Minki/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2024-11-15 00:21:59 +00:00
Code Issues Packages Projects Releases Wiki Activity
A mirror of the official Linux kernel repository just in case
1,197,456 Commits 7 Branches 861 Tags 6.6 GiB
C 97.6%
Assembly 1%
Shell 0.5%
Python 0.3%
Makefile 0.3%
f66066bc51
Go to file
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
arch parisc architecture fixes and updates for kernel v6.5-rc1: 2023-07-02 10:02:35 -07:00
block SCSI misc on 20230629 2023-06-30 11:57:07 -07:00
certs KEYS: Add missing function documentation 2023-04-24 16:15:52 +03:00
crypto This update includes the following changes: 2023-06-30 21:27:13 -07:00
Documentation Biggest news is not a patch this time 2023-07-02 10:22:38 -07:00
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 Kbuild updates for v6.5 2023-07-01 09:24:31 -07:00
io_uring \n 2023-06-29 13:31:44 -07:00
ipc Merge branch 'work.namespace' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2023-02-24 19:20:07 -08:00
kernel Kbuild updates for v6.5 2023-07-01 09:24:31 -07:00
lib This update includes the following changes: 2023-06-30 21:27:13 -07:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm mm: Update do_vmi_align_munmap() return semantics 2023-07-01 08:10:56 -07:00
net NFS client updates for Linux 6.5 2023-07-01 14:38:25 -07:00
rust rust: error: impl Debug for Error with errname() integration 2023-06-13 01:24:42 +02:00
samples Probes updates for v6.5: 2023-06-30 10:44:53 -07:00
scripts Kbuild updates for v6.5 2023-07-01 09:24:31 -07:00
security powerpc updates for 6.5 2023-06-30 09:20:08 -07:00
sound ARM: SoC changes for 6.5 2023-06-29 15:28:33 -07:00
tools cxl for v6.5 2023-07-01 08:58:41 -07:00
usr initramfs: Encode dependency on KBUILD_BUILD_TIMESTAMP 2023-06-06 17:54:49 +09:00
virt - Yosry Ahmed brought back some cgroup v1 stats in OOM logs. 2023-06-28 10:28:11 -07:00
.clang-format iommu: Add for_each_group_device() 2023-05-23 08:15:51 +02:00
.cocciconfig
.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: implement CONFIG_TRIM_UNUSED_KSYMS without recursion 2023-06-22 21:21:06 +09:00
.mailmap drm changes for 6.5-rc1: 2023-06-29 11:00:17 -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 - Address -Wmissing-prototype warnings 2023-06-26 16:43:54 -07:00
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 New code for 6.5: 2023-07-02 11:14:54 -07:00
Makefile Kbuild updates for v6.5 2023-07-01 09:24:31 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -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.

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.