Patch "s390: fix test_fp_ctl inline assembly contraints" has been added to the 4.6-stable tree

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

s390: fix test_fp_ctl inline assembly contraints

to the 4.6-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:
s390-fix-test_fp_ctl-inline-assembly-contraints.patch
and it can be found in the queue-4.6 subdirectory.

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

From: Martin Schwidefsky <[email protected]>
Date: Mon, 27 Jun 2016 17:06:45 +0200
Subject: s390: fix test_fp_ctl inline assembly contraints

From: Martin Schwidefsky <[email protected]>

commit bcf4dd5f9ee096bd1510f838dd4750c35df4e38b upstream.

The test_fp_ctl function is used to test if a given value is a valid floating-point control. The inline assembly in test_fp_ctl uses an incorrect constraint for the 'orig_fpc' variable. If the compiler chooses the same register for 'fpc' and 'orig_fpc' the test_fp_ctl() function always returns true. This allows user space to trigger kernel oopses with invalid floating-point control values on the signal stack.

This problem has been introduced with git commit 4725c86055f5bbdcdf "s390: fix save and restore of the floating-point-control register"

---
 arch/s390/include/asm/fpu/api.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

@@ -22,7 +22,7 @@ static inline int test_fp_ctl(u32 fpc)
 		"	la	%0,0\n"
 		"1:\n"
 		EX_TABLE(0b,1b)
-		: "=d" (rc), "=d" (orig_fpc)
+		: "=d" (rc), "=&d" (orig_fpc)
 		: "d" (fpc), "0" (-EINVAL));
 	return rc;
 }

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

queue-4.6/s390-fix-test_fp_ctl-inline-assembly-contraints.patch queue-4.6/kvm-s390-mm-fix-cmma-reset-during-reboot.patch queue-4.6/revert-s390-kdump-clear-subchannel-id-to-signal-non-ccw-scsi-ipl.patch