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Michael Mueller f87ef57235 KVM: s390: fix gisa destroy operation might lead to cpu stalls
A GISA cannot be destroyed as long it is linked in the GIB alert list
as this would break the alert list. Just waiting for its removal from
the list triggered by another vm is not sufficient as it might be the
only vm. The below shown cpu stall situation might occur when GIB alerts
are delayed and is fixed by calling process_gib_alert_list() instead of
waiting.

At this time the vcpus of the vm are already destroyed and thus
no vcpu can be kicked to enter the SIE again if for some reason an
interrupt is pending for that vm.

Additionally the IAM restore value is set to 0x00. That would be a bug
introduced by incomplete device de-registration, i.e. missing
kvm_s390_gisc_unregister() call.

Setting this value and the IAM in the GISA to 0x00 guarantees that late
interrupts don't bring the GISA back into the alert list.

CPU stall caused by kvm_s390_gisa_destroy():

 [ 4915.311372] rcu: INFO: rcu_sched detected expedited stalls on CPUs/tasks: { 14-.... } 24533 jiffies s: 5269 root: 0x1/.
 [ 4915.311390] rcu: blocking rcu_node structures (internal RCU debug): l=1:0-15:0x4000/.
 [ 4915.311394] Task dump for CPU 14:
 [ 4915.311395] task:qemu-system-s39 state:R  running task     stack:0     pid:217198 ppid:1      flags:0x00000045
 [ 4915.311399] Call Trace:
 [ 4915.311401]  [<0000038003a33a10>] 0x38003a33a10
 [ 4933.861321] rcu: INFO: rcu_sched self-detected stall on CPU
 [ 4933.861332] rcu: 	14-....: (42008 ticks this GP) idle=53f4/1/0x4000000000000000 softirq=61530/61530 fqs=14031
 [ 4933.861353] rcu: 	(t=42008 jiffies g=238109 q=100360 ncpus=18)
 [ 4933.861357] CPU: 14 PID: 217198 Comm: qemu-system-s39 Not tainted 6.5.0-20230816.rc6.git26.a9d17c5d8813.300.fc38.s390x #1
 [ 4933.861360] Hardware name: IBM 8561 T01 703 (LPAR)
 [ 4933.861361] Krnl PSW : 0704e00180000000 000003ff804bfc66 (kvm_s390_gisa_destroy+0x3e/0xe0 [kvm])
 [ 4933.861414]            R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:2 PM:0 RI:0 EA:3
 [ 4933.861416] Krnl GPRS: 0000000000000000 00000372000000fc 00000002134f8000 000000000d5f5900
 [ 4933.861419]            00000002f5ea1d18 00000002f5ea1d18 0000000000000000 0000000000000000
 [ 4933.861420]            00000002134fa890 00000002134f8958 000000000d5f5900 00000002134f8000
 [ 4933.861422]            000003ffa06acf98 000003ffa06858b0 0000038003a33c20 0000038003a33bc8
 [ 4933.861430] Krnl Code: 000003ff804bfc58: ec66002b007e	cij	%r6,0,6,000003ff804bfcae
                           000003ff804bfc5e: b904003a		lgr	%r3,%r10
                          #000003ff804bfc62: a7f40005		brc	15,000003ff804bfc6c
                          >000003ff804bfc66: e330b7300204	lg	%r3,10032(%r11)
                           000003ff804bfc6c: 58003000		l	%r0,0(%r3)
                           000003ff804bfc70: ec03fffb6076	crj	%r0,%r3,6,000003ff804bfc66
                           000003ff804bfc76: e320b7600271	lay	%r2,10080(%r11)
                           000003ff804bfc7c: c0e5fffea339	brasl	%r14,000003ff804942ee
 [ 4933.861444] Call Trace:
 [ 4933.861445]  [<000003ff804bfc66>] kvm_s390_gisa_destroy+0x3e/0xe0 [kvm]
 [ 4933.861460] ([<00000002623523de>] free_unref_page+0xee/0x148)
 [ 4933.861507]  [<000003ff804aea98>] kvm_arch_destroy_vm+0x50/0x120 [kvm]
 [ 4933.861521]  [<000003ff8049d374>] kvm_destroy_vm+0x174/0x288 [kvm]
 [ 4933.861532]  [<000003ff8049d4fe>] kvm_vm_release+0x36/0x48 [kvm]
 [ 4933.861542]  [<00000002623cd04a>] __fput+0xea/0x2a8
 [ 4933.861547]  [<00000002620d5bf8>] task_work_run+0x88/0xf0
 [ 4933.861551]  [<00000002620b0aa6>] do_exit+0x2c6/0x528
 [ 4933.861556]  [<00000002620b0f00>] do_group_exit+0x40/0xb8
 [ 4933.861557]  [<00000002620b0fa6>] __s390x_sys_exit_group+0x2e/0x30
 [ 4933.861559]  [<0000000262d481f4>] __do_syscall+0x1d4/0x200
 [ 4933.861563]  [<0000000262d59028>] system_call+0x70/0x98
 [ 4933.861565] Last Breaking-Event-Address:
 [ 4933.861566]  [<0000038003a33b60>] 0x38003a33b60

Fixes: 9f30f62163 ("KVM: s390: add gib_alert_irq_handler()")
Signed-off-by: Michael Mueller <mimu@linux.ibm.com>
Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Reviewed-by: Nico Boehr <nrb@linux.ibm.com>
Link: https://lore.kernel.org/r/20230901105823.3973928-1-mimu@linux.ibm.com
Message-ID: <20230901105823.3973928-1-mimu@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
History 2023-09-25 08:31:47 +02:00
arch KVM: s390: fix gisa destroy operation might lead to cpu stalls 2023-09-25 08:31:47 +02:00
block blk-mq: fix tags UAF when shrinking q->nr_hw_queues 2023-09-11 16:17:34 -06:00
certs certs: Reference revocation list for all keyrings 2023-08-17 20:12:41 +00:00
crypto crypto: sm2 - Fix crash caused by uninitialized context 2023-09-20 13:10:10 +08:00
Documentation LoongArch fixes for v6.6-rc3 2023-09-23 10:57:03 -07:00
drivers cxl fixes for v6.6-rc3 2023-09-24 13:50:28 -07:00
fs Tracing fixes for 6.6-rc2: 2023-09-24 13:55:34 -07:00
include ARM: 2023-09-24 14:14:35 -07:00
init workqueue: Changes for v6.6 2023-09-01 16:06:32 -07:00
io_uring io_uring/net: fix iter retargeting for selected buf 2023-09-14 10:12:55 -06:00
ipc Add x86 shadow stack support 2023-08-31 12:20:12 -07:00
kernel Tracing fixes for 6.6-rc2: 2023-09-24 13:55:34 -07:00
lib argv_split: fix kernel-doc warnings 2023-09-19 13:21:33 -07:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm 13 hotfixes, 10 of which pertain to post-6.5 issues. The other 3 are 2023-09-23 11:51:16 -07:00
net Networking fixes for 6.6-rc2, including fixes from netfilter and bpf 2023-09-21 11:28:16 -07:00
rust Documentation work keeps chugging along; stuff for 6.6 includes: 2023-08-30 20:05:42 -07:00
samples VFIO updates for v6.6-rc1 2023-08-30 20:36:01 -07:00
scripts 13 hotfixes, 10 of which pertain to post-6.5 issues. The other 3 are 2023-09-23 11:51:16 -07:00
security selinux: fix handling of empty opts in selinux_fs_context_submount() 2023-09-12 17:31:08 -04:00
sound ASoC: Fixes for v6.6 2023-09-20 15:02:16 +02:00
tools ARM: 2023-09-24 14:14:35 -07:00
usr initramfs: Encode dependency on KBUILD_BUILD_TIMESTAMP 2023-06-06 17:54:49 +09:00
virt ARM: 2023-09-07 13:52:20 -07:00
.clang-format iommu: Add for_each_group_device() 2023-05-23 08:15:51 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore kbuild: rpm-pkg: rename binkernel.spec to kernel.spec 2023-07-25 00:59:33 +09:00
.mailmap for-linus-2023083101 2023-09-01 12:31:44 -07:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS USB: Remove Wireless USB and UWB documentation 2023-08-09 14:17:32 +02:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS gpio fixes for v6.6-rc3 2023-09-23 11:56:57 -07:00
Makefile Linux 6.6-rc3 2023-09-24 14:31:13 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.