On Wed 22-08-18 22:12:29, Nadav Amit wrote:
> Commit d70f2a14b72a4 ("include/linux/sched/mm.h: uninline
> mmdrop_async(), etc") ignored the return value of arch_dup_mmap(). As a
> result, on x86, a failure to duplicate the LDT (e.g., due to memory
> allocation error), would leave the duplicated memory mapping in an
> inconsistent state.
>
> Fix by regarding the return value, as it was before the change.
Ohh, well spotted! I have a vague recollection I didn't really like the
patch. For other reasons. I didn't get to review it properly back then
because I didn't have much time and I didn't have a high motivation
because I simple disagreed with the patch.
> Fixes: d70f2a14b72a4 ("include/linux/sched/mm.h: uninline mmdrop_async(), etc")
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Nadav Amit <namit@xxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Thanks!
> ---
> kernel/fork.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/kernel/fork.c b/kernel/fork.c
> index 1b27babc4c78..4527d1d331de 100644
> --- a/kernel/fork.c
> +++ b/kernel/fork.c
> @@ -549,8 +549,7 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
> goto out;
> }
> /* a new mm has just been created */
> - arch_dup_mmap(oldmm, mm);
> - retval = 0;
> + retval = arch_dup_mmap(oldmm, mm);
> out:
> up_write(&mm->mmap_sem);
> flush_tlb_mm(oldmm);
> --
> 2.17.1
>
--
Michal Hocko
SUSE Labs
