From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnaldo Carvalho de Melo Subject: [PATCH 07/43] perf symbols: Using O_CLOEXEC in do_open Date: Tue, 23 Jan 2018 10:12:15 -0300 Message-ID: <20180123131251.28197-8-acme@kernel.org> References: <20180123131251.28197-1-acme@kernel.org> Return-path: In-Reply-To: <20180123131251.28197-1-acme@kernel.org> Sender: linux-kernel-owner@vger.kernel.org To: Ingo Molnar Cc: linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, Wang YanQing , Alexander Shishkin , Peter Zijlstra , Arnaldo Carvalho de Melo List-Id: linux-perf-users.vger.kernel.org From: Wang YanQing I've meet a strange behavior with these commands on my gentoo box: 1: perf kmem record 2: CTRL-C to stop 1 3: perf report 4: "Enter", "Enter", "Run scripts for all samples", "event_analyzing_sample". Then 'perf report' says: " No kallsyms or vmlinux with build-id xxxx was found /lib/modules/4.10.0+/build/vmlinux with build id xxxx not found, continuing without symbols ". It is strange because I am sure /lib/modules/4.10.0+/build/vmlinux is right for perf.data. After digging, I found out the reason is that "perf report" generates many open fds, then "script_browse" uses popen to run "perf script" which run out of open files. The gentoo box has a small default value for "max open files", 1024. Yes, "ulimit -n " with a bigger number could fix it, but I think that using O_CLOEXEC in do_open is a better way. Signed-off-by: Wang YanQing Acked-by: Jiri Olsa Cc: Alexander Shishkin Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20180115050448.GA20759@udknight [ Make sure O_CLOEXEC is available in old systems by adding a patch just before this one, to keep this bisectable in such systems ] Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/dso.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c index d5b6f7f5baff..36ef45b2e89d 100644 --- a/tools/perf/util/dso.c +++ b/tools/perf/util/dso.c @@ -446,7 +446,7 @@ static int do_open(char *name) char sbuf[STRERR_BUFSIZE]; do { - fd = open(name, O_RDONLY); + fd = open(name, O_RDONLY|O_CLOEXEC); if (fd >= 0) return fd; -- 2.14.3