From: Chao Yu <chao@kernel.org>
To: Huang Jianan <huangjianan@oppo.com>,
linux-erofs@lists.ozlabs.org, xiang@kernel.org
Cc: yh@oppo.com, guoweichao@oppo.com, zhangshiming@oppo.com,
guanyuwei@oppo.com
Subject: Re: [PATCH] erofs: fix deadlock when shrink erofs slab
Date: Fri, 19 Nov 2021 09:32:48 +0800 [thread overview]
Message-ID: <5e299ea7-0d23-2d9e-d401-be561287c9f6@kernel.org> (raw)
In-Reply-To: <20211118135844.3559-1-huangjianan@oppo.com>
On 2021/11/18 21:58, Huang Jianan via Linux-erofs wrote:
> We observed the following deadlock in the stress test under low
> memory scenario:
>
> Thread A Thread B
> - erofs_shrink_scan
> - erofs_try_to_release_workgroup
> - erofs_workgroup_try_to_freeze -- A
> - z_erofs_do_read_page
> - z_erofs_collection_begin
> - z_erofs_register_collection
> - erofs_insert_workgroup
> - xa_lock(&sbi->managed_pslots) -- B
> - erofs_workgroup_get
> - erofs_wait_on_workgroup_freezed -- A
> - xa_erase
> - xa_lock(&sbi->managed_pslots) -- B
>
> To fix this, it need to hold the xa lock before freeze the workgroup
> beacuse we will operate xarry. So let's hold the lock before access
> each workgroup, just like when we using the radix tree before.
>
> Fixes: 64094a04414f ("erofs: convert workstn to XArray")
> Signed-off-by: Huang Jianan <huangjianan@oppo.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Thanks,
next prev parent reply other threads:[~2021-11-19 1:33 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-18 13:58 [PATCH] erofs: fix deadlock when shrink erofs slab Huang Jianan via Linux-erofs
2021-11-19 1:32 ` Chao Yu [this message]
2021-11-19 2:19 ` Gao Xiang
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