From: Greg Kroah-Hartman Date: Thu, 31 Jan 2019 07:54:09 +0000 (+0100) Subject: 4.4-stable patches X-Git-Tag: v4.20.7~55 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=a8cbbf0d675bd843425e52e55c465d6e8ba36d99;p=thirdparty%2Fkernel%2Fstable-queue.git 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 index 00000000000..70fe1b85e0f --- /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 +Date: Fri, 11 Jan 2019 15:18:22 +0100 +Subject: s390/smp: Fix calling smp_call_ipl_cpu() from ipl CPU + +From: David Hildenbrand + +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 +Signed-off-by: David Hildenbrand +Signed-off-by: Martin Schwidefsky +Signed-off-by: Greg Kroah-Hartman + +--- + 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 56fe0284275..6cbd3a3f1bb 100644 --- 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