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Commit af0c11ca authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'arc-4.0-fixes-part-2' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc 

Pull ARC fixes from Vineet Gupta:
 "We found some issues with signal handling taking down the system.  I
  know its late, but these are important and all marked for stable.

  ARC signal handling related fixes uncovered during recent testing of
  NPTL tools"

* tag 'arc-4.0-fixes-part-2' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc:
  ARC: signal handling robustify
  ARC: SA_SIGINFO ucontext regs off-by-one
parents 38ae1dfc e4140819

arch/arc/kernel/signal.c

+18 −6
Original line number Diff line number Diff line
@@ -67,7 +67,7 @@ stash_usr_regs(struct rt_sigframe __user *sf, struct pt_regs *regs, 
	       sigset_t *set)

{

	int err;

	err = __copy_to_user(&(sf->uc.uc_mcontext.regs), regs,

	err = __copy_to_user(&(sf->uc.uc_mcontext.regs.scratch), regs,

			     sizeof(sf->uc.uc_mcontext.regs.scratch));

	err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(sigset_t));
@@ -83,7 +83,7 @@ static int restore_usr_regs(struct pt_regs *regs, struct rt_sigframe __user *sf) 
	if (!err)

		set_current_blocked(&set);



	err |= __copy_from_user(regs, &(sf->uc.uc_mcontext.regs),

	err |= __copy_from_user(regs, &(sf->uc.uc_mcontext.regs.scratch),

				sizeof(sf->uc.uc_mcontext.regs.scratch));



	return err;
@@ -131,6 +131,15 @@ SYSCALL_DEFINE0(rt_sigreturn) 
	/* Don't restart from sigreturn */

	syscall_wont_restart(regs);



	/*

	 * Ensure that sigreturn always returns to user mode (in case the

	 * regs saved on user stack got fudged between save and sigreturn)

	 * Otherwise it is easy to panic the kernel with a custom

	 * signal handler and/or restorer which clobberes the status32/ret

	 * to return to a bogus location in kernel mode.

	 */

	regs->status32 |= STATUS_U_MASK;



	return regs->r0;



badframe:
@@ -229,8 +238,11 @@ setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs) 


	/*

	 * handler returns using sigreturn stub provided already by userpsace

	 * If not, nuke the process right away

	 */

	BUG_ON(!(ksig->ka.sa.sa_flags & SA_RESTORER));

	if(!(ksig->ka.sa.sa_flags & SA_RESTORER))

		return 1;



	regs->blink = (unsigned long)ksig->ka.sa.sa_restorer;



	/* User Stack for signal handler will be above the frame just carved */
@@ -296,12 +308,12 @@ static void 
handle_signal(struct ksignal *ksig, struct pt_regs *regs)

{

	sigset_t *oldset = sigmask_to_save();

	int ret;

	int failed;



	/* Set up the stack frame */

	ret = setup_rt_frame(ksig, oldset, regs);

	failed = setup_rt_frame(ksig, oldset, regs);



	signal_setup_done(ret, ksig, 0);

	signal_setup_done(failed, ksig, 0);

}



void do_signal(struct pt_regs *regs)