On 09.07.23 13:14, Greg Kroah-Hartman wrote: > From: Suren Baghdasaryan <surenb@xxxxxxxxxx> > > commit 2b4f3b4987b56365b981f44a7e843efa5b6619b9 upstream. > > Patch series "Avoid memory corruption caused by per-VMA locks", v4. > > A memory corruption was reported in [1] with bisection pointing to the > patch [2] enabling per-VMA locks for x86. Based on the reproducer > provided in [1] we suspect this is caused by the lack of VMA locking while > forking a child process. > [...] Question from someone that is neither a C nor a git expert -- and thus might say something totally stupid below (and thus maybe should not have sent this mail at all). But I have to wonder: is adding this patch to stable necessary given patch 8/8? FWIW, this change looks like this: > --- > kernel/fork.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > --- a/kernel/fork.c > +++ b/kernel/fork.c > @@ -662,6 +662,12 @@ static __latent_entropy int dup_mmap(str > retval = -EINTR; > goto fail_uprobe_end; > } > +#ifdef CONFIG_PER_VMA_LOCK > + /* Disallow any page faults before calling flush_cache_dup_mm */ > + for_each_vma(old_vmi, mpnt) > + vma_start_write(mpnt); > + vma_iter_set(&old_vmi, 0); > +#endif > flush_cache_dup_mm(oldmm); > uprobe_dup_mmap(oldmm, mm); > /* But when I look at kernel/fork.c in mainline I can't see this bit. I also only see Linus' change (e.g. patch 8/8 in this series) when I look at https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/log/kernel/fork.c What am I missing? Ciao, Thorsten (who noticed this just by chance)
