From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org, "Blank-Burian, Markus,
Dr." <blankburian@uni-muenster.de>, Yufen Yu <yuyufen@huawei.com>,
Ming Lei <ming.lei@redhat.com>, Jens Axboe <axboe@kernel.dk>,
Yi Zhang <yi.zhang@redhat.com>
Subject: [PATCH 5.10 12/26] blk-mq: fix is_flush_rq
Date: Fri, 10 Sep 2021 14:30:16 +0200 [thread overview]
Message-ID: <20210910122916.652285519@linuxfoundation.org> (raw)
In-Reply-To: <20210910122916.253646001@linuxfoundation.org>
From: Ming Lei <ming.lei@redhat.com>
commit a9ed27a764156929efe714033edb3e9023c5f321 upstream.
is_flush_rq() is called from bt_iter()/bt_tags_iter(), and runs the
following check:
hctx->fq->flush_rq == req
but the passed hctx from bt_iter()/bt_tags_iter() may be NULL because:
1) memory re-order in blk_mq_rq_ctx_init():
rq->mq_hctx = data->hctx;
...
refcount_set(&rq->ref, 1);
OR
2) tag re-use and ->rqs[] isn't updated with new request.
Fix the issue by re-writing is_flush_rq() as:
return rq->end_io == flush_end_io;
which turns out simpler to follow and immune to data race since we have
ordered WRITE rq->end_io and refcount_set(&rq->ref, 1).
Fixes: 2e315dc07df0 ("blk-mq: grab rq->refcount before calling ->fn in blk_mq_tagset_busy_iter")
Cc: "Blank-Burian, Markus, Dr." <blankburian@uni-muenster.de>
Cc: Yufen Yu <yuyufen@huawei.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20210818010925.607383-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Cc: Yi Zhang <yi.zhang@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
block/blk-flush.c | 5 +++++
block/blk-mq.c | 2 +-
block/blk.h | 6 +-----
3 files changed, 7 insertions(+), 6 deletions(-)
--- a/block/blk-flush.c
+++ b/block/blk-flush.c
@@ -263,6 +263,11 @@ static void flush_end_io(struct request
spin_unlock_irqrestore(&fq->mq_flush_lock, flags);
}
+bool is_flush_rq(struct request *rq)
+{
+ return rq->end_io == flush_end_io;
+}
+
/**
* blk_kick_flush - consider issuing flush request
* @q: request_queue being kicked
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -929,7 +929,7 @@ static bool blk_mq_req_expired(struct re
void blk_mq_put_rq_ref(struct request *rq)
{
- if (is_flush_rq(rq, rq->mq_hctx))
+ if (is_flush_rq(rq))
rq->end_io(rq, 0);
else if (refcount_dec_and_test(&rq->ref))
__blk_mq_free_request(rq);
--- a/block/blk.h
+++ b/block/blk.h
@@ -44,11 +44,7 @@ static inline void __blk_get_queue(struc
kobject_get(&q->kobj);
}
-static inline bool
-is_flush_rq(struct request *req, struct blk_mq_hw_ctx *hctx)
-{
- return hctx->fq->flush_rq == req;
-}
+bool is_flush_rq(struct request *req);
struct blk_flush_queue *blk_alloc_flush_queue(int node, int cmd_size,
gfp_t flags);
next prev parent reply other threads:[~2021-09-10 12:33 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-10 12:30 [PATCH 5.10 00/26] 5.10.64-rc1 review Greg Kroah-Hartman
2021-09-10 12:30 ` [PATCH 5.10 01/26] igmp: Add ip_mc_list lock in ip_check_mc_rcu Greg Kroah-Hartman
2021-09-10 12:30 ` [PATCH 5.10 02/26] USB: serial: mos7720: improve OOM-handling in read_mos_reg() Greg Kroah-Hartman
2021-09-10 12:30 ` [PATCH 5.10 03/26] net: ll_temac: Remove left-over debug message Greg Kroah-Hartman
2021-09-10 12:30 ` [PATCH 5.10 04/26] mm/page_alloc: speed up the iteration of max_order Greg Kroah-Hartman
2021-09-10 12:30 ` [PATCH 5.10 05/26] net: kcov: dont select SKB_EXTENSIONS when there is no NET Greg Kroah-Hartman
2021-09-10 12:30 ` [PATCH 5.10 06/26] serial: 8250: 8250_omap: Fix unused variable warning Greg Kroah-Hartman
2021-09-10 12:30 ` [PATCH 5.10 07/26] net: linux/skbuff.h: combine SKB_EXTENSIONS + KCOV handling Greg Kroah-Hartman
2021-09-10 12:30 ` [PATCH 5.10 08/26] tty: drop termiox user definitions Greg Kroah-Hartman
2021-09-10 12:30 ` [PATCH 5.10 09/26] Revert "r8169: avoid link-up interrupt issue on RTL8106e if user enables ASPM" Greg Kroah-Hartman
2021-09-10 12:30 ` [PATCH 5.10 10/26] x86/events/amd/iommu: Fix invalid Perf result due to IOMMU PMC power-gating Greg Kroah-Hartman
2021-09-10 12:30 ` [PATCH 5.10 11/26] blk-mq: fix kernel panic during iterating over flush request Greg Kroah-Hartman
2021-09-10 12:30 ` Greg Kroah-Hartman [this message]
2021-09-10 12:30 ` [PATCH 5.10 13/26] netfilter: nftables: avoid potential overflows on 32bit arches Greg Kroah-Hartman
2021-09-10 12:30 ` [PATCH 5.10 14/26] netfilter: nf_tables: initialize set before expression setup Greg Kroah-Hartman
2021-09-10 12:30 ` [PATCH 5.10 15/26] netfilter: nftables: clone set element expression template Greg Kroah-Hartman
2021-09-10 12:30 ` [PATCH 5.10 16/26] blk-mq: clearing flush request reference in tags->rqs[] Greg Kroah-Hartman
2021-09-10 12:30 ` [PATCH 5.10 17/26] ALSA: usb-audio: Add registration quirk for JBL Quantum 800 Greg Kroah-Hartman
2021-09-10 12:30 ` [PATCH 5.10 18/26] usb: host: xhci-rcar: Dont reload firmware after the completion Greg Kroah-Hartman
2021-09-10 12:30 ` [PATCH 5.10 19/26] usb: gadget: tegra-xudc: fix the wrong mult value for HS isoc or intr Greg Kroah-Hartman
2021-09-10 12:30 ` [PATCH 5.10 20/26] usb: mtu3: restore HS function when set SS/SSP Greg Kroah-Hartman
2021-09-10 12:30 ` [PATCH 5.10 21/26] usb: mtu3: use @mult for HS isoc or intr Greg Kroah-Hartman
2021-09-10 12:30 ` [PATCH 5.10 22/26] usb: mtu3: fix the wrong HS mult value Greg Kroah-Hartman
2021-09-10 12:30 ` [PATCH 5.10 23/26] xhci: fix even more unsafe memory usage in xhci tracing Greg Kroah-Hartman
2021-09-10 12:30 ` [PATCH 5.10 24/26] xhci: fix " Greg Kroah-Hartman
2021-09-10 12:30 ` [PATCH 5.10 25/26] x86/reboot: Limit Dell Optiplex 990 quirk to early BIOS versions Greg Kroah-Hartman
2021-09-10 12:30 ` [PATCH 5.10 26/26] PCI: Call Max Payload Size-related fixup quirks early Greg Kroah-Hartman
2021-09-10 19:02 ` [PATCH 5.10 00/26] 5.10.64-rc1 review Florian Fainelli
2021-09-10 19:52 ` Pavel Machek
2021-09-10 22:51 ` Fox Chen
2021-09-10 23:17 ` Shuah Khan
2021-09-11 6:14 ` Samuel Zou
2021-09-11 15:56 ` Sudip Mukherjee
2021-09-11 19:37 ` Guenter Roeck
2021-09-12 0:49 ` Daniel Díaz
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210910122916.652285519@linuxfoundation.org \
--to=gregkh@linuxfoundation.org \
--cc=axboe@kernel.dk \
--cc=blankburian@uni-muenster.de \
--cc=linux-kernel@vger.kernel.org \
--cc=ming.lei@redhat.com \
--cc=stable@vger.kernel.org \
--cc=yi.zhang@redhat.com \
--cc=yuyufen@huawei.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).