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authorDave Airlie <airlied@redhat.com>2019-01-24 18:54:15 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-01-26 09:38:36 +0100
commit4b527f25a4ac64c0d17c882cdf8322be66f31611 (patch)
tree580fdaae32189aab0cdebe88442c777496f0cf45
parentcac2590d2582c04f995c2b1cd2c30d8a0c11b36e (diff)
locking/qspinlock: Pull in asm/byteorder.h to ensure correct endianness
This commit is not required upstream, but is required for the 4.9.y stable series. Upstream commit 101110f6271c ("Kbuild: always define endianess in kconfig.h") ensures that either __LITTLE_ENDIAN or __BIG_ENDIAN is defined to reflect the endianness of the target CPU architecture regardless of whether or not <asm/byteorder.h> has been #included. The upstream definition of 'struct qspinlock' relies on this property. Unfortunately, the 4.9.y stable series does not provide this guarantee, so the 'spin_unlock()' routine can erroneously treat the underlying lockword as big-endian on little-endian architectures using native qspinlock (i.e. x86_64 without PV) if the caller has not included <asm/byteorder.h>. This can lead to hangs such as the one in 'i915_gem_request()' reported via bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=202063 Fix the issue by ensuring that <asm/byteorder.h> is #included in <asm/qspinlock_types.h>, where 'struct qspinlock' is defined. Cc: <stable@vger.kernel.org> # 4.9 Signed-off-by: Dave Airlie <airlied@redhat.com> [will: wrote commit message] Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--include/asm-generic/qspinlock_types.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/include/asm-generic/qspinlock_types.h b/include/asm-generic/qspinlock_types.h
index d10f1e7d6ba8..6503e96710fa 100644
--- a/include/asm-generic/qspinlock_types.h
+++ b/include/asm-generic/qspinlock_types.h
@@ -18,6 +18,8 @@
#ifndef __ASM_GENERIC_QSPINLOCK_TYPES_H
#define __ASM_GENERIC_QSPINLOCK_TYPES_H
+#include <asm/byteorder.h>
+
/*
* Including atomic.h with PARAVIRT on will cause compilation errors because
* of recursive header file incluson via paravirt_types.h. So don't include