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 4.4-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-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From bcf4dd5f9ee096bd1510f838dd4750c35df4e38b Mon Sep 17 00:00:00 2001
From: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Date: Mon, 27 Jun 2016 17:06:45 +0200
Subject: s390: fix test_fp_ctl inline assembly contraints
From: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
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"
Reviewed-by: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Signed-off-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/s390/include/asm/fpu/api.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/s390/include/asm/fpu/api.h
+++ b/arch/s390/include/asm/fpu/api.h
@@ -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 schwidefsky@xxxxxxxxxx are
queue-4.4/s390-fix-test_fp_ctl-inline-assembly-contraints.patch
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