WSL2-Linux-Kernel

The source for the Linux kernel used in Windows Subsystem for Linux 2 (WSL2)

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Linus Torvalds f66066bc51 execve: always mark stack as growing down during early stack setup While our user stacks can grow either down (all common architectures) or up (parisc and the ia64 register stack), the initial stack setup when we copy the argument and environment strings to the new stack at execve() time is always done by extending the stack downwards. But it turns out that in commit `8d7071af89` ("mm: always expand the stack with the mmap write lock held"), as part of making the stack growing code more robust, 'expand_downwards()' was now made to actually check the vma flags: if (!(vma->vm_flags & VM_GROWSDOWN)) return -EFAULT; and that meant that this execve-time stack expansion started failing on parisc, because on that architecture, the stack flags do not contain the VM_GROWSDOWN bit. At the same time the new check in expand_downwards() is clearly correct, and simplified the callers, so let's not remove it. The solution is instead to just codify the fact that yes, during execve(), the stack grows down. This not only matches reality, it ends up being particularly simple: we already have special execve-time flags for the stack (VM_STACK_INCOMPLETE_SETUP) and use those flags to avoid page migration during this setup time (see vma_is_temporary_stack() and invalid_migration_vma()). So just add VM_GROWSDOWN to that set of temporary flags, and now our stack flags automatically match reality, and the parisc stack expansion works again. Note that the VM_STACK_INCOMPLETE_SETUP bits will be cleared when the stack is finalized, so we only add the extra VM_GROWSDOWN bit on CONFIG_STACK_GROWSUP architectures (ie parisc) rather than adding it in general. Link: https://lore.kernel.org/all/612eaa53-6904-6e16-67fc-394f4faa0e16@bell.net/ Link: https://lore.kernel.org/all/5fd98a09-4792-1433-752d-029ae3545168@gmx.de/ Fixes: `8d7071af89` ("mm: always expand the stack with the mmap write lock held") Reported-by: John David Anglin <dave.anglin@bell.net> Reported-and-tested-by: Helge Deller <deller@gmx.de> Reported-and-tested-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2023-07-03 09:50:57 -07:00
Documentation	Biggest news is not a patch this time	2023-07-02 10:22:38 -07:00
LICENSES	…
arch	parisc architecture fixes and updates for kernel v6.5-rc1:	2023-07-02 10:02:35 -07:00
block	…
certs	…
crypto	…
drivers	Biggest news is not a patch this time	2023-07-02 10:22:38 -07:00
fs	New code for 6.5:	2023-07-02 11:14:54 -07:00
include	execve: always mark stack as growing down during early stack setup	2023-07-03 09:50:57 -07:00
init	…
io_uring	…
ipc	…
kernel	…
lib	…
mm	…
net	…
rust	…
samples	…
scripts	…
security	…
sound	…
tools	…
usr	…
virt	…
.clang-format	…
.cocciconfig	…
.get_maintainer.ignore	…
.gitattributes	…
.gitignore	…
.mailmap	…
.rustfmt.toml	…
COPYING	…
CREDITS	…
Kbuild	…
Kconfig	…
MAINTAINERS	New code for 6.5:	2023-07-02 11:14:54 -07:00
Makefile	…
README	…

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.