Re: [PATCH v3] mm: Fix possible deadlock in console_trylock_spinning

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Mon, Aug 18, 2025 at 10:24:38AM +0800, Gu Bowen wrote:
> 
> 
> On 8/14/2025 9:08 PM, Catalin Marinas wrote:
> > On Thu, Aug 14, 2025 at 10:33:56AM +0800, Gu Bowen wrote:
> > > On 8/14/2025 6:56 AM, Andrew Morton wrote:
> > > > I'm not sure which kernel version this was against, but kmemleak.c has
> > > > changed quite a lot.
> > > > 
> > > > Could we please see a patch against a latest kernel version?  Linus
> > > > mainline will suit.
> > > > 
> > > > Thanks.
> > > 
> > > I discovered this issue in kernel version 5.10. Afterwards, I reviewed the
> > > code of the mainline version and found that this deadlock path no longer
> > > exists due to the refactoring of console_lock in v6.2-rc1. For details on
> > > the refactoring, you can refer to this link :
> > > https://lore.kernel.org/all/20221116162152.193147-1-john.ogness@linutronix.de/.
> > > Therefore, theoretically, this issue existed before the refactoring of
> > > console_lock.
> > 
> > Oh, so you can no longer hit this issue with mainline. This wasn't
> > mentioned (or I missed it) in the commit log.
> > 
> > So this would be a stable-only fix that does not have a correspondent
> > upstream. Adding Greg for his opinion.
> > 
> 
> I have discovered that I made a mistake, this fix patch should be merged
> into the mainline. Since we have identified two types of deadlocks, the AA
> deadlock [1] and the ABBA deadlock[2], the latter's deadlock path no longer
> exists in the mainline due to the 40 patches that refactored console_lock.
> However, the AA deadlock issue persists, so I believe this fix should be
> applied to the mainline.
> 
> [1] https://lore.kernel.org/all/20250731-kmemleak_lock-v1-1-728fd470198f@debian.org/#t
> [2] https://lore.kernel.org/all/20250730094914.566582-1-gubowen5@huawei.com/

Pleasae submit it as a normal patch then.

thanks,

greg k-h