From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7DA794685 for ; Thu, 20 Jun 2024 00:58:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718845114; cv=none; b=F1rBqjrvn7JLkabKOkbtKK0WZNREBJVimnxnfzeAeTkQKO5X7R7CsIMn6pksumIzb6T5/Rm9wc9kSfy0OKrKt9wiiz71VrrXt70Ie5SWHgrtSictcoGauMNbfmBGCUv8xDaQP8Yqt2wRSu4VCiDLjkgN+ltIxEUxEKwgQDafJo0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718845114; c=relaxed/simple; bh=nntejb8pigVV8RiwNvZGFmTsyxS85Fa+9ZYvnYwtwbE=; h=Date:To:From:Subject:Message-Id; b=oc2hfr/cmqmjU8nOBzvv0aD5VSjlztDG0qwolIZcAkm7cobIYhzcN4hj1rsCzT1qTl3EICsa4D5dqbwxrzwIjaf3Ww0BmG4sKqPDyXZWqhlXm4C2kNzFhrEcVLYp9w3P8WwUawG7QUW8MVRFdTowEU4+YozhZfsKLKWr/xOdqOQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=Ecq+QRmX; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="Ecq+QRmX" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F182AC2BBFC; Thu, 20 Jun 2024 00:58:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1718845114; bh=nntejb8pigVV8RiwNvZGFmTsyxS85Fa+9ZYvnYwtwbE=; h=Date:To:From:Subject:From; b=Ecq+QRmXLqmdvS/bPhBPRY2w4sEGOvz+b6gsFo3x9jjrMo9TUaia3jw3TJPtYhdQF nvOLpL5JIjAzk5B0GRvkrLwlwdi8rQSPi9tJd/buDTBl9ovQkyoEI0Z2uCFr4KVMoi B3wwZ6FoQxVDG/anxkTnT71H7OUvpw5Ng9YecQWg= Date: Wed, 19 Jun 2024 17:58:33 -0700 To: mm-commits@vger.kernel.org,vbabka@suse.cz,svens@linux.ibm.com,rostedt@goodmis.org,roman.gushchin@linux.dev,rientjes@google.com,penberg@kernel.org,mhiramat@kernel.org,mark.rutland@arm.com,kasan-dev@googlegroups.com,iamjoonsoo.kim@lge.com,hca@linux.ibm.com,gor@linux.ibm.com,glider@google.com,elver@google.com,dvyukov@google.com,cl@linux.com,borntraeger@linux.ibm.com,agordeev@linux.ibm.com,42.hyeyoo@gmail.com,iii@linux.ibm.com,akpm@linux-foundation.org From: Andrew Morton Subject: + kmsan-allow-disabling-kmsan-checks-for-the-current-task.patch added to mm-unstable branch Message-Id: <20240620005833.F182AC2BBFC@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: kmsan: allow disabling KMSAN checks for the current task has been added to the -mm mm-unstable branch. Its filename is kmsan-allow-disabling-kmsan-checks-for-the-current-task.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/kmsan-allow-disabling-kmsan-checks-for-the-current-task.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: Ilya Leoshkevich Subject: kmsan: allow disabling KMSAN checks for the current task Date: Wed, 19 Jun 2024 17:43:46 +0200 Like for KASAN, it's useful to temporarily disable KMSAN checks around, e.g., redzone accesses. Introduce kmsan_disable_current() and kmsan_enable_current(), which are similar to their KASAN counterparts. Make them reentrant in order to handle memory allocations in interrupt context. Repurpose the allow_reporting field for this. Link: https://lkml.kernel.org/r/20240619154530.163232-12-iii@linux.ibm.com Signed-off-by: Ilya Leoshkevich Reviewed-by: Alexander Potapenko Cc: Alexander Gordeev Cc: Christian Borntraeger Cc: Christoph Lameter Cc: David Rientjes Cc: Dmitry Vyukov Cc: Heiko Carstens Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Joonsoo Kim Cc: Cc: Marco Elver Cc: Mark Rutland Cc: Masami Hiramatsu (Google) Cc: Pekka Enberg Cc: Roman Gushchin Cc: Steven Rostedt (Google) Cc: Sven Schnelle Cc: Vasily Gorbik Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- Documentation/dev-tools/kmsan.rst | 11 +++++++++-- include/linux/kmsan.h | 24 ++++++++++++++++++++++++ include/linux/kmsan_types.h | 2 +- mm/kmsan/core.c | 1 - mm/kmsan/hooks.c | 18 +++++++++++++++--- mm/kmsan/report.c | 7 ++++--- tools/objtool/check.c | 2 ++ 7 files changed, 55 insertions(+), 10 deletions(-) --- a/Documentation/dev-tools/kmsan.rst~kmsan-allow-disabling-kmsan-checks-for-the-current-task +++ a/Documentation/dev-tools/kmsan.rst @@ -110,6 +110,13 @@ in the Makefile. Think of this as applyi function in the file or directory. Most users won't need KMSAN_SANITIZE, unless their code gets broken by KMSAN (e.g. runs at early boot time). +KMSAN checks can also be temporarily disabled for the current task using +``kmsan_disable_current()`` and ``kmsan_enable_current()`` calls. Each +``kmsan_enable_current()`` call must be preceded by a +``kmsan_disable_current()`` call; these call pairs may be nested. One needs to +be careful with these calls, keeping the regions short and preferring other +ways to disable instrumentation, where possible. + Support ======= @@ -338,11 +345,11 @@ Per-task KMSAN state ~~~~~~~~~~~~~~~~~~~~ Every task_struct has an associated KMSAN task state that holds the KMSAN -context (see above) and a per-task flag disallowing KMSAN reports:: +context (see above) and a per-task counter disallowing KMSAN reports:: struct kmsan_context { ... - bool allow_reporting; + unsigned int depth; struct kmsan_context_state cstate; ... } --- a/include/linux/kmsan.h~kmsan-allow-disabling-kmsan-checks-for-the-current-task +++ a/include/linux/kmsan.h @@ -239,6 +239,22 @@ void kmsan_unpoison_entry_regs(const str */ void *kmsan_get_metadata(void *addr, bool is_origin); +/* + * kmsan_enable_current(): Enable KMSAN for the current task. + * + * Each kmsan_enable_current() current call must be preceded by a + * kmsan_disable_current() call. These call pairs may be nested. + */ +void kmsan_enable_current(void); + +/* + * kmsan_disable_current(): Disable KMSAN for the current task. + * + * Each kmsan_disable_current() current call must be followed by a + * kmsan_enable_current() call. These call pairs may be nested. + */ +void kmsan_disable_current(void); + #else static inline void kmsan_init_shadow(void) @@ -338,6 +354,14 @@ static inline void kmsan_unpoison_entry_ { } +static inline void kmsan_enable_current(void) +{ +} + +static inline void kmsan_disable_current(void) +{ +} + #endif #endif /* _LINUX_KMSAN_H */ --- a/include/linux/kmsan_types.h~kmsan-allow-disabling-kmsan-checks-for-the-current-task +++ a/include/linux/kmsan_types.h @@ -31,7 +31,7 @@ struct kmsan_context_state { struct kmsan_ctx { struct kmsan_context_state cstate; int kmsan_in_runtime; - bool allow_reporting; + unsigned int depth; }; #endif /* _LINUX_KMSAN_TYPES_H */ --- a/mm/kmsan/core.c~kmsan-allow-disabling-kmsan-checks-for-the-current-task +++ a/mm/kmsan/core.c @@ -43,7 +43,6 @@ void kmsan_internal_task_create(struct t struct thread_info *info = current_thread_info(); __memset(ctx, 0, sizeof(*ctx)); - ctx->allow_reporting = true; kmsan_internal_unpoison_memory(info, sizeof(*info), false); } --- a/mm/kmsan/hooks.c~kmsan-allow-disabling-kmsan-checks-for-the-current-task +++ a/mm/kmsan/hooks.c @@ -39,12 +39,10 @@ void kmsan_task_create(struct task_struc void kmsan_task_exit(struct task_struct *task) { - struct kmsan_ctx *ctx = &task->kmsan_ctx; - if (!kmsan_enabled || kmsan_in_runtime()) return; - ctx->allow_reporting = false; + kmsan_disable_current(); } void kmsan_slab_alloc(struct kmem_cache *s, void *object, gfp_t flags) @@ -424,3 +422,17 @@ void kmsan_check_memory(const void *addr REASON_ANY); } EXPORT_SYMBOL(kmsan_check_memory); + +void kmsan_enable_current(void) +{ + KMSAN_WARN_ON(current->kmsan_ctx.depth == 0); + current->kmsan_ctx.depth--; +} +EXPORT_SYMBOL(kmsan_enable_current); + +void kmsan_disable_current(void) +{ + current->kmsan_ctx.depth++; + KMSAN_WARN_ON(current->kmsan_ctx.depth == 0); +} +EXPORT_SYMBOL(kmsan_disable_current); --- a/mm/kmsan/report.c~kmsan-allow-disabling-kmsan-checks-for-the-current-task +++ a/mm/kmsan/report.c @@ -8,6 +8,7 @@ */ #include +#include #include #include #include @@ -158,12 +159,12 @@ void kmsan_report(depot_stack_handle_t o if (!kmsan_enabled) return; - if (!current->kmsan_ctx.allow_reporting) + if (current->kmsan_ctx.depth) return; if (!origin) return; - current->kmsan_ctx.allow_reporting = false; + kmsan_disable_current(); ua_flags = user_access_save(); raw_spin_lock(&kmsan_report_lock); pr_err("=====================================================\n"); @@ -216,5 +217,5 @@ void kmsan_report(depot_stack_handle_t o if (panic_on_kmsan) panic("kmsan.panic set ...\n"); user_access_restore(ua_flags); - current->kmsan_ctx.allow_reporting = true; + kmsan_enable_current(); } --- a/tools/objtool/check.c~kmsan-allow-disabling-kmsan-checks-for-the-current-task +++ a/tools/objtool/check.c @@ -1202,6 +1202,8 @@ static const char *uaccess_safe_builtin[ "__sanitizer_cov_trace_switch", /* KMSAN */ "kmsan_copy_to_user", + "kmsan_disable_current", + "kmsan_enable_current", "kmsan_report", "kmsan_unpoison_entry_regs", "kmsan_unpoison_memory", _ Patches currently in -mm which might be from iii@linux.ibm.com are ftrace-unpoison-ftrace_regs-in-ftrace_ops_list_func.patch kmsan-make-the-tests-compatible-with-kmsanpanic=1.patch kmsan-disable-kmsan-when-deferred_struct_page_init-is-enabled.patch kmsan-increase-the-maximum-store-size-to-4096.patch kmsan-fix-is_bad_asm_addr-on-arches-with-overlapping-address-spaces.patch kmsan-fix-kmsan_copy_to_user-on-arches-with-overlapping-address-spaces.patch kmsan-remove-a-useless-assignment-from-kmsan_vmap_pages_range_noflush.patch kmsan-remove-an-x86-specific-include-from-kmsanh.patch kmsan-expose-kmsan_get_metadata.patch kmsan-export-panic_on_kmsan.patch kmsan-allow-disabling-kmsan-checks-for-the-current-task.patch kmsan-introduce-memset_no_sanitize_memory.patch kmsan-support-slab_poison.patch kmsan-use-align_down-in-kmsan_get_metadata.patch kmsan-do-not-round-up-pg_data_t-size.patch mm-slub-let-kmsan-access-metadata.patch mm-slub-disable-kmsan-when-checking-the-padding-bytes.patch mm-kfence-disable-kmsan-when-checking-the-canary.patch lib-zlib-unpoison-dfltcc-output-buffers.patch kmsan-accept-ranges-starting-with-0-on-s390.patch s390-boot-turn-off-kmsan.patch s390-use-a-larger-stack-for-kmsan.patch s390-boot-add-the-kmsan-runtime-stub.patch s390-checksum-add-a-kmsan-check.patch s390-cpacf-unpoison-the-results-of-cpacf_trng.patch s390-cpumf-unpoison-stcctm-output-buffer.patch s390-diag-unpoison-diag224-output-buffer.patch s390-ftrace-unpoison-ftrace_regs-in-kprobe_ftrace_handler.patch s390-irqflags-do-not-instrument-arch_local_irq_-with-kmsan.patch s390-mm-define-kmsan-metadata-for-vmalloc-and-modules.patch s390-string-add-kmsan-support.patch s390-traps-unpoison-the-kernel_stack_overflows-pt_regs.patch s390-uaccess-add-kmsan-support-to-put_user-and-get_user.patch s390-uaccess-add-the-missing-linux-instrumentedh-include.patch s390-unwind-disable-kmsan-checks.patch s390-kmsan-implement-the-architecture-specific-functions.patch kmsan-enable-on-s390.patch