From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from fanzine2.igalia.com (fanzine2.igalia.com [213.97.179.56]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0221653ECE9; Thu, 10 Sep 2026 16:50:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.97.179.56 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789059011; cv=none; b=RtOAISAYBb9/gUvyf0VpSkPh+MzVhJpAlWA3i6qevdaeptN5zoIqHRkC82NpH2mulIwZwxODCsP1rGRLDPAJlyaPOCel7N9GRo/2+Zh625z+fDfzyeYGAdqD23xGmtrJMpC4NMKqdaAkusPa3Lx2DzJdVSQ4W9AB8d6vbQ1LBjw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789059011; c=relaxed/simple; bh=ZobS2slsYgymP728EIsS1ZZzI/jDqEeK66f+TXlhRLQ=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=BmoxuR/l2deJbXkIN+z/32Zw/BWWaaENGHfspAS9VG0/T06XvJU8l3D+yQIYJFfBUQcW1zEs8UnW5goU95N3y7cqwL/agb88f20jqdGVGrf9HEDZNUI4HpL+yG98vi98AbWAckUaiiCLBHrGA3vrP95mabo7aH0ujPVf3fIoqys= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=igalia.com; spf=pass smtp.mailfrom=igalia.com; dkim=pass (2048-bit key) header.d=igalia.com header.i=@igalia.com header.b=XgKzfBTS; arc=none smtp.client-ip=213.97.179.56 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=igalia.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=igalia.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=igalia.com header.i=@igalia.com header.b="XgKzfBTS" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Cc:To:Message-Id:Content-Transfer-Encoding:Content-Type: MIME-Version:Subject:Date:From:From:Reply-To; bh=yEhMQLJIbP2So5XydAfHqKEdD7p0FcLEoTOB/mDNo2A=; b=XgKzfBTStCdsvTd4feuEEWqHBK c/YwChzbakcux2jWKS3mVcP+hlWrxBcSNl/EVcm00WoyINZpyl/SeI4nEuyx5DsmOucg1tMizMSGb LBeMHFiIOYEr2CiZzoZ7PzWHVf5oPqHZl0aOFd57yS85eZnXBtuatz2Nfp8hWrat3q6gWSDANou5I I7jg8gh6x+fMNGt/JCcDsE0v2O9PqD6qzkcQbGVpGMw6vs7e4BOC/Rzln9WoQnu6rRaCfgsTFp0rB L4l6ALJSYgBKN8NlGgKV2scyyU7lyMVA9T7XGnOFCeGJFMGh1OR/J2GGuk17HZnzW6vfSddk0a49r DdETPr0w==; Received: from [177.172.123.122] (helo=[192.168.15.100]) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim) id 1x4hyO-000GV1-5R; Thu, 10 Sep 2026 18:50:04 +0200 From: =?utf-8?q?Andr=C3=A9_Almeida?= Date: Thu, 10 Sep 2026 13:49:28 -0300 Subject: [PATCH v6 6/6] selftests: prctl: Add test for long thread names Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Message-Id: <20260910-tonyk-long_name-v6-6-d70afbf194c5@igalia.com> References: <20260910-tonyk-long_name-v6-0-d70afbf194c5@igalia.com> In-Reply-To: <20260910-tonyk-long_name-v6-0-d70afbf194c5@igalia.com> To: Peter Zijlstra , Juri Lelli , Vincent Guittot , Steven Rostedt , Christian Brauner , Kees Cook , Shuah Khan , willy@infradead.org, mathieu.desnoyers@efficios.com, David Laight , Linus Torvalds , akpm@linux-foundation.org, Yafang Shao , andrii.nakryiko@gmail.com, arnaldo.melo@gmail.com, Petr Mladek Cc: linux-kernel@vger.kernel.org, kernel-dev@igalia.com, linux-mm@kvack.org, linux-api@vger.kernel.org, linux-trace-kernel@vger.kernel.org, =?utf-8?q?Andr=C3=A9_Almeida?= X-Mailer: b4 0.15.2 Add tests for the new interface to set and get long thread names. The kernel should accept the LONG_NAME and returning it accordingly. For the old PR_GET_NAME interface, the kernel should truncate the name up to 16 chars. /proc//comm should return the same string ad PR_GET_NAME. While here, fix the check_is_name_correct() logic. It currently returns 1 for success, or a negative number for error. EXPECT_TRUE() evaluates any non-zero value as true, so the error will be evaluated as a success. Make the logic more robust and straightforward by returning the results of strcmp() and expecting zero as success. Signed-off-by: André Almeida --- Changes in v5: - fix check_is_name_correct() return logic --- tools/testing/selftests/prctl/set-process-name.c | 53 +++++++++++++++++++++--- 1 file changed, 48 insertions(+), 5 deletions(-) diff --git a/tools/testing/selftests/prctl/set-process-name.c b/tools/testing/selftests/prctl/set-process-name.c index 3f7b146d36df..27a0dbbce4db 100644 --- a/tools/testing/selftests/prctl/set-process-name.c +++ b/tools/testing/selftests/prctl/set-process-name.c @@ -9,9 +9,17 @@ #include "kselftest_harness.h" +#ifndef PR_SET_EXT_NAME +# define PR_SET_EXT_NAME 17 +# define PR_GET_EXT_NAME 18 +#endif + #define CHANGE_NAME "changename" +#define LONG_NAME "change_to_very_long_extended_name" +#define LONG_NAME_CAP "change_to_very_" #define EMPTY_NAME "" #define TASK_COMM_LEN 16 +#define TASK_COMM_EXT_LEN 64 #define MAX_PATH_LEN 50 int set_name(char *name) @@ -25,6 +33,20 @@ int set_name(char *name) return res; } +int set_ext_name(char *name) +{ + int res; + + res = prctl(PR_SET_EXT_NAME, name, NULL, NULL, NULL); + + if (res < 0) + return -errno; + return res; +} + +/* + * Return 0 if strings match + */ int check_is_name_correct(char *check_name) { char name[TASK_COMM_LEN]; @@ -35,7 +57,23 @@ int check_is_name_correct(char *check_name) if (res < 0) return -errno; - return !strcmp(name, check_name); + return strcmp(name, check_name); +} + +/* + * Return 0 if strings match + */ +int check_is_ext_name_correct(char *check_name) +{ + char name[TASK_COMM_EXT_LEN]; + int res; + + res = prctl(PR_GET_EXT_NAME, name, NULL, NULL, NULL); + + if (res < 0) + return -errno; + + return strcmp(name, check_name); } int check_null_pointer(char *check_name) @@ -56,8 +94,8 @@ int check_name(void) pid = getpid(); FILE *fptr = NULL; char path[MAX_PATH_LEN] = {}; - char name[TASK_COMM_LEN] = {}; - char output[TASK_COMM_LEN] = {}; + char name[TASK_COMM_EXT_LEN] = {}; + char output[TASK_COMM_EXT_LEN] = {}; int j; j = snprintf(path, MAX_PATH_LEN, "/proc/self/task/%d/comm", pid); @@ -80,10 +118,15 @@ int check_name(void) TEST(rename_process) { EXPECT_GE(set_name(CHANGE_NAME), 0); - EXPECT_TRUE(check_is_name_correct(CHANGE_NAME)); + EXPECT_FALSE(check_is_name_correct(CHANGE_NAME)); + + EXPECT_GE(set_ext_name(LONG_NAME), 0); + EXPECT_FALSE(check_is_ext_name_correct(LONG_NAME)); + EXPECT_FALSE(check_is_name_correct(LONG_NAME_CAP)); + EXPECT_TRUE(check_name()); EXPECT_GE(set_name(EMPTY_NAME), 0); - EXPECT_TRUE(check_is_name_correct(EMPTY_NAME)); + EXPECT_FALSE(check_is_name_correct(EMPTY_NAME)); EXPECT_GE(set_name(CHANGE_NAME), 0); EXPECT_LT(check_null_pointer(CHANGE_NAME), 0); -- 2.55.0