4.14-stable review patch. If anyone has any objections, please let me know.
------------------ From: Chunyu Hu <[email protected]> commit 55d2d0ad2fb4325f615d1950486fbc5e6fba1769 upstream. On a secondary, idt is first loaded in cpu_init() with load_current_idt(), i.e. no exceptions can be handled before that point. The conversion of WARN() to use UD requires the IDT being loaded earlier as any warning between start_secondary() and load_curren_idt() in cpu_init() will result in an unhandled @UD exception and therefore fail the bringup of the CPU. Install the IDT handlers right in start_secondary() before calling cpu_init(). [ tglx: Massaged changelog ] Fixes: 9a93848fe787 ("x86/debug: Implement __WARN() using UD0") Signed-off-by: Chunyu Hu <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]> --- arch/x86/kernel/smpboot.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -239,7 +239,7 @@ static void notrace start_secondary(void load_cr3(swapper_pg_dir); __flush_tlb_all(); #endif - + load_current_idt(); cpu_init(); x86_cpuinit.early_percpu_clock_init(); preempt_disable();
