[patch 3/8] uml: Fix SKAS sig-handler reentrancy [before 2.6.11]

[blaisorblade]

From: Jeff Dike <jdike@xxxxxxxxxxx>, Paolo 'Blaisorblade' Giarrusso <blaisorblade@xxxxxxxx>
CC: uml-devel <user-mode-linux-devel@xxxxxxxxxxxxxxxxxxxxx>

This adds code which enables SIGSEGV reception to the SKAS sig_handler_common,
which matches the tt code.

I still need to figure out why the SA_NODEFER flag was backed out in favor of this.

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@xxxxxxxx>
---

 linux-2.6.11-paolo/arch/um/kernel/skas/trap_user.c |    8 ++++++++
 1 files changed, 8 insertions(+)

diff -puN arch/um/kernel/skas/trap_user.c~uml-no-defer arch/um/kernel/skas/trap_user.c
--- linux-2.6.11/arch/um/kernel/skas/trap_user.c~uml-no-defer	2005-02-04 06:14:11.966064760 +0100
+++ linux-2.6.11-paolo/arch/um/kernel/skas/trap_user.c	2005-02-04 06:14:11.969064304 +0100
@@ -20,6 +20,14 @@ void sig_handler_common_skas(int sig, vo
 	int save_errno = errno;
 	int save_user;
 
+	/* This is done because to allow SIGSEGV to be delivered inside a SEGV
+	 * handler.  This can happen in copy_user, and if SEGV is disabled,
+	 * the process will die.
+	 * XXX Figure out why this is better than SA_NODEFER
+	 */
+	if(sig == SIGSEGV)
+		change_sig(SIGSEGV, 1);
+
 	r = &TASK_REGS(get_current())->skas;
 	save_user = r->is_user;
 	r->is_user = 0;
_
-
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