Re: [PATCH] kernfs: Move faulting copy_user operations outside of the mutex
On to, 2016-03-31 at 13:15 -0700, Greg Kroah-Hartman wrote: > On Thu, Mar 31, 2016 at 08:30:05PM +0300, Joonas Lahtinen wrote: > > > > On to, 2016-03-31 at 12:49 -0400, Tejun Heo wrote: > > > > > > On Thu, Mar 31, 2016 at 11:45:06AM +0100, Chris Wilson wrote: > > > > > > > > > > > > A fault in a user provided buffer may lead anywhere, and lockdep warns > > > > that we have a potential deadlock between the mm->mmap_sem and the > > > > kernfs file mutex: > > > ... > > > > > > > > > > > > Reported-by: Ville Syrjälä > > > > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=94350 > > > > Signed-off-by: Chris Wilson > > > > Reviewed-by: Joonas Lahtinen > > > > Cc: Ville Syrjälä > > > > Cc: Joonas Lahtinen > > > > Cc: Tejun Heo > > > > Cc: Greg Kroah-Hartman > > > > Cc: NeilBrown > > > > Cc: linux-kernel@vger.kernel.org > > > Acked-by: Tejun Heo > > > > > Thanks. > > > > I have applied this locally to our repo to be included into our CI > > builds. > > > > We will drop the local patch once this waterfalls from upstream to our > > drm-intel-nightly repo. > So is this something that needs to get into 4.6-final because it > resolves a reported issue? Or can it wait for 4.7-rc1? > It is only a getting rid of a lockdep splat describing a scenario very unlikely to ever happen, so it can wait for 4.7-rc1. Regards, Joonas > thanks, > > greg k-h -- Joonas Lahtinen Open Source Technology Center Intel Corporation
Re: [PATCH] kernfs: Move faulting copy_user operations outside of the mutex
On Thu, Mar 31, 2016 at 08:30:05PM +0300, Joonas Lahtinen wrote: > On to, 2016-03-31 at 12:49 -0400, Tejun Heo wrote: > > On Thu, Mar 31, 2016 at 11:45:06AM +0100, Chris Wilson wrote: > > > > > > A fault in a user provided buffer may lead anywhere, and lockdep warns > > > that we have a potential deadlock between the mm->mmap_sem and the > > > kernfs file mutex: > > ... > > > > > > Reported-by: Ville Syrjälä > > > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=94350 > > > Signed-off-by: Chris Wilson > > > Reviewed-by: Joonas Lahtinen > > > Cc: Ville Syrjälä > > > Cc: Joonas Lahtinen > > > Cc: Tejun Heo > > > Cc: Greg Kroah-Hartman > > > Cc: NeilBrown > > > Cc: linux-kernel@vger.kernel.org > > Acked-by: Tejun Heo > > > > Thanks. > > I have applied this locally to our repo to be included into our CI > builds. > > We will drop the local patch once this waterfalls from upstream to our > drm-intel-nightly repo. So is this something that needs to get into 4.6-final because it resolves a reported issue? Or can it wait for 4.7-rc1? thanks, greg k-h
Re: [PATCH] kernfs: Move faulting copy_user operations outside of the mutex
On to, 2016-03-31 at 12:49 -0400, Tejun Heo wrote: > On Thu, Mar 31, 2016 at 11:45:06AM +0100, Chris Wilson wrote: > > > > A fault in a user provided buffer may lead anywhere, and lockdep warns > > that we have a potential deadlock between the mm->mmap_sem and the > > kernfs file mutex: > ... > > > > Reported-by: Ville Syrjälä > > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=94350 > > Signed-off-by: Chris Wilson > > Reviewed-by: Joonas Lahtinen > > Cc: Ville Syrjälä > > Cc: Joonas Lahtinen > > Cc: Tejun Heo > > Cc: Greg Kroah-Hartman > > Cc: NeilBrown > > Cc: linux-kernel@vger.kernel.org > Acked-by: Tejun Heo > Thanks. I have applied this locally to our repo to be included into our CI builds. We will drop the local patch once this waterfalls from upstream to our drm-intel-nightly repo. Regards, Joonas -- Joonas Lahtinen Open Source Technology Center Intel Corporation
Re: [PATCH] kernfs: Move faulting copy_user operations outside of the mutex
On Thu, Mar 31, 2016 at 11:45:06AM +0100, Chris Wilson wrote: > A fault in a user provided buffer may lead anywhere, and lockdep warns > that we have a potential deadlock between the mm->mmap_sem and the > kernfs file mutex: ... > Reported-by: Ville Syrjälä > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=94350 > Signed-off-by: Chris Wilson > Reviewed-by: Joonas Lahtinen > Cc: Ville Syrjälä > Cc: Joonas Lahtinen > Cc: Tejun Heo > Cc: Greg Kroah-Hartman > Cc: NeilBrown > Cc: linux-kernel@vger.kernel.org Acked-by: Tejun Heo Thanks! -- tejun
