From nobody Sat Jul 25 16:20:10 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 53DD23B6BF2 for ; Thu, 16 Jul 2026 07:53:47 +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=1784188432; cv=none; b=SqmlDtgtjc1OezIVqzZncSgkcDWQfQQYYgbZXhSzbg69JKmIe/SF/FWjCSMe7mwm6nLwrgp8RPBL1Z1dP5TDTJGCL0I0MpgxpuYuQZAzML1imUOLluqalHWyqnZGwxFQxOhG1Iqn/Nd2hM7sD00YnSoLngByPmjJvDMktS0hZ4k= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784188432; c=relaxed/simple; bh=HPq5o/XGO1kBSoI+p4c5wjQef4FdhPotzYH68kw0T5U=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=VBU5qud/RBkrVw0IOAaW5GzuGoG2UGdj04P+ufViem5XPHzdng32D0YE2ChtxCkArjKmXGyHYcpcXcbrfaxYhJBg5eUGAecjdw+QLfF/0Odp1wFEDMkLXWG9xVKPCcuW7QxDnM/jYvPqRaQRZuN6XCGJSQpH+1jJ3yz4+Bsn5Rs= 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: 7721bcbe80eb11f1aa26b74ffac11d73-20260716 X-CID-P-RULE: Release_Ham X-CID-O-INFO: VERSION:1.3.12,REQID:590ff02d-05ea-403b-b9e2-15d0b1d08e55,IP:0,U RL:0,TC:0,Content:0,EDM:-20,RT:0,SF:0,FILE:0,BULK:0,RULE:Release_Ham,ACTIO N:release,TS:-20 X-CID-META: VersionHash:e7bac3a,CLOUDID:fb8aafd618545e3412dc1d3c6493e4ef,BulkI D:nil,BulkQuantity:0,Recheck:0,SF:102|850|865|898,TC:nil,Content:0|15|50,E DM:1,IP:nil,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 X-CID-RHF: D41D8CD98F00B204E9800998ECF8427E X-UUID: 7721bcbe80eb11f1aa26b74ffac11d73-20260716 X-User: xieyi@kylinos.cn Received: from localhost.localdomain [(10.44.16.150)] by mailgw.kylinos.cn (envelope-from ) (Generic MTA with TLSv1.3 TLS_AES_256_GCM_SHA384 256/256) with ESMTP id 1944482129; Thu, 16 Jul 2026 15:53:42 +0800 From: Yi Xie To: akpm@linux-foundation.org, ljs@kernel.org Cc: linux-kernel@vger.kernel.org, Yi Xie Subject: [PATCH v3] ipc/shm: check shm_lock() in do_shmat cleanup Date: Thu, 16 Jul 2026 15:53:30 +0800 Message-Id: <20260716075330.96378-1-xieyi@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" do_shmat() calls shm_lock() in the out_nattch branch and immediately dereferences it, however shm_lock() can return an error. Check for an error and handle it if there is one. Signed-off-by: Yi Xie Reviewed-by: Lorenzo Stoakes (ARM) --- ipc/shm.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/ipc/shm.c b/ipc/shm.c index b3e8a58e177d..d243137c4dbd 100644 --- a/ipc/shm.c +++ b/ipc/shm.c @@ -1677,12 +1677,16 @@ long do_shmat(int shmid, char __user *shmaddr, int = shmflg, out_nattch: down_write(&shm_ids(ns).rwsem); shp =3D shm_lock(ns, shmid); - shp->shm_nattch--; + if (IS_ERR(shp)) { + err =3D PTR_ERR(shp); + } else { + shp->shm_nattch--; =20 - if (shm_may_destroy(shp)) - shm_destroy(ns, shp); - else - shm_unlock(shp); + if (shm_may_destroy(shp)) + shm_destroy(ns, shp); + else + shm_unlock(shp); + } up_write(&shm_ids(ns).rwsem); return err; =20 --=20 2.25.1