| Message ID | 20230523004312.1807357-2-pcc@google.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm: Fix bug affecting swapping in MTE tagged pages | expand |
On Mon, Jun 05, 2023 at 10:41:12AM -0700, Peter Collingbourne wrote: > On Mon, Jun 5, 2023 at 7:06 AM Will Deacon <will@kernel.org> wrote: > > On Mon, May 22, 2023 at 05:43:08PM -0700, Peter Collingbourne wrote: > > > Commit c145e0b47c77 ("mm: streamline COW logic in do_swap_page()") moved > > > the call to swap_free() before the call to set_pte_at(), which meant that > > > the MTE tags could end up being freed before set_pte_at() had a chance > > > to restore them. Fix it by adding a call to the arch_swap_restore() hook > > > before the call to swap_free(). > > > > > > Signed-off-by: Peter Collingbourne <pcc@google.com> > > > Link: https://linux-review.googlesource.com/id/I6470efa669e8bd2f841049b8c61020c510678965 > > > Cc: <stable@vger.kernel.org> # 6.1 > > > Fixes: c145e0b47c77 ("mm: streamline COW logic in do_swap_page()") > > > Reported-by: Qun-wei Lin (林群崴) <Qun-wei.Lin@mediatek.com> > > > Closes: https://lore.kernel.org/all/5050805753ac469e8d727c797c2218a9d780d434.camel@mediatek.com/ > > > Acked-by: David Hildenbrand <david@redhat.com> > > > Acked-by: "Huang, Ying" <ying.huang@intel.com> > > > Reviewed-by: Steven Price <steven.price@arm.com> > > > Acked-by: Catalin Marinas <catalin.marinas@arm.com> > > > --- > > > v2: > > > - Call arch_swap_restore() directly instead of via arch_do_swap_page() > > > > > > mm/memory.c | 7 +++++++ > > > 1 file changed, 7 insertions(+) > > > > > > diff --git a/mm/memory.c b/mm/memory.c > > > index f69fbc251198..fc25764016b3 100644 > > > --- a/mm/memory.c > > > +++ b/mm/memory.c > > > @@ -3932,6 +3932,13 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) > > > } > > > } > > > > > > + /* > > > + * Some architectures may have to restore extra metadata to the page > > > + * when reading from swap. This metadata may be indexed by swap entry > > > + * so this must be called before swap_free(). > > > + */ > > > + arch_swap_restore(entry, folio); > > > + > > > /* > > > * Remove the swap entry and conditionally try to free up the swapcache. > > > * We're already holding a reference on the page but haven't mapped it > > > > It looks like the intention is for this patch to land in 6.4, whereas the > > other two in the series could go in later, right? If so, I was expecting > > Andrew to pick this one up but he's not actually on CC. I've added him now, > > but you may want to send this as a separate fix so it's obvious what needs > > picking up for this cycle. > > I was expecting that this whole series could be picked up in mm. There > was a previous attempt to apply v3 of this series to mm, but that > failed because a dependent patch (commit c4c597f1b367 ("arm64: mte: Do > not set PG_mte_tagged if tags were not initialized")) hadn't been > merged into Linus's master branch yet. The series should be good to go > in now that that patch has been merged. Did this series fall through the cracks? I can't see it in linux-next (or maybe my grep'ing failed). The commit mentioned above is in 6.4-rc3 AFAICT. Unfortunately Andrew was not cc'ed on the initial post, Will added him later, so he likely missed it. For reference, the series is here: https://lore.kernel.org/r/20230523004312.1807357-1-pcc@google.com/ Andrew, what's your preference for this series? I'd like at least the first patch to go into 6.5 as a fix. The second patch seems to be fairly low risk and I'm happy for the third arm64 patch/cleanup to go in 6.5-rc1 (but it depends on the second patch). If you prefer, I can pick them up and send a pull request to Linus next week before -rc1. Otherwise you (or I) can queue the first patch and leave the other two for 6.6. Thanks.
On Thu, 29 Jun 2023 10:57:14 +0100 Catalin Marinas <catalin.marinas@arm.com> wrote: > Andrew, what's your preference for this series? I'd like at least the > first patch to go into 6.5 as a fix. The second patch seems to be fairly > low risk and I'm happy for the third arm64 patch/cleanup to go in > 6.5-rc1 (but it depends on the second patch). If you prefer, I can pick > them up and send a pull request to Linus next week before -rc1. > Otherwise you (or I) can queue the first patch and leave the other two > for 6.6. Thanks. I queued [1/3] for 6.5-rcX with a cc:stable. And I queued [2/3] and [3/3] for 6.6-rc1. If you wish to grab any/all of these then please do so - Stephen will tell us of the duplicate and I'll drop the mm-git copy.
On Sun, Jul 02, 2023 at 12:38:21PM -0700, Andrew Morton wrote: > On Thu, 29 Jun 2023 10:57:14 +0100 Catalin Marinas <catalin.marinas@arm.com> wrote: > > Andrew, what's your preference for this series? I'd like at least the > > first patch to go into 6.5 as a fix. The second patch seems to be fairly > > low risk and I'm happy for the third arm64 patch/cleanup to go in > > 6.5-rc1 (but it depends on the second patch). If you prefer, I can pick > > them up and send a pull request to Linus next week before -rc1. > > Otherwise you (or I) can queue the first patch and leave the other two > > for 6.6. > > Thanks. I queued [1/3] for 6.5-rcX with a cc:stable. And I queued > [2/3] and [3/3] for 6.6-rc1. > > If you wish to grab any/all of these then please do so - Stephen > will tell us of the duplicate and I'll drop the mm-git copy. That's great, thanks. We'll let you know if there are any conflicts during the 6.6 preparation.
diff --git a/mm/memory.c b/mm/memory.c index f69fbc251198..fc25764016b3 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3932,6 +3932,13 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) } } + /* + * Some architectures may have to restore extra metadata to the page + * when reading from swap. This metadata may be indexed by swap entry + * so this must be called before swap_free(). + */ + arch_swap_restore(entry, folio); + /* * Remove the swap entry and conditionally try to free up the swapcache. * We're already holding a reference on the page but haven't mapped it
Commit c145e0b47c77 ("mm: streamline COW logic in do_swap_page()") moved the call to swap_free() before the call to set_pte_at(), which meant that the MTE tags could end up being freed before set_pte_at() had a chance to restore them. Fix it by adding a call to the arch_swap_restore() hook before the call to swap_free(). Signed-off-by: Peter Collingbourne <pcc@google.com> Link: https://linux-review.googlesource.com/id/I6470efa669e8bd2f841049b8c61020c510678965 Cc: <stable@vger.kernel.org> # 6.1 Fixes: c145e0b47c77 ("mm: streamline COW logic in do_swap_page()") Reported-by: Qun-wei Lin (林群崴) <Qun-wei.Lin@mediatek.com> Closes: https://lore.kernel.org/all/5050805753ac469e8d727c797c2218a9d780d434.camel@mediatek.com/ Acked-by: David Hildenbrand <david@redhat.com> Acked-by: "Huang, Ying" <ying.huang@intel.com> Reviewed-by: Steven Price <steven.price@arm.com> Acked-by: Catalin Marinas <catalin.marinas@arm.com> --- v2: - Call arch_swap_restore() directly instead of via arch_do_swap_page() mm/memory.c | 7 +++++++ 1 file changed, 7 insertions(+)