On 2015/3/13 17:46, Namhyung Kim wrote: > On Fri, Mar 13, 2015 at 08:41:32AM +0000, Wang Nan wrote: >> Without this patch, perf report cause segfault if pass "" as '-t': >> >> $ perf report -t "" >> >> # To display the perf.data header info, please use >> --header/--header-only options. >> # >> # Samples: 37 of event 'syscalls:sys_enter_write' >> # Event count (approx.): 37 >> # >> # Children SelfCommand Shared Object Symbol >> Segmentation fault >> >> This patch avoid the segfault by checking empty string for >> 'symbol_conf.field_sep'. > > What about resetting it to NULL if empty string was given? >
In fact I'm not very clear why we need such 'symbol_conf.field_sep', so I'm not sure whether '-t ""' is totally meanless or not. -t option replaces a group of character with '.' and appends them after a field. With -t 'abc' I get something like: # # OverheadabcCommand abcShared Object abcSymbol 100.00%abcb.beltr.ceabc[kernel.k.llsyms]abc[k] 0xffffffff810118f0 ... Hard to read... I read docs and your commit messages, but still not understand the option. Could you please explain the goal and usage of that option again? Thank you. > Thanks, > Namhyung > > >> >> Signed-off-by: Wang Nan <wangn...@huawei.com> >> --- >> tools/perf/util/sort.c | 3 ++- >> 1 file changed, 2 insertions(+), 1 deletion(-) >> >> diff --git a/tools/perf/util/sort.c b/tools/perf/util/sort.c >> index 4593f36..7f563a0 100644 >> --- a/tools/perf/util/sort.c >> +++ b/tools/perf/util/sort.c >> @@ -31,7 +31,8 @@ static int repsep_snprintf(char *bf, size_t size, const >> char *fmt, ...) >> >> va_start(ap, fmt); >> n = vsnprintf(bf, size, fmt, ap); >> - if (symbol_conf.field_sep && n > 0) { >> + if (symbol_conf.field_sep && n > 0 && >> + (symbol_conf.field_sep[0] != '\0')) { >> char *sep = bf; >> >> while (1) { >> -- >> 1.8.3.4 >> -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/