From e7ac9b5fc607f246a1ce62e418c0a7e5bb02c012 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sun, 18 Nov 2012 22:27:03 -0500 Subject: [PATCH] sparc64: not any error from do_sigaltstack() should fail rt_sigreturn() commit fae2ae2a900a5c7bb385fe4075f343e7e2d5daa2 upstream. If a signal handler is executed on altstack and another signal comes, we will end up with rt_sigreturn() on return from the second handler getting -EPERM from do_sigaltstack(). It's perfectly OK, since we are not asking to change the settings; in fact, they couldn't have been changed during the second handler execution exactly because we'd been on altstack all along. 64bit sigreturn on sparc treats any error from do_sigaltstack() as "SIGSEGV now"; we need to switch to the same semantics we are using on other architectures. Signed-off-by: Al Viro Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings --- arch/sparc/kernel/signal_64.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/arch/sparc/kernel/signal_64.c b/arch/sparc/kernel/signal_64.c index f0836cd0e2f2..d58d3edd05b3 100644 --- a/arch/sparc/kernel/signal_64.c +++ b/arch/sparc/kernel/signal_64.c @@ -307,9 +307,7 @@ void do_rt_sigreturn(struct pt_regs *regs) err |= restore_fpu_state(regs, fpu_save); err |= __copy_from_user(&set, &sf->mask, sizeof(sigset_t)); - err |= do_sigaltstack(&sf->stack, NULL, (unsigned long)sf); - - if (err) + if (err || do_sigaltstack(&sf->stack, NULL, (unsigned long)sf) == -EFAULT) goto segv; err |= __get_user(rwin_save, &sf->rwin_save); -- 2.39.5