The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 467ba14e1660b52a2f9338b484704c461bd23019 Mon Sep 17 00:00:00 2001 From: Nicholas Piggin npiggin@gmail.com Date: Thu, 16 Dec 2021 20:33:42 +1000 Subject: [PATCH] powerpc/64s/radix: Fix huge vmap false positive
pmd_huge() is defined to false when HUGETLB_PAGE is not configured, but the vmap code still installs huge PMDs. This leads to false bad PMD errors when vunmapping because it is not seen as a huge PTE, and the bad PMD check catches it. The end result may not be much more serious than some bad pmd warning messages, because the pmd_none_or_clear_bad() does what we wanted and clears the huge PTE anyway.
Fix this by checking pmd_is_leaf(), which checks for a PTE regardless of config options. The whole huge/large/leaf stuff is a tangled mess but that's kernel-wide and not something we can improve much in arch/powerpc code.
pmd_page(), pud_page(), etc., called by vmalloc_to_page() on huge vmaps can similarly trigger a false VM_BUG_ON when CONFIG_HUGETLB_PAGE=n, so those checks are adjusted. The checks were added by commit d6eacedd1f0e ("powerpc/book3s: Use config independent helpers for page table walk"), while implementing a similar fix for other page table walking functions.
Fixes: d909f9109c30 ("powerpc/64s/radix: Enable HAVE_ARCH_HUGE_VMAP") Cc: stable@vger.kernel.org # v5.3+ Signed-off-by: Nicholas Piggin npiggin@gmail.com Signed-off-by: Michael Ellerman mpe@ellerman.id.au Link: https://lore.kernel.org/r/20211216103342.609192-1-npiggin@gmail.com
diff --git a/arch/powerpc/mm/book3s64/radix_pgtable.c b/arch/powerpc/mm/book3s64/radix_pgtable.c index 3c4f0ebe5df8..ca23f5d1883a 100644 --- a/arch/powerpc/mm/book3s64/radix_pgtable.c +++ b/arch/powerpc/mm/book3s64/radix_pgtable.c @@ -1076,7 +1076,7 @@ int pud_set_huge(pud_t *pud, phys_addr_t addr, pgprot_t prot)
int pud_clear_huge(pud_t *pud) { - if (pud_huge(*pud)) { + if (pud_is_leaf(*pud)) { pud_clear(pud); return 1; } @@ -1123,7 +1123,7 @@ int pmd_set_huge(pmd_t *pmd, phys_addr_t addr, pgprot_t prot)
int pmd_clear_huge(pmd_t *pmd) { - if (pmd_huge(*pmd)) { + if (pmd_is_leaf(*pmd)) { pmd_clear(pmd); return 1; } diff --git a/arch/powerpc/mm/pgtable_64.c b/arch/powerpc/mm/pgtable_64.c index 78c8cf01db5f..175aabf101e8 100644 --- a/arch/powerpc/mm/pgtable_64.c +++ b/arch/powerpc/mm/pgtable_64.c @@ -102,7 +102,8 @@ EXPORT_SYMBOL(__pte_frag_size_shift); struct page *p4d_page(p4d_t p4d) { if (p4d_is_leaf(p4d)) { - VM_WARN_ON(!p4d_huge(p4d)); + if (!IS_ENABLED(CONFIG_HAVE_ARCH_HUGE_VMAP)) + VM_WARN_ON(!p4d_huge(p4d)); return pte_page(p4d_pte(p4d)); } return virt_to_page(p4d_pgtable(p4d)); @@ -112,7 +113,8 @@ struct page *p4d_page(p4d_t p4d) struct page *pud_page(pud_t pud) { if (pud_is_leaf(pud)) { - VM_WARN_ON(!pud_huge(pud)); + if (!IS_ENABLED(CONFIG_HAVE_ARCH_HUGE_VMAP)) + VM_WARN_ON(!pud_huge(pud)); return pte_page(pud_pte(pud)); } return virt_to_page(pud_pgtable(pud)); @@ -125,7 +127,13 @@ struct page *pud_page(pud_t pud) struct page *pmd_page(pmd_t pmd) { if (pmd_is_leaf(pmd)) { - VM_WARN_ON(!(pmd_large(pmd) || pmd_huge(pmd))); + /* + * vmalloc_to_page may be called on any vmap address (not only + * vmalloc), and it uses pmd_page() etc., when huge vmap is + * enabled so these checks can't be used. + */ + if (!IS_ENABLED(CONFIG_HAVE_ARCH_HUGE_VMAP)) + VM_WARN_ON(!(pmd_large(pmd) || pmd_huge(pmd))); return pte_page(pmd_pte(pmd)); } return virt_to_page(pmd_page_vaddr(pmd));