From aae36332eb42d286f27fe09883ee71b5bc0835cc Mon Sep 17 00:00:00 2001 From: Li Wang Date: Wed, 18 Sep 2024 15:32:57 +0800 Subject: [PATCH] lib: handle ENOENT errors when processes exit during PID scanning There is a race window between readdir() and fopen() in line 125~131 of lib function get_used_pids. A process could terminate after its directory entry is read but before its status file is opened. When fopen() is called, the status file may no longer exist, resulting in an error like: tag=msgstress01__with_dmesg_entry stime=1723563200 ... tst_test.c:1617: TINFO: Timeout per run is 0h 03m 30s tst_pid.c:128: TBROK: Failed to open FILE '/proc/73429/status' for reading: ENOENT (2) To resolve this, the file_lines_scanf() function is modified to handle ENOENT errors gracefully when strict mode is not enabled. If fopen() fails due to ENOENT, the function now returns 1 to skip the missing file instead of treating it as a critical error. Reported-by: Paul Bunyan Analysed-by: Charles Mirabile Signed-off-by: Li Wang Reviewed-by: Cyril Hrubis --- lib/safe_file_ops.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/lib/safe_file_ops.c b/lib/safe_file_ops.c index 63ae2dbbe08..4cf0d6e0fbf 100644 --- a/lib/safe_file_ops.c +++ b/lib/safe_file_ops.c @@ -182,6 +182,9 @@ int file_lines_scanf(const char *file, const int lineno, fp = fopen(path, "r"); if (fp == NULL) { + if (strict == 0 && errno == ENOENT) + return 1; + tst_brkm_(file, lineno, TBROK | TERRNO, cleanup_fn, "Failed to open FILE '%s' for reading", path); return 1;