Re: [PATCH] mm:Avoid soft lockup due to possible attempt of double locking object's lock in __delete_object

[nick <xerofoify@gmail.com>]

On 2016-08-31 05:08 PM, Valdis.Kletnieks@vt.edu wrote:
> On Wed, 31 Aug 2016 08:54:21 +0100, Catalin Marinas said:
>> On Tue, Aug 30, 2016 at 02:35:12PM -0400, Nicholas Krause wrote:
>>> This fixes a issue in the current locking logic of the function,
>>> __delete_object where we are trying to attempt to lock the passed
>>> object structure's spinlock again after being previously held
>>> elsewhere by the kmemleak code. Fix this by instead of assuming
>>> we are the only one contending for the object's lock their are
>>> possible other users and create two branches, one where we get
>>> the lock when calling spin_trylock_irqsave on the object's lock
>>> and the other when the lock is held else where by kmemleak.
>>
>> Have you actually got a deadlock that requires this fix?
> 
> Almost certainly not, but that's never stopped Nicholas before.  He's a well-known
> submitter of bad patches, usually totally incorrect, not even compile tested.
> 
> He's infamous enough that he's not allowed to post to any list hosted at vger.
>
Valdis,
Rather then argue since that will go nowhere. I am posing actual patches that have been tested on
hardware. Yes I known that is surprising but it's true.