Fixes for 5.15

Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/queue-5.15/revert-arm64-kasan-revert-arm64-mte-reset-the-page-t.patch b/queue-5.15/revert-arm64-kasan-revert-arm64-mte-reset-the-page-t.patch
new file mode 100644 (file)
index 0000000..972e176
--- /dev/null
+++ b/queue-5.15/revert-arm64-kasan-revert-arm64-mte-reset-the-page-t.patch
@@ -0,0 +1,108 @@
+From 529446ff084b82f1e73c32a293f94a19a2b01a81 Mon Sep 17 00:00:00 2001
+From: Sasha Levin <sashal@kernel.org>
+Date: Mon, 12 Sep 2022 07:07:56 -0400
+Subject: Revert "arm64: kasan: Revert "arm64: mte: reset the page tag in
+ page->flags""
+
+This reverts commit add4bc9281e8704e5ab15616b429576c84f453a2.
+
+On Mon, Sep 12, 2022 at 10:52:45AM +0100, Catalin Marinas wrote:
+>I missed this (holidays) and it looks like it's in stable already. On
+>its own it will likely break kasan_hw if used together with user-space
+>MTE as this change relies on two previous commits:
+>
+>70c248aca9e7 ("mm: kasan: Skip unpoisoning of user pages")
+>6d05141a3930 ("mm: kasan: Skip page unpoisoning only if __GFP_SKIP_KASAN_UNPOISON")
+>
+>The reason I did not cc stable is that there are other dependencies in
+>this area. The potential issues without the above commits were rather
+>theoretical, so take these patches rather as clean-ups/refactoring than
+>fixes.
+
+Signed-off-by: Sasha Levin <sashal@kernel.org>
+---
+ arch/arm64/kernel/hibernate.c | 5 +++++
+ arch/arm64/kernel/mte.c       | 9 +++++++++
+ arch/arm64/mm/copypage.c      | 9 +++++++++
+ arch/arm64/mm/mteswap.c       | 9 +++++++++
+ 4 files changed, 32 insertions(+)
+
+diff --git a/arch/arm64/kernel/hibernate.c b/arch/arm64/kernel/hibernate.c
+index db93ce2b0113b..46a0b4d6e2519 100644
+--- a/arch/arm64/kernel/hibernate.c
++++ b/arch/arm64/kernel/hibernate.c
+@@ -326,6 +326,11 @@ static void swsusp_mte_restore_tags(void)
+               unsigned long pfn = xa_state.xa_index;
+               struct page *page = pfn_to_online_page(pfn);
+ 
++              /*
++               * It is not required to invoke page_kasan_tag_reset(page)
++               * at this point since the tags stored in page->flags are
++               * already restored.
++               */
+               mte_restore_page_tags(page_address(page), tags);
+ 
+               mte_free_tag_storage(tags);
+diff --git a/arch/arm64/kernel/mte.c b/arch/arm64/kernel/mte.c
+index 10207e3e5ae20..7c1c82c8115cc 100644
+--- a/arch/arm64/kernel/mte.c
++++ b/arch/arm64/kernel/mte.c
+@@ -44,6 +44,15 @@ static void mte_sync_page_tags(struct page *page, pte_t old_pte,
+       if (!pte_is_tagged)
+               return;
+ 
++      page_kasan_tag_reset(page);
++      /*
++       * We need smp_wmb() in between setting the flags and clearing the
++       * tags because if another thread reads page->flags and builds a
++       * tagged address out of it, there is an actual dependency to the
++       * memory access, but on the current thread we do not guarantee that
++       * the new page->flags are visible before the tags were updated.
++       */
++      smp_wmb();
+       mte_clear_page_tags(page_address(page));
+ }
+ 
+diff --git a/arch/arm64/mm/copypage.c b/arch/arm64/mm/copypage.c
+index 24913271e898c..0dea80bf6de46 100644
+--- a/arch/arm64/mm/copypage.c
++++ b/arch/arm64/mm/copypage.c
+@@ -23,6 +23,15 @@ void copy_highpage(struct page *to, struct page *from)
+ 
+       if (system_supports_mte() && test_bit(PG_mte_tagged, &from->flags)) {
+               set_bit(PG_mte_tagged, &to->flags);
++              page_kasan_tag_reset(to);
++              /*
++               * We need smp_wmb() in between setting the flags and clearing the
++               * tags because if another thread reads page->flags and builds a
++               * tagged address out of it, there is an actual dependency to the
++               * memory access, but on the current thread we do not guarantee that
++               * the new page->flags are visible before the tags were updated.
++               */
++              smp_wmb();
+               mte_copy_page_tags(kto, kfrom);
+       }
+ }
+diff --git a/arch/arm64/mm/mteswap.c b/arch/arm64/mm/mteswap.c
+index c52c1847079c1..7c4ef56265ee1 100644
+--- a/arch/arm64/mm/mteswap.c
++++ b/arch/arm64/mm/mteswap.c
+@@ -53,6 +53,15 @@ bool mte_restore_tags(swp_entry_t entry, struct page *page)
+       if (!tags)
+               return false;
+ 
++      page_kasan_tag_reset(page);
++      /*
++       * We need smp_wmb() in between setting the flags and clearing the
++       * tags because if another thread reads page->flags and builds a
++       * tagged address out of it, there is an actual dependency to the
++       * memory access, but on the current thread we do not guarantee that
++       * the new page->flags are visible before the tags were updated.
++       */
++      smp_wmb();
+       mte_restore_page_tags(page_address(page), tags);
+ 
+       return true;
+-- 
+2.35.1
+

diff --git a/queue-5.15/series b/queue-5.15/series
index d3b140993ad852622395ec239ced08d13b628f02..5c3fd1da54fc39ec5c744f8e9dbb44aa61fb1e5d 100644 (file)
--- a/queue-5.15/series
+++ b/queue-5.15/series
@@ -112,3 +112,4 @@ hwmon-mr75203-update-pvt-v_num-and-vm_num-to-the-act.patch
 hwmon-mr75203-fix-voltage-equation-for-negative-sour.patch
 hwmon-mr75203-fix-multi-channel-voltage-reading.patch
 hwmon-mr75203-enable-polling-for-all-vm-channels.patch
+revert-arm64-kasan-revert-arm64-mte-reset-the-page-t.patch