From: Will Deacon <will.deacon@arm.com>
To: gregkh@linuxfoundation.org
Cc: linux-kernel@vger.kernel.org, Dave Airlie <airlied@redhat.com>,
stable@vger.kernel.org, Will Deacon <will.deacon@arm.com>
Subject: [PATCH stable-4.9.y] locking/qspinlock: Pull in asm/byteorder.h to ensure correct endianness
Date: Thu, 24 Jan 2019 18:54:15 +0000 [thread overview]
Message-ID: <20190124185415.29830-1-will.deacon@arm.com> (raw)
From: Dave Airlie <airlied@redhat.com>
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>
---
include/asm-generic/qspinlock_types.h | 2 ++
1 file changed, 2 insertions(+)
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
--
2.17.1
next reply other threads:[~2019-01-24 18:54 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-24 18:54 Will Deacon [this message]
2019-01-24 19:04 ` [PATCH stable-4.9.y] locking/qspinlock: Pull in asm/byteorder.h to ensure correct endianness Greg KH
2019-01-24 19:14 ` David Airlie
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190124185415.29830-1-will.deacon@arm.com \
--to=will.deacon@arm.com \
--cc=airlied@redhat.com \
--cc=gregkh@linuxfoundation.org \
--cc=linux-kernel@vger.kernel.org \
--cc=stable@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).