Re: [PATCH 5.15.y, 5.10.y] exfat: fix potential deadlock on __exfat_get_dentry_set

[Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>]

Hi Greg,

On 14/12/24 23:36, Greg KH wrote:
> On Sat, Dec 14, 2024 at 05:57:01PM +0000, Sherry Yang wrote:
>> Hi,
>>
>>> On Dec 14, 2024, at 6:26 AM, Sasha Levin <sashal@kernel.org> wrote:
>>>
>>> [ Sasha's backport helper bot ]
>>>
>>> Hi,
>>>
>>> The upstream commit SHA1 provided is correct: 89fc548767a2155231128cb98726d6d2ea1256c9
>>>
>>> WARNING: Author mismatch between patch and upstream commit:
>>> Backport author: Sherry Yang <sherry.yang@oracle.com>
>>> Commit author: Sungjong Seo <sj1557.seo@samsung.com>
>>>
>>>
>>> Status in newer kernel trees:
>>> 6.12.y | Present (exact SHA1)
>>> 6.6.y | Present (different SHA1: a7ac198f8dba)
>>> 6.1.y | Not found
>>> 5.15.y | Not found
>>
>> I didn’t backport the commit to linux-stable-6.1.y, because 6.1.y didn’t backport the culprit commit
>> a3ff29a95fde ("exfat: support dynamic allocate bh for exfat_entry_set_cache”), so not influenced.
>>
>> However, both linux-stable-5.15.y and linux-stable-5.10.y actually backported the culprit commit. So I’m trying to fix it on 5.15.y and 5.10.y.
>>
>> Let me know if you have more questions about it.
> 
> That's confusing, why doesn't 6.1.y have that commit?  Shouldn't we also
> add it there along with this one?
> 

https://lore.kernel.org/all/20230809103650.353831735@linuxfoundation.org/#t

Commit a3ff29a95fde ("exfat: support dynamic allocate bh for 
exfat_entry_set_cache”) which is present in 5.10.y and 5.15.y but not in 
6.1.y is added as a stable-dependency "Stable-dep-of: d42334578eba 
("exfat: check if filename entries exceeds max filename length") ", but 
this(d42334578eba - filename length check) is present in 6.1.y without 
commit a3ff29a95fde , so probably stable-dep-of is not accurate.

Given that now we already have a3ff29a95fde ("exfat: support dynamic 
allocate bh for exfat_entry_set_cache”) to 5.15.y and 5.10.y, I think we 
should add it and the fix to 6.1.y as well.

For 6.1.y here are the upstream commits: (Starting from 1 -- cleanly 
applies and builds fine, haven't done any exfat related testing though.)
1. a3ff29a95fde ("exfat: support dynamic allocate bh for 
exfat_entry_set_cache”)
2. commit: 89fc548767a2 ("exfat: fix potential deadlock on 
__exfat_get_dentry_set")

Let me know if you want me to send two patches instead, I can do that.

Thanks,
Harshit

> thanks,
> 
> greg k-h
>