From: Peter Zijlstra <peterz@infradead.org>
To: tglx@linutronix.de
Cc: x86@kernel.org, elver@google.com, paulmck@kernel.org,
kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org,
peterz@infradead.org, will@kernel.org, dvyukov@google.com,
glider@google.com, andreyknvl@google.com
Subject: [PATCH 8/8] x86/entry, bug: Comment the instrumentation_begin() usage for WARN()
Date: Thu, 04 Jun 2020 12:22:49 +0200 [thread overview]
Message-ID: <20200604102428.364746275@infradead.org> (raw)
In-Reply-To: 20200604102241.466509982@infradead.org
Explain the rationale for annotating WARN(), even though, strictly
speaking printk() and friends are very much not safe in many of the
places we put them.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
arch/x86/include/asm/bug.h | 6 ++++++
1 file changed, 6 insertions(+)
--- a/arch/x86/include/asm/bug.h
+++ b/arch/x86/include/asm/bug.h
@@ -76,6 +76,12 @@ do { \
unreachable(); \
} while (0)
+/*
+ * This instrumentation_begin() is strictly speaking incorrect; but it
+ * suppresses the complaints from WARN()s in noinstr code. If such a WARN()
+ * were to trigger, we'd rather wreck the machine in an attempt to get the
+ * message out than not know about it.
+ */
#define __WARN_FLAGS(flags) \
do { \
instrumentation_begin(); \
next prev parent reply other threads:[~2020-06-04 10:25 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-04 10:22 [PATCH 0/8] x86/entry: KCSAN/KASAN/UBSAN vs noinstr Peter Zijlstra
2020-06-04 10:22 ` [PATCH 1/8] x86, kcsan: Remove __no_kcsan_or_inline usage Peter Zijlstra
2020-06-04 10:22 ` [PATCH 2/8] kcsan: Remove __no_kcsan_or_inline Peter Zijlstra
2020-06-04 10:22 ` [PATCH 3/8] x86, kcsan: Add __no_kcsan to noinstr Peter Zijlstra
2020-06-04 10:22 ` [PATCH 4/8] kasan: Bump required compiler version Peter Zijlstra
2020-06-04 10:22 ` [PATCH 5/8] compiler_types.h: Add __no_sanitize_{address,undefined} to noinstr Peter Zijlstra
2020-06-04 10:22 ` [PATCH 6/8] x86/entry, cpumask: Provide non-instrumented variant of cpu_is_offline() Peter Zijlstra
2020-06-04 10:22 ` [PATCH 7/8] x86/entry, ubsan, objtool: Whitelist __ubsan_handle_*() Peter Zijlstra
2020-06-04 10:22 ` Peter Zijlstra [this message]
2020-06-04 11:01 ` [PATCH 0/8] x86/entry: KCSAN/KASAN/UBSAN vs noinstr Marco Elver
2020-06-15 10:07 ` Marco Elver
2020-06-15 14:57 ` Qian Cai
2020-06-15 15:06 ` Peter Zijlstra
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