Patch "arch: define weak abort()" has been added to the 4.14-stable tree

This is a note to let you know that I've just added the patch titled

arch: define weak abort()

to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
arch-define-weak-abort.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Sudip Mukherjee <[email protected]>
Date: Thu, 14 Dec 2017 15:33:19 -0800
Subject: arch: define weak abort()

From: Sudip Mukherjee <[email protected]>

commit 7c2c11b208be09c156573fc0076b7b3646e05219 upstream.

gcc toggle -fisolate-erroneous-paths-dereference (default at -O2 onwards) isolates faulty code paths such as null pointer access, divide by zero etc. If gcc port doesnt implement __builtin_trap, an abort() is generated which causes kernel link error.

In this case, gcc is generating abort due to 'divide by zero' in lib/mpi/mpih-div.c.

Currently 'frv' and 'arc' are failing. Previously other arch was also broken like m32r was fixed by commit d22e3d69ee1a ("m32r: fix build failure").

Let's define this weak function which is common for all arch and fix the problem permanently. We can even remove the arch specific 'abort' after this is done.

---
 kernel/exit.c |    8 ++++++++
 1 file changed, 8 insertions(+)

@@ -1755,3 +1755,11 @@ Efault:
 	return -EFAULT;
 }
 #endif
+
+__weak void abort(void)
+{
+	BUG();
+
+	/* if that doesn't kill us, halt */
+	panic("Oops failed to kill thread");
+}

Patches currently in stable-queue which might be from [email protected] are

queue-4.14/arch-define-weak-abort.patch queue-4.14/kernel-exit.c-export-abort-to-modules.patch