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Commit c5d343b6 authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Steven Rostedt (VMware)
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tracing: probeevent: Fix to support minus offset from symbol 

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 2fba0c88 ("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: 2fba0c88 ("tracing/kprobes: Fix probe offset to be unsigned")
Acked-by: default avatarNamhyung Kim <namhyung@kernel.org>
Signed-off-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
parent 661e50bc

kernel/trace/trace_kprobe.c

+2 −2
Original line number Diff line number Diff line
@@ -659,7 +659,7 @@ static int create_trace_kprobe(int argc, char **argv) 
	char *symbol = NULL, *event = NULL, *group = NULL;

	int maxactive = 0;

	char *arg;

	unsigned long offset = 0;

	long offset = 0;

	void *addr = NULL;

	char buf[MAX_EVENT_NAME_LEN];
@@ -747,7 +747,7 @@ static int create_trace_kprobe(int argc, char **argv) 
		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;

		}

kernel/trace/trace_probe.c

+3 −5
Original line number Diff line number Diff line
@@ -320,7 +320,7 @@ static fetch_func_t get_fetch_size_function(const struct fetch_type *type, 
}



/* 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;
@@ -328,13 +328,11 @@ int traceprobe_split_symbol_offset(char *symbol, unsigned long *offset) 
	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;

kernel/trace/trace_probe.h

+1 −1
Original line number Diff line number Diff line
@@ -365,7 +365,7 @@ extern int traceprobe_conflict_field_name(const char *name, 
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);



/* Sum up total data length for dynamic arraies (strings) */

static nokprobe_inline int