Commit-ID:  16df4ff8604881db0130f93f4b6ade759fa48e87
Gitweb:     http://git.kernel.org/tip/16df4ff8604881db0130f93f4b6ade759fa48e87
Author:     Josh Poimboeuf <jpoim...@redhat.com>
AuthorDate: Thu, 21 Jan 2016 16:49:32 -0600
Committer:  Ingo Molnar <mi...@kernel.org>
CommitDate: Wed, 24 Feb 2016 08:35:44 +0100

x86/locking: Create stack frame in PV unlock

The assembly PV_UNLOCK function is a callable non-leaf function which
doesn't honor CONFIG_FRAME_POINTER, which can result in bad stack
traces.

Create a stack frame when CONFIG_FRAME_POINTER is enabled.

Signed-off-by: Josh Poimboeuf <jpoim...@redhat.com>
Cc: Andrew Morton <a...@linux-foundation.org>
Cc: Andy Lutomirski <l...@amacapital.net>
Cc: Andy Lutomirski <l...@kernel.org>
Cc: Arnaldo Carvalho de Melo <a...@kernel.org>
Cc: Bernd Petrovitsch <be...@petrovitsch.priv.at>
Cc: Borislav Petkov <b...@alien8.de>
Cc: Brian Gerst <brge...@gmail.com>
Cc: Chris J Arges <chris.j.ar...@canonical.com>
Cc: Denys Vlasenko <dvlas...@redhat.com>
Cc: H. Peter Anvin <h...@zytor.com>
Cc: Jiri Slaby <jsl...@suse.cz>
Cc: Linus Torvalds <torva...@linux-foundation.org>
Cc: Michal Marek <mma...@suse.cz>
Cc: Namhyung Kim <namhy...@gmail.com>
Cc: Pedro Alves <pal...@redhat.com>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Waiman Long <waiman.l...@hpe.com>
Cc: live-patch...@vger.kernel.org
Link: 
http://lkml.kernel.org/r/6685a72ddbbd0ad3694337cca0af4b4ea09f5f40.1453405861.git.jpoim...@redhat.com
Signed-off-by: Ingo Molnar <mi...@kernel.org>
---
 arch/x86/include/asm/qspinlock_paravirt.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/x86/include/asm/qspinlock_paravirt.h 
b/arch/x86/include/asm/qspinlock_paravirt.h
index 9f92c18..9d55f9b 100644
--- a/arch/x86/include/asm/qspinlock_paravirt.h
+++ b/arch/x86/include/asm/qspinlock_paravirt.h
@@ -36,8 +36,10 @@ PV_CALLEE_SAVE_REGS_THUNK(__pv_queued_spin_unlock_slowpath);
  */
 asm    (".pushsection .text;"
        ".globl " PV_UNLOCK ";"
+       ".type " PV_UNLOCK ", @function;"
        ".align 4,0x90;"
        PV_UNLOCK ": "
+       FRAME_BEGIN
        "push  %rdx;"
        "mov   $0x1,%eax;"
        "xor   %edx,%edx;"
@@ -45,6 +47,7 @@ asm    (".pushsection .text;"
        "cmp   $0x1,%al;"
        "jne   .slowpath;"
        "pop   %rdx;"
+       FRAME_END
        "ret;"
        ".slowpath: "
        "push   %rsi;"
@@ -52,6 +55,7 @@ asm    (".pushsection .text;"
        "call " PV_UNLOCK_SLOWPATH ";"
        "pop    %rsi;"
        "pop    %rdx;"
+       FRAME_END
        "ret;"
        ".size " PV_UNLOCK ", .-" PV_UNLOCK ";"
        ".popsection");

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