kprobes.c | 21 ++++++--------------- 1 file changed, 6 insertions(+), 15 deletions(-) diff --git a/kernel/test_kprobes.c b/kernel/test_kprobes.c index 06b6395b45b2..9c0127ead6ab 100644 --- a/kernel/test_kprobes.c +++ b/kernel/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); -- 2.20.1