linux-kernel - Re: [BUG] fs/super: a possible sleep-in-atomic bug in put

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Message-ID: <20171006090604.m5oxcyb2xtllpmpu@dhcp22.suse.cz>
Date:   Fri, 6 Oct 2017 11:06:04 +0200
From:   Michal Hocko <mhocko@...nel.org>
To:     Jia-Ju Bai <baijiaju1990@....com>
Cc:     viro@...iv.linux.org.uk, torbjorn.lindh@...ta.se,
        rgooch@...f.csiro.au, linux-fsdevel@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Vladimir Davydov <vdavydov.dev@...il.com>
Subject: Re: [BUG] fs/super: a possible sleep-in-atomic bug in put_super

[CC Vladimir]

On Fri 06-10-17 16:59:18, Jia-Ju Bai wrote:
> According to fs/super.c, the kernel may sleep under a spinlock.
> The function call path is:
> put_super (acquire the spinlock)
>   __put_super
>     destroy_super
>       list_lru_destroy
>         list_lru_unregister
>           mutex_lock --> may sleep
>         memcg_get_cache_ids
>           down_read --> may sleep
> 
> This bug is found by my static analysis tool and my code review.
> 
> Thanks,
> Jia-Ju Bai

-- 
Michal Hocko
SUSE Labs