xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

ANDROID: mm: prevent speculative page fault handling for userfaults

Browse Source 
handle_userfault() should be protected against a concurrent
userfaultfd_release(), therefore handling a userfaults speculatively
without mmap_lock protection should be disallowed.

Bug: 257443051
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Change-Id: Ic6ae39329c73e8849048ea15b5351a49346404d3
This commit is contained in:
Suren Baghdasaryan
2022-11-18 15:20:34 -08:00
parent 1169f70f8f
commit 0560f5f7b3
1 changed files with 3 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
mm/memory.c
View File

@@ -3387,6 +3387,8 @@ static vm_fault_t do_wp_page(struct vm_fault *vmf)
if (userfaultfd_pte_wp(vma, *vmf->pte)) {
pte_unmap_unlock(vmf->pte, vmf->ptl);
if (vmf->flags & FAULT_FLAG_SPECULATIVE)
return VM_FAULT_RETRY;
return handle_userfault(vmf, VM_UFFD_WP);
}
@@ -5010,7 +5012,7 @@ static vm_fault_t ___handle_speculative_fault(struct mm_struct *mm,
vmf.vma_page_prot = READ_ONCE(vmf.vma->vm_page_prot);
/* Can't call userland page fault handler in the speculative path */
if (unlikely(vmf.vma_flags & VM_UFFD_MISSING)) {
if (unlikely(vmf.vma_flags & __VM_UFFD_FLAGS)) {
trace_spf_vma_notsup(_RET_IP_, vmf.vma, address);
return VM_FAULT_RETRY;
}