linux/arch/s390
Heiko Carstens d911e03d09 s390/timer: avoid overflow when programming clock comparator
Since ed4f209 "s390/time: fix sched_clock() overflow" a new helper function
is used to avoid overflows when converting TOD format values to nanosecond
values.
The kvm interrupt code formerly however only worked by accident because of
an overflow. It tried to program a timer that would expire in more than ~29
years. Because of the old TOD-to-nanoseconds overflow bug the real expiry
value however was much smaller, but now it isn't anymore.
This however triggers yet another bug in the function that programs the clock
comparator s390_next_ktime(): if the absolute "expires" value is after 2042
this will result in an overflow and the programmed value is lower than the
current TOD value which immediatly triggers a clock comparator (= timer)
interrupt.
Since the timer isn't expired it will be programmed immediately again and so
on... the result is a dead system.
To fix this simply program the maximum possible value if an overflow is
detected.

Reported-by: Christian Borntraeger <borntraeger@de.ibm.com>
Tested-by: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: stable@vger.kernel.org # v3.3+
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2013-01-31 14:01:52 +01:00
..
appldata
boot s390: fix linker script for 31 bit builds 2012-10-18 17:50:10 +02:00
crypto s390/crypto: Don't panic after crypto instruction failures 2012-11-23 11:14:27 +01:00
hypfs
include s390/thp: implement pmdp_set_wrprotect() 2013-01-22 13:32:16 +01:00
kernel s390/timer: avoid overflow when programming clock comparator 2013-01-31 14:01:52 +01:00
kvm Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux 2013-01-17 08:56:30 -08:00
lib s390/mm: use pmd_large() instead of pmd_huge() 2012-10-26 16:44:23 +02:00
math-emu
mm s390/irq: remove split irq fields from /proc/stat 2013-01-08 10:57:07 +01:00
net s390/bpf,jit: add support for XOR instruction 2012-12-03 10:44:05 -05:00
oprofile s390/irq: remove split irq fields from /proc/stat 2013-01-08 10:57:07 +01:00
pci s390/irq: remove split irq fields from /proc/stat 2013-01-08 10:57:07 +01:00
defconfig
Kbuild s390/pci: base support 2012-11-30 15:40:45 +01:00
Kconfig Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal 2012-12-20 18:05:28 -08:00
Kconfig.debug s390/mm: add page table dumper 2012-10-09 14:16:58 +02:00
Makefile s390: use -fPIC for module compile 2013-01-12 18:49:26 +01:00