From nobody Fri Jun 12 18:35:46 2026 Received: from mailgw.kylinos.cn (mailgw.kylinos.cn [124.126.103.232]) (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 99AB23E715F; Wed, 13 May 2026 09:55:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=124.126.103.232 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778666162; cv=none; b=bgIWwDZRyyebrbbppyoGvR8RvFLH2AlXQG8zPiS4w3OaOrkpq7B628+IN9yefmuJO6+44sqBfk/cxao5GjfjeoNPr3hqbTO2yH89zzN2bsHzOPVDk9CmLcpCclb1rUdxtBlMWHOVQHTObdEOiilOF3v2pAwezqyGM3ZA5EJOMmY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778666162; c=relaxed/simple; bh=JTYs9I+WX+ggsipr515TXTzepLL+RN7A12BxK8SVK1o=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=IrXI9UEVDEM8vL8nozGai+XGrGBKtYFfq5KS9qv9/PsUS5JZWyKKB8bNLMpUdKM2gCPZzcXWHZWmVFPMOrN5IoHX3h6RANAa/I1WlInGOL2rxl1sPmdAU0yY93O5wMt119utYCnyExmKEcZsah1dtQ78emvLlkosHJS/yvYZJ+8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=kylinos.cn; spf=pass smtp.mailfrom=kylinos.cn; arc=none smtp.client-ip=124.126.103.232 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=kylinos.cn Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=kylinos.cn X-UUID: ed78ad764eb111f1aa26b74ffac11d73-20260513 X-CTIC-Tags: HR_CC_COUNT, HR_CC_DOMAIN_COUNT, HR_CC_NAME, HR_CC_NO_NAME, HR_CTE_8B HR_CTT_MISS, HR_DATE_H, HR_DATE_WKD, HR_DATE_ZONE, HR_FROM_NAME HR_SJ_DIGIT_LEN, HR_SJ_LANG, HR_SJ_LEN, HR_SJ_LETTER, HR_SJ_NOR_SYM HR_SJ_PHRASE, HR_SJ_PHRASE_LEN, HR_SJ_WS, HR_TO_COUNT, HR_TO_DOMAIN_COUNT HR_TO_NO_NAME, IP_TRUSTED, SRC_TRUSTED, DN_TRUSTED, SA_TRUSTED SA_EXISTED, SN_TRUSTED, SN_EXISTED, SPF_NOPASS, DKIM_NOPASS DMARC_NOPASS, CIE_GOOD, CIE_GOOD_SPF, GTI_FG_BS, GTI_RG_INFO GTI_C_BU, AMN_GOOD, ABX_MISS_RDNS X-CID-P-RULE: Release_Ham X-CID-O-INFO: VERSION:1.3.12,REQID:ba50d5f9-2f04-4cad-8789-fb21824c9da1,IP:10, URL:0,TC:0,Content:-5,EDM:0,RT:0,SF:-5,FILE:0,BULK:0,RULE:Release_Ham,ACTI ON:release,TS:0 X-CID-INFO: VERSION:1.3.12,REQID:ba50d5f9-2f04-4cad-8789-fb21824c9da1,IP:10,UR L:0,TC:0,Content:-5,EDM:0,RT:0,SF:-5,FILE:0,BULK:0,RULE:Release_Ham,ACTION :release,TS:0 X-CID-META: VersionHash:e7bac3a,CLOUDID:381afc9b0b0b2ed385ed99c719338255,BulkI D:260513175554GO8UB3XL,BulkQuantity:0,Recheck:0,SF:17|19|38|66|78|102|127| 850|898,TC:nil,Content:0|15|50,EDM:-3,IP:-2,URL:0,File:nil,RT:nil,Bulk:nil ,QS:nil,BEC:nil,COL:0,OSI:0,OSA:0,AV:0,LES:1,SPR:NO,DKR:0,DKP:0,BRR:0,BRE: 0,ARC:0 X-CID-BVR: 2,SSN|SDN X-CID-BAS: 2,SSN|SDN,0,_ X-CID-FACTOR: TF_CID_SPAM_SNR,TF_CID_SPAM_FAS,TF_CID_SPAM_FSD X-CID-RHF: D41D8CD98F00B204E9800998ECF8427E X-UUID: ed78ad764eb111f1aa26b74ffac11d73-20260513 X-User: lihongfu@kylinos.cn Received: from localhost.localdomain [(223.70.159.239)] by mailgw.kylinos.cn (envelope-from ) (Generic MTA with TLSv1.3 TLS_AES_256_GCM_SHA384 256/256) with ESMTP id 928600640; Wed, 13 May 2026 17:55:52 +0800 From: Hongfu Li To: akpm@linux-foundation.org, david@kernel.org, ljs@kernel.org, liam@infradead.org, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, shuah@kernel.org Cc: linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, Hongfu Li , Dev Jain Subject: [PATCH v2] selftests/mm: Fix incorrect mmap() error handling with NULL instead of MAP_FAILED Date: Wed, 13 May 2026 17:56:09 +0800 Message-Id: <20260513095609.789935-1-lihongfu@kylinos.cn> X-Mailer: git-send-email 2.25.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" mmap() returns MAP_FAILED, which is defined as (void *)-1, on error, not NULL. Several selftests incorrectly check the return value of mmap() using !ptr or ptr =3D=3D NULL, which would erroneously treat MAP_FAILED as a valid pointer since MAP_FAILED is non-zero and non-NULL. This can lead to segfaults when mmap() actually fails under memory pressure. Signed-off-by: Hongfu Li Reviewed-by: Dev Jain --- v2: - Add missing mmap() return value checks in pkey_sighandler_tests.c and protection_keys.c --- tools/testing/selftests/mm/ksm_tests.c | 2 +- tools/testing/selftests/mm/madv_populate.c | 2 +- tools/testing/selftests/mm/pkey_sighandler_tests.c | 2 ++ tools/testing/selftests/mm/protection_keys.c | 1 + tools/testing/selftests/mm/soft-dirty.c | 4 ++-- tools/testing/selftests/mm/vm_util.c | 2 +- 6 files changed, 8 insertions(+), 5 deletions(-) diff --git a/tools/testing/selftests/mm/ksm_tests.c b/tools/testing/selftes= ts/mm/ksm_tests.c index a0b48b839d54..ed481f817282 100644 --- a/tools/testing/selftests/mm/ksm_tests.c +++ b/tools/testing/selftests/mm/ksm_tests.c @@ -174,7 +174,7 @@ static void *allocate_memory(void *ptr, int prot, int = mapping, char data, size_ { void *map_ptr =3D mmap(ptr, map_size, PROT_WRITE, mapping, -1, 0); =20 - if (!map_ptr) { + if (map_ptr =3D=3D MAP_FAILED) { perror("mmap"); return NULL; } diff --git a/tools/testing/selftests/mm/madv_populate.c b/tools/testing/sel= ftests/mm/madv_populate.c index 88050e0f829a..7fce5d0b622b 100644 --- a/tools/testing/selftests/mm/madv_populate.c +++ b/tools/testing/selftests/mm/madv_populate.c @@ -34,7 +34,7 @@ static void sense_support(void) =20 addr =3D mmap(0, pagesize, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, 0, 0); - if (!addr) + if (addr =3D=3D MAP_FAILED) ksft_exit_fail_msg("mmap failed\n"); =20 ret =3D madvise(addr, pagesize, MADV_POPULATE_READ); diff --git a/tools/testing/selftests/mm/pkey_sighandler_tests.c b/tools/tes= ting/selftests/mm/pkey_sighandler_tests.c index 302fef54049c..4637809192f9 100644 --- a/tools/testing/selftests/mm/pkey_sighandler_tests.c +++ b/tools/testing/selftests/mm/pkey_sighandler_tests.c @@ -317,6 +317,7 @@ static void test_sigsegv_handler_with_different_pkey_fo= r_stack(void) /* Set up alternate signal stack that will use the default MPK */ sigstack.ss_sp =3D mmap(0, STACK_SIZE, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + assert(sigstack.ss_sp !=3D MAP_FAILED); sigstack.ss_flags =3D 0; sigstack.ss_size =3D STACK_SIZE; =20 @@ -490,6 +491,7 @@ static void test_pkru_sigreturn(void) /* Set up alternate signal stack that will use the default MPK */ sigstack.ss_sp =3D mmap(0, STACK_SIZE, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + assert(sigstack.ss_sp !=3D MAP_FAILED); sigstack.ss_flags =3D 0; sigstack.ss_size =3D STACK_SIZE; =20 diff --git a/tools/testing/selftests/mm/protection_keys.c b/tools/testing/s= elftests/mm/protection_keys.c index 2085982dba69..580bf1668c71 100644 --- a/tools/testing/selftests/mm/protection_keys.c +++ b/tools/testing/selftests/mm/protection_keys.c @@ -1217,6 +1217,7 @@ static void arch_force_pkey_reg_init(void) * doing the XSAVE size enumeration dance. */ buf =3D mmap(NULL, 1*MB, PROT_READ|PROT_WRITE, MAP_ANONYMOUS|MAP_PRIVATE,= -1, 0); + pkey_assert(buf !=3D (void *)-1); =20 /* These __builtins require compiling with -mxsave */ =20 diff --git a/tools/testing/selftests/mm/soft-dirty.c b/tools/testing/selfte= sts/mm/soft-dirty.c index bcfcac99b436..67c26c265880 100644 --- a/tools/testing/selftests/mm/soft-dirty.c +++ b/tools/testing/selftests/mm/soft-dirty.c @@ -143,7 +143,7 @@ static void test_mprotect(int pagemap_fd, int pagesize,= bool anon) if (anon) { map =3D mmap(NULL, pagesize, PROT_READ|PROT_WRITE, MAP_ANONYMOUS|MAP_PRIVATE, -1, 0); - if (!map) + if (map =3D=3D MAP_FAILED) ksft_exit_fail_msg("anon mmap failed\n"); } else { test_fd =3D open(fname, O_RDWR | O_CREAT, 0664); @@ -155,7 +155,7 @@ static void test_mprotect(int pagemap_fd, int pagesize,= bool anon) ftruncate(test_fd, pagesize); map =3D mmap(NULL, pagesize, PROT_READ|PROT_WRITE, MAP_SHARED, test_fd, 0); - if (!map) + if (map =3D=3D MAP_FAILED) ksft_exit_fail_msg("file mmap failed\n"); } =20 diff --git a/tools/testing/selftests/mm/vm_util.c b/tools/testing/selftests= /mm/vm_util.c index db94564f4431..63aaa2d9ec0b 100644 --- a/tools/testing/selftests/mm/vm_util.c +++ b/tools/testing/selftests/mm/vm_util.c @@ -463,7 +463,7 @@ bool softdirty_supported(void) /* New mappings are expected to be marked with VM_SOFTDIRTY (sd). */ addr =3D mmap(0, pagesize, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, 0, 0); - if (!addr) + if (addr =3D=3D MAP_FAILED) ksft_exit_fail_msg("mmap failed\n"); =20 supported =3D check_vmflag(addr, "sd"); --=20 2.25.1