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Sat, 26 Jul 2025 02:18:51 -0700 (PDT) Received: from eric-wcnlab.tail151456.ts.net ([2001:288:7001:1099:3fec:e266:6de8:8b66]) by smtp.gmail.com with ESMTPSA id 41be03b00d2f7-b3f7f569d24sm1295025a12.1.2025.07.26.02.18.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 26 Jul 2025 02:18:51 -0700 (PDT) From: Cheng-Yang Chou To: williams@redhat.com, jkacur@redhat.com Cc: linux-rt-users@vger.kernel.org, jserv@ccns.ncku.edu.tw, yphbchou0911@gmail.com Subject: [PATCH v2 6/8] deadline_test.c: Check return values of write() and ftruncate() Date: Sat, 26 Jul 2025 17:18:35 +0800 Message-ID: <20250726091837.493915-7-yphbchou0911@gmail.com> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250726091837.493915-1-yphbchou0911@gmail.com> References: <20250726091837.493915-1-yphbchou0911@gmail.com> Precedence: bulk X-Mailing-List: linux-rt-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Add error handling for write() to tracefs, cpuset control files, and system() calls to avoid ignoring errors. Signed-off-by: Cheng-Yang Chou --- src/sched_deadline/deadline_test.c | 37 ++++++++++++++++++++++++++---- 1 file changed, 32 insertions(+), 5 deletions(-) diff --git a/src/sched_deadline/deadline_test.c b/src/sched_deadline/deadline_test.c index ca2da47..a74d514 100644 --- a/src/sched_deadline/deadline_test.c +++ b/src/sched_deadline/deadline_test.c @@ -325,6 +325,7 @@ static void ftrace_write(char *buf, const char *fmt, ...) { va_list ap; int n; + int ret; if (mark_fd < 0) return; @@ -333,7 +334,9 @@ static void ftrace_write(char *buf, const char *fmt, ...) n = my_vsprintf(buf, BUFSIZ, fmt, ap); va_end(ap); - write(mark_fd, buf, n); + ret = write(mark_fd, buf, n); + if (ret < 0) + perror("ftrace write failed"); } /** @@ -626,6 +629,10 @@ static int mount_cpuset(void) if (fd < 0) return fd; ret = write(fd, "0", 2); + if (ret < 0) { + close(fd); + return ret; + } close(fd); return 0; @@ -875,7 +882,19 @@ static void destroy_cpuset(const char *name, int print) sprintf(buf, "%d", pid); if (print) printf("Moving %d out of %s\n", pid, name); - write(fd, buf, strlen(buf)); + ret = write(fd, buf, strlen(buf)); + if (ret < 0 && errno == ENOSPC) { + /* + * If we get ENOSPC, then we have a problem, as it + * means that the cpuset is full, and we cannot move + * the tasks out of it. + */ + fclose(fp); + close(fd); + fprintf(stderr, "Failed to move %d out of %s\n", pid, name); + perror("write"); + return; + } } fclose(fp); close(fd); @@ -910,16 +929,21 @@ static void destroy_cpuset(const char *name, int print) static void teardown(void) { int fd; + int ret; fd = open_cpuset(CPUSET_PATH, "cpuset.cpu_exclusive"); if (fd >= 0) { - write(fd, "0", 2); + ret = write(fd, "0", 2); + if (ret < 0) + perror("cpuset.cpu_exclusive"); close(fd); } fd = open_cpuset(CPUSET_PATH, "cpuset.sched_load_balance"); if (fd >= 0) { - write(fd, "1", 2); + ret = write(fd, "1", 2); + if (ret < 0) + perror("cpuset.sched_load_balance"); close(fd); } @@ -1790,6 +1814,7 @@ int main(int argc, char **argv) int rt_task = 0; int i; int c; + int ret; cpu_count = sysconf(_SC_NPROCESSORS_CONF); if (cpu_count < 1) { @@ -2041,7 +2066,9 @@ int main(int argc, char **argv) exit(-1); } - system("cat /sys/fs/cgroup/cpuset/my_cpuset/tasks"); + ret = system("cat /sys/fs/cgroup/cpuset/my_cpuset/tasks"); + if (ret < 0) + perror("system call failed"); } pthread_barrier_wait(&barrier); -- 2.48.1