--- /dev/null
+From 39d3454c3513840eb123b3913fda6903e45ce671 Mon Sep 17 00:00:00 2001
+From: Russell King <rmk+kernel@armlinux.org.uk>
+Date: Sun, 18 Oct 2020 09:39:21 +0100
+Subject: ARM: footbridge: fix dc21285 PCI configuration accessors
+
+From: Russell King <rmk+kernel@armlinux.org.uk>
+
+commit 39d3454c3513840eb123b3913fda6903e45ce671 upstream.
+
+Building with gcc 4.9.2 reveals a latent bug in the PCI accessors
+for Footbridge platforms, which causes a fatal alignment fault
+while accessing IO memory. Fix this by making the assembly volatile.
+
+Cc: stable@vger.kernel.org
+Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ arch/arm/mach-footbridge/dc21285.c | 12 ++++++------
+ 1 file changed, 6 insertions(+), 6 deletions(-)
+
+--- a/arch/arm/mach-footbridge/dc21285.c
++++ b/arch/arm/mach-footbridge/dc21285.c
+@@ -66,15 +66,15 @@ dc21285_read_config(struct pci_bus *bus,
+ if (addr)
+ switch (size) {
+ case 1:
+- asm("ldrb %0, [%1, %2]"
++ asm volatile("ldrb %0, [%1, %2]"
+ : "=r" (v) : "r" (addr), "r" (where) : "cc");
+ break;
+ case 2:
+- asm("ldrh %0, [%1, %2]"
++ asm volatile("ldrh %0, [%1, %2]"
+ : "=r" (v) : "r" (addr), "r" (where) : "cc");
+ break;
+ case 4:
+- asm("ldr %0, [%1, %2]"
++ asm volatile("ldr %0, [%1, %2]"
+ : "=r" (v) : "r" (addr), "r" (where) : "cc");
+ break;
+ }
+@@ -100,17 +100,17 @@ dc21285_write_config(struct pci_bus *bus
+ if (addr)
+ switch (size) {
+ case 1:
+- asm("strb %0, [%1, %2]"
++ asm volatile("strb %0, [%1, %2]"
+ : : "r" (value), "r" (addr), "r" (where)
+ : "cc");
+ break;
+ case 2:
+- asm("strh %0, [%1, %2]"
++ asm volatile("strh %0, [%1, %2]"
+ : : "r" (value), "r" (addr), "r" (where)
+ : "cc");
+ break;
+ case 4:
+- asm("str %0, [%1, %2]"
++ asm volatile("str %0, [%1, %2]"
+ : : "r" (value), "r" (addr), "r" (where)
+ : "cc");
+ break;
--- /dev/null
+From ccd85d90ce092bdb047a7f6580f3955393833b22 Mon Sep 17 00:00:00 2001
+From: Sean Christopherson <seanjc@google.com>
+Date: Tue, 2 Feb 2021 13:20:17 -0800
+Subject: KVM: SVM: Treat SVM as unsupported when running as an SEV guest
+
+From: Sean Christopherson <seanjc@google.com>
+
+commit ccd85d90ce092bdb047a7f6580f3955393833b22 upstream.
+
+Don't let KVM load when running as an SEV guest, regardless of what
+CPUID says. Memory is encrypted with a key that is not accessible to
+the host (L0), thus it's impossible for L0 to emulate SVM, e.g. it'll
+see garbage when reading the VMCB.
+
+Technically, KVM could decrypt all memory that needs to be accessible to
+the L0 and use shadow paging so that L0 does not need to shadow NPT, but
+exposing such information to L0 largely defeats the purpose of running as
+an SEV guest. This can always be revisited if someone comes up with a
+use case for running VMs inside SEV guests.
+
+Note, VMLOAD, VMRUN, etc... will also #GP on GPAs with C-bit set, i.e. KVM
+is doomed even if the SEV guest is debuggable and the hypervisor is willing
+to decrypt the VMCB. This may or may not be fixed on CPUs that have the
+SVME_ADDR_CHK fix.
+
+Cc: stable@vger.kernel.org
+Signed-off-by: Sean Christopherson <seanjc@google.com>
+Message-Id: <20210202212017.2486595-1-seanjc@google.com>
+Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ arch/x86/kvm/svm.c | 5 +++++
+ arch/x86/mm/mem_encrypt.c | 1 +
+ 2 files changed, 6 insertions(+)
+
+--- a/arch/x86/kvm/svm.c
++++ b/arch/x86/kvm/svm.c
+@@ -889,6 +889,11 @@ static int has_svm(void)
+ return 0;
+ }
+
++ if (sev_active()) {
++ pr_info("KVM is unsupported when running as an SEV guest\n");
++ return 0;
++ }
++
+ return 1;
+ }
+
+--- a/arch/x86/mm/mem_encrypt.c
++++ b/arch/x86/mm/mem_encrypt.c
+@@ -375,6 +375,7 @@ bool force_dma_unencrypted(struct device
+
+ return false;
+ }
++EXPORT_SYMBOL_GPL(sev_active);
+
+ /* Architecture __weak replacement functions */
+ void __init mem_encrypt_free_decrypted_mem(void)
--- /dev/null
+From 943dea8af21bd896e0d6c30ea221203fb3cd3265 Mon Sep 17 00:00:00 2001
+From: Sean Christopherson <seanjc@google.com>
+Date: Tue, 2 Feb 2021 08:55:46 -0800
+Subject: KVM: x86: Update emulator context mode if SYSENTER xfers to 64-bit mode
+
+From: Sean Christopherson <seanjc@google.com>
+
+commit 943dea8af21bd896e0d6c30ea221203fb3cd3265 upstream.
+
+Set the emulator context to PROT64 if SYSENTER transitions from 32-bit
+userspace (compat mode) to a 64-bit kernel, otherwise the RIP update at
+the end of x86_emulate_insn() will incorrectly truncate the new RIP.
+
+Note, this bug is mostly limited to running an Intel virtual CPU model on
+an AMD physical CPU, as other combinations of virtual and physical CPUs
+do not trigger full emulation. On Intel CPUs, SYSENTER in compatibility
+mode is legal, and unconditionally transitions to 64-bit mode. On AMD
+CPUs, SYSENTER is illegal in compatibility mode and #UDs. If the vCPU is
+AMD, KVM injects a #UD on SYSENTER in compat mode. If the pCPU is Intel,
+SYSENTER will execute natively and not trigger #UD->VM-Exit (ignoring
+guest TLB shenanigans).
+
+Fixes: fede8076aab4 ("KVM: x86: handle wrap around 32-bit address space")
+Cc: stable@vger.kernel.org
+Signed-off-by: Jonny Barker <jonny@jonnybarker.com>
+[sean: wrote changelog]
+Signed-off-by: Sean Christopherson <seanjc@google.com>
+Message-Id: <20210202165546.2390296-1-seanjc@google.com>
+Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ arch/x86/kvm/emulate.c | 2 ++
+ 1 file changed, 2 insertions(+)
+
+--- a/arch/x86/kvm/emulate.c
++++ b/arch/x86/kvm/emulate.c
+@@ -2890,6 +2890,8 @@ static int em_sysenter(struct x86_emulat
+ ops->get_msr(ctxt, MSR_IA32_SYSENTER_ESP, &msr_data);
+ *reg_write(ctxt, VCPU_REGS_RSP) = (efer & EFER_LMA) ? msr_data :
+ (u32)msr_data;
++ if (efer & EFER_LMA)
++ ctxt->mode = X86EMUL_MODE_PROT64;
+
+ return X86EMUL_CONTINUE;
+ }
--- /dev/null
+From 74e21484e40bb8ce0f9828bbfe1c9fc9b04249c6 Mon Sep 17 00:00:00 2001
+From: Rokudo Yan <wu-yan@tcl.com>
+Date: Thu, 4 Feb 2021 18:32:20 -0800
+Subject: mm, compaction: move high_pfn to the for loop scope
+
+From: Rokudo Yan <wu-yan@tcl.com>
+
+commit 74e21484e40bb8ce0f9828bbfe1c9fc9b04249c6 upstream.
+
+In fast_isolate_freepages, high_pfn will be used if a prefered one (ie
+PFN >= low_fn) not found.
+
+But the high_pfn is not reset before searching an free area, so when it
+was used as freepage, it may from another free area searched before. As
+a result move_freelist_head(freelist, freepage) will have unexpected
+behavior (eg corrupt the MOVABLE freelist)
+
+ Unable to handle kernel paging request at virtual address dead000000000200
+ Mem abort info:
+ ESR = 0x96000044
+ Exception class = DABT (current EL), IL = 32 bits
+ SET = 0, FnV = 0
+ EA = 0, S1PTW = 0
+ Data abort info:
+ ISV = 0, ISS = 0x00000044
+ CM = 0, WnR = 1
+ [dead000000000200] address between user and kernel address ranges
+
+ -000|list_cut_before(inline)
+ -000|move_freelist_head(inline)
+ -000|fast_isolate_freepages(inline)
+ -000|isolate_freepages(inline)
+ -000|compaction_alloc(?, ?)
+ -001|unmap_and_move(inline)
+ -001|migrate_pages([NSD:0xFFFFFF80088CBBD0] from = 0xFFFFFF80088CBD88, [NSD:0xFFFFFF80088CBBC8] get_new_p
+ -002|__read_once_size(inline)
+ -002|static_key_count(inline)
+ -002|static_key_false(inline)
+ -002|trace_mm_compaction_migratepages(inline)
+ -002|compact_zone(?, [NSD:0xFFFFFF80088CBCB0] capc = 0x0)
+ -003|kcompactd_do_work(inline)
+ -003|kcompactd([X19] p = 0xFFFFFF93227FBC40)
+ -004|kthread([X20] _create = 0xFFFFFFE1AFB26380)
+ -005|ret_from_fork(asm)
+
+The issue was reported on an smart phone product with 6GB ram and 3GB
+zram as swap device.
+
+This patch fixes the issue by reset high_pfn before searching each free
+area, which ensure freepage and freelist match when call
+move_freelist_head in fast_isolate_freepages().
+
+Link: http://lkml.kernel.org/r/20190118175136.31341-12-mgorman@techsingularity.net
+Link: https://lkml.kernel.org/r/20210112094720.1238444-1-wu-yan@tcl.com
+Fixes: 5a811889de10f1eb ("mm, compaction: use free lists to quickly locate a migration target")
+Signed-off-by: Rokudo Yan <wu-yan@tcl.com>
+Acked-by: Mel Gorman <mgorman@techsingularity.net>
+Acked-by: Vlastimil Babka <vbabka@suse.cz>
+Cc: <stable@vger.kernel.org>
+Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
+Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ mm/compaction.c | 3 ++-
+ 1 file changed, 2 insertions(+), 1 deletion(-)
+
+--- a/mm/compaction.c
++++ b/mm/compaction.c
+@@ -1276,7 +1276,7 @@ fast_isolate_freepages(struct compact_co
+ {
+ unsigned int limit = min(1U, freelist_scan_limit(cc) >> 1);
+ unsigned int nr_scanned = 0;
+- unsigned long low_pfn, min_pfn, high_pfn = 0, highest = 0;
++ unsigned long low_pfn, min_pfn, highest = 0;
+ unsigned long nr_isolated = 0;
+ unsigned long distance;
+ struct page *page = NULL;
+@@ -1321,6 +1321,7 @@ fast_isolate_freepages(struct compact_co
+ struct page *freepage;
+ unsigned long flags;
+ unsigned int order_scanned = 0;
++ unsigned long high_pfn = 0;
+
+ if (!area->nr_free)
+ continue;
--- /dev/null
+From 7ffddd499ba6122b1a07828f023d1d67629aa017 Mon Sep 17 00:00:00 2001
+From: Muchun Song <songmuchun@bytedance.com>
+Date: Thu, 4 Feb 2021 18:32:06 -0800
+Subject: mm: hugetlb: fix a race between freeing and dissolving the page
+
+From: Muchun Song <songmuchun@bytedance.com>
+
+commit 7ffddd499ba6122b1a07828f023d1d67629aa017 upstream.
+
+There is a race condition between __free_huge_page()
+and dissolve_free_huge_page().
+
+ CPU0: CPU1:
+
+ // page_count(page) == 1
+ put_page(page)
+ __free_huge_page(page)
+ dissolve_free_huge_page(page)
+ spin_lock(&hugetlb_lock)
+ // PageHuge(page) && !page_count(page)
+ update_and_free_page(page)
+ // page is freed to the buddy
+ spin_unlock(&hugetlb_lock)
+ spin_lock(&hugetlb_lock)
+ clear_page_huge_active(page)
+ enqueue_huge_page(page)
+ // It is wrong, the page is already freed
+ spin_unlock(&hugetlb_lock)
+
+The race window is between put_page() and dissolve_free_huge_page().
+
+We should make sure that the page is already on the free list when it is
+dissolved.
+
+As a result __free_huge_page would corrupt page(s) already in the buddy
+allocator.
+
+Link: https://lkml.kernel.org/r/20210115124942.46403-4-songmuchun@bytedance.com
+Fixes: c8721bbbdd36 ("mm: memory-hotplug: enable memory hotplug to handle hugepage")
+Signed-off-by: Muchun Song <songmuchun@bytedance.com>
+Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
+Reviewed-by: Oscar Salvador <osalvador@suse.de>
+Acked-by: Michal Hocko <mhocko@suse.com>
+Cc: David Hildenbrand <david@redhat.com>
+Cc: Yang Shi <shy828301@gmail.com>
+Cc: <stable@vger.kernel.org>
+Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
+Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ mm/hugetlb.c | 39 +++++++++++++++++++++++++++++++++++++++
+ 1 file changed, 39 insertions(+)
+
+--- a/mm/hugetlb.c
++++ b/mm/hugetlb.c
+@@ -71,6 +71,21 @@ DEFINE_SPINLOCK(hugetlb_lock);
+ static int num_fault_mutexes;
+ struct mutex *hugetlb_fault_mutex_table ____cacheline_aligned_in_smp;
+
++static inline bool PageHugeFreed(struct page *head)
++{
++ return page_private(head + 4) == -1UL;
++}
++
++static inline void SetPageHugeFreed(struct page *head)
++{
++ set_page_private(head + 4, -1UL);
++}
++
++static inline void ClearPageHugeFreed(struct page *head)
++{
++ set_page_private(head + 4, 0);
++}
++
+ /* Forward declaration */
+ static int hugetlb_acct_memory(struct hstate *h, long delta);
+
+@@ -869,6 +884,7 @@ static void enqueue_huge_page(struct hst
+ list_move(&page->lru, &h->hugepage_freelists[nid]);
+ h->free_huge_pages++;
+ h->free_huge_pages_node[nid]++;
++ SetPageHugeFreed(page);
+ }
+
+ static struct page *dequeue_huge_page_node_exact(struct hstate *h, int nid)
+@@ -886,6 +902,7 @@ static struct page *dequeue_huge_page_no
+ return NULL;
+ list_move(&page->lru, &h->hugepage_activelist);
+ set_page_refcounted(page);
++ ClearPageHugeFreed(page);
+ h->free_huge_pages--;
+ h->free_huge_pages_node[nid]--;
+ return page;
+@@ -1375,6 +1392,7 @@ static void prep_new_huge_page(struct hs
+ set_hugetlb_cgroup(page, NULL);
+ h->nr_huge_pages++;
+ h->nr_huge_pages_node[nid]++;
++ ClearPageHugeFreed(page);
+ spin_unlock(&hugetlb_lock);
+ }
+
+@@ -1602,6 +1620,7 @@ int dissolve_free_huge_page(struct page
+ {
+ int rc = -EBUSY;
+
++retry:
+ /* Not to disrupt normal path by vainly holding hugetlb_lock */
+ if (!PageHuge(page))
+ return 0;
+@@ -1618,6 +1637,26 @@ int dissolve_free_huge_page(struct page
+ int nid = page_to_nid(head);
+ if (h->free_huge_pages - h->resv_huge_pages == 0)
+ goto out;
++
++ /*
++ * We should make sure that the page is already on the free list
++ * when it is dissolved.
++ */
++ if (unlikely(!PageHugeFreed(head))) {
++ spin_unlock(&hugetlb_lock);
++ cond_resched();
++
++ /*
++ * Theoretically, we should return -EBUSY when we
++ * encounter this race. In fact, we have a chance
++ * to successfully dissolve the page if we do a
++ * retry. Because the race window is quite small.
++ * If we seize this opportunity, it is an optimization
++ * for increasing the success rate of dissolving page.
++ */
++ goto retry;
++ }
++
+ /*
+ * Move PageHWPoison flag from head page to the raw error page,
+ * which makes any subpages rather than the error page reusable.
--- /dev/null
+From 0eb2df2b5629794020f75e94655e1994af63f0d4 Mon Sep 17 00:00:00 2001
+From: Muchun Song <songmuchun@bytedance.com>
+Date: Thu, 4 Feb 2021 18:32:10 -0800
+Subject: mm: hugetlb: fix a race between isolating and freeing page
+
+From: Muchun Song <songmuchun@bytedance.com>
+
+commit 0eb2df2b5629794020f75e94655e1994af63f0d4 upstream.
+
+There is a race between isolate_huge_page() and __free_huge_page().
+
+ CPU0: CPU1:
+
+ if (PageHuge(page))
+ put_page(page)
+ __free_huge_page(page)
+ spin_lock(&hugetlb_lock)
+ update_and_free_page(page)
+ set_compound_page_dtor(page,
+ NULL_COMPOUND_DTOR)
+ spin_unlock(&hugetlb_lock)
+ isolate_huge_page(page)
+ // trigger BUG_ON
+ VM_BUG_ON_PAGE(!PageHead(page), page)
+ spin_lock(&hugetlb_lock)
+ page_huge_active(page)
+ // trigger BUG_ON
+ VM_BUG_ON_PAGE(!PageHuge(page), page)
+ spin_unlock(&hugetlb_lock)
+
+When we isolate a HugeTLB page on CPU0. Meanwhile, we free it to the
+buddy allocator on CPU1. Then, we can trigger a BUG_ON on CPU0, because
+it is already freed to the buddy allocator.
+
+Link: https://lkml.kernel.org/r/20210115124942.46403-5-songmuchun@bytedance.com
+Fixes: c8721bbbdd36 ("mm: memory-hotplug: enable memory hotplug to handle hugepage")
+Signed-off-by: Muchun Song <songmuchun@bytedance.com>
+Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
+Acked-by: Michal Hocko <mhocko@suse.com>
+Reviewed-by: Oscar Salvador <osalvador@suse.de>
+Cc: David Hildenbrand <david@redhat.com>
+Cc: Yang Shi <shy828301@gmail.com>
+Cc: <stable@vger.kernel.org>
+Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
+Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ mm/hugetlb.c | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+--- a/mm/hugetlb.c
++++ b/mm/hugetlb.c
+@@ -5175,9 +5175,9 @@ bool isolate_huge_page(struct page *page
+ {
+ bool ret = true;
+
+- VM_BUG_ON_PAGE(!PageHead(page), page);
+ spin_lock(&hugetlb_lock);
+- if (!page_huge_active(page) || !get_page_unless_zero(page)) {
++ if (!PageHeadHuge(page) || !page_huge_active(page) ||
++ !get_page_unless_zero(page)) {
+ ret = false;
+ goto unlock;
+ }
--- /dev/null
+From ecbf4724e6061b4b01be20f6d797d64d462b2bc8 Mon Sep 17 00:00:00 2001
+From: Muchun Song <songmuchun@bytedance.com>
+Date: Thu, 4 Feb 2021 18:32:13 -0800
+Subject: mm: hugetlb: remove VM_BUG_ON_PAGE from page_huge_active
+
+From: Muchun Song <songmuchun@bytedance.com>
+
+commit ecbf4724e6061b4b01be20f6d797d64d462b2bc8 upstream.
+
+The page_huge_active() can be called from scan_movable_pages() which do
+not hold a reference count to the HugeTLB page. So when we call
+page_huge_active() from scan_movable_pages(), the HugeTLB page can be
+freed parallel. Then we will trigger a BUG_ON which is in the
+page_huge_active() when CONFIG_DEBUG_VM is enabled. Just remove the
+VM_BUG_ON_PAGE.
+
+Link: https://lkml.kernel.org/r/20210115124942.46403-6-songmuchun@bytedance.com
+Fixes: 7e1f049efb86 ("mm: hugetlb: cleanup using paeg_huge_active()")
+Signed-off-by: Muchun Song <songmuchun@bytedance.com>
+Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
+Acked-by: Michal Hocko <mhocko@suse.com>
+Reviewed-by: Oscar Salvador <osalvador@suse.de>
+Cc: David Hildenbrand <david@redhat.com>
+Cc: Yang Shi <shy828301@gmail.com>
+Cc: <stable@vger.kernel.org>
+Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
+Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ mm/hugetlb.c | 3 +--
+ 1 file changed, 1 insertion(+), 2 deletions(-)
+
+--- a/mm/hugetlb.c
++++ b/mm/hugetlb.c
+@@ -1234,8 +1234,7 @@ struct hstate *size_to_hstate(unsigned l
+ */
+ bool page_huge_active(struct page *page)
+ {
+- VM_BUG_ON_PAGE(!PageHuge(page), page);
+- return PageHead(page) && PagePrivate(&page[1]);
++ return PageHeadHuge(page) && PagePrivate(&page[1]);
+ }
+
+ /* never called for tail page */
--- /dev/null
+From 585fc0d2871c9318c949fbf45b1f081edd489e96 Mon Sep 17 00:00:00 2001
+From: Muchun Song <songmuchun@bytedance.com>
+Date: Thu, 4 Feb 2021 18:32:03 -0800
+Subject: mm: hugetlbfs: fix cannot migrate the fallocated HugeTLB page
+
+From: Muchun Song <songmuchun@bytedance.com>
+
+commit 585fc0d2871c9318c949fbf45b1f081edd489e96 upstream.
+
+If a new hugetlb page is allocated during fallocate it will not be
+marked as active (set_page_huge_active) which will result in a later
+isolate_huge_page failure when the page migration code would like to
+move that page. Such a failure would be unexpected and wrong.
+
+Only export set_page_huge_active, just leave clear_page_huge_active as
+static. Because there are no external users.
+
+Link: https://lkml.kernel.org/r/20210115124942.46403-3-songmuchun@bytedance.com
+Fixes: 70c3547e36f5 (hugetlbfs: add hugetlbfs_fallocate())
+Signed-off-by: Muchun Song <songmuchun@bytedance.com>
+Acked-by: Michal Hocko <mhocko@suse.com>
+Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
+Reviewed-by: Oscar Salvador <osalvador@suse.de>
+Cc: David Hildenbrand <david@redhat.com>
+Cc: Yang Shi <shy828301@gmail.com>
+Cc: <stable@vger.kernel.org>
+Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
+Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ fs/hugetlbfs/inode.c | 3 ++-
+ include/linux/hugetlb.h | 2 ++
+ mm/hugetlb.c | 2 +-
+ 3 files changed, 5 insertions(+), 2 deletions(-)
+
+--- a/fs/hugetlbfs/inode.c
++++ b/fs/hugetlbfs/inode.c
+@@ -675,9 +675,10 @@ static long hugetlbfs_fallocate(struct f
+
+ mutex_unlock(&hugetlb_fault_mutex_table[hash]);
+
++ set_page_huge_active(page);
+ /*
+ * unlock_page because locked by add_to_page_cache()
+- * page_put due to reference from alloc_huge_page()
++ * put_page() due to reference from alloc_huge_page()
+ */
+ unlock_page(page);
+ put_page(page);
+--- a/include/linux/hugetlb.h
++++ b/include/linux/hugetlb.h
+@@ -590,6 +590,8 @@ static inline void huge_ptep_modify_prot
+ }
+ #endif
+
++void set_page_huge_active(struct page *page);
++
+ #else /* CONFIG_HUGETLB_PAGE */
+ struct hstate {};
+
+--- a/mm/hugetlb.c
++++ b/mm/hugetlb.c
+@@ -1222,7 +1222,7 @@ bool page_huge_active(struct page *page)
+ }
+
+ /* never called for tail page */
+-static void set_page_huge_active(struct page *page)
++void set_page_huge_active(struct page *page)
+ {
+ VM_BUG_ON_PAGE(!PageHeadHuge(page), page);
+ SetPagePrivate(&page[1]);
--- /dev/null
+From 1c2f67308af4c102b4e1e6cd6f69819ae59408e0 Mon Sep 17 00:00:00 2001
+From: Hugh Dickins <hughd@google.com>
+Date: Thu, 4 Feb 2021 18:32:31 -0800
+Subject: mm: thp: fix MADV_REMOVE deadlock on shmem THP
+
+From: Hugh Dickins <hughd@google.com>
+
+commit 1c2f67308af4c102b4e1e6cd6f69819ae59408e0 upstream.
+
+Sergey reported deadlock between kswapd correctly doing its usual
+lock_page(page) followed by down_read(page->mapping->i_mmap_rwsem), and
+madvise(MADV_REMOVE) on an madvise(MADV_HUGEPAGE) area doing
+down_write(page->mapping->i_mmap_rwsem) followed by lock_page(page).
+
+This happened when shmem_fallocate(punch hole)'s unmap_mapping_range()
+reaches zap_pmd_range()'s call to __split_huge_pmd(). The same deadlock
+could occur when partially truncating a mapped huge tmpfs file, or using
+fallocate(FALLOC_FL_PUNCH_HOLE) on it.
+
+__split_huge_pmd()'s page lock was added in 5.8, to make sure that any
+concurrent use of reuse_swap_page() (holding page lock) could not catch
+the anon THP's mapcounts and swapcounts while they were being split.
+
+Fortunately, reuse_swap_page() is never applied to a shmem or file THP
+(not even by khugepaged, which checks PageSwapCache before calling), and
+anonymous THPs are never created in shmem or file areas: so that
+__split_huge_pmd()'s page lock can only be necessary for anonymous THPs,
+on which there is no risk of deadlock with i_mmap_rwsem.
+
+Link: https://lkml.kernel.org/r/alpine.LSU.2.11.2101161409470.2022@eggly.anvils
+Fixes: c444eb564fb1 ("mm: thp: make the THP mapcount atomic against __split_huge_pmd_locked()")
+Signed-off-by: Hugh Dickins <hughd@google.com>
+Reported-by: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
+Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
+Cc: <stable@vger.kernel.org>
+Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
+Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ mm/huge_memory.c | 37 +++++++++++++++++++++++--------------
+ 1 file changed, 23 insertions(+), 14 deletions(-)
+
+--- a/mm/huge_memory.c
++++ b/mm/huge_memory.c
+@@ -2306,7 +2306,7 @@ void __split_huge_pmd(struct vm_area_str
+ {
+ spinlock_t *ptl;
+ struct mmu_notifier_range range;
+- bool was_locked = false;
++ bool do_unlock_page = false;
+ pmd_t _pmd;
+
+ mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm,
+@@ -2322,7 +2322,6 @@ void __split_huge_pmd(struct vm_area_str
+ VM_BUG_ON(freeze && !page);
+ if (page) {
+ VM_WARN_ON_ONCE(!PageLocked(page));
+- was_locked = true;
+ if (page != pmd_page(*pmd))
+ goto out;
+ }
+@@ -2331,19 +2330,29 @@ repeat:
+ if (pmd_trans_huge(*pmd)) {
+ if (!page) {
+ page = pmd_page(*pmd);
+- if (unlikely(!trylock_page(page))) {
+- get_page(page);
+- _pmd = *pmd;
+- spin_unlock(ptl);
+- lock_page(page);
+- spin_lock(ptl);
+- if (unlikely(!pmd_same(*pmd, _pmd))) {
+- unlock_page(page);
++ /*
++ * An anonymous page must be locked, to ensure that a
++ * concurrent reuse_swap_page() sees stable mapcount;
++ * but reuse_swap_page() is not used on shmem or file,
++ * and page lock must not be taken when zap_pmd_range()
++ * calls __split_huge_pmd() while i_mmap_lock is held.
++ */
++ if (PageAnon(page)) {
++ if (unlikely(!trylock_page(page))) {
++ get_page(page);
++ _pmd = *pmd;
++ spin_unlock(ptl);
++ lock_page(page);
++ spin_lock(ptl);
++ if (unlikely(!pmd_same(*pmd, _pmd))) {
++ unlock_page(page);
++ put_page(page);
++ page = NULL;
++ goto repeat;
++ }
+ put_page(page);
+- page = NULL;
+- goto repeat;
+ }
+- put_page(page);
++ do_unlock_page = true;
+ }
+ }
+ if (PageMlocked(page))
+@@ -2353,7 +2362,7 @@ repeat:
+ __split_huge_pmd_locked(vma, pmd, range.start, freeze);
+ out:
+ spin_unlock(ptl);
+- if (!was_locked && page)
++ if (do_unlock_page)
+ unlock_page(page);
+ /*
+ * No need to double call mmu_notifier->invalidate_range() callback.
mmc-core-limit-retries-when-analyse-of-sdio-tuples-fails.patch
drm-amd-display-revert-fix-edid-parsing-after-resume-from-suspend.patch
nvme-pci-avoid-the-deepest-sleep-state-on-kingston-a2000-ssds.patch
+kvm-svm-treat-svm-as-unsupported-when-running-as-an-sev-guest.patch
+kvm-x86-update-emulator-context-mode-if-sysenter-xfers-to-64-bit-mode.patch
+arm-footbridge-fix-dc21285-pci-configuration-accessors.patch
+mm-hugetlbfs-fix-cannot-migrate-the-fallocated-hugetlb-page.patch
+mm-hugetlb-fix-a-race-between-freeing-and-dissolving-the-page.patch
+mm-hugetlb-fix-a-race-between-isolating-and-freeing-page.patch
+mm-hugetlb-remove-vm_bug_on_page-from-page_huge_active.patch
+mm-compaction-move-high_pfn-to-the-for-loop-scope.patch
+mm-thp-fix-madv_remove-deadlock-on-shmem-thp.patch
projects / thirdparty / kernel / stable-queue.git / commitdiff
