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charset="UTF-8" Authentication-Results: imf07.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=g+76lc8h; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf07.hostedemail.com: domain of andreyknvl@gmail.com designates 209.85.166.54 as permitted sender) smtp.mailfrom=andreyknvl@gmail.com X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 8EB0840014 X-Stat-Signature: zu7x5c36oaxdxomboedicqfqf4eimpcz X-HE-Tag: 1639506440-162253 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, Dec 14, 2021 at 6:11 PM Catalin Marinas wrote: > > On Mon, Dec 13, 2021 at 10:54:21PM +0100, andrey.konovalov@linux.dev wrote: > > diff --git a/arch/arm64/include/asm/vmalloc.h b/arch/arm64/include/asm/vmalloc.h > > index b9185503feae..3d35adf365bf 100644 > > --- a/arch/arm64/include/asm/vmalloc.h > > +++ b/arch/arm64/include/asm/vmalloc.h > > @@ -25,4 +25,14 @@ static inline bool arch_vmap_pmd_supported(pgprot_t prot) > > > > #endif > > > > +#define arch_vmalloc_pgprot_modify arch_vmalloc_pgprot_modify > > +static inline pgprot_t arch_vmalloc_pgprot_modify(pgprot_t prot) > > +{ > > + if (IS_ENABLED(CONFIG_KASAN_HW_TAGS) && > > + (pgprot_val(prot) == pgprot_val(PAGE_KERNEL))) > > + prot = pgprot_tagged(prot); > > + > > + return prot; > > +} > > + > > #endif /* _ASM_ARM64_VMALLOC_H */ > > diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h > > index 28becb10d013..760caeedd749 100644 > > --- a/include/linux/vmalloc.h > > +++ b/include/linux/vmalloc.h > > @@ -115,6 +115,13 @@ static inline int arch_vmap_pte_supported_shift(unsigned long size) > > } > > #endif > > > > +#ifndef arch_vmalloc_pgprot_modify > > +static inline pgprot_t arch_vmalloc_pgprot_modify(pgprot_t prot) > > +{ > > + return prot; > > +} > > +#endif > > + > > /* > > * Highlevel APIs for driver use > > */ > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > > index 837ed355bfc6..58bd2f7f86d7 100644 > > --- a/mm/vmalloc.c > > +++ b/mm/vmalloc.c > > @@ -3060,6 +3060,8 @@ void *__vmalloc_node_range(unsigned long size, unsigned long align, > > return NULL; > > } > > > > + prot = arch_vmalloc_pgprot_modify(prot); > > + > > if (vmap_allow_huge && !(vm_flags & VM_NO_HUGE_VMAP)) { > > unsigned long size_per_node; > > I wonder whether we could fix the prot bits in the caller instead and we > won't need to worry about the exec or the module_alloc() case. Something > like: > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > index d2a00ad4e1dd..4e8c61255b92 100644 > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -3112,7 +3112,7 @@ void *__vmalloc_node(unsigned long size, unsigned long align, > gfp_t gfp_mask, int node, const void *caller) > { > return __vmalloc_node_range(size, align, VMALLOC_START, VMALLOC_END, > - gfp_mask, PAGE_KERNEL, 0, node, caller); > + gfp_mask, pgprot_hwasan(PAGE_KERNEL), 0, node, caller); > } > /* > * This is only for performance analysis of vmalloc and stress purpose. > @@ -3161,7 +3161,7 @@ EXPORT_SYMBOL(vmalloc); > void *vmalloc_no_huge(unsigned long size) > { > return __vmalloc_node_range(size, 1, VMALLOC_START, VMALLOC_END, > - GFP_KERNEL, PAGE_KERNEL, VM_NO_HUGE_VMAP, > + GFP_KERNEL, pgprot_hwasan(PAGE_KERNEL), VM_NO_HUGE_VMAP, > NUMA_NO_NODE, __builtin_return_address(0)); > } > EXPORT_SYMBOL(vmalloc_no_huge); > > with pgprot_hwasan() defined to pgprot_tagged() only if KASAN_HW_TAGS is > enabled. And also change kasan_unpoison_vmalloc() to tag only if pgprot_tagged() has been applied, I assume. Hm. Then __vmalloc_node_range() callers will never get tagged memory unless requested. I suppose that's OK, most of them untag the pointer anyway. But this won't work for SW_TAGS mode, which is also affected by the exec issue and needs those kasan_reset_tag()s in module_alloc()/BPF. We could invent some virtual protection bit for it and reuse pgprot_hwasan(). Not sure if this would be acceptable.