Commit e902e508 authored by Al Viro's avatar Al Viro
Browse files

nios2: fix livelock in uaccess 



nios2 equivalent of 26178ec1 "x86: mm: consolidate VM_FAULT_RETRY handling"
If e.g. get_user() triggers a page fault and a fatal signal is caught, we might
end up with handle_mm_fault() returning VM_FAULT_RETRY and not doing anything
to page tables.  In such case we must *not* return to the faulting insn -
that would repeat the entire thing without making any progress; what we need
instead is to treat that as failed (user) memory access.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent a1179ac7

arch/nios2/mm/fault.c

+4 −1
Original line number Diff line number Diff line
@@ -136,8 +136,11 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long cause, 
	 */

	fault = handle_mm_fault(vma, address, flags, regs);



	if (fault_signal_pending(fault, regs))

	if (fault_signal_pending(fault, regs)) {

		if (!user_mode(regs))

			goto no_context;

		return;

	}



	/* The fault is fully completed (including releasing mmap lock) */

	if (fault & VM_FAULT_COMPLETED)