github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-06-10 07:32:29 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph
db5ae6596a
linux/arch/s390/kernel
History
Heiko Carstens 8dd6066066 s390/idle: fix cpu idle time calculation 
commit 3d7efa4edd upstream.

The idle time reported in /proc/stat sometimes incorrectly contains
huge values on s390. This is caused by a bug in arch_cpu_idle_time().

The kernel tries to figure out when a different cpu entered idle by
accessing its per-cpu data structure. There is an ordering problem: if
the remote cpu has an idle_enter value which is not zero, and an
idle_exit value which is zero, it is assumed it is idle since
"now". The "now" timestamp however is taken before the idle_enter
value is read.

Which in turn means that "now" can be smaller than idle_enter of the
remote cpu. Unconditionally subtracting idle_enter from "now" can thus
lead to a negative value (aka large unsigned value).

Fix this by moving the get_tod_clock() invocation out of the
loop. While at it also make the code a bit more readable.

A similar bug also exists for show_idle_time(). Fix this is as well.

Cc: <stable@vger.kernel.org>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-11-06 13:06:20 +01:00
..
syscalls kbuild: do not redirect the first prerequisite for filechk 2018-07-28 10:34:10 +09:00
vdso32 s390/vdso: add missing FORCE to build targets 2018-11-27 16:13:02 +01:00
vdso64 s390/vdso: add missing FORCE to build targets 2018-11-27 16:13:02 +01:00
.gitignore
alternative.c s390: add automatic detection of the spectre defense 2018-03-28 08:38:24 +02:00
asm-offsets.c s390: remove gcc version check (4.3 or newer) 2018-08-21 15:57:58 +02:00
audit.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
audit.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
base.S s390/kernel: use expoline for indirect branches 2018-05-07 21:12:39 +02:00
cache.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
compat_audit.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
compat_linux.c mm: add ksys_readahead() helper; remove in-kernel calls to sys_readahead() 2018-04-02 20:16:12 +02:00
compat_linux.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
compat_ptrace.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
compat_signal.c s390/compat: fix setup_frame32 2018-04-10 07:38:54 +02:00
compat_wrapper.c s390: wire up rseq system call 2018-07-04 08:35:18 +02:00
cpcmd.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
crash_dump.c s390/kdump: Remove kzalloc_panic 2018-08-16 14:49:15 +02:00
debug.c treewide: kmalloc() -> kmalloc_array() 2018-06-12 16:19:22 -07:00
diag.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
dis.c s390: kernel: add SPDX identifiers to the remaining files 2017-11-24 15:37:12 +01:00
dumpstack.c s390: kernel: add SPDX identifiers to the remaining files 2017-11-24 15:37:12 +01:00
early_nobss.c s390/early: move functions which may not access bss section to extra file 2018-05-09 10:55:01 +02:00
early_printk.c s390/hibernate: fix error handling when suspend cpu != resume cpu 2018-09-20 13:20:23 +02:00
early.c s390/early: improve machine detection 2019-01-31 08:14:35 +01:00
ebcdic.c s390: ebcdic: convert comments to UTF-8 2018-08-23 18:48:43 -07:00
entry.h s390/boot: make head.S and als.c be part of the decompressor only 2018-06-25 10:14:38 +02:00
entry.S s390: wire up rseq system call 2018-07-04 08:35:18 +02:00
fpu.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
ftrace.c s390/function_graph: Simplify with function_graph_enter() 2018-12-05 19:32:10 +01:00
guarded_storage.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux 2017-11-13 11:47:01 -08:00
head64.S s390: correct _stext offset 2018-07-02 11:24:59 +02:00
idle.c s390/idle: fix cpu idle time calculation 2019-11-06 13:06:20 +01:00
ipl.c s390/ipl: remove reipl_method and dump_method 2018-04-10 07:39:00 +02:00
irq.c s390: remove indirect branch from do_softirq_own_stack 2018-05-07 21:12:42 +02:00
jump_label.c jump_label: move 'asm goto' support test to Kconfig 2019-06-04 08:02:34 +02:00
kdebugfs.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
kexec_elf.c s390/kexec_file: Fix detection of text segment in ELF loader 2019-05-31 06:46:13 -07:00
kexec_image.c s390/kexec_file: Add crash support to image loader 2018-04-16 09:10:22 +02:00
kprobes.c bpf/error-inject/kprobes: Clear current_kprobe and enable preempt in kprobe 2018-06-21 12:33:19 +02:00
lgr.c s390: kernel: add SPDX identifiers to the remaining files 2017-11-24 15:37:12 +01:00
machine_kexec_file.c s390/kexec_file: Add ELF loader 2018-04-16 09:10:23 +02:00
machine_kexec.c s390/ipl: correct kdump reipl block checksum calculation 2018-04-10 07:39:00 +02:00
Makefile jump_label: move 'asm goto' support test to Kconfig 2019-06-04 08:02:34 +02:00
mcount.S s390/ftrace: Add -mfentry and -mnop-mcount support 2018-08-15 22:39:53 -04:00
module.c treewide: Use array_size() in vmalloc() 2018-06-12 16:19:22 -07:00
nmi.c headers: untangle kmemleak.h from mm.h 2018-04-05 21:36:27 -07:00
nospec-branch.c s390/speculation: Support 'mitigations=' cmdline option 2019-05-14 19:17:59 +02:00
nospec-sysfs.c s390: detect etoken facility 2018-07-18 08:32:17 +02:00
os_info.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
perf_cpum_cf_events.c treewide: kmalloc() -> kmalloc_array() 2018-06-12 16:19:22 -07:00
perf_cpum_cf.c s390/cpum_cf: Reject request for sampling in event initialization 2018-12-17 09:24:32 +01:00
perf_cpum_sf.c perf/aux: Make perf_event accessible to setup_aux() 2019-04-05 22:33:11 +02:00
perf_event.c s390: kernel: Remove redundant license text 2017-11-24 15:37:20 +01:00
perf_regs.c s390/perf: fix gcc 8 array-bounds warning 2018-07-02 11:24:54 +02:00
pgm_check.S License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
process.c s390/process: avoid potential reading of freed stack 2019-10-11 18:20:41 +02:00
processor.c s390: run user space and KVM guests with modified branch prediction 2018-02-05 14:48:50 +01:00
ptrace.c s390/gs: add compat regset for the guarded storage broadcast control block 2017-11-28 17:33:15 +01:00
reipl.S s390/kernel: use expoline for indirect branches 2018-05-07 21:12:39 +02:00
relocate_kernel.S s390: assume diag308 set always works 2018-04-10 07:38:59 +02:00
runtime_instr.c s390/runtime_instrumentation: re-add signum system call parameter 2018-02-05 07:34:50 +01:00
setup.c s390/setup: fix boot crash for machine without EDAT-1 2019-03-23 20:10:13 +01:00
signal.c s390: wire up rseq system call 2018-07-04 08:35:18 +02:00
smp.c s390/smp: Fix calling smp_call_ipl_cpu() from ipl CPU 2019-01-31 08:14:41 +01:00
stacktrace.c s390: kernel: add SPDX identifiers to the remaining files 2017-11-24 15:37:12 +01:00
sthyi.c s390/sthyi: Fix machine name validity indication 2018-11-13 11:08:21 -08:00
suspend.c s390: unify linker symbols usage 2018-02-27 08:05:23 +01:00
swsusp.S s390/hibernate: fix error handling when suspend cpu != resume cpu 2018-09-20 13:20:23 +02:00
sys_s390.c mm: add ksys_mmap_pgoff() helper; remove in-kernel calls to sys_mmap_pgoff() 2018-04-02 20:16:11 +02:00
sysinfo.c s390/sysinfo: add missing #ifdef CONFIG_PROC_FS 2018-07-02 12:32:20 +02:00
time.c s390/time: Remove read_boot_clock64() 2018-07-20 00:02:41 +02:00
topology.c s390/topology: avoid firing events before kobjs are created 2019-10-11 18:20:42 +02:00
trace.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
traps.c signal/s390: Use force_sig_fault where appropriate 2018-04-25 10:44:08 -05:00
uprobes.c s390/uprobes: implement arch_uretprobe_is_alive() 2018-04-23 07:57:16 +02:00
vdso.c s390: vdso_fault return type 2018-07-23 13:49:57 +02:00
vmlinux.lds.S s390: put _stext and _etext into .text section 2019-08-29 08:28:41 +02:00
vtime.c s390: kernel: add SPDX identifiers to the remaining files 2017-11-24 15:37:12 +01:00