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authorMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>2012-09-05 23:31:25 +0900
committerSteven Rostedt <rostedt@goodmis.org>2012-09-13 22:52:11 -0400
commitc6aaf4d0bb86e2154ea31a33804cec300611255f (patch)
tree34f973a7ee081daa773b8d4cea9cffaf28bf018a /kernel
parent47d5a5f88b9d25d6464c9b60c28f391e84e3ed65 (diff)
kprobes/x86: Fix to support jprobes on ftrace-based kprobe
Fix kprobes/x86 to support jprobes on ftrace-based kprobes. Because of -mfentry support of ftrace, ftrace is now put on the beginning of function where jprobes are put. Originally ftrace-based kprobes doesn't support jprobe because it will change regs->ip and ftrace doesn't support changing IP and ftrace itself doesn't conflict jprobe. However, ftrace -mfentry support moves mcount call on the top of functions where jprobes are put. This means that jprobe always conflicts with ftrace-based kprobe and fails. This patch allows ftrace-based kprobes to support jprobes by allowing to modify regs->ip and kprobes breakpoint handler also allows to skip singlestepping because there is a ftrace call (not an original instruction). Link: http://lkml.kernel.org/r/20120905143125.10329.90836.stgit@localhost.localdomain Reported-by: Fengguang Wu <fengguang.wu@intel.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/kprobes.c3
1 files changed, 0 insertions, 3 deletions
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 35b4315d84f5..098f396aa409 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1418,9 +1418,6 @@ static __kprobes int check_kprobe_address_safe(struct kprobe *p,
/* Given address is not on the instruction boundary */
if ((unsigned long)p->addr != ftrace_addr)
return -EILSEQ;
- /* break_handler (jprobe) can not work with ftrace */
- if (p->break_handler)
- return -EINVAL;
p->flags |= KPROBE_FLAG_FTRACE;
#else /* !KPROBES_CAN_USE_FTRACE */
return -EINVAL;