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a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=K3THHtce7/ygl6Gpfs3Di2sEUO2VBikWbOhVCkSY9ac=; b=f+yKi0J9ffV8i8QvlGTJT2DaXozqkVD7z+s4s/qfmSoYPRyD7Ipv3C9O2JoWpb9xZu WaccYVAK30P6mC4Y+TwJKxTnQoCAK97t/xOCTf0RZPBJ0qHOzQlgex4SsYhpc8DB0+yB eV8/t/tYjrwVlNNGJ3eYJoS2ziGjPQNbUYL7X8KqNP1QnwjIDDSH40aUvyCgkEGJO0Np /WumabQAnZdP3tq9FyInJnJCY8ROtA4X0374eZJeRnIL+F1KLrccsXOuLL2sjNUizJui 7ttaMtszXRzLa5zEYMLfbs90+PW0W853EY0YGu/3l34RplIDVdp6b49pzUINoN2fCBLW vL2w== X-Gm-Message-State: AOAM533Et3gO+16PRtSzKlI0IO9crA13ENLdKAM9U8lzGLMrc+pQjhd3 0I9zBEr4QicaweIR55tKoyIgvUMVn6KKVb3F X-Google-Smtp-Source: ABdhPJyemLAvJCZ5NV1PNi6ia9mIG5BPvNuaojX/Vqve5Fg8GAq9MsC5vRUJBJF4bO4tLtErmJICS+Uki60iFkJH X-Received: from andreyknvl3.muc.corp.google.com ([2a00:79e0:15:13:7220:84ff:fe09:7e9d]) (user=andreyknvl job=sendgmr) by 2002:a17:906:578e:: with SMTP id k14mr6448146ejq.90.1610652846821; Thu, 14 Jan 2021 11:34:06 -0800 (PST) Date: Thu, 14 Jan 2021 20:33:56 +0100 In-Reply-To: Message-Id: <89cd4db80c3ee8c1975eb9171e99fcbc894eb1dd.1610652791.git.andreyknvl@google.com> Mime-Version: 1.0 References: X-Mailer: git-send-email 2.30.0.284.gd98b1dd5eaa7-goog Subject: [PATCH v2 1/2] kasan, mm: fix conflicts with init_on_alloc/free From: Andrey Konovalov To: Andrew Morton , Catalin Marinas , Vincenzo Frascino , Dmitry Vyukov , Alexander Potapenko , Marco Elver X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210114_143411_771677_D3047CC1 X-CRM114-Status: GOOD ( 10.55 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Branislav Rankov , Vlastimil Babka , Andrey Konovalov , Kevin Brodsky , Will Deacon , linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, Andrey Ryabinin , Peter Collingbourne , Evgenii Stepanov Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org A few places where SLUB accesses object's data or metadata were missed in a previous patch. This leads to false positives with hardware tag-based KASAN when bulk allocations are used with init_on_alloc/free. Fix the false-positives by resetting pointer tags during these accesses. (The kasan_reset_tag call is removed from slab_alloc_node, as it's added into maybe_wipe_obj_freeptr.) Link: https://linux-review.googlesource.com/id/I50dd32838a666e173fe06c3c5c766f2c36aae901 Fixes: aa1ef4d7b3f67 ("kasan, mm: reset tags when accessing metadata") Reported-by: Dmitry Vyukov Acked-by: Vlastimil Babka Signed-off-by: Andrey Konovalov --- mm/slub.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/mm/slub.c b/mm/slub.c index dc5b42e700b8..75fb097d990d 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -2791,7 +2791,8 @@ static __always_inline void maybe_wipe_obj_freeptr(struct kmem_cache *s, void *obj) { if (unlikely(slab_want_init_on_free(s)) && obj) - memset((void *)((char *)obj + s->offset), 0, sizeof(void *)); + memset((void *)((char *)kasan_reset_tag(obj) + s->offset), + 0, sizeof(void *)); } /* @@ -2883,7 +2884,7 @@ static __always_inline void *slab_alloc_node(struct kmem_cache *s, stat(s, ALLOC_FASTPATH); } - maybe_wipe_obj_freeptr(s, kasan_reset_tag(object)); + maybe_wipe_obj_freeptr(s, object); if (unlikely(slab_want_init_on_alloc(gfpflags, s)) && object) memset(kasan_reset_tag(object), 0, s->object_size); @@ -3329,7 +3330,7 @@ int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size, int j; for (j = 0; j < i; j++) - memset(p[j], 0, s->object_size); + memset(kasan_reset_tag(p[j]), 0, s->object_size); } /* memcg and kmem_cache debug support */