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spf=pass (imf04.hostedemail.com: domain of andreyknvl@gmail.com designates 209.85.166.174 as permitted sender) smtp.mailfrom=andreyknvl@gmail.com Authentication-Results: imf04.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=RWIKj3WM; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf04.hostedemail.com: domain of andreyknvl@gmail.com designates 209.85.166.174 as permitted sender) smtp.mailfrom=andreyknvl@gmail.com X-Stat-Signature: mgnmqcryafu4w5z46xy5oz9x449nom6m X-Rspamd-Queue-Id: A95064006C X-Rspamd-Server: rspam12 X-Rspam-User: X-HE-Tag: 1654798366-683015 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 Wed, Jun 1, 2022 at 2:28 PM Marco Elver wrote: > > On Tue, May 31, 2022 at 05:43PM +0200, andrey.konovalov@linux.dev wrote: > > From: Andrey Konovalov > > > > HW_TAGS KASAN skips zeroing page_alloc allocations backing vmalloc > > mappings via __GFP_SKIP_ZERO. Instead, these pages are zeroed via > > kasan_unpoison_vmalloc() by passing the KASAN_VMALLOC_INIT flag. > > > > The problem is that __kasan_unpoison_vmalloc() does not zero pages > > when either kasan_vmalloc_enabled() or is_vmalloc_or_module_addr() fail. > > > > Thus: > > > > 1. Change __vmalloc_node_range() to only set KASAN_VMALLOC_INIT when > > __GFP_SKIP_ZERO is set. > > > > 2. Change __kasan_unpoison_vmalloc() to always zero pages when the > > KASAN_VMALLOC_INIT flag is set. > > > > 3. Add WARN_ON() asserts to check that KASAN_VMALLOC_INIT cannot be set > > in other early return paths of __kasan_unpoison_vmalloc(). > > > > Also clean up the comment in __kasan_unpoison_vmalloc. > > > > Fixes: 23689e91fb22 ("kasan, vmalloc: add vmalloc tagging for HW_TAGS") > > Signed-off-by: Andrey Konovalov > > --- > > mm/kasan/hw_tags.c | 30 ++++++++++++++++++++++-------- > > mm/vmalloc.c | 10 +++++----- > > 2 files changed, 27 insertions(+), 13 deletions(-) > > > > diff --git a/mm/kasan/hw_tags.c b/mm/kasan/hw_tags.c > > index 9e1b6544bfa8..c0ec01eadf20 100644 > > --- a/mm/kasan/hw_tags.c > > +++ b/mm/kasan/hw_tags.c > > @@ -263,21 +263,31 @@ void *__kasan_unpoison_vmalloc(const void *start, unsigned long size, > > u8 tag; > > unsigned long redzone_start, redzone_size; > > > > - if (!kasan_vmalloc_enabled()) > > - return (void *)start; > > + if (!kasan_vmalloc_enabled() || !is_vmalloc_or_module_addr(start)) { > > + struct page *page; > > + const void *addr; > > + > > + /* Initialize memory if required. */ > > + > > This whole block of code looks out-of-place in this function, since it's > not at all related to unpoisoning but a fallback if KASAN-vmalloc is off > but we still want to initialize the memory. > > Maybe to ease readability here I'd change it to look like: Sounds good, will do in v2! Thanks!