From: Will Deacon <will@kernel.org>
To: linux-kernel@vger.kernel.org
Cc: linux-arch@vger.kernel.org, kernel-team@android.com,
Will Deacon <will@kernel.org>,
Michael Ellerman <mpe@ellerman.id.au>,
Peter Zijlstra <peterz@infradead.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Segher Boessenkool <segher@kernel.crashing.org>,
Christian Borntraeger <borntraeger@de.ibm.com>,
Luc Van Oostenryck <luc.vanoostenryck@gmail.com>,
Arnd Bergmann <arnd@arndb.de>,
Peter Oberparleiter <oberpar@linux.ibm.com>,
Masahiro Yamada <masahiroy@kernel.org>,
Nick Desaulniers <ndesaulniers@google.com>,
Akinobu Mita <akinobu.mita@gmail.com>
Subject: [PATCH v3 04/12] fault_inject: Don't rely on "return value" from WRITE_ONCE()
Date: Wed, 15 Apr 2020 17:52:10 +0100 [thread overview]
Message-ID: <20200415165218.20251-5-will@kernel.org> (raw)
In-Reply-To: <20200415165218.20251-1-will@kernel.org>
It's a bit weird that WRITE_ONCE() evaluates to the value it stores and
it's different to smp_store_release(), which can't be used this way.
In preparation for preventing this in WRITE_ONCE(), change the fault
injection code to use a local variable instead.
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Will Deacon <will@kernel.org>
---
lib/fault-inject.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/lib/fault-inject.c b/lib/fault-inject.c
index 8186ca84910b..ce12621b4275 100644
--- a/lib/fault-inject.c
+++ b/lib/fault-inject.c
@@ -106,7 +106,9 @@ bool should_fail(struct fault_attr *attr, ssize_t size)
unsigned int fail_nth = READ_ONCE(current->fail_nth);
if (fail_nth) {
- if (!WRITE_ONCE(current->fail_nth, fail_nth - 1))
+ fail_nth--;
+ WRITE_ONCE(current->fail_nth, fail_nth);
+ if (!fail_nth)
goto fail;
return false;
--
2.26.0.110.g2183baf09c-goog
next prev parent reply other threads:[~2020-04-15 16:53 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-15 16:52 [PATCH v3 00/12] Rework READ_ONCE() to improve codegen Will Deacon
2020-04-15 16:52 ` [PATCH v3 01/12] compiler/gcc: Emit build-time warning for GCC prior to version 4.8 Will Deacon
2020-04-15 17:20 ` Masahiro Yamada
2020-04-15 16:52 ` [PATCH v3 02/12] netfilter: Avoid assigning 'const' pointer to non-const pointer Will Deacon
2020-04-15 16:52 ` [PATCH v3 03/12] net: tls: " Will Deacon
2020-04-15 16:52 ` Will Deacon [this message]
2020-04-15 16:52 ` [PATCH v3 05/12] arm64: csum: Disable KASAN for do_csum() Will Deacon
2020-04-15 17:28 ` Mark Rutland
2020-04-15 18:42 ` Arnd Bergmann
2020-04-15 19:43 ` Will Deacon
2020-04-15 20:10 ` Will Deacon
2020-04-15 19:26 ` Will Deacon
2020-04-16 9:31 ` Mark Rutland
2020-04-16 11:53 ` Will Deacon
2020-04-16 12:11 ` Mark Rutland
2020-04-15 19:26 ` Robin Murphy
2020-04-15 16:52 ` [PATCH v3 06/12] READ_ONCE: Simplify implementations of {READ,WRITE}_ONCE() Will Deacon
2020-04-15 16:52 ` [PATCH v3 07/12] READ_ONCE: Enforce atomicity for {READ,WRITE}_ONCE() memory accesses Will Deacon
2020-04-15 16:52 ` [PATCH v3 08/12] READ_ONCE: Drop pointer qualifiers when reading from scalar types Will Deacon
2020-04-15 16:52 ` [PATCH v3 09/12] locking/barriers: Use '__unqual_scalar_typeof' for load-acquire macros Will Deacon
2020-04-15 16:52 ` [PATCH v3 10/12] arm64: barrier: Use '__unqual_scalar_typeof' for acquire/release macros Will Deacon
2020-04-15 16:52 ` [PATCH v3 11/12] compiler/gcc: Raise minimum GCC version for kernel builds to 4.8 Will Deacon
2020-04-15 18:37 ` Arnd Bergmann
2020-04-15 16:52 ` [PATCH v3 12/12] gcov: Remove old GCC 3.4 support Will Deacon
2020-04-16 12:30 ` [PATCH v3 00/12] Rework READ_ONCE() to improve codegen Christian Borntraeger
2020-04-16 12:48 ` Will Deacon
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