From: Dan Williams dan.j.williams@intel.com Subject: mm/huge_memory: fix vmf_insert_pfn_{pmd, pud}() crash, handle unaligned addresses

Starting with c6f3c5ee40c1 ("mm/huge_memory.c: fix modifying of page protection by insert_pfn_pmd()") vmf_insert_pfn_pmd() internally calls pmdp_set_access_flags(). That helper enforces a pmd aligned @address argument via VM_BUG_ON() assertion.

Update the implementation to take a 'struct vm_fault' argument directly and apply the address alignment fixup internally to fix crash signatures like:

kernel BUG at arch/x86/mm/pgtable.c:515! invalid opcode: 0000 [#1] SMP NOPTI CPU: 51 PID: 43713 Comm: java Tainted: G OE 4.19.35 #1 [..] RIP: 0010:pmdp_set_access_flags+0x48/0x50 [..] Call Trace: vmf_insert_pfn_pmd+0x198/0x350 dax_iomap_fault+0xe82/0x1190 ext4_dax_huge_fault+0x103/0x1f0 ? __switch_to_asm+0x40/0x70 __handle_mm_fault+0x3f6/0x1370 ? __switch_to_asm+0x34/0x70 ? __switch_to_asm+0x40/0x70 handle_mm_fault+0xda/0x200 __do_page_fault+0x249/0x4f0 do_page_fault+0x32/0x110 ? page_fault+0x8/0x30 page_fault+0x1e/0x30

Link: http://lkml.kernel.org/r/155741946350.372037.11148198430068238140.stgit@dwil... Fixes: c6f3c5ee40c1 ("mm/huge_memory.c: fix modifying of page protection by insert_pfn_pmd()") Signed-off-by: Dan Williams dan.j.williams@intel.com Reported-by: Piotr Balcer piotr.balcer@intel.com Tested-by: Yan Ma yan.ma@intel.com Tested-by: Pankaj Gupta pagupta@redhat.com Reviewed-by: Matthew Wilcox willy@infradead.org Reviewed-by: Jan Kara jack@suse.cz Reviewed-by: Aneesh Kumar K.V aneesh.kumar@linux.ibm.com Cc: Chandan Rajendra chandan@linux.ibm.com Cc: Souptick Joarder jrdr.linux@gmail.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

drivers/dax/device.c | 6 ++---- fs/dax.c | 6 ++---- include/linux/huge_mm.h | 6 ++---- mm/huge_memory.c | 16 ++++++++++------ 4 files changed, 16 insertions(+), 18 deletions(-)

--- a/drivers/dax/device.c~mm-huge_memory-fix-vmf_insert_pfn_pmd-pud-crash-handle-unaligned-addresses +++ a/drivers/dax/device.c @@ -184,8 +184,7 @@ static vm_fault_t __dev_dax_pmd_fault(st

*pfn = phys_to_pfn_t(phys, dax_region->pfn_flags);

- return vmf_insert_pfn_pmd(vmf->vma, vmf->address, vmf->pmd, *pfn, - vmf->flags & FAULT_FLAG_WRITE); + return vmf_insert_pfn_pmd(vmf, *pfn, vmf->flags & FAULT_FLAG_WRITE); }

#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD @@ -235,8 +234,7 @@ static vm_fault_t __dev_dax_pud_fault(st

*pfn = phys_to_pfn_t(phys, dax_region->pfn_flags);

- return vmf_insert_pfn_pud(vmf->vma, vmf->address, vmf->pud, *pfn, - vmf->flags & FAULT_FLAG_WRITE); + return vmf_insert_pfn_pud(vmf, *pfn, vmf->flags & FAULT_FLAG_WRITE); } #else static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax, --- a/fs/dax.c~mm-huge_memory-fix-vmf_insert_pfn_pmd-pud-crash-handle-unaligned-addresses +++ a/fs/dax.c @@ -1575,8 +1575,7 @@ static vm_fault_t dax_iomap_pmd_fault(st }

trace_dax_pmd_insert_mapping(inode, vmf, PMD_SIZE, pfn, entry); - result = vmf_insert_pfn_pmd(vma, vmf->address, vmf->pmd, pfn, - write); + result = vmf_insert_pfn_pmd(vmf, pfn, write); break; case IOMAP_UNWRITTEN: case IOMAP_HOLE: @@ -1686,8 +1685,7 @@ dax_insert_pfn_mkwrite(struct vm_fault * ret = vmf_insert_mixed_mkwrite(vmf->vma, vmf->address, pfn); #ifdef CONFIG_FS_DAX_PMD else if (order == PMD_ORDER) - ret = vmf_insert_pfn_pmd(vmf->vma, vmf->address, vmf->pmd, - pfn, true); + ret = vmf_insert_pfn_pmd(vmf, pfn, FAULT_FLAG_WRITE); #endif else ret = VM_FAULT_FALLBACK; --- a/include/linux/huge_mm.h~mm-huge_memory-fix-vmf_insert_pfn_pmd-pud-crash-handle-unaligned-addresses +++ a/include/linux/huge_mm.h @@ -47,10 +47,8 @@ extern bool move_huge_pmd(struct vm_area extern int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, unsigned long addr, pgprot_t newprot, int prot_numa); -vm_fault_t vmf_insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, - pmd_t *pmd, pfn_t pfn, bool write); -vm_fault_t vmf_insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr, - pud_t *pud, pfn_t pfn, bool write); +vm_fault_t vmf_insert_pfn_pmd(struct vm_fault *vmf, pfn_t pfn, bool write); +vm_fault_t vmf_insert_pfn_pud(struct vm_fault *vmf, pfn_t pfn, bool write); enum transparent_hugepage_flag { TRANSPARENT_HUGEPAGE_FLAG, TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, --- a/mm/huge_memory.c~mm-huge_memory-fix-vmf_insert_pfn_pmd-pud-crash-handle-unaligned-addresses +++ a/mm/huge_memory.c @@ -793,11 +793,13 @@ out_unlock: pte_free(mm, pgtable); }

-vm_fault_t vmf_insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, - pmd_t *pmd, pfn_t pfn, bool write) +vm_fault_t vmf_insert_pfn_pmd(struct vm_fault *vmf, pfn_t pfn, bool write) { + unsigned long addr = vmf->address & PMD_MASK; + struct vm_area_struct *vma = vmf->vma; pgprot_t pgprot = vma->vm_page_prot; pgtable_t pgtable = NULL; + /* * If we had pmd_special, we could avoid all these restrictions, * but we need to be consistent with PTEs and architectures that @@ -820,7 +822,7 @@ vm_fault_t vmf_insert_pfn_pmd(struct vm_

track_pfn_insert(vma, &pgprot, pfn);

- insert_pfn_pmd(vma, addr, pmd, pfn, pgprot, write, pgtable); + insert_pfn_pmd(vma, addr, vmf->pmd, pfn, pgprot, write, pgtable); return VM_FAULT_NOPAGE; } EXPORT_SYMBOL_GPL(vmf_insert_pfn_pmd); @@ -869,10 +871,12 @@ out_unlock: spin_unlock(ptl); }

-vm_fault_t vmf_insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr, - pud_t *pud, pfn_t pfn, bool write) +vm_fault_t vmf_insert_pfn_pud(struct vm_fault *vmf, pfn_t pfn, bool write) { + unsigned long addr = vmf->address & PUD_MASK; + struct vm_area_struct *vma = vmf->vma; pgprot_t pgprot = vma->vm_page_prot; + /* * If we had pud_special, we could avoid all these restrictions, * but we need to be consistent with PTEs and architectures that @@ -889,7 +893,7 @@ vm_fault_t vmf_insert_pfn_pud(struct vm_

track_pfn_insert(vma, &pgprot, pfn);

- insert_pfn_pud(vma, addr, pud, pfn, pgprot, write); + insert_pfn_pud(vma, addr, vmf->pud, pfn, pgprot, write); return VM_FAULT_NOPAGE; } EXPORT_SYMBOL_GPL(vmf_insert_pfn_pud); _