diff options
| author | Mark Brown <broonie@kernel.org> | 2016-03-18 09:45:54 +0000 |
|---|---|---|
| committer | Mark Brown <broonie@kernel.org> | 2016-03-18 09:45:54 +0000 |
| commit | ddbcfcba5fdc56f30e4d02c3bac8cf965502cece (patch) | |
| tree | 235f05605003ed8dc119ead980cf86157eb695e8 /mm/memory.c | |
| parent | dfabba9c3737ce7a2574dcf58940f038e536e233 (diff) | |
| parent | 62e21959dc6f25c5fce0c1a0934e4a9d982bf99b (diff) | |
Merge tag 'v4.4.5' into linux-linaro-lsk-v4.4
This is the 4.4.5 stable release
# gpg: Signature made Wed 09 Mar 2016 23:36:03 GMT using RSA key ID 6092693E
# gpg: Good signature from "Greg Kroah-Hartman (Linux kernel stable release signing key) <greg@kroah.com>"
# gpg: WARNING: This key is not certified with a trusted signature!
# gpg: There is no indication that the signature belongs to the owner.
# Primary key fingerprint: 647F 2865 4894 E3BD 4571 99BE 38DB BDC8 6092 693E
Diffstat (limited to 'mm/memory.c')
| -rw-r--r-- | mm/memory.c | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/mm/memory.c b/mm/memory.c index c387430f06c3..b80bf4746b67 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3399,8 +3399,18 @@ static int __handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma, if (unlikely(pmd_none(*pmd)) && unlikely(__pte_alloc(mm, vma, pmd, address))) return VM_FAULT_OOM; - /* if an huge pmd materialized from under us just retry later */ - if (unlikely(pmd_trans_huge(*pmd))) + /* + * If a huge pmd materialized under us just retry later. Use + * pmd_trans_unstable() instead of pmd_trans_huge() to ensure the pmd + * didn't become pmd_trans_huge under us and then back to pmd_none, as + * a result of MADV_DONTNEED running immediately after a huge pmd fault + * in a different thread of this mm, in turn leading to a misleading + * pmd_trans_huge() retval. All we have to ensure is that it is a + * regular pmd that we can walk with pte_offset_map() and we can do that + * through an atomic read in C, which is what pmd_trans_unstable() + * provides. + */ + if (unlikely(pmd_trans_unstable(pmd))) return 0; /* * A regular pmd is established and it can't morph into a huge pmd |