| From | Greg Kroah-Hartman <> | Subject | [ 34/56] sparc64: not any error from do_sigaltstack() should fail rt_sigreturn() | Date | Fri, 30 Nov 2012 10:55:26 -0800 |
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3.4-stable review patch. If anyone has any objections, please let me know.
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From: Al Viro <viro@zeniv.linux.org.uk>
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 <viro@zeniv.linux.org.uk> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- arch/sparc/kernel/signal_64.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-)
--- a/arch/sparc/kernel/signal_64.c +++ b/arch/sparc/kernel/signal_64.c @@ -309,9 +309,7 @@ void do_rt_sigreturn(struct pt_regs *reg 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);
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