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Subject[tip:x86/urgent] x86/entry/64: Fix entry_SYSCALL_64_after_hwframe() IRQ tracing
Commit-ID:  548c3050ea8d16997ae27f9e080a8338a606fc93
Author: Andy Lutomirski <>
AuthorDate: Tue, 21 Nov 2017 20:43:56 -0800
Committer: Ingo Molnar <>
CommitDate: Wed, 22 Nov 2017 06:35:48 +0100

x86/entry/64: Fix entry_SYSCALL_64_after_hwframe() IRQ tracing

When I added entry_SYSCALL_64_after_hwframe(), I left TRACE_IRQS_OFF
before it. This means that users of entry_SYSCALL_64_after_hwframe()
were responsible for invoking TRACE_IRQS_OFF, and the one and only
user (Xen, added in the same commit) got it wrong.

I think this would manifest as a warning if a Xen PV guest with
CONFIG_DEBUG_LOCKDEP=y were used with context tracking. (The
context tracking bit is to cause lockdep to get invoked before we
turn IRQs back on.) I haven't tested that for real yet because I
can't get a kernel configured like that to boot at all on Xen PV.

Move TRACE_IRQS_OFF below the label.

Signed-off-by: Andy Lutomirski <>
Cc: Boris Ostrovsky <>
Cc: Borislav Petkov <>
Cc: Brian Gerst <>
Cc: Dave Hansen <>
Cc: Josh Poimboeuf <>
Cc: Juergen Gross <>
Cc: Linus Torvalds <>
Cc: Peter Zijlstra <>
Cc: Thomas Gleixner <>
Fixes: 8a9949bc71a7 ("x86/xen/64: Rearrange the SYSCALL entries")
Signed-off-by: Ingo Molnar <>
arch/x86/entry/entry_64.S | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index a2b30ec..5063ed1 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -148,8 +148,6 @@ ENTRY(entry_SYSCALL_64)
movq %rsp, PER_CPU_VAR(rsp_scratch)
movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp

/* Construct struct pt_regs on stack */
pushq $__USER_DS /* pt_regs->ss */
pushq PER_CPU_VAR(rsp_scratch) /* pt_regs->sp */
@@ -170,6 +168,8 @@ GLOBAL(entry_SYSCALL_64_after_hwframe)
sub $(6*8), %rsp /* pt_regs->bp, bx, r12-15 not saved */

* If we need to do entry work or if we guess we'll need to do
* exit work, go straight to the slow path.
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