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From: Sami Tolvanen <samitolvanen@google.com>
To: linux-kernel@vger.kernel.org
Cc: Kees Cook <keescook@chromium.org>,
	Josh Poimboeuf <jpoimboe@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	x86@kernel.org, Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Nathan Chancellor <nathan@kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Joao Moreira <joao@overdrivepizza.com>,
	Sedat Dilek <sedat.dilek@gmail.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	linux-hardening@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, llvm@lists.linux.dev,
	Sami Tolvanen <samitolvanen@google.com>
Subject: [RFC PATCH v3 13/20] treewide: Drop WARN_ON_FUNCTION_MISMATCH
Date: Fri, 10 Jun 2022 16:35:06 -0700	[thread overview]
Message-ID: <20220610233513.1798771-14-samitolvanen@google.com> (raw)
In-Reply-To: <20220610233513.1798771-1-samitolvanen@google.com>

CONFIG_CFI_CLANG no longer breaks cross-module function address
equality, which makes WARN_ON_FUNCTION_MISMATCH unnecessary. Remove
the definition and switch back to WARN_ON_ONCE.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
---
 include/asm-generic/bug.h | 16 ----------------
 kernel/kthread.c          |  3 +--
 kernel/workqueue.c        |  2 +-
 3 files changed, 2 insertions(+), 19 deletions(-)

diff --git a/include/asm-generic/bug.h b/include/asm-generic/bug.h
index ba1f860af38b..4050b191e1a9 100644
--- a/include/asm-generic/bug.h
+++ b/include/asm-generic/bug.h
@@ -220,22 +220,6 @@ extern __printf(1, 2) void __warn_printk(const char *fmt, ...);
 # define WARN_ON_SMP(x)			({0;})
 #endif
 
-/*
- * WARN_ON_FUNCTION_MISMATCH() warns if a value doesn't match a
- * function address, and can be useful for catching issues with
- * callback functions, for example.
- *
- * With CONFIG_CFI_CLANG, the warning is disabled because the
- * compiler replaces function addresses taken in C code with
- * local jump table addresses, which breaks cross-module function
- * address equality.
- */
-#if defined(CONFIG_CFI_CLANG) && defined(CONFIG_MODULES)
-# define WARN_ON_FUNCTION_MISMATCH(x, fn) ({ 0; })
-#else
-# define WARN_ON_FUNCTION_MISMATCH(x, fn) WARN_ON_ONCE((x) != (fn))
-#endif
-
 #endif /* __ASSEMBLY__ */
 
 #endif
diff --git a/kernel/kthread.c b/kernel/kthread.c
index 544fd4097406..19d446f4e3a9 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -1050,8 +1050,7 @@ static void __kthread_queue_delayed_work(struct kthread_worker *worker,
 	struct timer_list *timer = &dwork->timer;
 	struct kthread_work *work = &dwork->work;
 
-	WARN_ON_FUNCTION_MISMATCH(timer->function,
-				  kthread_delayed_work_timer_fn);
+	WARN_ON_ONCE(timer->function != kthread_delayed_work_timer_fn);
 
 	/*
 	 * If @delay is 0, queue @dwork->work immediately.  This is for
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 4056f2a3f9d5..2fed7bb018a7 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -1651,7 +1651,7 @@ static void __queue_delayed_work(int cpu, struct workqueue_struct *wq,
 	struct work_struct *work = &dwork->work;
 
 	WARN_ON_ONCE(!wq);
-	WARN_ON_FUNCTION_MISMATCH(timer->function, delayed_work_timer_fn);
+	WARN_ON_ONCE(timer->function != delayed_work_timer_fn);
 	WARN_ON_ONCE(timer_pending(timer));
 	WARN_ON_ONCE(!list_empty(&work->entry));
 
-- 
2.36.1.476.g0c4daa206d-goog


  parent reply	other threads:[~2022-06-10 23:37 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-06-10 23:34 [RFC PATCH v3 00/20] KCFI support Sami Tolvanen
2022-06-10 23:34 ` [RFC PATCH v3 01/20] treewide: Filter out CC_FLAGS_CFI Sami Tolvanen
2022-06-10 23:34 ` [RFC PATCH v3 02/20] scripts/kallsyms: Ignore __kcfi_typeid_ Sami Tolvanen
2022-06-10 23:34 ` [RFC PATCH v3 03/20] cfi: Remove CONFIG_CFI_CLANG_SHADOW Sami Tolvanen
2022-06-10 23:34 ` [RFC PATCH v3 04/20] cfi: Drop __CFI_ADDRESSABLE Sami Tolvanen
2022-06-10 23:34 ` [RFC PATCH v3 05/20] cfi: Switch to -fsanitize=kcfi Sami Tolvanen
2022-06-10 23:34 ` [RFC PATCH v3 06/20] cfi: Add type helper macros Sami Tolvanen
2022-06-10 23:35 ` [RFC PATCH v3 07/20] lkdtm: Emit an indirect call for CFI tests Sami Tolvanen
2022-06-10 23:43   ` Nick Desaulniers
2022-06-11  6:01   ` Kees Cook
2022-06-10 23:35 ` [RFC PATCH v3 08/20] arm64: Add types to indirect called assembly functions Sami Tolvanen
2022-06-10 23:35 ` [RFC PATCH v3 09/20] arm64: Add CFI error handling Sami Tolvanen
2022-06-10 23:35 ` [RFC PATCH v3 10/20] arm64: Drop unneeded __nocfi attributes Sami Tolvanen
2022-06-10 23:35 ` [RFC PATCH v3 11/20] init: Drop __nocfi from __init Sami Tolvanen
2022-06-10 23:35 ` [RFC PATCH v3 12/20] treewide: Drop function_nocfi Sami Tolvanen
2022-06-10 23:35 ` Sami Tolvanen [this message]
2022-06-10 23:35 ` [RFC PATCH v3 14/20] treewide: Drop __cficanonical Sami Tolvanen
2022-06-10 23:35 ` [RFC PATCH v3 15/20] objtool: Disable CFI warnings Sami Tolvanen
2022-06-13 16:10   ` Josh Poimboeuf
2022-06-10 23:35 ` [RFC PATCH v3 16/20] kallsyms: Drop CONFIG_CFI_CLANG workarounds Sami Tolvanen
2022-06-10 23:40   ` Nick Desaulniers
2022-06-13 19:19     ` Bill Wendling
2022-06-10 23:35 ` [RFC PATCH v3 17/20] x86/tools/relocs: Ignore __kcfi_typeid_ relocations Sami Tolvanen
2022-06-10 23:35 ` [RFC PATCH v3 18/20] x86: Add types to indirectly called assembly functions Sami Tolvanen
2022-06-10 23:35 ` [RFC PATCH v3 19/20] x86/purgatory: Disable CFI Sami Tolvanen
2022-06-10 23:35 ` [RFC PATCH v3 20/20] x86: Add support for CONFIG_CFI_CLANG Sami Tolvanen
2022-07-23 11:21   ` Peter Zijlstra
2022-07-26  0:09     ` Sami Tolvanen
2022-06-13 17:04 ` [RFC PATCH v3 00/20] KCFI support Kees Cook
2022-07-18 21:46   ` Peter Zijlstra
2022-07-19 13:36   ` Will Deacon

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