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[93.103.32.68]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-a7dc9c12ad3sm478517266b.88.2024.08.05.11.40.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 05 Aug 2024 11:40:32 -0700 (PDT) From: Uros Bizjak To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: Uros Bizjak , Dennis Zhou , Tejun Heo , Christoph Lameter , Andy Lutomirski , Ingo Molnar , Nadav Amit , Brian Gerst , Denys Vlasenko , "H . Peter Anvin" , Linus Torvalds , Peter Zijlstra , Thomas Gleixner , Borislav Petkov , Luc Van Oostenryck Subject: [RFC PATCH 0/3] Enable strict percpu address space checks Date: Mon, 5 Aug 2024 20:38:58 +0200 Message-ID: <20240805184012.358023-1-ubizjak@gmail.com> X-Mailer: git-send-email 2.45.2 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit This patchset enables strict percpu address space checks via x86 named address space qualifiers. Percpu variables are declared in __seg_gs/__seg_fs named AS and kept named AS qualified until they are dereferenced via percpu accessor. This approach enables various compiler checks for cross-namespace variable assignments. Please note that sparse doesn't know anything about __typeof_unqual__() operator, so the usage of __typeof_unqual__() breaks sparse checking. Also, the last patch hijacks __percpu tag and repurposes it as a named address space qualifier. While this works surprisingly well in this RFC patchset, I would really appreciate some help on how to rewrite this hack into some "production ready" code. Cc: Dennis Zhou Cc: Tejun Heo Cc: Christoph Lameter Cc: Andy Lutomirski Cc: Ingo Molnar Cc: Nadav Amit Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Borislav Petkov Cc: Luc Van Oostenryck Uros Bizjak (3): percpu: Define __pcpu_typeof() percpu: Assorted fixes found by strict percpu address space checks percpu/x86: [RFH] Enable strict percpu checks via named AS qualifiers arch/x86/include/asm/percpu.h | 53 ++++++++++++++++++++++++---------- arch/x86/kernel/head64.c | 3 +- drivers/base/devres.c | 2 +- fs/aio.c | 2 +- include/linux/cleanup.h | 4 +-- include/linux/compiler_types.h | 2 +- include/linux/part_stat.h | 2 +- include/linux/percpu-defs.h | 39 ++++++++++++++++++++----- include/linux/prandom.h | 1 + init/Kconfig | 3 ++ kernel/events/hw_breakpoint.c | 4 +-- kernel/locking/percpu-rwsem.c | 2 +- kernel/workqueue.c | 2 +- lib/percpu_counter.c | 2 +- net/core/dev.c | 2 +- 15 files changed, 87 insertions(+), 36 deletions(-) -- 2.45.2