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 82BFD1E492A for ; Wed, 2 Oct 2024 11:45:40 +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=1727869540; cv=none; b=h0vVaP7uG+Kh27Yayvrg5N9QiDELxM6MksS+Z0i1wLhJTPlo/q9PwssBmv1MKLtvBRiFn/fO1uvEKIeanuhsl0b8oWJQZsrZKHecdxOPRvZWNpka3T+mCKJUMdhOXPaywLgX2vV7vibDBIdWWez3eLyiauu9uEkNXE+84JVdyhs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727869540; c=relaxed/simple; bh=cimU70s8f/klXKS8VxQz0rgK/rj9YwqvC88vkYZ2Mfw=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=fpsDkmKFSIN7ztiKcuanCusEl8SBj09CbIC7smR+JeEnWuUmcOWevF5Tt+J5rKza0K56WaT9xdbKXg4Wbqfli8XgHiKktAQUXcDggoXbj10PlUwLcilf29htqnfKp/RuRj2q4BJozaXfSkUkdZomMnd5BaHlRlFdNncROuqZVJY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=r+diG6sU; 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="r+diG6sU" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A49BBC4CEC5; Wed, 2 Oct 2024 11:45:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1727869540; bh=cimU70s8f/klXKS8VxQz0rgK/rj9YwqvC88vkYZ2Mfw=; h=Subject:To:Cc:From:Date:From; b=r+diG6sUbS3THSvWEqUU5TjISiXRDyhyUkwkvvTIsjgv/sHPWQ9e6hMHfwiYQgEyJ EeJulyZFR7L54qKdGrCZgIvwUJznomEpeD6DPhaOcVRreNR2dgoGAT0aqo2Iyc3tgQ V/D3Fxewa67Kwh0EkR2QpN3zI/RAlfEDtehgqE7Q= Subject: FAILED: patch "[PATCH] block, bfq: fix procress reference leakage for bfqq in merge" failed to apply to 6.1-stable tree To: yukuai3@huawei.com,axboe@kernel.dk Cc: From: Date: Wed, 02 Oct 2024 13:45:29 +0200 Message-ID: <2024100229-lazy-atonable-fd03@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The patch below does not apply to the 6.1-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y git checkout FETCH_HEAD git cherry-pick -x 73aeab373557fa6ee4ae0b742c6211ccd9859280 # git commit -s git send-email --to '' --in-reply-to '2024100229-lazy-atonable-fd03@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^.. Possible dependencies: 73aeab373557 ("block, bfq: fix procress reference leakage for bfqq in merge chain") 9778369a2d6c ("block, bfq: split sync bfq_queues on a per-actuator basis") 246cf66e300b ("block, bfq: fix uaf for bfqq in bfq_exit_icq_bfqq") 337366e02b37 ("block, bfq: replace 0/1 with false/true in bic apis") 64dc8c732f5c ("block, bfq: fix possible uaf for 'bfqq->bic'") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 73aeab373557fa6ee4ae0b742c6211ccd9859280 Mon Sep 17 00:00:00 2001 From: Yu Kuai Date: Mon, 9 Sep 2024 21:41:49 +0800 Subject: [PATCH] block, bfq: fix procress reference leakage for bfqq in merge chain MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index d5d39974c674..f4192d5411d2 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -3129,10 +3129,12 @@ 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 */ @@ -3226,6 +3228,8 @@ bfq_merge_bfqqs(struct bfq_data *bfqd, struct bfq_io_cq *bic, bfq_reassign_last_bfqq(bfqq, new_bfqq); bfq_release_process_ref(bfqd, bfqq); + + return new_bfqq; } static bool bfq_allow_bio_merge(struct request_queue *q, struct request *rq, @@ -3261,14 +3265,8 @@ 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 @@ -5705,9 +5703,7 @@ bfq_do_early_stable_merge(struct bfq_data *bfqd, struct bfq_queue *bfqq, * state before killing it. */ bfqq->bic = bic; - bfq_merge_bfqqs(bfqd, bic, bfqq, new_bfqq); - - return new_bfqq; + return bfq_merge_bfqqs(bfqd, bic, bfqq); } /* @@ -6162,6 +6158,7 @@ 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. @@ -6178,18 +6175,18 @@ static bool __bfq_insert_request(struct bfq_data *bfqd, struct request *rq) * new_bfqq. */ if (bic_to_bfqq(RQ_BIC(rq), true, - bfq_actuator_index(bfqd, rq->bio)) == bfqq) - bfq_merge_bfqqs(bfqd, RQ_BIC(rq), - bfqq, new_bfqq); + bfq_actuator_index(bfqd, rq->bio)) == 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);