This is a note to let you know that I've just added the patch titled
[PATCH] Revert "x86/entry/64: Add missing irqflags tracing to
to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: revert-x86-entry-64-add-missing-irqflags-tracing-to.patch and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From 0ed6c0c778e67f00978a778612862441e48cc529 Mon Sep 17 00:00:00 2001
From: Greg Kroah-Hartman gregkh@linuxfoundation.org Date: Mon, 4 Dec 2017 12:59:57 +0100 Subject: [PATCH] Revert "x86/entry/64: Add missing irqflags tracing to native_load_gs_index()"
This reverts commit 0d794d0d018f23fb09c50f6ae26868bd6ae343d6 which is commit 0d794d0d018f23fb09c50f6ae26868bd6ae343d6 upstream.
Andy writes:
I think the thing to do is to revert the patch from -stable. The bug it fixes is very minor, and the regression is that it made a pre-existing bug in some nearly-undebuggable core resume code much easier to hit. I don't feel comfortable with a backport of the latter fix until it has a good long soak in Linus' tree.
Reported-by: Andy Lutomirski luto@kernel.org Cc: Borislav Petkov bpetkov@suse.de Cc: Brian Gerst brgerst@gmail.com Cc: Dave Hansen dave.hansen@intel.com Cc: Josh Poimboeuf jpoimboe@redhat.com Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Peter Zijlstra peterz@infradead.org Cc: Thomas Gleixner tglx@linutronix.de Cc: Ingo Molnar mingo@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/entry/entry_64.S | 10 ++-------- 1 file changed, 2 insertions(+), 8 deletions(-)
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index be9df513141e..e7b0e7ff4c58 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -54,19 +54,15 @@ ENTRY(native_usergs_sysret64) ENDPROC(native_usergs_sysret64) #endif /* CONFIG_PARAVIRT */
-.macro TRACE_IRQS_FLAGS flags:req +.macro TRACE_IRQS_IRETQ #ifdef CONFIG_TRACE_IRQFLAGS - bt $9, \flags /* interrupts off? */ + bt $9, EFLAGS(%rsp) /* interrupts off? */ jnc 1f TRACE_IRQS_ON 1: #endif .endm
-.macro TRACE_IRQS_IRETQ - TRACE_IRQS_FLAGS EFLAGS(%rsp) -.endm - /* * When dynamic function tracer is enabled it will add a breakpoint * to all locations that it is about to modify, sync CPUs, update @@ -872,13 +868,11 @@ idtentry simd_coprocessor_error do_simd_coprocessor_error has_error_code=0 ENTRY(native_load_gs_index) pushfq DISABLE_INTERRUPTS(CLBR_ANY & ~CLBR_RDI) - TRACE_IRQS_OFF SWAPGS .Lgs_change: movl %edi, %gs 2: ALTERNATIVE "", "mfence", X86_BUG_SWAPGS_FENCE SWAPGS - TRACE_IRQS_FLAGS (%rsp) popfq ret END(native_load_gs_index)