[PATCH 4.9 37/66] perf jevents: Fix getting maximum number of fds

Greg Kroah-Hartman
2021-05-31T13:30:08Z

From: Felix Fietkau <nbd@nbd.name>

commit 75ea44e356b5de8c817f821c9dd68ae329e82add upstream.

On some hosts, rlim.rlim_max can be returned as RLIM_INFINITY.
By casting it to int, it is interpreted as -1, which will cause get_maxfds
to return 0, causing "Invalid argument" errors in nftw() calls.
Fix this by casting the second argument of min() to rlim_t instead.

Fixes: 80eeb67fe577 ("perf jevents: Program to convert JSON file")
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Link: http://lore.kernel.org/lkml/20210525160758.97829-1-nbd@nbd.name
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
tools/perf/pmu-events/jevents.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/tools/perf/pmu-events/jevents.c
+++ b/tools/perf/pmu-events/jevents.c
@@ -603,7 +603,7 @@ static int get_maxfds(void)
struct rlimit rlim;

if (getrlimit(RLIMIT_NOFILE, &rlim) == 0)
- return min((int)rlim.rlim_max / 2, 512);
+ return min(rlim.rlim_max / 2, (rlim_t)512);

return 512;
}