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Kernel sources for Moto G9 (Play) (Guamp)
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Dongli Zhang 0848767dee xen: delay xen_hvm_init_time_ops() if kdump is boot on vcpu>=32 
[ Upstream commit eed05744322da07dd7e419432dcedf3c2e017179 ]

The sched_clock() can be used very early since commit 857baa87b6
("sched/clock: Enable sched clock early"). In addition, with commit
38669ba205 ("x86/xen/time: Output xen sched_clock time from 0"), kdump
kernel in Xen HVM guest may panic at very early stage when accessing
&__this_cpu_read(xen_vcpu)->time as in below:

setup_arch()
 -> init_hypervisor_platform()
     -> x86_init.hyper.init_platform = xen_hvm_guest_init()
         -> xen_hvm_init_time_ops()
             -> xen_clocksource_read()
                 -> src = &__this_cpu_read(xen_vcpu)->time;

This is because Xen HVM supports at most MAX_VIRT_CPUS=32 'vcpu_info'
embedded inside 'shared_info' during early stage until xen_vcpu_setup() is
used to allocate/relocate 'vcpu_info' for boot cpu at arbitrary address.

However, when Xen HVM guest panic on vcpu >= 32, since
xen_vcpu_info_reset(0) would set per_cpu(xen_vcpu, cpu) = NULL when
vcpu >= 32, xen_clocksource_read() on vcpu >= 32 would panic.

This patch calls xen_hvm_init_time_ops() again later in
xen_hvm_smp_prepare_boot_cpu() after the 'vcpu_info' for boot vcpu is
registered when the boot vcpu is >= 32.

This issue can be reproduced on purpose via below command at the guest
side when kdump/kexec is enabled:

"taskset -c 33 echo c > /proc/sysrq-trigger"

The bugfix for PVM is not implemented due to the lack of testing
environment.

[boris: xen_hvm_init_time_ops() returns on errors instead of jumping to end]

Cc: Joe Jin <joe.jin@oracle.com>
Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Link: https://lore.kernel.org/r/20220302164032.14569-3-dongli.zhang@oracle.com
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-04-15 14:15:03 +02:00
arch xen: delay xen_hvm_init_time_ops() if kdump is boot on vcpu>=32 2022-04-15 14:15:03 +02:00
block Revert "Revert "block, bfq: honor already-setup queue merges"" 2022-04-15 14:14:54 +02:00
certs certs: Trigger creation of RSA module signing key if it's not an RSA key 2021-09-22 11:47:51 +02:00
crypto crypto: authenc - Fix sleep in atomic context in decrypt_tail 2022-04-15 14:14:42 +02:00
Documentation Documentation: update stable tree link 2022-04-15 14:14:38 +02:00
drivers w1: w1_therm: fixes w1_seq for ds28ea00 sensors 2022-04-15 14:15:03 +02:00
firmware Fix built-in early-load Intel microcode alignment 2020-01-23 08:21:29 +01:00
fs NFSv4: Protect the state recovery thread against direct reclaim 2022-04-15 14:15:03 +02:00
include ipv4: Invalidate neighbour for broadcast address upon address addition 2022-04-15 14:15:01 +02:00
init init/main.c: return 1 from handled __setup() functions 2022-04-15 14:15:03 +02:00
ipc shm: extend forced shm destroy to support objects from several IPC nses 2021-12-08 08:50:11 +01:00
kernel dma-debug: fix return value of __setup handlers 2022-04-15 14:14:51 +02:00
lib lib/raid6/test/Makefile: Use $(pound) instead of \# for Make 4.3 2022-04-15 14:14:54 +02:00
LICENSES LICENSES: Remove CC-BY-SA-4.0 license text 2018-10-18 11:28:50 +02:00
mm mm/usercopy: return 1 from hardened_usercopy __setup() handler 2022-04-15 14:14:59 +02:00
net Bluetooth: Fix use after free in hci_send_acl 2022-04-15 14:15:03 +02:00
samples samples/kretprobes: Fix return value if register_kretprobe() failed 2021-11-26 11:36:11 +01:00
scripts kconfig: let 'shell' return enough output for deep path names 2022-02-23 11:58:42 +01:00
security Fix incorrect type in assignment of ipv6 port for audit 2022-04-15 14:14:54 +02:00
sound ASoC: topology: Allow TLV control to be either read or write 2022-04-15 14:14:59 +02:00
tools bpf: Fix comment for helper bpf_current_task_under_cgroup() 2022-04-15 14:14:59 +02:00
usr initramfs: restore default compression behavior 2020-04-13 10:44:59 +02:00
virt KVM: Prevent module exit until all VMs are freed 2022-04-15 14:14:57 +02:00
.clang-format clang-format: Set IndentWrappedFunctionNames false 2018-08-01 18:38:51 +02:00
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore Kbuild updates for v4.17 (2nd) 2018-04-15 17:21:30 -07:00
.mailmap libnvdimm-for-4.19_misc 2018-08-25 18:13:10 -07:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS 9p: remove Ron Minnich from MAINTAINERS 2018-08-17 16:20:26 -07:00
Kbuild Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt 2018-08-02 08:06:55 +09:00
MAINTAINERS Documentation/llvm: add documentation on building w/ Clang/LLVM 2020-09-26 18:01:31 +02:00
Makefile Linux 4.19.237 2022-03-28 08:41:44 +02:00
README Docs: Added a pointer to the formatted docs to README 2018-03-21 09:02:53 -06:00

README 

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.
See Documentation/00-INDEX for a list of what is contained in each file.

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.