From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 7842D304BCB; Sat, 30 May 2026 17:49:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780163400; cv=none; b=WqaK6T7hn3bbyekxd54S7sUX4yis2UrhVH6krXeXtjvtTkGTJYyjt2pjigreYVvwWgC+fbTXWLgp7gCIXzOmkh2a0oOWRY5lB/Gx1TQOOBB7e3IaPgLCfux5bUUqaQVUmXtWmWcB9ua2ZXUUAyrb/qBx3CkuOsC3JQaGv3EkZE0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780163400; c=relaxed/simple; bh=RG5hCrTyE0pGsIbd3IBoABB3/XfP9XAYNjQeFGSMr+w=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ZS9gzcwYyvLo2yPpcrrJHFGeepa9W+YEnt7hC9gkN+ruCOPlho0sWM/HcfQGI7G/fIfY1Eq7RoUnH0/4rS50tjwraL4jvu686IhDMfAesgRyH24Bl8fqcwslbzx/R3k4/iY8aRlqVrTxp1Vzm8fkbbpc528sx2mpgu1dcpegb5w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=yn84Xn1M; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="yn84Xn1M" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9211F1F00893; Sat, 30 May 2026 17:49:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1780163399; bh=VZMNnt5CTI0Jw0SYb2+lsuOtffM3s78L9xhCKbE+7ls=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=yn84Xn1MC9ap0DdCLK05Gx0stkgoh4Zz5CeZK5RTmh5LybxYogC1oATcE6/ktIWpM IzAn1INTw3rCKFBwAztKOmR7bh1hdXuidM/48jFhVFy5IFMIlHTMJo4rTVvDPYK1pr QxFVzD/a23fsoWMlLqb5dqfF80EX1iTInlpCmIsI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Chia-Ming Chang , robbieko , Nikolay Borisov , Jan Kara Subject: [PATCH 5.15 247/776] inotify: fix watch count leak when fsnotify_add_inode_mark_locked() fails Date: Sat, 30 May 2026 17:59:21 +0200 Message-ID: <20260530160246.915429975@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260530160240.228940103@linuxfoundation.org> References: <20260530160240.228940103@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Chia-Ming Chang commit 6a320935fa4293e9e599ec9f85dc9eb3be7029f8 upstream. When fsnotify_add_inode_mark_locked() fails in inotify_new_watch(), the error path calls inotify_remove_from_idr() but does not call dec_inotify_watches() to undo the preceding inc_inotify_watches(). This leaks a watch count, and repeated failures can exhaust the max_user_watches limit with -ENOSPC even when no watches are active. Prior to commit 1cce1eea0aff ("inotify: Convert to using per-namespace limits"), the watch count was incremented after fsnotify_add_mark_locked() succeeded, so this path was not affected. The conversion moved inc_inotify_watches() before the mark insertion without adding the corresponding rollback. Add the missing dec_inotify_watches() call in the error path. Fixes: 1cce1eea0aff ("inotify: Convert to using per-namespace limits") Cc: stable@vger.kernel.org Signed-off-by: Chia-Ming Chang Signed-off-by: robbieko Reviewed-by: Nikolay Borisov Link: https://patch.msgid.link/20260224093442.3076294-1-chiamingc@synology.com Signed-off-by: Jan Kara Signed-off-by: Greg Kroah-Hartman --- fs/notify/inotify/inotify_user.c | 1 + 1 file changed, 1 insertion(+) --- a/fs/notify/inotify/inotify_user.c +++ b/fs/notify/inotify/inotify_user.c @@ -614,6 +614,7 @@ static int inotify_new_watch(struct fsno if (ret) { /* we failed to get on the inode, get off the idr */ inotify_remove_from_idr(group, tmp_i_mark); + dec_inotify_watches(group->inotify_data.ucounts); goto out_err; }