On 2022-03-23 12:48:29 [+0100], Vlastimil Babka wrote: > > +#ifdef CONFIG_KASAN_HW_TAGS > > #define ___GFP_SKIP_KASAN_POISON 0x1000000u > > +#else > > +#define ___GFP_SKIP_KASAN_POISON 0 > > +#endif > > #ifdef CONFIG_LOCKDEP > > #define ___GFP_NOLOCKDEP 0x2000000u > > #else > > @@ -251,7 +255,9 @@ struct vm_area_struct; > > #define __GFP_NOLOCKDEP ((__force gfp_t)___GFP_NOLOCKDEP) > > > > /* Room for N __GFP_FOO bits */ > > -#define __GFP_BITS_SHIFT (25 + IS_ENABLED(CONFIG_LOCKDEP)) > > +#define __GFP_BITS_SHIFT (24 + \ > > + IS_ENABLED(CONFIG_KASAN_HW_TAGS) + \ > > + IS_ENABLED(CONFIG_LOCKDEP)) > > This breaks __GFP_NOLOCKDEP, see: > https://lore.kernel.org/all/YjoJ4CzB3yfWSV1F@xxxxxxxxxxxxx/ This could work because ___GFP_NOLOCKDEP is still 0x2000000u. In ("kasan, page_alloc: allow skipping memory init for HW_TAGS") https://lore.kernel.org/all/0d53efeff345de7d708e0baa0d8829167772521e.1643047180.git.andreyknvl@xxxxxxxxxx/ This is replaced with 0x8000000u which breaks lockdep. Sebastian
