From: Anand Jain <anand.jain@oracle.com>
To: dsterba@suse.cz, linux-btrfs@vger.kernel.org, dsterba@suse.com
Subject: Re: [PATCH] btrfs: fix lockdep warning chunk_mutex vs device_list_mutex
Date: Sat, 16 May 2020 11:43:58 +0800 [thread overview]
Message-ID: <4fa7f041-5816-1d94-1148-780b10e705af@oracle.com> (raw)
In-Reply-To: <20200515174047.GN18421@twin.jikos.cz>
On 16/5/20 1:40 am, David Sterba wrote:
> On Thu, May 14, 2020 at 03:46:59AM +0800, Anand Jain wrote:
>> A full list of tests just started.
>>
>> fs/btrfs/volumes.c | 8 +++++---
>> 1 file changed, 5 insertions(+), 3 deletions(-)
>>
>> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
>> index 60ab41c12e50..ebc8565d0f73 100644
>> --- a/fs/btrfs/volumes.c
>> +++ b/fs/btrfs/volumes.c
>> @@ -984,7 +984,6 @@ static struct btrfs_fs_devices *clone_fs_devices(struct btrfs_fs_devices *orig)
>> if (IS_ERR(fs_devices))
>> return fs_devices;
>>
>
> So now here's the device_list_mutex taken by a caller but inside
> clone_fs_devices there's
>
> fs_devices = alloc_fs_devices(orig->fsid, NULL);
>
> just before this line and it does a GFP_KERNEL allocation.
Oh right the allocations. Its not just about the other locks
as I thought before.
There are two ways to fix.
Use GFP_NOFS
I am not yet sure if it not possible. There were some previous
work on the GFP flags. I need to review them. or,
Move the allocation outside the locks.
Looking into both of these choices.
Thanks, Anand
> This could
> deadlock through the allocator trying to flush data and then superblock
> write locking the device_list_mutex again.
>
>> - mutex_lock(&orig->device_list_mutex);
>> fs_devices->total_devices = orig->total_devices;
>>
>> list_for_each_entry(orig_dev, &orig->devices, dev_list) {
next prev parent reply other threads:[~2020-05-16 3:44 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-12 14:12 Pending bugs for 5.7 David Sterba
2020-05-12 14:14 ` Bug 5.7-rc: root leak, eb leak David Sterba
2020-05-12 23:03 ` David Sterba
2020-05-13 11:54 ` Johannes Thumshirn
2020-05-13 11:57 ` Qu Wenruo
2020-05-13 12:06 ` Johannes Thumshirn
2020-05-13 12:11 ` Qu Wenruo
2020-05-13 12:17 ` Johannes Thumshirn
2020-05-13 12:29 ` Johannes Thumshirn
2020-05-12 14:15 ` Bug 5.7-rc: write-time leaf corruption detected David Sterba
2020-05-12 14:26 ` Filipe Manana
2020-05-13 3:10 ` Qu Wenruo
2020-05-13 3:17 ` Qu Wenruo
2020-05-13 9:25 ` Filipe Manana
2020-05-19 14:26 ` Bug 5.7-rc: write-time leaf corruption detected (fixed) David Sterba
2020-05-12 14:15 ` Bug 5.7-rc: lockdep warning, chunk_mutex/device_list_mutex David Sterba
2020-05-12 23:28 ` David Sterba
2020-05-12 19:25 ` Anand Jain
2020-05-13 19:46 ` [PATCH] btrfs: fix lockdep warning chunk_mutex vs device_list_mutex Anand Jain
2020-05-15 17:40 ` David Sterba
2020-05-16 3:43 ` Anand Jain [this message]
2020-05-18 11:07 ` Anand Jain
2020-05-18 15:28 ` David Sterba
2020-05-12 14:15 ` Bug 5.7-rc: lockdep warning, fs_reclaim David Sterba
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=4fa7f041-5816-1d94-1148-780b10e705af@oracle.com \
--to=anand.jain@oracle.com \
--cc=dsterba@suse.com \
--cc=dsterba@suse.cz \
--cc=linux-btrfs@vger.kernel.org \
/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).