4.14-stable review patch. If anyone has any objections, please let me know.
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This reverts commit f9a64e23a9da528e7d8aa1bd2c7bb92be4ebb724 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(-)
--- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -51,19 +51,15 @@ ENTRY(native_usergs_sysret64) END(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 @@ -927,13 +923,11 @@ ENTRY(native_load_gs_index) FRAME_BEGIN 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 FRAME_END ret