Subject: [Fwd: [PATCH] powerpc: _exception: kill the obsolete code under is_global_init()]

From: Benjamin Herrenschmidt <[email-masked]>
Date: Wed, 11 Nov 2009 12:13:15 +1100

Subject: [PATCH] powerpc: _exception: kill the obsolete code under is_global_init()
From: Oleg Nesterov <[email-masked]>
To: Andrew Morton <[email-masked]>
Cc: Benjamin Herrenschmidt <[email-masked]>, Geert Uytterhoeven <[email-masked]>, Kumar Gala <[email-masked]>, Liu Yu <[email-masked]>, Roland McGrath <[email-masked]>, [email-masked]
Date: Tue, 10 Nov 2009 01:25:42 +0100
List-Id: <linux-kernel.vger.kernel.org>

The code under "if (is_global_init())" is bogus, and is_global_init()
itself is not right in mt case.

Contrary to what the comment says, nowadays force_sig_info() does kill
init even if the handler is SIG_DFL. Note that force_sig_info() clears
SIGNAL_UNKILLABLE exactly for this case.

Signed-off-by: Oleg Nesterov <[email-masked]>
---

 arch/powerpc/kernel/traps.c |   22 ----------------------
 1 file changed, 22 deletions(-)

--- TH/arch/powerpc/kernel/traps.c~PPC_EXCEPTION_DONT_CK_INIT	2009-11-10 01:03:23.000000000 +0100
+++ TH/arch/powerpc/kernel/traps.c	2009-11-10 01:06:41.000000000 +0100
@@ -198,28 +198,6 @@ void _exception(int signr, struct pt_reg
 	info.si_code = code;
 	info.si_addr = (void __user *) addr;
 	force_sig_info(signr, &info, current);
-
-	/*
-	 * Init gets no signals that it doesn't have a handler for.
-	 * That's all very well, but if it has caused a synchronous
-	 * exception and we ignore the resulting signal, it will just
-	 * generate the same exception over and over again and we get
-	 * nowhere.  Better to kill it and let the kernel panic.
-	 */
-	if (is_global_init(current)) {
-		__sighandler_t handler;
-
-		spin_lock_irq(&current->sighand->siglock);
-		handler = current->sighand->action[signr-1].sa.sa_handler;
-		spin_unlock_irq(&current->sighand->siglock);
-		if (handler == SIG_DFL) {
-			/* init has generated a synchronous exception
-			   and it doesn't have a handler for the signal */
-			printk(KERN_CRIT "init has generated signal %d "
-			       "but has no handler for it\n", signr);
-			do_exit(signr);
-		}
-	}
 }
 
 #ifdef CONFIG_PPC64

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