On Tue, May 11, 2021 at 03:31:15PM +0200, Matteo Croce wrote:
quoted hunk ↗ jump to hunk
@@ -101,6 +101,7 @@ struct page {
* 32-bit architectures.
*/
unsigned long dma_addr[2];
+ unsigned long signature;
};
struct { /* slab, slob and slub */
union {
No. Signature now aliases with page->mapping, which is going to go
badly wrong for drivers which map this page into userspace.
I had this as:
+ unsigned long pp_magic;
+ unsigned long xmi;
+ unsigned long _pp_mapping_pad;
unsigned long dma_addr[2];
and pp_magic needs to be set to something with bits 0&1 clear and
clearly isn't a pointer. I went with POISON_POINTER_DELTA + 0x40.