Patch "tracing: probeevent: Fix to support minus offset from symbol" has been added to the 3.18-stable tree

Patch "tracing: probeevent: Fix to support minus offset from symbol" has been added to the 3.18-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    tracing: probeevent: Fix to support minus offset from symbol

to the 3.18-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     tracing-probeevent-fix-to-support-minus-offset-from-symbol.patch
and it can be found in the queue-3.18 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From c5d343b6b7badd1f5fe0873eff2e8d63a193e732 Mon Sep 17 00:00:00 2001
From: Masami Hiramatsu <mhiramat@kernel.org>
Date: Sat, 17 Mar 2018 21:38:10 +0900
Subject: tracing: probeevent: Fix to support minus offset from symbol

From: Masami Hiramatsu <mhiramat@kernel.org>

commit c5d343b6b7badd1f5fe0873eff2e8d63a193e732 upstream.

In Documentation/trace/kprobetrace.txt, it says

 @SYM[+|-offs] : Fetch memory at SYM +|- offs (SYM should be a data symbol)

However, the parser doesn't parse minus offset correctly, since
commit 2fba0c8867af ("tracing/kprobes: Fix probe offset to be
unsigned") drops minus ("-") offset support for kprobe probe
address usage.

This fixes the traceprobe_split_symbol_offset() to parse minus
offset again with checking the offset range, and add a minus
offset check in kprobe probe address usage.

Link: http://lkml.kernel.org/r/152129028983.31874.13419301530285775521.stgit@devbox

Cc: Ingo Molnar <mingo@redhat.com>
Cc: Tom Zanussi <tom.zanussi@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Cc: stable@vger.kernel.org
Fixes: 2fba0c8867af ("tracing/kprobes: Fix probe offset to be unsigned")
Acked-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 kernel/trace/trace_kprobe.c |    4 ++--
 kernel/trace/trace_probe.c  |    8 +++-----
 kernel/trace/trace_probe.h  |    2 +-
 3 files changed, 6 insertions(+), 8 deletions(-)

--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -611,7 +611,7 @@ static int create_trace_kprobe(int argc,
 	bool is_return = false, is_delete = false;
 	char *symbol = NULL, *event = NULL, *group = NULL;
 	char *arg;
-	unsigned long offset = 0;
+	long offset = 0;
 	void *addr = NULL;
 	char buf[MAX_EVENT_NAME_LEN];
 
@@ -679,7 +679,7 @@ static int create_trace_kprobe(int argc,
 		symbol = argv[1];
 		/* TODO: support .init module functions */
 		ret = traceprobe_split_symbol_offset(symbol, &offset);
-		if (ret) {
+		if (ret || offset < 0 || offset > UINT_MAX) {
 			pr_info("Failed to parse either an address or a symbol.\n");
 			return ret;
 		}
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -291,7 +291,7 @@ static fetch_func_t get_fetch_size_funct
 }
 
 /* Split symbol and offset. */
-int traceprobe_split_symbol_offset(char *symbol, unsigned long *offset)
+int traceprobe_split_symbol_offset(char *symbol, long *offset)
 {
 	char *tmp;
 	int ret;
@@ -299,13 +299,11 @@ int traceprobe_split_symbol_offset(char
 	if (!offset)
 		return -EINVAL;
 
-	tmp = strchr(symbol, '+');
+	tmp = strpbrk(symbol, "+-");
 	if (tmp) {
-		/* skip sign because kstrtoul doesn't accept '+' */
-		ret = kstrtoul(tmp + 1, 0, offset);
+		ret = kstrtol(tmp, 0, offset);
 		if (ret)
 			return ret;
-
 		*tmp = '\0';
 	} else
 		*offset = 0;
--- a/kernel/trace/trace_probe.h
+++ b/kernel/trace/trace_probe.h
@@ -341,7 +341,7 @@ extern int traceprobe_conflict_field_nam
 extern void traceprobe_update_arg(struct probe_arg *arg);
 extern void traceprobe_free_probe_arg(struct probe_arg *arg);
 
-extern int traceprobe_split_symbol_offset(char *symbol, unsigned long *offset);
+extern int traceprobe_split_symbol_offset(char *symbol, long *offset);
 
 extern ssize_t traceprobe_probes_write(struct file *file,
 		const char __user *buffer, size_t count, loff_t *ppos,


Patches currently in stable-queue which might be from mhiramat@kernel.org are

queue-3.18/tracing-probeevent-fix-to-support-minus-offset-from-symbol.patch