On Fri, May 28, 2021 at 05:27:39PM +0200, Rodrigo Campos wrote: > On Thu, May 27, 2021 at 8:42 PM Kees Cook <keescook@xxxxxxxxxxxx> wrote: > > > > On Thu, May 27, 2021 at 01:51:13PM +0200, Rodrigo Campos wrote: > > > > > > Kees, as I mentioned in the linked thread, this issue is present in > > > 5.9+ kernels. Should we add the cc to stable for this patch? Or should > > > we cc to stable the one linked, that just fixes the issue without > > > semantic changes to userspace? > > > > It sounds like the problem is with Go, using addfd, on 5.9-5.13 kernels, > > yes? > > Yes. > > > Would the semantic change be a problem there? (i.e. it sounds like > > the semantic change was fine for the 5.14+ kernels, so I'm assuming it's > > fine for earlier ones too.) > > No, I don't think it will cause any problem. > > > > Just to be clear, the other patch that fixes the problem without > > > userspace visible changes is this: > > > https://lore.kernel.org/lkml/20210413160151.3301-1-rodrigo@xxxxxxxxxx/ > > > > I'd prefer to use the now-in-next fix if we can. Is it possible to build > > a test case that triggers the race so we can have some certainty that > > any fix in -stable covers it appropriately? > > I've verified that Sargun's patch also solves the problem in mainline. > I have now also verified that it applies cleany and fixes the issue > for linux-stable/5.10.y and linux-stable/5.12.y too (without the patch > I see the problem, with the patch I don't see it). 5.11 is already > EOL, so I didn't try it (probably will work as well). Oh, btw, may I add a Tested-by: from you for this fix? Thanks! -Kees -- Kees Cook
