https://github.com/torvalds/linux
Revision ff8acf929014b7f87315588e0daf8597c8aa9d1c authored by Nathan Chancellor on 17 April 2019, 07:21:21 UTC, committed by Catalin Marinas on 18 April 2019, 17:17:08 UTC
Commit 045afc24124d ("arm64: futex: Fix FUTEX_WAKE_OP atomic ops with non-zero result value") removed oldval's zero initialization in arch_futex_atomic_op_inuser because it is not necessary. Unfortunately, Android's arm64 GCC 4.9.4 [1] does not agree: ../kernel/futex.c: In function 'do_futex': ../kernel/futex.c:1658:17: warning: 'oldval' may be used uninitialized in this function [-Wmaybe-uninitialized] return oldval == cmparg; ^ In file included from ../kernel/futex.c:73:0: ../arch/arm64/include/asm/futex.h:53:6: note: 'oldval' was declared here int oldval, ret, tmp; ^ GCC fails to follow that when ret is non-zero, futex_atomic_op_inuser returns right away, avoiding the uninitialized use that it claims. Restoring the zero initialization works around this issue. [1]: https://android.googlesource.com/platform/prebuilts/gcc/linux-x86/aarch64/aarch64-linux-android-4.9/ Cc: stable@vger.kernel.org Fixes: 045afc24124d ("arm64: futex: Fix FUTEX_WAKE_OP atomic ops with non-zero result value") Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Tip revision: ff8acf929014b7f87315588e0daf8597c8aa9d1c authored by Nathan Chancellor on 17 April 2019, 07:21:21 UTC
arm64: futex: Restore oldval initialization to work around buggy compilers
arm64: futex: Restore oldval initialization to work around buggy compilers
Tip revision: ff8acf9
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.cocciconfig | -rw-r--r-- | 59 bytes |
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COPYING | -rw-r--r-- | 423 bytes |
CREDITS | -rw-r--r-- | 96.9 KB |
Kbuild | -rw-r--r-- | 1.5 KB |
Kconfig | -rw-r--r-- | 563 bytes |
MAINTAINERS | -rw-r--r-- | 491.4 KB |
Makefile | -rw-r--r-- | 58.3 KB |
README | -rw-r--r-- | 727 bytes |
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