Re: [PATCH v2] f2fs: fix use-after-free issue when accessing sbi->stat_info

[Chao Yu]

On 2018/12/26 13:50, Sahitya Tummala wrote:
> iput() on sbi->node_inode can update sbi->stat_info
> in the below context, if the f2fs_write_checkpoint()
> has failed with error.
> 
> f2fs_balance_fs_bg+0x1ac/0x1ec
> f2fs_write_node_pages+0x4c/0x260
> do_writepages+0x80/0xbc
> __writeback_single_inode+0xdc/0x4ac
> writeback_single_inode+0x9c/0x144
> write_inode_now+0xc4/0xec
> iput+0x194/0x22c
> f2fs_put_super+0x11c/0x1e8
> generic_shutdown_super+0x70/0xf4
> kill_block_super+0x2c/0x5c
> kill_f2fs_super+0x44/0x50
> deactivate_locked_super+0x60/0x8c
> deactivate_super+0x68/0x74
> cleanup_mnt+0x40/0x78
> 
> Fix this by moving f2fs_destroy_stats() further below iput() in
> both f2fs_put_super() and f2fs_fill_super() paths.
> 
> Signed-off-by: Sahitya Tummala <stummala@xxxxxxxxxxxxxx>

It looks good to me now. :)

Reviewed-by: Chao Yu <yuchao0@xxxxxxxxxx>

Thanks,