Re: BISECT result: 6.0.0-RC kernels trigger Firefox snap bug with 6.0.0-rc3 through 6.0.0-rc7

[Bagas Sanjaya]

On 10/16/22 03:59, Phillip Lougher wrote:
> 
> Which identified the "squashfs: support reading fragments in readahead call"
> patch.
> 
> There is a race-condition introduced in that patch, which involves cache
> releasing and reuse.
> 
> The following diff will fix that race-condition.  It would be great if
> someone could test and verify before sending it out as a patch.
> 
> Thanks
> 
> Phillip
> 
> diff --git a/fs/squashfs/file.c b/fs/squashfs/file.c
> index e56510964b22..6cc23178e9ad 100644
> --- a/fs/squashfs/file.c
> +++ b/fs/squashfs/file.c
> @@ -506,8 +506,9 @@ static int squashfs_readahead_fragment(struct page **page,
>  		squashfs_i(inode)->fragment_size);
>  	struct squashfs_sb_info *msblk = inode->i_sb->s_fs_info;
>  	unsigned int n, mask = (1 << (msblk->block_log - PAGE_SHIFT)) - 1;
> +	int error = buffer->error;
>  
> -	if (buffer->error)
> +	if (error)
>  		goto out;
>  
>  	expected += squashfs_i(inode)->fragment_offset;
> @@ -529,7 +530,7 @@ static int squashfs_readahead_fragment(struct page **page,
>  
>  out:
>  	squashfs_cache_put(buffer);
> -	return buffer->error;
> +	return error;
>  }
>  
>  static void squashfs_readahead(struct readahead_control *ractl)
> 

No Verneed warnings so far. However, I need to test for a longer time
(a day) to check if any warnings are reported.

Thanks.

-- 
An old man doll... just what I always wanted! - Clara