From f630a5d0ca59a6e73b61e3f82c371dc230da99ff Mon Sep 17 00:00:00 2001 From: Alexander Potapenko Date: Thu, 15 Sep 2022 17:04:01 +0200 Subject: kmsan: disable physical page merging in biovec KMSAN metadata for adjacent physical pages may not be adjacent, therefore accessing such pages together may lead to metadata corruption. We disable merging pages in biovec to prevent such corruptions. Link: https://lkml.kernel.org/r/20220915150417.722975-28-glider@google.com Signed-off-by: Alexander Potapenko Cc: Alexander Viro Cc: Alexei Starovoitov Cc: Andrey Konovalov Cc: Andrey Konovalov Cc: Andy Lutomirski Cc: Arnd Bergmann Cc: Borislav Petkov Cc: Christoph Hellwig Cc: Christoph Lameter Cc: David Rientjes Cc: Dmitry Vyukov Cc: Eric Biggers Cc: Eric Biggers Cc: Eric Dumazet Cc: Greg Kroah-Hartman Cc: Herbert Xu Cc: Ilya Leoshkevich Cc: Ingo Molnar Cc: Jens Axboe Cc: Joonsoo Kim Cc: Kees Cook Cc: Marco Elver Cc: Mark Rutland Cc: Matthew Wilcox Cc: Michael S. Tsirkin Cc: Pekka Enberg Cc: Peter Zijlstra Cc: Petr Mladek Cc: Stephen Rothwell Cc: Steven Rostedt Cc: Thomas Gleixner Cc: Vasily Gorbik Cc: Vegard Nossum Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- block/blk.h | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'block') diff --git a/block/blk.h b/block/blk.h index d7142c4d2fef..af02b93c1dba 100644 --- a/block/blk.h +++ b/block/blk.h @@ -88,6 +88,13 @@ static inline bool biovec_phys_mergeable(struct request_queue *q, phys_addr_t addr1 = page_to_phys(vec1->bv_page) + vec1->bv_offset; phys_addr_t addr2 = page_to_phys(vec2->bv_page) + vec2->bv_offset; + /* + * Merging adjacent physical pages may not work correctly under KMSAN + * if their metadata pages aren't adjacent. Just disable merging. + */ + if (IS_ENABLED(CONFIG_KMSAN)) + return false; + if (addr1 + vec1->bv_len != addr2) return false; if (xen_domain() && !xen_biovec_phys_mergeable(vec1, vec2->bv_page)) -- cgit v1.2.3-70-g09d2 From 11b331f857b5fc3ff76bfec36c44a137a6b37de1 Mon Sep 17 00:00:00 2001 From: Alexander Potapenko Date: Thu, 15 Sep 2022 17:04:02 +0200 Subject: block: kmsan: skip bio block merging logic for KMSAN KMSAN doesn't allow treating adjacent memory pages as such, if they were allocated by different alloc_pages() calls. The block layer however does so: adjacent pages end up being used together. To prevent this, make page_is_mergeable() return false under KMSAN. Link: https://lkml.kernel.org/r/20220915150417.722975-29-glider@google.com Signed-off-by: Alexander Potapenko Suggested-by: Eric Biggers Cc: Alexander Viro Cc: Alexei Starovoitov Cc: Andrey Konovalov Cc: Andrey Konovalov Cc: Andy Lutomirski Cc: Arnd Bergmann Cc: Borislav Petkov Cc: Christoph Hellwig Cc: Christoph Lameter Cc: David Rientjes Cc: Dmitry Vyukov Cc: Eric Biggers Cc: Eric Dumazet Cc: Greg Kroah-Hartman Cc: Herbert Xu Cc: Ilya Leoshkevich Cc: Ingo Molnar Cc: Jens Axboe Cc: Joonsoo Kim Cc: Kees Cook Cc: Marco Elver Cc: Mark Rutland Cc: Matthew Wilcox Cc: Michael S. Tsirkin Cc: Pekka Enberg Cc: Peter Zijlstra Cc: Petr Mladek Cc: Stephen Rothwell Cc: Steven Rostedt Cc: Thomas Gleixner Cc: Vasily Gorbik Cc: Vegard Nossum Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- block/bio.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'block') diff --git a/block/bio.c b/block/bio.c index 3d3a2678fea2..106ef14f28c2 100644 --- a/block/bio.c +++ b/block/bio.c @@ -869,6 +869,8 @@ static inline bool page_is_mergeable(const struct bio_vec *bv, *same_page = ((vec_end_addr & PAGE_MASK) == page_addr); if (*same_page) return true; + else if (IS_ENABLED(CONFIG_KMSAN)) + return false; return (bv->bv_page + bv_end / PAGE_SIZE) == (page + off / PAGE_SIZE); } -- cgit v1.2.3-70-g09d2