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Linux kernel source tree
a6d066f705
Currently arch_dup_task_struct() doesn't handle cases where the parent
task has PSTATE.SM==1. Since syscall entry exits streaming mode, the
parent will usually have PSTATE.SM==0, but this can be change by ptrace
after syscall entry. When this happens, arch_dup_task_struct() will
initialise the new task into an invalid state. The new task inherits the
parent's configuration of PSTATE.SM, but fp_type is set to
FP_STATE_FPSIMD, TIF_SVE and SME may be cleared, and both sve_state and
sme_state may be set to NULL.
This can result in a variety of problems whenever the new task's state
is manipulated, including kernel NULL pointer dereferences and leaking
of streaming mode state between tasks.
When ptrace is not involved, the parent will have PSTATE.SM==0 as a
result of syscall entry, and the documentation in
Documentation/arch/arm64/sme.rst says:
| On process creation (eg, clone()) the newly created process will have
| PSTATE.SM cleared.
... so make this true by using task_smstop_sm() to exit streaming mode
in the child task, avoiding the problems above.
Fixes:
|
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .clippy.toml | ||
| .cocciconfig | ||
| .editorconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .rustfmt.toml | ||
| 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 reStructuredText 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.