From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 09B6A1F667B; Wed, 6 Nov 2024 12:37:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730896646; cv=none; b=SsSPep04TJqAGKdpm0PbMsAiBT/E5da1ObruoeTlPNbiQoQIkbjjgKY7S1ZGx41c9qXdUGhsUzzdXtBUJDr5Vh5VLSpG7rDxxG4ZAa1aVYZJ5Uj3XVQAulz+VMcSkA/wK9nFbwOD+65g6VQGLOUcBw7M7KJIGcpsLGGY7M9doi4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730896646; c=relaxed/simple; bh=U7p9NqYk6eyBim1hd5Fg2AHCNh2EgeAPI/dY6dWzjdQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=Akf8TnBBWqpMavnRW1hOG8vb3xGmpIGpmnceedPPxDFklC1wr2olFSBZVOli1zYwv/Dj1WkGgHfuyQF5+woyJpKSAOOub67voTwRnTv3olIDbA1ROAHmWmmqh0X1ZAfbdxVRF+FmR2+gxdT0/IOWSPWRKM+7uBMiyrwhvJe5zEI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=ogOKzu29; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="ogOKzu29" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 765DFC4CECD; Wed, 6 Nov 2024 12:37:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1730896645; bh=U7p9NqYk6eyBim1hd5Fg2AHCNh2EgeAPI/dY6dWzjdQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ogOKzu29A9Eh8iErJxZS7djA6iEyYU7GXADVvlt4kLq2Kolz1DeVfYMlBwXIlnfVG hLDlK5quOVd4MJ8GOVQB0B10Cqe0rRrcM9jVgvEPsuUdug+50J1LKuXkDX9zvNRteJ 3xzMonqltvFGzVOZ3VnTvrnSlqBmVUxfe1ptTArA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Yu Kuai , Jens Axboe , Sasha Levin Subject: [PATCH 5.10 025/110] block, bfq: fix procress reference leakage for bfqq in merge chain Date: Wed, 6 Nov 2024 13:03:51 +0100 Message-ID: <20241106120303.861634649@linuxfoundation.org> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241106120303.135636370@linuxfoundation.org> References: <20241106120303.135636370@linuxfoundation.org> User-Agent: quilt/0.67 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 5.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Yu Kuai [ Upstream commit 73aeab373557fa6ee4ae0b742c6211ccd9859280 ] Original state: Process 1 Process 2 Process 3 Process 4 (BIC1) (BIC2) (BIC3) (BIC4) Λ | | | \--------------\ \-------------\ \-------------\| V V V bfqq1--------->bfqq2---------->bfqq3----------->bfqq4 ref 0 1 2 4 After commit 0e456dba86c7 ("block, bfq: choose the last bfqq from merge chain in bfq_setup_cooperator()"), if P1 issues a new IO: Without the patch: Process 1 Process 2 Process 3 Process 4 (BIC1) (BIC2) (BIC3) (BIC4) Λ | | | \------------------------------\ \-------------\| V V bfqq1--------->bfqq2---------->bfqq3----------->bfqq4 ref 0 0 2 4 bfqq3 will be used to handle IO from P1, this is not expected, IO should be redirected to bfqq4; With the patch: ------------------------------------------- | | Process 1 Process 2 Process 3 | Process 4 (BIC1) (BIC2) (BIC3) | (BIC4) | | | | \-------------\ \-------------\| V V bfqq1--------->bfqq2---------->bfqq3----------->bfqq4 ref 0 0 2 4 IO is redirected to bfqq4, however, procress reference of bfqq3 is still 2, while there is only P2 using it. Fix the problem by calling bfq_merge_bfqqs() for each bfqq in the merge chain. Also change bfqq_merge_bfqqs() to return new_bfqq to simplify code. Fixes: 0e456dba86c7 ("block, bfq: choose the last bfqq from merge chain in bfq_setup_cooperator()") Signed-off-by: Yu Kuai Link: https://lore.kernel.org/r/20240909134154.954924-3-yukuai1@huaweicloud.com Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- block/bfq-iosched.c | 33 ++++++++++++++++----------------- 1 file changed, 16 insertions(+), 17 deletions(-) diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index 515e3c1a54759..c1600e3ac3339 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -2774,10 +2774,12 @@ void bfq_release_process_ref(struct bfq_data *bfqd, struct bfq_queue *bfqq) bfq_put_queue(bfqq); } -static void -bfq_merge_bfqqs(struct bfq_data *bfqd, struct bfq_io_cq *bic, - struct bfq_queue *bfqq, struct bfq_queue *new_bfqq) +static struct bfq_queue *bfq_merge_bfqqs(struct bfq_data *bfqd, + struct bfq_io_cq *bic, + struct bfq_queue *bfqq) { + struct bfq_queue *new_bfqq = bfqq->new_bfqq; + bfq_log_bfqq(bfqd, bfqq, "merging with queue %lu", (unsigned long)new_bfqq->pid); /* Save weight raising and idle window of the merged queues */ @@ -2845,6 +2847,8 @@ bfq_merge_bfqqs(struct bfq_data *bfqd, struct bfq_io_cq *bic, new_bfqq->pid = -1; bfqq->bic = NULL; bfq_release_process_ref(bfqd, bfqq); + + return new_bfqq; } static bool bfq_allow_bio_merge(struct request_queue *q, struct request *rq, @@ -2880,14 +2884,8 @@ static bool bfq_allow_bio_merge(struct request_queue *q, struct request *rq, * fulfilled, i.e., bic can be redirected to new_bfqq * and bfqq can be put. */ - bfq_merge_bfqqs(bfqd, bfqd->bio_bic, bfqq, - new_bfqq); - /* - * If we get here, bio will be queued into new_queue, - * so use new_bfqq to decide whether bio and rq can be - * merged. - */ - bfqq = new_bfqq; + while (bfqq != new_bfqq) + bfqq = bfq_merge_bfqqs(bfqd, bfqd->bio_bic, bfqq); /* * Change also bqfd->bio_bfqq, as @@ -5444,6 +5442,7 @@ static bool __bfq_insert_request(struct bfq_data *bfqd, struct request *rq) bool waiting, idle_timer_disabled = false; if (new_bfqq) { + struct bfq_queue *old_bfqq = bfqq; /* * Release the request's reference to the old bfqq * and make sure one is taken to the shared queue. @@ -5459,18 +5458,18 @@ static bool __bfq_insert_request(struct bfq_data *bfqd, struct request *rq) * then complete the merge and redirect it to * new_bfqq. */ - if (bic_to_bfqq(RQ_BIC(rq), 1) == bfqq) - bfq_merge_bfqqs(bfqd, RQ_BIC(rq), - bfqq, new_bfqq); + if (bic_to_bfqq(RQ_BIC(rq), 1) == bfqq) { + while (bfqq != new_bfqq) + bfqq = bfq_merge_bfqqs(bfqd, RQ_BIC(rq), bfqq); + } - bfq_clear_bfqq_just_created(bfqq); + bfq_clear_bfqq_just_created(old_bfqq); /* * rq is about to be enqueued into new_bfqq, * release rq reference on bfqq */ - bfq_put_queue(bfqq); + bfq_put_queue(old_bfqq); rq->elv.priv[1] = new_bfqq; - bfqq = new_bfqq; } bfq_update_io_thinktime(bfqd, bfqq); -- 2.43.0