4.4-stable patches

added patches:
	s390-smp-fix-calling-smp_call_ipl_cpu-from-ipl-cpu.patch

diff --git a/queue-4.4/s390-smp-fix-calling-smp_call_ipl_cpu-from-ipl-cpu.patch b/queue-4.4/s390-smp-fix-calling-smp_call_ipl_cpu-from-ipl-cpu.patch
new file mode 100644 (file)
index 0000000..70fe1b8
--- /dev/null
+++ b/queue-4.4/s390-smp-fix-calling-smp_call_ipl_cpu-from-ipl-cpu.patch
@@ -0,0 +1,78 @@
+From 60f1bf29c0b2519989927cae640cd1f50f59dc7f Mon Sep 17 00:00:00 2001
+From: David Hildenbrand <david@redhat.com>
+Date: Fri, 11 Jan 2019 15:18:22 +0100
+Subject: s390/smp: Fix calling smp_call_ipl_cpu() from ipl CPU
+
+From: David Hildenbrand <david@redhat.com>
+
+commit 60f1bf29c0b2519989927cae640cd1f50f59dc7f upstream.
+
+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: 2f859d0dad81 ("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>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ arch/s390/kernel/smp.c |    8 ++++++--
+ 1 file changed, 6 insertions(+), 2 deletions(-)
+
+--- a/arch/s390/kernel/smp.c
++++ b/arch/s390/kernel/smp.c
+@@ -360,9 +360,13 @@ void smp_call_online_cpu(void (*func)(vo
+  */
+ void smp_call_ipl_cpu(void (*func)(void *), void *data)
+ {
++      struct _lowcore *lc = pcpu_devices->lowcore;
++
++      if (pcpu_devices[0].address == stap())
++              lc = &S390_lowcore;
++
+       pcpu_delegate(&pcpu_devices[0], func, data,
+-                    pcpu_devices->lowcore->panic_stack -
+-                    PANIC_FRAME_OFFSET + PAGE_SIZE);
++                    lc->panic_stack - PANIC_FRAME_OFFSET + PAGE_SIZE);
+ }
+ 
+ int smp_find_processor_id(u16 address)

diff --git a/queue-4.4/series b/queue-4.4/series
index 56fe02842758aad94de13e0a5acd650f13db6c37..6cbd3a3f1bbaacbbdd59e32855849fc4625e442f 100644 (file)
--- a/queue-4.4/series
+++ b/queue-4.4/series
@@ -29,3 +29,4 @@ f2fs-read-page-index-before-freeing.patch
 0001-Revert-loop-Fix-double-mutex_unlock-loop_ctl_mutex-i.patch
 0002-Revert-loop-Get-rid-of-loop_index_mutex.patch
 0003-Revert-loop-Fold-__loop_release-into-loop_release.patch
+s390-smp-fix-calling-smp_call_ipl_cpu-from-ipl-cpu.patch