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tracing: probeevent: Fix to support minus offset from symbol

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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 2fba0c8867 ("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: 2fba0c8867 ("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>
This commit is contained in:
Masami Hiramatsu 2018-03-17 21:38:10 +09:00 committed by Steven Rostedt (VMware)
parent 661e50bc85
commit c5d343b6b7
3 changed files with 6 additions and 8 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

4
kernel/trace/trace_kprobe.c
View file

@ -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;
}

8
kernel/trace/trace_probe.c
View file

@ -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;

2
kernel/trace/trace_probe.h
View file

@ -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