The following commit has been merged in the linux branch: commit b3dcf3de8e4d71d79235fc67b6c5def6506c27f8 Author: Heiko Carstens heiko.carstens@de.ibm.com Date: Thu Oct 29 15:04:14 2009 +0100

[S390] smp: fix sigp sense handling

sigp sense only returns the status of a cpu if it is non zero. If the status of the sensed cpu is all zeros condition code 0 (accpeted) is set and no status bits are returned. The current code however assumes that a status was returned and tests bits in it. This means uninitalized data is accessed with random results. Worst case is that the code that checks if cpu is offline on cpu hotplug assumes that the target cpu is offline while it is still running. This leads potentially to memory corruption since resources that are still needed by the target cpu will be freed and could be resused while still in use.

Signed-off-by: Heiko Carstens heiko.carstens@de.ibm.com Signed-off-by: Martin Schwidefsky schwidefsky@de.ibm.com

diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c index c99c45b..93e5203 100644 --- a/arch/s390/kernel/smp.c +++ b/arch/s390/kernel/smp.c @@ -76,7 +76,6 @@ static int cpu_stopped(int cpu) __u32 status;

switch (signal_processor_ps(&status, 0, cpu, sigp_sense)) { - case sigp_order_code_accepted: case sigp_status_stored: /* Check for stopped and check stop state */ if (status & 0x50) diff --git a/arch/s390/kernel/swsusp_asm64.S b/arch/s390/kernel/swsusp_asm64.S index 0f4ef3b..0c26cc1 100644 --- a/arch/s390/kernel/swsusp_asm64.S +++ b/arch/s390/kernel/swsusp_asm64.S @@ -207,6 +207,7 @@ restart_suspend: llgh %r2,0(%r1) 7: sigp %r9,%r2,__SIGP_SENSE /* Wait for resume CPU */ + brc 8,7b /* accepted, status 0, still running */ brc 2,7b /* busy, try again */ tmll %r9,0x40 /* Test if resume CPU is stopped */ jz 7b