Revision 0d777df5d8953293be090d9ab5a355db893e8357 authored by Naoya Horiguchi on 11 December 2015, 21:40:49 UTC, committed by Linus Torvalds on 12 December 2015, 18:15:34 UTC
Currently at the beginning of hugetlb_fault(), we call huge_pte_offset()
and check whether the obtained *ptep is a migration/hwpoison entry or
not. And if not, then we get to call huge_pte_alloc(). This is racy
because the *ptep could turn into migration/hwpoison entry after the
huge_pte_offset() check. This race results in BUG_ON in
huge_pte_alloc().
We don't have to call huge_pte_alloc() when the huge_pte_offset()
returns non-NULL, so let's fix this bug with moving the code into else
block.
Note that the *ptep could turn into a migration/hwpoison entry after
this block, but that's not a problem because we have another
!pte_present check later (we never go into hugetlb_no_page() in that
case.)
Fixes: 290408d4a250 ("hugetlb: hugepage migration core")
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: <stable@vger.kernel.org> [2.6.36+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 86fffe4
.gitignore
#
# NOTE! Don't add files that are generated in specific
# subdirectories here. Add them in the ".gitignore" file
# in that subdirectory instead.
#
# NOTE! Please use 'git ls-files -i --exclude-standard'
# command after changing this file, to see if there are
# any tracked files which get ignored after the change.
#
# Normal rules
#
.*
*.o
*.o.*
*.a
*.s
*.ko
*.so
*.so.dbg
*.mod.c
*.i
*.lst
*.symtypes
*.order
*.elf
*.bin
*.tar
*.gz
*.bz2
*.lzma
*.xz
*.lz4
*.lzo
*.patch
*.gcno
modules.builtin
Module.symvers
*.dwo
*.su
#
# Top-level generic files
#
/tags
/TAGS
/linux
/vmlinux
/vmlinux.32
/vmlinux-gdb.py
/vmlinuz
/System.map
/Module.markers
#
# Debian directory (make deb-pkg)
#
/debian/
#
# tar directory (make tar*-pkg)
#
/tar-install/
#
# git files that we don't want to ignore even it they are dot-files
#
!.gitignore
!.mailmap
#
# Generated include files
#
include/config
include/generated
arch/*/include/generated
# stgit generated dirs
patches-*
# quilt's files
patches
series
# cscope files
cscope.*
ncscope.*
# gnu global files
GPATH
GRTAGS
GSYMS
GTAGS
# id-utils files
ID
*.orig
*~
\#*#
#
# Leavings from module signing
#
extra_certificates
signing_key.pem
signing_key.priv
signing_key.x509
x509.genkey
# Kconfig presets
all.config
# Kdevelop4
*.kdev4
Computing file changes ...
