From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3F7EDECAAD5 for ; Sat, 27 Aug 2022 02:09:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345336AbiH0CJT (ORCPT ); Fri, 26 Aug 2022 22:09:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34354 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345453AbiH0CJI (ORCPT ); Fri, 26 Aug 2022 22:09:08 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DC041EE4B7 for ; Fri, 26 Aug 2022 19:08:43 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id BDFBC61D29 for ; Sat, 27 Aug 2022 02:08:42 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1002BC433D6; Sat, 27 Aug 2022 02:08:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1661566122; bh=J4PQ8TychDagP5RFYOPqvbvUeek2upezv470RAGwwPk=; h=Date:To:From:Subject:From; b=JP4tpTN9MO7PRQsvLdvmr87Bv3ckARNF0z0GpeyD7c/tIVRgcvM2kYhTte/bOGyzz O7xJcdbHYoGd9T8rbPFugEFvibrESvqvNsZ9NPXt9MEN1Yb+2xN2vvAJz3QIO69kP6 XJZEPrs/H9fNGb6VhGSYBD4n6biJki60rLZWTdXk= Date: Fri, 26 Aug 2022 19:08:41 -0700 To: mm-commits@vger.kernel.org, willy@infradead.org, viro@zeniv.linux.org.uk, vegard.nossum@oracle.com, vbabka@suse.cz, tglx@linutronix.de, rostedt@goodmis.org, rientjes@google.com, pmladek@suse.com, peterz@infradead.org, penberg@kernel.org, mst@redhat.com, mingo@redhat.com, mark.rutland@arm.com, luto@kernel.org, keescook@chromium.org, iii@linux.ibm.com, iamjoonsoo.kim@lge.com, herbert@gondor.apana.org.au, hch@lst.de, gregkh@linuxfoundation.org, gor@linux.ibm.com, elver@google.com, edumazet@google.com, ebiggers@google.com, dvyukov@google.com, cl@linux.com, bp@alien8.de, axboe@kernel.dk, ast@kernel.org, arnd@arndb.de, andreyknvl@google.com, andreyknvl@gmail.com, glider@google.com, akpm@linux-foundation.org From: Andrew Morton Subject: + stackdepot-reserve-5-extra-bits-in-depot_stack_handle_t.patch added to mm-unstable branch Message-Id: <20220827020842.1002BC433D6@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The patch titled Subject: stackdepot: reserve 5 extra bits in depot_stack_handle_t has been added to the -mm mm-unstable branch. Its filename is stackdepot-reserve-5-extra-bits-in-depot_stack_handle_t.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/stackdepot-reserve-5-extra-bits-in-depot_stack_handle_t.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Alexander Potapenko Subject: stackdepot: reserve 5 extra bits in depot_stack_handle_t Date: Fri, 26 Aug 2022 17:07:25 +0200 Some users (currently only KMSAN) may want to use spare bits in depot_stack_handle_t. Let them do so by adding @extra_bits to __stack_depot_save() to store arbitrary flags, and providing stack_depot_get_extra_bits() to retrieve those flags. Also adapt KASAN to the new prototype by passing extra_bits=0, as KASAN does not intend to store additional information in the stack handle. Link: https://lkml.kernel.org/r/20220826150807.723137-3-glider@google.com Signed-off-by: Alexander Potapenko Reviewed-by: Marco Elver 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: Mark Rutland Cc: Matthew Wilcox Cc: Michael S. Tsirkin Cc: Pekka Enberg Cc: Peter Zijlstra Cc: Petr Mladek Cc: Steven Rostedt Cc: Thomas Gleixner Cc: Vasily Gorbik Cc: Vegard Nossum Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- include/linux/stackdepot.h | 8 ++++++++ lib/stackdepot.c | 29 ++++++++++++++++++++++++----- mm/kasan/common.c | 2 +- 3 files changed, 33 insertions(+), 6 deletions(-) --- a/include/linux/stackdepot.h~stackdepot-reserve-5-extra-bits-in-depot_stack_handle_t +++ a/include/linux/stackdepot.h @@ -14,9 +14,15 @@ #include typedef u32 depot_stack_handle_t; +/* + * Number of bits in the handle that stack depot doesn't use. Users may store + * information in them. + */ +#define STACK_DEPOT_EXTRA_BITS 5 depot_stack_handle_t __stack_depot_save(unsigned long *entries, unsigned int nr_entries, + unsigned int extra_bits, gfp_t gfp_flags, bool can_alloc); /* @@ -59,6 +65,8 @@ depot_stack_handle_t stack_depot_save(un unsigned int stack_depot_fetch(depot_stack_handle_t handle, unsigned long **entries); +unsigned int stack_depot_get_extra_bits(depot_stack_handle_t handle); + int stack_depot_snprint(depot_stack_handle_t handle, char *buf, size_t size, int spaces); --- a/lib/stackdepot.c~stackdepot-reserve-5-extra-bits-in-depot_stack_handle_t +++ a/lib/stackdepot.c @@ -43,7 +43,8 @@ #define STACK_ALLOC_OFFSET_BITS (STACK_ALLOC_ORDER + PAGE_SHIFT - \ STACK_ALLOC_ALIGN) #define STACK_ALLOC_INDEX_BITS (DEPOT_STACK_BITS - \ - STACK_ALLOC_NULL_PROTECTION_BITS - STACK_ALLOC_OFFSET_BITS) + STACK_ALLOC_NULL_PROTECTION_BITS - \ + STACK_ALLOC_OFFSET_BITS - STACK_DEPOT_EXTRA_BITS) #define STACK_ALLOC_SLABS_CAP 8192 #define STACK_ALLOC_MAX_SLABS \ (((1LL << (STACK_ALLOC_INDEX_BITS)) < STACK_ALLOC_SLABS_CAP) ? \ @@ -56,6 +57,7 @@ union handle_parts { u32 slabindex : STACK_ALLOC_INDEX_BITS; u32 offset : STACK_ALLOC_OFFSET_BITS; u32 valid : STACK_ALLOC_NULL_PROTECTION_BITS; + u32 extra : STACK_DEPOT_EXTRA_BITS; }; }; @@ -77,6 +79,14 @@ static int next_slab_inited; static size_t depot_offset; static DEFINE_RAW_SPINLOCK(depot_lock); +unsigned int stack_depot_get_extra_bits(depot_stack_handle_t handle) +{ + union handle_parts parts = { .handle = handle }; + + return parts.extra; +} +EXPORT_SYMBOL(stack_depot_get_extra_bits); + static bool init_stack_slab(void **prealloc) { if (!*prealloc) @@ -140,6 +150,7 @@ depot_alloc_stack(unsigned long *entries stack->handle.slabindex = depot_index; stack->handle.offset = depot_offset >> STACK_ALLOC_ALIGN; stack->handle.valid = 1; + stack->handle.extra = 0; memcpy(stack->entries, entries, flex_array_size(stack, entries, size)); depot_offset += required_size; @@ -382,6 +393,7 @@ EXPORT_SYMBOL_GPL(stack_depot_fetch); * * @entries: Pointer to storage array * @nr_entries: Size of the storage array + * @extra_bits: Flags to store in unused bits of depot_stack_handle_t * @alloc_flags: Allocation gfp flags * @can_alloc: Allocate stack slabs (increased chance of failure if false) * @@ -393,6 +405,10 @@ EXPORT_SYMBOL_GPL(stack_depot_fetch); * If the stack trace in @entries is from an interrupt, only the portion up to * interrupt entry is saved. * + * Additional opaque flags can be passed in @extra_bits, stored in the unused + * bits of the stack handle, and retrieved using stack_depot_get_extra_bits() + * without calling stack_depot_fetch(). + * * Context: Any context, but setting @can_alloc to %false is required if * alloc_pages() cannot be used from the current context. Currently * this is the case from contexts where neither %GFP_ATOMIC nor @@ -402,10 +418,11 @@ EXPORT_SYMBOL_GPL(stack_depot_fetch); */ depot_stack_handle_t __stack_depot_save(unsigned long *entries, unsigned int nr_entries, + unsigned int extra_bits, gfp_t alloc_flags, bool can_alloc) { struct stack_record *found = NULL, **bucket; - depot_stack_handle_t retval = 0; + union handle_parts retval = { .handle = 0 }; struct page *page = NULL; void *prealloc = NULL; unsigned long flags; @@ -489,9 +506,11 @@ exit: free_pages((unsigned long)prealloc, STACK_ALLOC_ORDER); } if (found) - retval = found->handle.handle; + retval.handle = found->handle.handle; fast_exit: - return retval; + retval.extra = extra_bits; + + return retval.handle; } EXPORT_SYMBOL_GPL(__stack_depot_save); @@ -511,6 +530,6 @@ depot_stack_handle_t stack_depot_save(un unsigned int nr_entries, gfp_t alloc_flags) { - return __stack_depot_save(entries, nr_entries, alloc_flags, true); + return __stack_depot_save(entries, nr_entries, 0, alloc_flags, true); } EXPORT_SYMBOL_GPL(stack_depot_save); --- a/mm/kasan/common.c~stackdepot-reserve-5-extra-bits-in-depot_stack_handle_t +++ a/mm/kasan/common.c @@ -36,7 +36,7 @@ depot_stack_handle_t kasan_save_stack(gf unsigned int nr_entries; nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 0); - return __stack_depot_save(entries, nr_entries, flags, can_alloc); + return __stack_depot_save(entries, nr_entries, 0, flags, can_alloc); } void kasan_set_track(struct kasan_track *track, gfp_t flags) _ Patches currently in -mm which might be from glider@google.com are stackdepot-reserve-5-extra-bits-in-depot_stack_handle_t.patch instrumentedh-allow-instrumenting-both-sides-of-copy_from_user.patch x86-asm-instrument-usercopy-in-get_user-and-put_user.patch asm-generic-instrument-usercopy-in-cacheflushh.patch kmsan-add-rest-documentation.patch kmsan-introduce-__no_sanitize_memory-and-__no_kmsan_checks.patch kmsan-mark-noinstr-as-__no_sanitize_memory.patch x86-kmsan-pgtable-reduce-vmalloc-space.patch libnvdimm-pfn_dev-increase-max_struct_page_size.patch kmsan-add-kmsan-runtime-core.patch kmsan-disable-instrumentation-of-unsupported-common-kernel-code.patch maintainers-add-entry-for-kmsan.patch mm-kmsan-maintain-kmsan-metadata-for-page-operations.patch mm-kmsan-call-kmsan-hooks-from-slub-code.patch kmsan-handle-task-creation-and-exiting.patch init-kmsan-call-kmsan-initialization-routines.patch instrumentedh-add-kmsan-support.patch kmsan-unpoison-tlb-in-arch_tlb_gather_mmu.patch kmsan-add-iomap-support.patch input-libps2-mark-data-received-in-__ps2_command-as-initialized.patch dma-kmsan-unpoison-dma-mappings.patch virtio-kmsan-check-unpoison-scatterlist-in-vring_map_one_sg.patch kmsan-handle-memory-sent-to-from-usb.patch kmsan-add-tests-for-kmsan.patch kmsan-disable-strscpy-optimization-under-kmsan.patch crypto-kmsan-disable-accelerated-configs-under-kmsan.patch kmsan-disable-physical-page-merging-in-biovec.patch block-kmsan-skip-bio-block-merging-logic-for-kmsan.patch kcov-kmsan-unpoison-area-list-in-kcov_remote_area_put.patch security-kmsan-fix-interoperability-with-auto-initialization.patch objtool-kmsan-list-kmsan-api-functions-as-uaccess-safe.patch x86-kmsan-disable-instrumentation-of-unsupported-code.patch x86-kmsan-skip-shadow-checks-in-__switch_to.patch x86-kmsan-handle-open-coded-assembly-in-lib-iomemc.patch x86-kmsan-use-__msan_-string-functions-where-possible.patch x86-kmsan-sync-metadata-pages-on-page-fault.patch x86-kasan-kmsan-support-config_generic_csum-on-x86-enable-it-for-kasan-kmsan.patch x86-fs-kmsan-disable-config_dcache_word_access.patch x86-kmsan-dont-instrument-stack-walking-functions.patch entry-kmsan-introduce-kmsan_unpoison_entry_regs.patch bpf-kmsan-initialize-bpf-registers-with-zeroes.patch mm-fs-initialize-fsdata-passed-to-write_begin-write_end-interface.patch x86-kmsan-enable-kmsan-builds-for-x86.patch