diff options
author | Hugh Dickins <hughd@google.com> | 2017-10-02 10:57:24 -0700 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-01-05 15:44:24 +0100 |
commit | f127705d26b34c053e59b47aef84b3ea564dd743 (patch) | |
tree | 0ce1bc263c875d791ca23eb9ac6854627e24f2c9 /arch | |
parent | 0c68228f7b39c96cabd89bee3e1d6bd55926df80 (diff) |
kaiser: kaiser_remove_mapping() move along the pgd
When removing the bogus comment from kaiser_remove_mapping(),
I really ought to have checked the extent of its bogosity: as
Neel points out, there is nothing to stop unmap_pud_range_nofree()
from continuing beyond the end of a pud (and starting in the wrong
position on the next).
Fix kaiser_remove_mapping() to constrain the extent and advance pgd
pointer correctly: use pgd_addr_end() macro as used throughout base
mm (but don't assume page-rounded start and size in this case).
But this bug was very unlikely to trigger in this backport: since
any buddy allocation is contained within a single pud extent, and
we are not using vmapped stacks (and are only mapping one page of
stack anyway): the only way to hit this bug here would be when
freeing a large modified ldt.
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch')
-rw-r--r-- | arch/x86/mm/kaiser.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/arch/x86/mm/kaiser.c b/arch/x86/mm/kaiser.c index 34e1d48e1339..1d50c44ff6a7 100644 --- a/arch/x86/mm/kaiser.c +++ b/arch/x86/mm/kaiser.c @@ -297,11 +297,13 @@ void kaiser_remove_mapping(unsigned long start, unsigned long size) extern void unmap_pud_range_nofree(pgd_t *pgd, unsigned long start, unsigned long end); unsigned long end = start + size; - unsigned long addr; + unsigned long addr, next; + pgd_t *pgd; - for (addr = start; addr < end; addr += PGDIR_SIZE) { - pgd_t *pgd = native_get_shadow_pgd(pgd_offset_k(addr)); - unmap_pud_range_nofree(pgd, addr, end); + pgd = native_get_shadow_pgd(pgd_offset_k(start)); + for (addr = start; addr < end; pgd++, addr = next) { + next = pgd_addr_end(addr, end); + unmap_pud_range_nofree(pgd, addr, next); } } |