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 4723C4E77FA; Thu, 17 Sep 2026 18:07:02 +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=1789668425; cv=none; b=gnZdvhJYre5KUjnLgAys+Cl0LzuSYsXKUV/hdUlJOlzv9CoNoWCEZ0P58qczWQ498hGZFLRbWwNlGylR7QzeYYO8iHrqNBmimRIh0sfFZitakWO3ezbgulo2nafR1Hhx7SQv7rOB4bTeDCbysZlsdBONDJVmr7sjH3Mv5ffiGjM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789668425; c=relaxed/simple; bh=x0jPxA3/dnhKz7DJ9ABtm6F9hW4sd3tG2hqxk37fRLI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=nRuL9/CkI8Jc/ijNMmXs+i+lL0xBzdo23kOKsKEjSwQj53EgPkgtoSVn66jpZnZJPWU8fnkPap/INOdf78YuKT32h8eTzGktM2vqTZty9yd61+RF8IrTdWjNzk+LKXAniSreKnYjGb2UNPC9EYqEEdpjkCa+R2PyrjGcOFzJC2s= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=BSKZ7Ulf; 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="BSKZ7Ulf" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 238181F000FF; Thu, 17 Sep 2026 18:07:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789668422; bh=fq0MZWaufRTUmOrwLToLVOKj6wAbsRofuDtFoWbVzTs=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=BSKZ7UlfGPGf42Fpu2vTzxjSqfZA5i5+4BQzaS3lcF6bXJq++u2KdP7YcFXbbPEAR w7zbGFtEV+KmMPMHbB2MJF+JTFCom0by9a6+PvwmIRyP0nZNoNTQl3b/9OaR4UycoO FEvFyWYGo6OiV+mvNxjrEU9eyC1nmxV3XYVMrPFA= 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 6.12 0421/1102] blk-cgroup: fix leaks and online flag on radix_tree_insert failure Date: Thu, 17 Sep 2026 16:06:04 +0100 Message-ID: <20260917151550.237513001@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260917151539.408551884@linuxfoundation.org> References: <20260917151539.408551884@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 6.12-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 7f00e9e9cc061..d89da7e067f42 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