Patchwork [116/241] sparc64: not any error from do_sigaltstack() should fail rt_sigreturn()

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Submitter Herton Ronaldo Krzesinski
Date Dec. 13, 2012, 1:58 p.m.
Message ID <>
Download mbox | patch
Permalink /patch/205966/
State New
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Herton Ronaldo Krzesinski - Dec. 13, 2012, 1:58 p.m. -stable review patch.  If anyone has any objections, please let me know.


From: Al Viro <>

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: Herton Ronaldo Krzesinski <>
 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 867de2f..689e1ba 100644
--- a/arch/sparc/kernel/signal_64.c
+++ b/arch/sparc/kernel/signal_64.c
@@ -295,9 +295,7 @@  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);