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

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 19:21, Bagas Sanjaya wrote:
> 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.
> 

Also, since this regression is also found on linux-6.0.y stable branch,
don't forget to Cc stable list.

Thanks.

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

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

[Thorsten Leemhuis]

On 16.10.22 14:24, Bagas Sanjaya wrote:
> On 10/16/22 19:21, Bagas Sanjaya wrote:
>> On 10/16/22 03:59, Phillip Lougher wrote:
>>>
>>> Which identified the "squashfs: support reading fragments in readahead call"
>>> patch.

BTW, Phillip, sorry for specifying the wrong culprit in an earlier mail.

> Also, since this regression is also found on linux-6.0.y stable branch,
> don't forget to Cc stable list.

FWIW, that's afaics not needed (and actually slightly confusing I'd
say). That is only important when the problem was introduced in a stable
release to make the stable team aware of it, as then they might be
willing to revert the culprit if the problem is not present in mainline.

But this problem was introduced in the 6.0 mainline cycle and thus needs
to be fixed there first.

Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)

P.S.: As the Linux kernel's regression tracker I deal with a lot of
reports and sometimes miss something important when writing mails like
this. If that's the case here, don't hesitate to tell me in a public
reply, it's in everyone's interest to set the public record straight.

P.P.S.:

#regzbot introduced: b09a7a036d2035b14636c

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

[Thorsten Leemhuis]

[Note: this mail is primarily send for documentation purposes and/or for
regzbot, my Linux kernel regression tracking bot. That's why I removed
most or all folks from the list of recipients, but left any that looked
like a mailing lists. These mails usually contain '#forregzbot' in the
subject, to make them easy to spot and filter out.]

On 16.10.22 14:43, Thorsten Leemhuis wrote:
> #regzbot introduced: b09a7a036d2035b14636c

#regzbot fixed-by: e11c4e088be