Re: linux-next: slab shrinkers: BUG at mm/list_lru.c:92

From: Michal Hocko <mhocko@suse.cz>
To: Glauber Costa <glommer@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Dave Chinner <david@fromorbit.com>,
	linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>
Subject: Re: linux-next: slab shrinkers: BUG at mm/list_lru.c:92
Date: Wed, 19 Jun 2013 09:13:46 +0200	[thread overview]
Message-ID: <20130619071346.GA9545@dhcp22.suse.cz> (raw)
In-Reply-To: <20130618062623.GA20528@localhost.localdomain>

On Tue 18-06-13 10:26:24, Glauber Costa wrote:
[...]
> Michal, would you mind testing the following patch?
>
> diff --git a/fs/inode.c b/fs/inode.c
> index 00b804e..48eafa6 100644
> --- a/fs/inode.c
> +++ b/fs/inode.c
> @@ -419,6 +419,8 @@ void inode_add_lru(struct inode *inode)
>  
>  static void inode_lru_list_del(struct inode *inode)
>  {
> +	if (inode->i_state & I_FREEING)
> +		return;
>  
>  	if (list_lru_del(&inode->i_sb->s_inode_lru, &inode->i_lru))
>  		this_cpu_dec(nr_unused);
> @@ -609,8 +611,8 @@ void evict_inodes(struct super_block *sb)
>  			continue;
>  		}
>  
> -		inode->i_state |= I_FREEING;
>  		inode_lru_list_del(inode);
> +		inode->i_state |= I_FREEING;
>  		spin_unlock(&inode->i_lock);
>  		list_add(&inode->i_lru, &dispose);
>  	}
> @@ -653,8 +655,8 @@ int invalidate_inodes(struct super_block *sb, bool kill_dirty)
>  			continue;
>  		}
>  
> -		inode->i_state |= I_FREEING;
>  		inode_lru_list_del(inode);
> +		inode->i_state |= I_FREEING;
>  		spin_unlock(&inode->i_lock);
>  		list_add(&inode->i_lru, &dispose);
>  	}
> @@ -1381,9 +1383,8 @@ static void iput_final(struct inode *inode)
>  		inode->i_state &= ~I_WILL_FREE;
>  	}
>  
> +	inode_lru_list_del(inode);
>  	inode->i_state |= I_FREEING;
> -	if (!list_empty(&inode->i_lru))
> -		inode_lru_list_del(inode);
>  	spin_unlock(&inode->i_lock);
>  
>  	evict(inode);

No luck. I have this on top of inode_lru_isolate one but still can see
hangs:
911 [<ffffffff8118325e>] __wait_on_freeing_inode+0x9e/0xc0
[<ffffffff81183321>] find_inode_fast+0xa1/0xc0
[<ffffffff8118529f>] iget_locked+0x4f/0x180
[<ffffffff811efa23>] ext4_iget+0x33/0x9f0
[<ffffffff811f6a5c>] ext4_lookup+0xbc/0x160
[<ffffffff81174ad0>] lookup_real+0x20/0x60
[<ffffffff81175254>] __lookup_hash+0x34/0x40
[<ffffffff81179872>] path_lookupat+0x7a2/0x830
[<ffffffff81179933>] filename_lookup+0x33/0xd0
[<ffffffff8117ab0b>] user_path_at_empty+0x7b/0xb0
[<ffffffff8117ab4c>] user_path_at+0xc/0x10
[<ffffffff8116ff91>] vfs_fstatat+0x51/0xb0
[<ffffffff81170116>] vfs_stat+0x16/0x20
[<ffffffff8117013f>] sys_newstat+0x1f/0x50
[<ffffffff81583129>] system_call_fastpath+0x16/0x1b
[<ffffffffffffffff>] 0xffffffffffffffff
21409 [<ffffffff8118325e>] __wait_on_freeing_inode+0x9e/0xc0
[<ffffffff81183321>] find_inode_fast+0xa1/0xc0
[<ffffffff8118529f>] iget_locked+0x4f/0x180
[<ffffffff811efa23>] ext4_iget+0x33/0x9f0
[<ffffffff811f6a5c>] ext4_lookup+0xbc/0x160
[<ffffffff81174ad0>] lookup_real+0x20/0x60
[<ffffffff81177e25>] lookup_open+0x175/0x1d0
[<ffffffff8117815e>] do_last+0x2de/0x780
[<ffffffff8117ae9a>] path_openat+0xda/0x400
[<ffffffff8117b303>] do_filp_open+0x43/0xa0
[<ffffffff81168ee0>] do_sys_open+0x160/0x1e0
[<ffffffff81168f9c>] sys_open+0x1c/0x20
[<ffffffff81583129>] system_call_fastpath+0x16/0x1b
[<ffffffffffffffff>] 0xffffffffffffffff
21745 [<ffffffff81179862>] path_lookupat+0x792/0x830
[<ffffffff81179933>] filename_lookup+0x33/0xd0
[<ffffffff8117ab0b>] user_path_at_empty+0x7b/0xb0
[<ffffffff8117ab4c>] user_path_at+0xc/0x10
[<ffffffff8116ff91>] vfs_fstatat+0x51/0xb0
[<ffffffff81170116>] vfs_stat+0x16/0x20
[<ffffffff8117013f>] sys_newstat+0x1f/0x50
[<ffffffff81583129>] system_call_fastpath+0x16/0x1b
[<ffffffffffffffff>] 0xffffffffffffffff
22032 [<ffffffff81179862>] path_lookupat+0x792/0x830
[<ffffffff81179933>] filename_lookup+0x33/0xd0
[<ffffffff8117ab0b>] user_path_at_empty+0x7b/0xb0
[<ffffffff8117ab4c>] user_path_at+0xc/0x10
[<ffffffff8116ff91>] vfs_fstatat+0x51/0xb0
[<ffffffff81170116>] vfs_stat+0x16/0x20
[<ffffffff8117013f>] sys_newstat+0x1f/0x50
[<ffffffff81583129>] system_call_fastpath+0x16/0x1b
[<ffffffffffffffff>] 0xffffffffffffffff
22621 [<ffffffff8118325e>] __wait_on_freeing_inode+0x9e/0xc0
[<ffffffff81183321>] find_inode_fast+0xa1/0xc0
[<ffffffff8118529f>] iget_locked+0x4f/0x180
[<ffffffff811efa23>] ext4_iget+0x33/0x9f0
[<ffffffff811f6a5c>] ext4_lookup+0xbc/0x160
[<ffffffff81174ad0>] lookup_real+0x20/0x60
[<ffffffff81177e25>] lookup_open+0x175/0x1d0
[<ffffffff8117815e>] do_last+0x2de/0x780
[<ffffffff8117ae9a>] path_openat+0xda/0x400
[<ffffffff8117b303>] do_filp_open+0x43/0xa0
[<ffffffff81168ee0>] do_sys_open+0x160/0x1e0
[<ffffffff81168f9c>] sys_open+0x1c/0x20
[<ffffffff81583129>] system_call_fastpath+0x16/0x1b
[<ffffffffffffffff>] 0xffffffffffffffff
22711 [<ffffffff81178144>] do_last+0x2c4/0x780
[<ffffffff8117ae9a>] path_openat+0xda/0x400
[<ffffffff8117b303>] do_filp_open+0x43/0xa0
[<ffffffff81168ee0>] do_sys_open+0x160/0x1e0
[<ffffffff81168f9c>] sys_open+0x1c/0x20
[<ffffffff81583129>] system_call_fastpath+0x16/0x1b
[<ffffffffffffffff>] 0xffffffffffffffff
22946 [<ffffffff81178144>] do_last+0x2c4/0x780
[<ffffffff8117ae9a>] path_openat+0xda/0x400
[<ffffffff8117b303>] do_filp_open+0x43/0xa0
[<ffffffff81168ee0>] do_sys_open+0x160/0x1e0
[<ffffffff81168f9c>] sys_open+0x1c/0x20
[<ffffffff81583129>] system_call_fastpath+0x16/0x1b
[<ffffffffffffffff>] 0xffffffffffffffff
23393 [<ffffffff81178144>] do_last+0x2c4/0x780
[<ffffffff8117ae9a>] path_openat+0xda/0x400
[<ffffffff8117b303>] do_filp_open+0x43/0xa0
[<ffffffff81168ee0>] do_sys_open+0x160/0x1e0
[<ffffffff81168f9c>] sys_open+0x1c/0x20
[<ffffffff81583129>] system_call_fastpath+0x16/0x1b
[<ffffffffffffffff>] 0xffffffffffffffff
-- 
Michal Hocko
SUSE Labs