Linux mainline fork with MSM8998 patches | https://mainline.space | Currently supported devices:
OnePlus 5/5T, Xiaomi Mi 6, F(x)tec Pro¹ (2019 QX1000 model) & Sony Xperia XZ Premium (UNTESTED!)
94fea1d8a3
Zero vmcs.HOST_IA32_SYSENTER_ESP when initializing *constant* host state
if and only if SYSENTER cannot be used, i.e. the kernel is a 64-bit
kernel and is not emulating 32-bit syscalls. As the name suggests,
vmx_set_constant_host_state() is intended for state that is *constant*.
When SYSENTER is used, SYSENTER_ESP isn't constant because stacks are
per-CPU, and the VMCS must be updated whenever the vCPU is migrated to a
new CPU. The logic in vmx_vcpu_load_vmcs() doesn't differentiate between
"never loaded" and "loaded on a different CPU", i.e. setting SYSENTER_ESP
on VMCS load also handles setting correct host state when the VMCS is
first loaded.
Because a VMCS must be loaded before it is initialized during vCPU RESET,
zeroing the field in vmx_set_constant_host_state() obliterates the value
that was written when the VMCS was loaded. If the vCPU is run before it
is migrated, the subsequent VM-Exit will zero out MSR_IA32_SYSENTER_ESP,
leading to a #DF on the next 32-bit syscall.
double fault: 0000 [#1] SMP
CPU: 0 PID: 990 Comm: stable Not tainted 5.16.0+ #97
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
EIP: entry_SYSENTER_32+0x0/0xe7
Code: <9c> 50 eb 17 0f 20 d8 a9 00 10 00 00 74 0d 25 ff ef ff ff 0f 22 d8
EAX: 000000a2 EBX: a8d1300c ECX: a8d13014 EDX: 00000000
ESI: a8f87000 EDI: a8d13014 EBP: a8d12fc0 ESP: 00000000
DS: 007b ES: 007b FS: 0000 GS: 0000 SS: 0068 EFLAGS: 00210093
CR0: 80050033 CR2: fffffffc CR3: 02c3b000 CR4: 00152e90
Fixes:
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|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| 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.
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.