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[2.135.54.165]) by smtp.gmail.com with ESMTPSA id 2adb3069b0e04-5550b2ce1fasm42792e87.174.2025.06.26.08.32.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 26 Jun 2025 08:32:10 -0700 (PDT) From: Sabyrzhan Tasbolatov To: ryabinin.a.a@gmail.com, glider@google.com, andreyknvl@gmail.com, dvyukov@google.com, vincenzo.frascino@arm.com, linux@armlinux.org.uk, catalin.marinas@arm.com, will@kernel.org, chenhuacai@kernel.org, kernel@xen0n.name, maddy@linux.ibm.com, mpe@ellerman.id.au, npiggin@gmail.com, christophe.leroy@csgroup.eu, paul.walmsley@sifive.com, palmer@dabbelt.com, aou@eecs.berkeley.edu, alex@ghiti.fr, hca@linux.ibm.com, gor@linux.ibm.com, agordeev@linux.ibm.com, borntraeger@linux.ibm.com, svens@linux.ibm.com, richard@nod.at, anton.ivanov@cambridgegreys.com, johannes@sipsolutions.net, dave.hansen@linux.intel.com, luto@kernel.org, peterz@infradead.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, x86@kernel.org, hpa@zytor.com, chris@zankel.net, jcmvbkbc@gmail.com, akpm@linux-foundation.org, nathan@kernel.org, nick.desaulniers+lkml@gmail.com, morbo@google.com, justinstitt@google.com Cc: arnd@arndb.de, rppt@kernel.org, geert@linux-m68k.org, mcgrof@kernel.org, guoweikang.kernel@gmail.com, tiwei.btw@antgroup.com, kevin.brodsky@arm.com, benjamin.berg@intel.com, kasan-dev@googlegroups.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, loongarch@lists.linux.dev, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-um@lists.infradead.org, linux-mm@kvack.org, llvm@lists.linux.dev, snovitoll@gmail.com Subject: [PATCH v2 01/11] kasan: unify static kasan_flag_enabled across modes Date: Thu, 26 Jun 2025 20:31:37 +0500 Message-Id: <20250626153147.145312-2-snovitoll@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20250626153147.145312-1-snovitoll@gmail.com> References: <20250626153147.145312-1-snovitoll@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Historically, the runtime static key kasan_flag_enabled existed only for CONFIG_KASAN_HW_TAGS mode. Generic and SW_TAGS modes either relied on architecture-specific kasan_arch_is_ready() implementations or evaluated KASAN checks unconditionally, leading to code duplication. This patch unifies the approach by: 1. Moving kasan_flag_enabled declaration under CONFIG_KASAN (all modes) instead of only CONFIG_KASAN_HW_TAGS 2. Moving the static key definition to common.c for shared usage 3. Adding kasan_init_generic() function that enables the static key and handles initialization for Generic mode 4. Updating SW_TAGS mode to enable the unified static key 5. Removing the duplicate static key definition from HW_TAGS After this change, all KASAN modes use the same underlying static key infrastructure. The kasan_enabled() function now provides consistent runtime enable behavior across Generic, SW_TAGS, and HW_TAGS modes. This maintains a backward compatibility - existing architecture code continues to work unchanged, but now benefits from the unified runtime control mechanism. The architecture-specific kasan_arch_is_ready() implementations can be gradually replaced with calls to the new kasan_init_generic() function. Closes: https://bugzilla.kernel.org/show_bug.cgi?id=3D218315 Signed-off-by: Sabyrzhan Tasbolatov --- include/linux/kasan-enabled.h | 10 ++++++++-- include/linux/kasan.h | 6 ++++++ mm/kasan/common.c | 7 +++++++ mm/kasan/generic.c | 11 +++++++++++ mm/kasan/hw_tags.c | 7 ------- mm/kasan/sw_tags.c | 2 ++ 6 files changed, 34 insertions(+), 9 deletions(-) diff --git a/include/linux/kasan-enabled.h b/include/linux/kasan-enabled.h index 6f612d69ea0..2b1351c30c6 100644 --- a/include/linux/kasan-enabled.h +++ b/include/linux/kasan-enabled.h @@ -4,9 +4,15 @@ =20 #include =20 -#ifdef CONFIG_KASAN_HW_TAGS - +#ifdef CONFIG_KASAN +/* + * Global runtime flag. Starts =E2=80=98false=E2=80=99; switched to =E2=80= =98true=E2=80=99 by + * the appropriate kasan_init_*() once KASAN is fully initialized. + */ DECLARE_STATIC_KEY_FALSE(kasan_flag_enabled); +#endif + +#ifdef CONFIG_KASAN_HW_TAGS =20 static __always_inline bool kasan_enabled(void) { diff --git a/include/linux/kasan.h b/include/linux/kasan.h index 890011071f2..51a8293d1af 100644 --- a/include/linux/kasan.h +++ b/include/linux/kasan.h @@ -543,6 +543,12 @@ void kasan_report_async(void); =20 #endif /* CONFIG_KASAN_HW_TAGS */ =20 +#ifdef CONFIG_KASAN_GENERIC +void __init kasan_init_generic(void); +#else +static inline void kasan_init_generic(void) { } +#endif + #ifdef CONFIG_KASAN_SW_TAGS void __init kasan_init_sw_tags(void); #else diff --git a/mm/kasan/common.c b/mm/kasan/common.c index ed4873e18c7..525194da25f 100644 --- a/mm/kasan/common.c +++ b/mm/kasan/common.c @@ -32,6 +32,13 @@ #include "kasan.h" #include "../slab.h" =20 +/* + * Definition of the unified static key declared in kasan-enabled.h. + * This provides consistent runtime enable/disable across all KASAN modes. + */ +DEFINE_STATIC_KEY_FALSE(kasan_flag_enabled); +EXPORT_SYMBOL(kasan_flag_enabled); + struct slab *kasan_addr_to_slab(const void *addr) { if (virt_addr_valid(addr)) diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c index d54e89f8c3e..32c432df24a 100644 --- a/mm/kasan/generic.c +++ b/mm/kasan/generic.c @@ -36,6 +36,17 @@ #include "kasan.h" #include "../slab.h" =20 +/* + * Initialize Generic KASAN and enable runtime checks. + * This should be called from arch kasan_init() once shadow memory is read= y. + */ +void __init kasan_init_generic(void) +{ + static_branch_enable(&kasan_flag_enabled); + + pr_info("KernelAddressSanitizer initialized (generic)\n"); +} + /* * All functions below always inlined so compiler could * perform better optimizations in each of __asan_loadX/__assn_storeX diff --git a/mm/kasan/hw_tags.c b/mm/kasan/hw_tags.c index 9a6927394b5..8e819fc4a26 100644 --- a/mm/kasan/hw_tags.c +++ b/mm/kasan/hw_tags.c @@ -45,13 +45,6 @@ static enum kasan_arg kasan_arg __ro_after_init; static enum kasan_arg_mode kasan_arg_mode __ro_after_init; static enum kasan_arg_vmalloc kasan_arg_vmalloc __initdata; =20 -/* - * Whether KASAN is enabled at all. - * The value remains false until KASAN is initialized by kasan_init_hw_tag= s(). - */ -DEFINE_STATIC_KEY_FALSE(kasan_flag_enabled); -EXPORT_SYMBOL(kasan_flag_enabled); - /* * Whether the selected mode is synchronous, asynchronous, or asymmetric. * Defaults to KASAN_MODE_SYNC. diff --git a/mm/kasan/sw_tags.c b/mm/kasan/sw_tags.c index b9382b5b6a3..525bc91e2fc 100644 --- a/mm/kasan/sw_tags.c +++ b/mm/kasan/sw_tags.c @@ -45,6 +45,8 @@ void __init kasan_init_sw_tags(void) =20 kasan_init_tags(); =20 + static_branch_enable(&kasan_flag_enabled); + pr_info("KernelAddressSanitizer initialized (sw-tags, stacktrace=3D%s)\n", str_on_off(kasan_stack_collection_enabled())); } --=20 2.34.1