selftests/coredump: ignore ENOSPC errors

If we crash multiple processes at the same time we may run out of space.
Just ignore those errors. They're not actually all that relevant for the
test.

Link: https://patch.msgid.link/20251028-work-coredump-signal-v1-20-ca449b7b7aa0@kernel.org
Reviewed-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>

Author: brauner

tools/testing/selftests/coredump/coredump_socket_protocol_test.c

@@ -184,6 +184,8 @@ TEST_F(coredump, socket_request_kernel)
 
 			bytes_write = write(fd_core_file, buffer, bytes_read);
 			if (bytes_read != bytes_write) {
+				if (bytes_write < 0 && errno == ENOSPC)
+					continue;
 				fprintf(stderr, "socket_request_kernel: write to core file failed (read=%zd, write=%zd): %m\n",
 					bytes_read, bytes_write);
 				goto out;
@@ -1366,6 +1368,8 @@ TEST_F_TIMEOUT(coredump, socket_multiple_crashing_coredumps, 500)
 
 				bytes_write = write(fd_core_file, buffer, bytes_read);
 				if (bytes_read != bytes_write) {
+					if (bytes_write < 0 && errno == ENOSPC)
+						continue;
 					fprintf(stderr, "write failed for fd %d: %m\n", fd_core_file);
 					goto out;
 				}

tools/testing/selftests/coredump/coredump_socket_test.c

@@ -158,8 +158,9 @@ TEST_F(coredump, socket)
 
 			bytes_write = write(fd_core_file, buffer, bytes_read);
 			if (bytes_read != bytes_write) {
-				fprintf(stderr, "socket test: write to core file failed (read=%zd, write=%zd): %m\n",
-					bytes_read, bytes_write);
+				if (bytes_write < 0 && errno == ENOSPC)
+					continue;
+				fprintf(stderr, "socket test: write to core file failed (read=%zd, write=%zd): %m\n", bytes_read, bytes_write);
 				goto out;
 			}
 		}

tools/testing/selftests/coredump/coredump_test_helpers.c

@@ -357,6 +357,8 @@ void process_coredump_worker(int fd_coredump, int fd_peer_pidfd, int fd_core_fil
 					goto done;
 				ssize_t bytes_write = write(fd_core_file, buffer, bytes_read);
 				if (bytes_write != bytes_read) {
+					if (bytes_write < 0 && errno == ENOSPC)
+						continue;
 					fprintf(stderr, "Worker: write() failed (read=%zd, write=%zd): %m\n",
 						bytes_read, bytes_write);
 					goto out;