David Hildenbrand 60f1bf29c0 s390/smp: Fix calling smp_call_ipl_cpu() from ipl CPU ... When calling smp_call_ipl_cpu() from the IPL CPU, we will try to read from pcpu_devices->lowcore. However, due to prefixing, that will result in reading from absolute address 0 on that CPU. We have to go via the actual lowcore instead. This means that right now, we will read lc->nodat_stack == 0 and therfore work on a very wrong stack. This BUG essentially broke rebooting under QEMU TCG (which will report a low address protection exception). And checking under KVM, it is also broken under KVM. With 1 VCPU it can be easily triggered. :/# echo 1 > /proc/sys/kernel/sysrq :/# echo b > /proc/sysrq-trigger [ 28.476745] sysrq: SysRq : Resetting [ 28.476793] Kernel stack overflow. [ 28.476817] CPU: 0 PID: 424 Comm: sh Not tainted 5.0.0-rc1+ #13 [ 28.476820] Hardware name: IBM 2964 NE1 716 (KVM/Linux) [ 28.476826] Krnl PSW : 0400c00180000000 0000000000115c0c (pcpu_delegate+0x12c/0x140) [ 28.476861] R:0 T:1 IO:0 EX:0 Key:0 M:0 W:0 P:0 AS:3 CC:0 PM:0 RI:0 EA:3 [ 28.476863] Krnl GPRS: ffffffffffffffff 0000000000000000 000000000010dff8 0000000000000000 [ 28.476864] 0000000000000000 0000000000000000 0000000000ab7090 000003e0006efbf0 [ 28.476864] 000000000010dff8 0000000000000000 0000000000000000 0000000000000000 [ 28.476865] 000000007fffc000 0000000000730408 000003e0006efc58 0000000000000000 [ 28.476887] Krnl Code: 0000000000115bfe: 4170f000 la %r7,0(%r15) [ 28.476887] 0000000000115c02: 41f0a000 la %r15,0(%r10) [ 28.476887] #0000000000115c06: e370f0980024 stg %r7,152(%r15) [ 28.476887] >0000000000115c0c: c0e5fffff86e brasl %r14,114ce8 [ 28.476887] 0000000000115c12: 41f07000 la %r15,0(%r7) [ 28.476887] 0000000000115c16: a7f4ffa8 brc 15,115b66 [ 28.476887] 0000000000115c1a: 0707 bcr 0,%r7 [ 28.476887] 0000000000115c1c: 0707 bcr 0,%r7 [ 28.476901] Call Trace: [ 28.476902] Last Breaking-Event-Address: [ 28.476920] [<0000000000a01c4a>] arch_call_rest_init+0x22/0x80 [ 28.476927] Kernel panic - not syncing: Corrupt kernel stack, can't continue. [ 28.476930] CPU: 0 PID: 424 Comm: sh Not tainted 5.0.0-rc1+ #13 [ 28.476932] Hardware name: IBM 2964 NE1 716 (KVM/Linux) [ 28.476932] Call Trace: Fixes: 2f859d0dad ("s390/smp: reduce size of struct pcpu") Cc: stable@vger.kernel.org # 4.0+ Reported-by: Cornelia Huck <cohuck@redhat.com> Signed-off-by: David Hildenbrand <david@redhat.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>		2019-01-11 17:12:03 +01:00
..
appldata	sched: loadavg: consolidate LOAD_INT, LOAD_FRAC, CALC_LOAD	2018-10-26 16:26:32 -07:00
boot	s390: avoid vmlinux segments overlap	2018-10-26 10:19:40 +02:00
configs	s390: update defconfigs	2018-11-05 15:10:27 +01:00
crypto	crypto: drop mask=CRYPTO_ALG_ASYNC from 'cipher' tfm allocations	2018-11-20 14:26:55 +08:00
hypfs	s390/hypfs: do not use stack buffers for hardware data	2018-10-09 11:20:53 +02:00
include	s390/vdso: correct vdso mapping for compat tasks	2019-01-11 17:12:02 +01:00
kernel	s390/smp: Fix calling smp_call_ipl_cpu() from ipl CPU	2019-01-11 17:12:03 +01:00
kvm	Kconfig updates for v4.21	2018-12-29 13:03:29 -08:00
lib	s390/kasan: avoid user access code instrumentation	2018-10-09 11:21:21 +02:00
mm	s390 updates for the 4.21 merge window	2019-01-02 18:37:01 -08:00
net	s390: bpf: implement jitting of BPF_ALU | BPF_ARSH | BPF_*	2018-12-07 13:30:48 -08:00
numa	s390 updates for 4.20-rc2	2018-11-09 06:30:44 -06:00
oprofile
pci	pci-v4.21-changes	2019-01-05 17:57:34 -08:00
purgatory	s390: clean up stacks setup	2018-09-20 13:20:29 +02:00
scripts	s390/build: add *.o.chkbss files to targets list	2018-07-02 12:32:23 +02:00
tools	kbuild: use assignment instead of define ... endef for filechk_* rules	2019-01-06 10:22:35 +09:00
defconfig	s390: update defconfigs	2018-11-05 15:10:27 +01:00
Kbuild
Kconfig	Kconfig file consolidation for v4.21	2018-12-29 13:40:29 -08:00
Kconfig.debug	Kconfig: consolidate the "Kernel hacking" menu	2018-08-02 08:06:48 +09:00
Makefile	s390/kasan: increase instrumented stack size to 64k	2018-11-02 08:31:57 +01:00