From patchwork Tue Jun 10 19:05:29 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Viacheslav Dubeyko X-Patchwork-Id: 895219 Received: from mail-oi1-f171.google.com (mail-oi1-f171.google.com [209.85.167.171]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E3E7125FA03 for ; Tue, 10 Jun 2025 19:05:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.167.171 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749582350; cv=none; b=L717gr73QXDXoUVOfvtSUdRQeFFuJeKQBCNN/UP7qj+wi0Seh1Lgy7447IAHjZhwhXeHn+QywJUCIHfD/clQzCcov6Ap2sl7MSOkvFXN8427C6IZdtfT4M1cR6BmXGBS37LLMi/IgBZiAitVJdCWBJ14iCwP/qE71L6QSRjqFoA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749582350; c=relaxed/simple; bh=Tg699knSwAu7/S2bRyHGf0H8ipYDR18FoTJSAJIzyMQ=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=FCv72v75WoOFIjAWFEu9sFwG8PQg963mgT56rDcpFRWoRC71Db23CQM27XWFmvESXMYjzTMIiH0BFGOMpnFvJrU+0mSuAaFk4eJxvz52PTsxZRcFPW7RmZglR3wfsSzEX0dqsaDkGasYezBhk+BwmYEIpZ9Uvnzv7tw2djs9UH4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=dubeyko.com; spf=pass smtp.mailfrom=dubeyko.com; dkim=pass (2048-bit key) header.d=dubeyko-com.20230601.gappssmtp.com header.i=@dubeyko-com.20230601.gappssmtp.com header.b=uJrmVteX; arc=none smtp.client-ip=209.85.167.171 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=dubeyko.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=dubeyko.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=dubeyko-com.20230601.gappssmtp.com header.i=@dubeyko-com.20230601.gappssmtp.com header.b="uJrmVteX" Received: by mail-oi1-f171.google.com with SMTP id 5614622812f47-4091180d3e5so1786745b6e.0 for ; Tue, 10 Jun 2025 12:05:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=dubeyko-com.20230601.gappssmtp.com; s=20230601; t=1749582348; x=1750187148; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=FSaz2XVQb6c3ZnRbvHxNR/Gxmxkpkd2WgMTi88UzzMM=; b=uJrmVteXrHOyfVDVgePrGN6yaMfo2HxVJcNCxVBCdlXaO4Iv8lODuovi+QFvll+XiL EQcEqWRnT+54M5DYTSW2/fDdoQaw05sxX229ddz0HYm3RIsuTdVImA9YiOondFssvbOr KoO8fSC7IhOo4QP7LhQ4KN2JBNpVBp5RI1fS758XuWkBoyLjH4zLGIhp7m7As5Hyx51B EIsPFlxqcmk7ujO+9nZQlJ24EsRZIacqTc08VcsSX56YXhzrea2CsOIfLMxshllArZdl 05atifapnn4N2YCb+Zilf5Tk/xpjRsXCyJ0R3BL+s64SwizjsODTc0llfMIdWo1xI8vX bZrw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1749582348; x=1750187148; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=FSaz2XVQb6c3ZnRbvHxNR/Gxmxkpkd2WgMTi88UzzMM=; b=pXTSFYm4osxVv6WGZ/c8+ZOP1WdnvhMt/hGC4N+rwvDN1SgghtLrZYZHX1ByRkPM7z q0OQ1WUPrQQB0IVZeJwHJUlCbcLImrQwnhXa3tcSt5gjaVCnNwXk5tdmb3W9CCPdl5oj vWSFkNksYjdU97XzewqM8U2PmDNOP3bUCqFe9bp230y1S3czKjFeJHh1VIQGyCUajInl d6Fkqt+dlFzGoBAW/1Bx7KqsKKE5iKX0RI9YtWfTwCnpg4Ak2Pjtrmb8Zx8QUW58V1MF GGIYR1DsOj1d0tf2cD//FwVvmIw2BL4AaKORNIXGwS4dsBUB9yqWvRKnsVGBRqkvcRYp s+Cw== X-Gm-Message-State: AOJu0YwTaZXrAZGRW1o+6U/5WkInMiH6rkGcbTeC5NfejbJjr4+FWxJm ddZfw5Q3AjgB0mMQen4NTR+ODkb2SbFsaJdt7bJ6fepK/9F2Sw0qxVJTyXtjOoNsWiIWCFRtS0g r/tCY X-Gm-Gg: ASbGncsFAgNN76n99Bo+jKMRLM6x6axJ1BGt1cVuMlXaLlRxFvloBG2QIsQ47oOOw3A lOs4CUuIg0yZ+97IqjZ2uW6XQiLCUYf7v75a47RaUrLr48sJNEsw7+UhYtqi0RNx+J/q8d9Rz6J kAXd7Ge9m2PTCGLsmkL0rynuKVdNuUibrsE9BPww1pv2GoKNrG97WW/u6+mTwhIkBeV1KQG4MuY UKdUZ3qsHa3rtJyInSuR0kgKDLWz0+6HxefoU3HcVLgzv5w3gN0r80K5tew2yQwdI2LR0GoK3tR ApcyT8W+skQ6GvWGrlAkb86GuvES1ElOwB+kFfREDOMZel4avbGkUk6O7YPiuSQFOvRlWVcrW7m /Sp1Iz4HkOMWLwuwbgNdoGzlAHEfqdRB3ABIRVdZy4btkncev08L6ug== X-Google-Smtp-Source: AGHT+IE4RCwrwROQPI9KAHBsZxY8PBwtUrCyxVC2tiwe/+NWIB5GTbtZv/R7pqnA/19vQn+Tf5HjkA== X-Received: by 2002:a05:6808:1806:b0:408:ed52:c62f with SMTP id 5614622812f47-40a5d0553a5mr391077b6e.2.1749582347461; Tue, 10 Jun 2025 12:05:47 -0700 (PDT) Received: from system76-pc.attlocal.net (162-197-212-70.lightspeed.sntcca.sbcglobal.net. [162.197.212.70]) by smtp.gmail.com with ESMTPSA id 5614622812f47-40a5d95e89csm16503b6e.38.2025.06.10.12.05.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 10 Jun 2025 12:05:46 -0700 (PDT) From: Viacheslav Dubeyko To: ceph-devel@vger.kernel.org Cc: idryomov@gmail.com, linux-fsdevel@vger.kernel.org, pdonnell@redhat.com, amarkuze@redhat.com, Slava.Dubeyko@ibm.com, slava@dubeyko.com Subject: [PATCH] ceph: fix potential race condition of i_cap_delay_list access Date: Tue, 10 Jun 2025 12:05:29 -0700 Message-ID: <20250610190529.516586-1-slava@dubeyko.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: ceph-devel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Viacheslav Dubeyko The Coverity Scan service has detected potential race condition of i_cap_delay_list access [1]. The CID 1596363 contains explanation: "Accessing ci->i_cap_delay_list without holding lock ceph_mds_client.cap_delay_lock. Elsewhere, ceph_inode_info.i_cap_delay_list is written to with ceph_mds_client.cap_delay_lock held 9 out of 9 times. The value of the shared data will be determined by the interleaving of thread execution. In ceph_check_caps: Thread shared data is accessed without holding an appropriate lock, possibly causing a race condition (CWE-366)". The patch reworks __cap_delay_cancel() logic by means moving list_empty(&ci->i_cap_delay_list) under mdsc->cap_delay_lock protection. Patch introduces is_cap_delay_list_empty_safe() function that checks the emptiness of i_cap_delay_list under mdsc->cap_delay_lock protection. This function is used in ceph_check_caps() and __ceph_touch_fmode() methods to resolve the race condition issue. [1] https://scan5.scan.coverity.com/#/project-view/64304/10063?selectedIssue=1596363 Signed-off-by: Viacheslav Dubeyko --- fs/ceph/caps.c | 23 ++++++++++++++++++----- 1 file changed, 18 insertions(+), 5 deletions(-) diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c index a8d8b56cf9d2..eceee464ec50 100644 --- a/fs/ceph/caps.c +++ b/fs/ceph/caps.c @@ -566,13 +566,26 @@ static void __cap_delay_cancel(struct ceph_mds_client *mdsc, struct inode *inode = &ci->netfs.inode; doutc(mdsc->fsc->client, "%p %llx.%llx\n", inode, ceph_vinop(inode)); - if (list_empty(&ci->i_cap_delay_list)) - return; + spin_lock(&mdsc->cap_delay_lock); - list_del_init(&ci->i_cap_delay_list); + if (!list_empty(&ci->i_cap_delay_list)) { + list_del_init(&ci->i_cap_delay_list); + } spin_unlock(&mdsc->cap_delay_lock); } +static inline bool is_cap_delay_list_empty_safe(struct ceph_mds_client *mdsc, + struct ceph_inode_info *ci) +{ + bool is_empty; + + spin_lock(&mdsc->cap_delay_lock); + is_empty = list_empty(&ci->i_cap_delay_list); + spin_unlock(&mdsc->cap_delay_lock); + + return is_empty; +} + /* Common issue checks for add_cap, handle_cap_grant. */ static void __check_cap_issue(struct ceph_inode_info *ci, struct ceph_cap *cap, unsigned issued) @@ -2260,7 +2273,7 @@ void ceph_check_caps(struct ceph_inode_info *ci, int flags) /* periodically re-calculate caps wanted by open files */ if (__ceph_is_any_real_caps(ci) && - list_empty(&ci->i_cap_delay_list) && + is_cap_delay_list_empty_safe(mdsc, ci) && (file_wanted & ~CEPH_CAP_PIN) && !(used & (CEPH_CAP_FILE_RD | CEPH_CAP_ANY_FILE_WR))) { __cap_delay_requeue(mdsc, ci); @@ -4720,7 +4733,7 @@ void __ceph_touch_fmode(struct ceph_inode_info *ci, /* queue periodic check */ if (fmode && __ceph_is_any_real_caps(ci) && - list_empty(&ci->i_cap_delay_list)) + is_cap_delay_list_empty_safe(mdsc, ci)) __cap_delay_requeue(mdsc, ci); }