From 35b6f55aa9ba65141f2def0997e23aab13715d3f Mon Sep 17 00:00:00 2001 From: "Naveen N. Rao" Date: Wed, 22 Feb 2017 19:23:39 +0530 Subject: trace/kprobes: Allow return probes with offsets and absolute addresses Since the kernel includes many non-global functions with same names, we will need to use offsets from other symbols (typically _text/_stext) or absolute addresses to place return probes on specific functions. Also, the core register_kretprobe() API never forbid use of offsets or absolute addresses with kretprobes. Allow its use with the trace infrastructure. To distinguish kernels that support this, update ftrace README to explicitly call this out. Signed-off-by: Naveen N. Rao Acked-by: Masami Hiramatsu Cc: Ananth N Mavinakayanahalli Cc: Michael Ellerman Cc: Steven Rostedt Cc: linuxppc-dev@lists.ozlabs.org Link: http://lkml.kernel.org/r/183e7ce2921a08c9c755ee9a5da3134febc6695b.1487770934.git.naveen.n.rao@linux.vnet.ibm.com Signed-off-by: Arnaldo Carvalho de Melo --- kernel/trace/trace_kprobe.c | 8 -------- 1 file changed, 8 deletions(-) (limited to 'kernel/trace/trace_kprobe.c') diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index eadd96ef772f..18775ef182f8 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -680,10 +680,6 @@ static int create_trace_kprobe(int argc, char **argv) return -EINVAL; } if (isdigit(argv[1][0])) { - if (is_return) { - pr_info("Return probe point must be a symbol.\n"); - return -EINVAL; - } /* an address specified */ ret = kstrtoul(&argv[1][0], 0, (unsigned long *)&addr); if (ret) { @@ -699,10 +695,6 @@ static int create_trace_kprobe(int argc, char **argv) pr_info("Failed to parse symbol.\n"); return ret; } - if (offset && is_return) { - pr_info("Return probe must be used without offset.\n"); - return -EINVAL; - } } argc -= 2; argv += 2; -- cgit v1.2.3 From d0e02579c282ccf34c79818045ec2d2934b56c19 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Mon, 27 Feb 2017 11:52:04 -0500 Subject: trace/kprobes: Add back warning about offset in return probes Let's not remove the warning about offsets and return probes when the offset is invalid. Signed-off-by: Steven Rostedt Acked-by: Masami Hiramatsu Acked-by: Naveen N. Rao Cc: Ananth N Mavinakayanahalli Cc: Michael Ellerman Cc: linuxppc-dev@lists.ozlabs.org Link: http://lkml.kernel.org/r/20170227115204.00f92846@gandalf.local.home Signed-off-by: Arnaldo Carvalho de Melo --- kernel/trace/trace_kprobe.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'kernel/trace/trace_kprobe.c') diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index 18775ef182f8..2b7d0dd938ba 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -695,6 +695,11 @@ static int create_trace_kprobe(int argc, char **argv) pr_info("Failed to parse symbol.\n"); return ret; } + if (offset && is_return && + !arch_function_offset_within_entry(offset)) { + pr_info("Given offset is not valid for return probe.\n"); + return -EINVAL; + } } argc -= 2; argv += 2; -- cgit v1.2.3