On Tue, Jan 25, 2022 at 08:26:20AM +0100, Christian König wrote: > Hi Greg, > > Am 24.01.22 um 19:41 schrieb Greg Kroah-Hartman: > > From: Rajneesh Bhardwaj <rajneesh.bhardwaj@xxxxxxx> > > > > [ Upstream commit fbcdbfde87509d523132b59f661a355c731139d0 ] > > > > When an application having open file access to a node forks, its shared > > mappings also get reflected in the address space of child process even > > though it cannot access them with the object permissions applied. With the > > existing permission checks on the gem objects, it might be reasonable to > > also create the VMAs with VM_DONTCOPY flag so a user space application > > doesn't need to explicitly call the madvise(addr, len, MADV_DONTFORK) > > system call to prevent the pages in the mapped range to appear in the > > address space of the child process. It also prevents the memory leaks > > due to additional reference counts on the mapped BOs in the child > > process that prevented freeing the memory in the parent for which we had > > worked around earlier in the user space inside the thunk library. > > > > Additionally, we faced this issue when using CRIU to checkpoint restore > > an application that had such inherited mappings in the child which > > confuse CRIU when it mmaps on restore. Having this flag set for the > > render node VMAs helps. VMAs mapped via KFD already take care of this so > > this is needed only for the render nodes. > > > > To limit the impact of the change to user space consumers such as OpenGL > > etc, limit it to KFD BOs only. > > > > Acked-by: Felix Kuehling <Felix.Kuehling@xxxxxxx> > > Reviewed-by: Christian König <christian.koenig@xxxxxxx> > > Signed-off-by: David Yat Sin <david.yatsin@xxxxxxx> > > Signed-off-by: Rajneesh Bhardwaj <rajneesh.bhardwaj@xxxxxxx> > > Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx> > > Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> > > Please drop this patch from all stable versions since it was reverted from > upstream later on. The revert comes later in the patch series, so all should be ok :) thanks, greg k-h
