From: Greg KH <email@example.com>
To: Yu Kuai <firstname.lastname@example.org>
Cc: email@example.com, firstname.lastname@example.org,
email@example.com, firstname.lastname@example.org, email@example.com
Subject: Re: [PATCH linux-4.19.y] blk-mq: fix divide by zero crash in tg_may_dispatch()
Date: Wed, 15 Sep 2021 13:27:39 +0200 [thread overview]
Message-ID: <YUHYqwVeeXtfD0qf@kroah.com> (raw)
On Tue, Sep 14, 2021 at 08:54:02PM +0800, Yu Kuai wrote:
> If blk-throttle is enabled and io is issued before
> blk_throtl_register_queue() is done. Divide by zero crash will be
> triggered in tg_may_dispatch() because 'throtl_slice' is uninitialized.
> The problem is fixed in commit 75f4dca59694 ("block: call
> blk_register_queue earlier in device_add_disk") from mainline, however
> it's too hard to backport this patch due to lots of refactoring.
> Thus introduce a new flag QUEUE_FLAG_THROTL_INIT_DONE. It will be set
> after blk_throtl_register_queue() is done, and will be checked before
> applying any config.
> Signed-off-by: Yu Kuai <firstname.lastname@example.org>
> block/blk-sysfs.c | 2 ++
> block/blk-throttle.c | 41 +++++++++++++++++++++++++++++++++++++++--
> include/linux/blkdev.h | 1 +
> 3 files changed, 42 insertions(+), 2 deletions(-)
The commit you reference above is in 5.15-rc1. What about all of the
other stable kernel releases newer than 4.19.y? You do not want to move
to a newer release and have a regression.
And I would _REALLY_ like to take the identical commits that are
upstream if at all possible. What is needed to backport instead of
doing this one-off patch instead?
When we take changes that are not upstream, almost always they are
broken so we almost never want to do that.
next prev parent reply other threads:[~2021-09-15 11:27 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-14 12:54 [PATCH linux-4.19.y] blk-mq: fix divide by zero crash in tg_may_dispatch() Yu Kuai
2021-09-15 11:27 ` Greg KH [this message]
2021-09-15 11:58 ` yukuai (C)
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:
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
* 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).