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path: root/init/noinitramfs.c
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2021-09-08init: move usermodehelper_enable() to populate_rootfs()Rasmus Villemoes1-0/+2
Currently, usermodehelper is enabled right before PID1 starts going through the initcalls. However, any call of a usermodehelper from a pure_, core_, postcore_, arch_, subsys_ or fs_ initcall is futile, as there is no filesystem contents yet. Up until commit e7cb072eb988 ("init/initramfs.c: do unpacking asynchronously"), such calls, whether via some request_module(), a legacy uevent "/sbin/hotplug" notification or something else, would just fail silently with (presumably) -ENOENT from kernel_execve(). However, that commit introduced the wait_for_initramfs() synchronization hook which must be called from the usermodehelper exec path right before the kernel_execve, in order that request_module() et al done from *after* rootfs_initcall() time (i.e. device_ and late_ initcalls) would continue to find a populated initramfs as they used to. Any call of wait_for_initramfs() done before the unpacking has been scheduled (i.e. before rootfs_initcall time) must just return immediately [and let the caller find an empty file system] in order not to deadlock the machine. I mistakenly thought, and my limited testing confirmed, that there were no such calls, so I added a pr_warn_once() in wait_for_initramfs(). It turns out that one can indeed hit request_module() as well as kobject_uevent_env() during those early init calls, leading to a user-visible warning in the kernel log emitted consistently for certain configurations. We could just remove the pr_warn_once(), but I think it's better to postpone enabling the usermodehelper framework until there is at least some chance of finding the executable. That is also a little more efficient in that a lot of work done in umh.c will be elided. However, it does change the error seen by those early callers from -ENOENT to -EBUSY, so there is a risk of a regression if any caller care about the exact error value. Link: https://lkml.kernel.org/r/20210728134638.329060-1-linux@rasmusvillemoes.dk Fixes: e7cb072eb988 ("init/initramfs.c: do unpacking asynchronously") Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Reported-by: Alexander Egorenkov <egorenar@linux.ibm.com> Reported-by: Bruno Goncalves <bgoncalv@redhat.com> Reported-by: Heiner Kallweit <hkallweit1@gmail.com> Cc: Luis Chamberlain <mcgrof@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-07-31init: add an init_mknod helperChristoph Hellwig1-2/+1
Add a simple helper to mknod with a kernel space file name and switch the early init code over to it. Remove the now unused ksys_mknod. Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31init: add an init_mkdir helperChristoph Hellwig1-2/+3
Add a simple helper to mkdir with a kernel space file name and switch the early init code over to it. Remove the now unused ksys_mkdir. Signed-off-by: Christoph Hellwig <hch@lst.de>
2019-05-30treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 167Thomas Gleixner1-13/+1
Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation version 2 of the license this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not write to the free software foundation inc 59 temple place suite 330 boston ma 02111 1307 usa extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 83 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Richard Fontana <rfontana@redhat.com> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070034.021731668@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-04-02fs: add do_mknodat() helper and ksys_mknod() wrapper; remove in-kernel calls ↵Dominik Brodowski1-1/+1
to syscall Using the fs-internal do_mknodat() helper allows us to get rid of fs-internal calls to the sys_mknodat() syscall. Introducing the ksys_mknod() wrapper allows us to avoid the in-kernel calls to sys_mknod() syscall. The ksys_ prefix denotes that this function is meant as a drop-in replacement for the syscall. In particular, it uses the same calling convention as sys_mknod(). This patch is part of a series which removes in-kernel calls to syscalls. On this basis, the syscall entry path can be streamlined. For details, see http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
2018-04-02fs: add do_mkdirat() helper and ksys_mkdir() wrapper; remove in-kernel calls ↵Dominik Brodowski1-2/+2
to syscall Using the fs-internal do_mkdirat() helper allows us to get rid of fs-internal calls to the sys_mkdirat() syscall. Introducing the ksys_mkdir() wrapper allows us to avoid the in-kernel calls to the sys_mkdir() syscall. The ksys_ prefix denotes that this function is meant as a drop-in replacement for the syscall. In particular, it uses the same calling convention as sys_mkdir(). This patch is part of a series which removes in-kernel calls to syscalls. On this basis, the syscall entry path can be streamlined. For details, see http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
2010-10-27init: mark __user address space on string literalsNamhyung Kim1-3/+3
When calling syscall service routines in kernel, some of arguments should be user pointers but were missing __user markup on string literals. Add it. Removes some sparse warnings. Signed-off-by: Namhyung Kim <namhyung@gmail.com> Cc: Phillip Lougher <phillip@lougher.demon.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-11[PATCH] disable init/initramfs.cJean-Paul Saman1-0/+52
The file init/initramfs.c is always compiled and linked in the kernel vmlinux even when BLK_DEV_RAM and BLK_DEV_INITRD are disabled and the system isn't using any form of an initramfs or initrd. In this situation the code is only used to unpack a (static) default initial rootfilesystem. The current init/initramfs.c code. usr/initramfs_data.o compiles to a size of ~15 kbytes. Disabling BLK_DEV_RAM and BLK_DEV_INTRD shrinks the kernel code size with ~60 Kbytes. This patch avoids compiling in the code and data for initramfs support if CONFIG_BLK_DEV_INITRD is not defined. Instead of the initramfs code and data it uses a small routine in init/noinitramfs.c to setup an initial static default environment for mounting a rootfilesystem later on in the kernel initialisation process. The new code is: 164 bytes of size. The patch is separated in two parts: 1) doesn't compile initramfs code when CONFIG_BLK_DEV_INITRD is not set 2) changing all plaforms vmlinux.lds.S files to not reserve an area of PAGE_SIZE when CONFIG_BLK_DEV_INITRD is not set. [deweerdt@free.fr: warning fix] Signed-off-by: Jean-Paul Saman <jean-paul.saman@nxp.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: <linux-arch@vger.kernel.org> Signed-off-by: Frederik Deweerdt <frederik.deweerdt@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>