s390/vdso: fix stack corruption
authorHeiko Carstens <heiko.carstens@de.ibm.com>
Mon, 27 Oct 2014 07:28:08 +0000 (08:28 +0100)
committerMartin Schwidefsky <schwidefsky@de.ibm.com>
Mon, 27 Oct 2014 12:27:02 +0000 (13:27 +0100)
commit9b2efe035eafb1a29ff3dfe21ed0e755aac09130
tree37f0a0c357aaf7305ca9acf2850c78da576c4f93
parent1f759bb3a2a0d75ceeeec729b1c66a7f443631ba
s390/vdso: fix stack corruption

The kernel provided vdso functions do not get a stack frame from the
calling function and therefore may not change the stack contents, unless
they allocate space on their own.

This problem was exposed with 070b7be633dc "s390/vdso: replace stck with
stcke" which writes 16 bytes instead of 8 bytes into the stack frame. These
additional 8 bytes however were indeed used by the caller (glibc) to save
data and therefore this data was corrupted by the vdso code.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
arch/s390/kernel/vdso32/clock_gettime.S
arch/s390/kernel/vdso32/gettimeofday.S
arch/s390/kernel/vdso64/clock_gettime.S
arch/s390/kernel/vdso64/gettimeofday.S