From a0d14b8909de55139b8702fe0c7e80b69763dcfb Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 11 Jul 2019 13:40:59 +0200 Subject: x86/mm, tracing: Fix CR2 corruption Despite the current efforts to read CR2 before tracing happens there still exist a number of possible holes: idtentry page_fault do_page_fault has_error_code=1 call error_entry TRACE_IRQS_OFF call trace_hardirqs_off* #PF // modifies CR2 CALL_enter_from_user_mode __context_tracking_exit() trace_user_exit(0) #PF // modifies CR2 call do_page_fault address = read_cr2(); /* whoopsie */ And similar for i386. Fix it by pulling the CR2 read into the entry code, before any of that stuff gets a chance to run and ruin things. Reported-by: He Zhe Reported-by: Eiichi Tsukata Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Thomas Gleixner Reviewed-by: Andy Lutomirski Cc: bp@alien8.de Cc: rostedt@goodmis.org Cc: torvalds@linux-foundation.org Cc: hpa@zytor.com Cc: dave.hansen@linux.intel.com Cc: jgross@suse.com Cc: joel@joelfernandes.org Link: https://lkml.kernel.org/r/20190711114336.116812491@infradead.org Debugged-by: Steven Rostedt --- arch/x86/include/asm/kvm_para.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/x86/include/asm/kvm_para.h') diff --git a/arch/x86/include/asm/kvm_para.h b/arch/x86/include/asm/kvm_para.h index 5ed3cf1c3934..9b4df6eaa11a 100644 --- a/arch/x86/include/asm/kvm_para.h +++ b/arch/x86/include/asm/kvm_para.h @@ -92,7 +92,7 @@ void kvm_async_pf_task_wait(u32 token, int interrupt_kernel); void kvm_async_pf_task_wake(u32 token); u32 kvm_read_and_reset_pf_reason(void); extern void kvm_disable_steal_time(void); -void do_async_page_fault(struct pt_regs *regs, unsigned long error_code); +void do_async_page_fault(struct pt_regs *regs, unsigned long error_code, unsigned long address); #ifdef CONFIG_PARAVIRT_SPINLOCKS void __init kvm_spinlock_init(void); -- cgit v1.2.3