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 08D7250128E; Thu, 17 Sep 2026 17:08:11 +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=1789664893; cv=none; b=MGO/AK4+DYXHdufy5h5/2U40zAbvxIkxAraFs+FAM6mxAtvN/68d1p0e2ShkYH329PjXXtzwlZHUt6VEPANmoZzuaP0L136rzIQ5cZzubcHaazxqhkMlQB0S19EQefPd5rynXWuiBtrJ3pTWS5DOa2AoLXlzGOUWRtVjuXxD6VY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789664893; c=relaxed/simple; bh=DYGWe4KhtoPkqMk+vAzOzzNyGbqzm5lV+T+ylOxLQfY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=E1WzvQCzIGEpFJO0kOK+vPXEz5JjN2+Iq8PIlw7exB1TM/EaJXmHXAczDtVn+0zmn0dLGWmCHryj8BUnxHRhyrOcUkdpJDprk/ggjiewGw5n8PKeBELQZ4S4FlBS+bNYCoUjBHm8HLbljZAzNZ/nBN12/qS4tZ1rltG9B4J5obY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Q20pjbm7; 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="Q20pjbm7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0D99D1F00898; Thu, 17 Sep 2026 17:08:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789664891; bh=Y2pVZJDvUu+sJ13f8Y0ZTuxSH9WH5zDcbZrnqW6/ZbI=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Q20pjbm74akdERux2k5Pb7KHFfFZqiVK299hJHVgEyvvSTC+a4PuGmIhfyTIQU74n aVk641FMqxacs+boDEPoxhhspLzm/pC2hpKH4T3Wj30Rjy7dz6onx2nF1gVgi+UfKe MBc+r6l+BTmerKGyTExcXDv0iP8Rw4EwV2x2jPr4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Tejun Heo , Tao Cui , Jens Axboe , Sasha Levin Subject: [PATCH 6.18 0524/1250] blk-cgroup: fix leaks and online flag on radix_tree_insert failure Date: Thu, 17 Sep 2026 16:05:19 +0100 Message-ID: <20260917151606.149119836@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260917151551.901433442@linuxfoundation.org> References: <20260917151551.901433442@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-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Tao Cui [ Upstream commit dbbca20764382b4d411ec2918f4e278ffe547acc ] When radix_tree_insert() fails in blkg_create(), the error path has two issues: 1. blkg->online is set to true unconditionally, even when the blkg was never fully inserted. Move the assignment inside the success block. 2. The error path calls blkg_put() without first calling percpu_ref_kill(). Because the refcount is still in percpu mode, percpu_ref_put() only does this_cpu_sub() without checking for zero, so blkg_release() is never triggered. This permanently leaks the blkg memory, its percpu iostat, policy data, the parent blkg reference, and the cgroup css reference — the latter preventing the cgroup from ever being destroyed. Fix by replacing blkg_put() with percpu_ref_kill(), matching the pattern used in blkg_destroy(). Acked-by: Tejun Heo Signed-off-by: Tao Cui Link: https://patch.msgid.link/20260715132407.1469777-1-cui.tao@linux.dev Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- block/blk-cgroup.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index f638d3dd5ebcf..171efbbd3c8a8 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -432,15 +432,15 @@ static struct blkcg_gq *blkg_create(struct blkcg *blkcg, struct gendisk *disk, blkg->pd[i]->online = true; } } + blkg->online = true; } - blkg->online = true; spin_unlock(&blkcg->lock); if (!ret) return blkg; /* @blkg failed fully initialized, use the usual release path */ - blkg_put(blkg); + percpu_ref_kill(&blkg->refcnt); return ERR_PTR(ret); err_put_css: -- 2.53.0