[PATCH] ppc32: Kill init on unhandled synchronous signals

This is a patch that I have had in my tree for ages.  If init causes
an exception that raises a signal, such as a SIGSEGV, SIGILL or
SIGFPE, and it hasn't registered a handler for it, we don't deliver
the signal, since init doesn't get any signals that it doesn't have a
handler for.  But that means that we just return to userland and
generate the same exception again immediately.  With this patch we
print a message and kill init in this situation.

This is very useful when you have a bug in the kernel that means that
init doesn't get as far as executing its first instruction. :)
Without this patch the system hangs when it gets to starting the
userland init; with it you at least get a message giving you a clue
about what has gone wrong.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 1 insertions, 5 deletions

diff --git a/arch/ppc/mm/fault.c b/arch/ppc/mm/fault.c
index 57d9930843ac..ee5e9f25baf9 100644
--- a/arch/ppc/mm/fault.c
+++ b/arch/ppc/mm/fault.c
@@ -278,11 +278,7 @@ bad_area:
 
         /* User mode accesses cause a SIGSEGV */
         if (user_mode(regs)) {
-                info.si_signo = SIGSEGV;
-                info.si_errno = 0;
-                info.si_code = code;
-                info.si_addr = (void __user *) address;
-                force_sig_info(SIGSEGV, &info, current);
+                _exception(SIGSEGV, regs, code, address);
                 return 0;
         }