| Message ID | 20180809135356.4070-1-zhouxianrong@tom.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | zsmalloc: fix linking bug in init_zspage | expand |
On 08/09/2018 03:53 PM, zhouxianrong wrote: > The last partial object in last subpage of zspage should not be linked > in allocation list. Please expand the changelog. Why it should not be? What happens if it is? Kernel panic, data corruption or whatnot? So that people not familiar with zsmalloc internals can judge how important the patch is for e.g. backporting. Thanks, Vlastimil > Signed-off-by: zhouxianrong <zhouxianrong@tom.com> > --- > mm/zsmalloc.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c > index 8d87e973a4f5..24dd8da0aa59 100644 > --- a/mm/zsmalloc.c > +++ b/mm/zsmalloc.c > @@ -1040,6 +1040,8 @@ static void init_zspage(struct size_class *class, struct zspage *zspage) > * Reset OBJ_TAG_BITS bit to last link to tell > * whether it's allocated object or not. > */ > + if (off > PAGE_SIZE) > + link -= class->size / sizeof(*link); > link->next = -1UL << OBJ_TAG_BITS; > } > kunmap_atomic(vaddr); >
diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c index 8d87e973a4f5..24dd8da0aa59 100644 --- a/mm/zsmalloc.c +++ b/mm/zsmalloc.c @@ -1040,6 +1040,8 @@ static void init_zspage(struct size_class *class, struct zspage *zspage) * Reset OBJ_TAG_BITS bit to last link to tell * whether it's allocated object or not. */ + if (off > PAGE_SIZE) + link -= class->size / sizeof(*link); link->next = -1UL << OBJ_TAG_BITS; } kunmap_atomic(vaddr);
The last partial object in last subpage of zspage should not be linked in allocation list. Signed-off-by: zhouxianrong <zhouxianrong@tom.com> --- mm/zsmalloc.c | 2 ++ 1 file changed, 2 insertions(+)