From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Gao Xiang <gaoxiang25@huawei.com>
Cc: stable@vger.kernel.org, Chao Yu <yuchao0@huawei.com>,
linux-erofs@lists.ozlabs.org, miaoxie@huawei.com,
Matthew Wilcox <willy@infradead.org>
Subject: Re: [PATCH for-4.19 06/12] staging: erofs: fix race when the managed cache is enabled
Date: Mon, 25 Feb 2019 16:04:49 +0100 [thread overview]
Message-ID: <20190225150449.GD16015@kroah.com> (raw)
In-Reply-To: <20190220091854.19242-7-gaoxiang25@huawei.com>
On Wed, Feb 20, 2019 at 05:18:48PM +0800, Gao Xiang wrote:
> commit 51232df5e4b268936beccde5248f312a316800be upstream.
>
> When the managed cache is enabled, the last reference count
> of a workgroup must be used for its workstation.
>
> Otherwise, it could lead to incorrect (un)freezes in
> the reclaim path, and it would be harmful.
>
> A typical race as follows:
>
> Thread 1 (In the reclaim path) Thread 2
> workgroup_freeze(grp, 1) refcnt = 1
> ...
> workgroup_unfreeze(grp, 1) refcnt = 1
> workgroup_get(grp) refcnt = 2 (x)
> workgroup_put(grp) refcnt = 1 (x)
> ...unexpected behaviors
>
> * grp is detached but still used, which violates cache-managed
> freeze constraint.
>
> Reviewed-by: Chao Yu <yuchao0@huawei.com>
> Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
>
> Conflicts:
> drivers/staging/erofs/utils.c
> Updates:
> include/linux/xarray.h:
> add xa_untag_pointer,xa_tag_pointer,xa_pointer_tag
> from upstream 3159f943aafd in order to reduce
> conflicts.
No, sorry, I don't want to add xarray.h to 4.19.y, that's crazy.
And even if we did, you do not slip it in as part of a different patch,
it should come in as its own patch, with the same git commit id that it
landed in 4.20 with.
Please fix this up...
greg k-h
next prev parent reply other threads:[~2019-02-25 15:04 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-20 9:18 [PATCH for-4.19 00/12] erofs fixes for linux-4.19.y Gao Xiang
2019-02-20 9:18 ` [PATCH for-4.19 01/12] staging: erofs: fix a bug when appling cache strategy Gao Xiang
2019-02-20 9:18 ` [PATCH for-4.19 02/12] staging: erofs: complete error handing of z_erofs_do_read_page Gao Xiang
2019-02-25 14:59 ` Greg Kroah-Hartman
2019-02-25 15:04 ` Gao Xiang
2019-02-20 9:18 ` [PATCH for-4.19 03/12] staging: erofs: replace BUG_ON with DBG_BUGON in data.c Gao Xiang
2019-02-20 9:18 ` [PATCH for-4.19 04/12] staging: erofs: drop multiref support temporarily Gao Xiang
2019-02-20 9:18 ` [PATCH for-4.19 05/12] staging: erofs: remove the redundant d_rehash() for the root dentry Gao Xiang
2019-02-20 9:18 ` [PATCH for-4.19 06/12] staging: erofs: fix race when the managed cache is enabled Gao Xiang
2019-02-25 15:04 ` Greg Kroah-Hartman [this message]
2019-02-25 15:07 ` Gao Xiang
2019-02-25 15:51 ` Greg Kroah-Hartman
2019-02-25 15:57 ` Gao Xiang
2019-02-25 17:58 ` [PATCH for-4.19 1/2] xarray: Replace exceptional entries Gao Xiang
2019-02-25 17:58 ` [PATCH for-4.19 2/2] staging: erofs: fix race when the managed cache is enabled Gao Xiang
2019-02-25 18:27 ` [PATCH for-4.19 1/2] xarray: Replace exceptional entries Matthew Wilcox
2019-02-26 1:21 ` Gao Xiang
2019-02-26 5:14 ` [PATCH v2 " Gao Xiang
2019-02-26 5:14 ` [PATCH v2 for-4.19 2/2] staging: erofs: fix race when the managed cache is enabled Gao Xiang
2019-02-26 12:43 ` [PATCH v2 for-4.19 1/2] xarray: Replace exceptional entries Gao Xiang
2019-03-04 5:13 ` Gao Xiang
2019-03-13 9:18 ` Gao Xiang
2019-02-25 15:25 ` [PATCH for-4.19 06/12] staging: erofs: fix race when the managed cache is enabled Matthew Wilcox
2019-02-25 15:52 ` Greg Kroah-Hartman
2019-02-25 16:04 ` Matthew Wilcox
2019-02-20 9:18 ` [PATCH for-4.19 07/12] staging: erofs: atomic_cond_read_relaxed on ref-locked workgroup Gao Xiang
2019-02-20 9:18 ` [PATCH for-4.19 08/12] staging: erofs: fix `erofs_workgroup_{try_to_freeze, unfreeze}' Gao Xiang
2019-02-20 9:18 ` [PATCH for-4.19 09/12] staging: erofs: add a full barrier in erofs_workgroup_unfreeze Gao Xiang
2019-02-20 9:18 ` [PATCH for-4.19 10/12] staging: erofs: {dir,inode,super}.c: rectify BUG_ONs Gao Xiang
2019-02-20 9:18 ` [PATCH for-4.19 11/12] staging: erofs: unzip_{pagevec.h,vle.c}: " Gao Xiang
2019-02-20 9:18 ` [PATCH for-4.19 12/12] staging: erofs: unzip_vle_lz4.c,utils.c: " Gao Xiang
2019-02-22 8:35 ` [PATCH for-4.19 00/12] erofs fixes for linux-4.19.y Greg Kroah-Hartman
2019-02-22 9:03 ` Gao Xiang
2019-02-25 15:28 ` Greg Kroah-Hartman
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=20190225150449.GD16015@kroah.com \
--to=gregkh@linuxfoundation.org \
--cc=gaoxiang25@huawei.com \
--cc=linux-erofs@lists.ozlabs.org \
--cc=miaoxie@huawei.com \
--cc=stable@vger.kernel.org \
--cc=willy@infradead.org \
--cc=yuchao0@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