linux/init/initramfs.c, branch v6.8

initramfs: Expose retained initrd as sysfs file

2023-12-15T16:23:00Z

When the kernel command line option "retain_initrd" is set, we do not free the initrd memory. However, we also don't expose it to anyone for consumption. That leaves us in a weird situation where the only user of this feature is ppc64 and arm64 specific kexec tooling. To make it more generally useful, this patch adds a kobject to the firmware object that contains the initrd context when "retain_initrd" is set. That way, we can access the initrd any time after boot from user space and for example hand it into kexec as --initrd parameter if we want to reboot the same initrd. Or inspect it directly locally. With this patch applied, there is a new /sys/firmware/initrd file when the kernel was booted with an initrd and "retain_initrd" command line option is set. Signed-off-by: Alexander Graf Tested-by: Bagas Sanjaya Link: https://lore.kernel.org/r/20231207235654.16622-1-graf@amazon.com Signed-off-by: Greg Kroah-Hartman

mm: remove arguments of show_mem()

2023-08-18T17:12:02Z

All callers of show_mem() pass 0 and NULL, so we can remove the two arguments by directly calling __show_mem(0, NULL, MAX_NR_ZONES - 1) in show_mem(). Link: https://lkml.kernel.org/r/20230630062253.189440-1-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang Cc: Christophe Leroy Cc: Greg Kroah-Hartman Cc: Matthew Wilcox Cc: Michael Ellerman Cc: Nicholas Piggin Signed-off-by: Andrew Morton

init/initramfs: Fix argument forwarding to panic() in panic_show_mem()

2023-04-16T08:37:01Z

Forwarding variadic argument lists can't be done by passing a va_list to a function with signature foo(...) (as panic() has). It ends up interpreting the va_list itself as a single argument instead of iterating it. printf() happily accepts it of course, leading to corrupt output. Convert panic_show_mem() to a macro to allow forwarding the arguments. The function is trivial enough that it's easier than trying to introduce a vpanic() variant. Signed-off-by: Benjamin Gray Reviewed-by: Andrew Donnellan Signed-off-by: Masahiro Yamada

initramfs: use kstrtobool() instead of strtobool()

2023-02-03T06:50:05Z

strtobool() is the same as kstrtobool(). However, the latter is more used within the kernel. In order to remove strtobool() and slightly simplify kstrtox.h, switch to the other function name. While at it, include the corresponding header file () Link: https://lkml.kernel.org/r/2597e80cb7059ec6ad63a01b77d7c944dcc99195.1673716768.git.christophe.jaillet@wanadoo.fr Signed-off-by: Christophe JAILLET Cc: Christian Brauner Cc: David Disseldorp Cc: "Eric W. Biederman" Cc: Martin Wilck Cc: wuchi Cc: XU pengfei Signed-off-by: Andrew Morton

initramfs: remove unnecessary (void*) conversion

2022-11-18T21:55:08Z

Remove unnecessary void* type casting. Link: https://lkml.kernel.org/r/20221026080517.3221-1-xupengfei@nfschina.com Signed-off-by: XU pengfei Cc: Christian Brauner Cc: David Disseldorp Cc: "Eric W . Biederman" Cc: Martin Wilck Cc: Mike Rapoport Cc: wuchi Signed-off-by: Andrew Morton

initramfs: mark my_inptr as __initdata

2022-09-12T04:55:11Z

As my_inptr is only used in __init function unpack_to_rootfs(), mark it as __initdata to allow it be freed after boot. Link: https://lkml.kernel.org/r/20220827071116.83078-1-wuchi.zero@gmail.com Signed-off-by: wuchi Reviewed-by: David Disseldorp Cc: Alexander Viro Cc: Martin Wilck Cc: Matthew Wilcox Signed-off-by: Andrew Morton

Merge tag 'kthread-cleanups-for-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

2022-06-03T23:03:05Z

Pull kthread updates from Eric Biederman: "This updates init and user mode helper tasks to be ordinary user mode tasks. Commit 40966e316f86 ("kthread: Ensure struct kthread is present for all kthreads") caused init and the user mode helper threads that call kernel_execve to have struct kthread allocated for them. This struct kthread going away during execve in turned made a use after free of struct kthread possible. Here, commit 343f4c49f243 ("kthread: Don't allocate kthread_struct for init and umh") is enough to fix the use after free and is simple enough to be backportable. The rest of the changes pass struct kernel_clone_args to clean things up and cause the code to make sense. In making init and the user mode helpers tasks purely user mode tasks I ran into two complications. The function task_tick_numa was detecting tasks without an mm by testing for the presence of PF_KTHREAD. The initramfs code in populate_initrd_image was using flush_delayed_fput to ensuere the closing of all it's file descriptors was complete, and flush_delayed_fput does not work in a userspace thread. I have looked and looked and more complications and in my code review I have not found any, and neither has anyone else with the code sitting in linux-next" * tag 'kthread-cleanups-for-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: sched: Update task_tick_numa to ignore tasks without an mm fork: Stop allowing kthreads to call execve fork: Explicitly set PF_KTHREAD init: Deal with the init process being a user mode process fork: Generalize PF_IO_WORKER handling fork: Explicity test for idle tasks in copy_thread fork: Pass struct kernel_clone_args into copy_thread kthread: Don't allocate kthread_struct for init and umh

initramfs: support cpio extraction with file checksums

2022-05-10T01:29:20Z

Add support for extraction of checksum-enabled "070702" cpio archives, specified in Documentation/driver-api/early-userspace/buffer-format.rst. Fail extraction if the calculated file data checksum doesn't match the value carried in the header. Link: https://lkml.kernel.org/r/20220404093429.27570-7-ddiss@suse.de Signed-off-by: David Disseldorp Suggested-by: Matthew Wilcox (Oracle) Cc: Al Viro Cc: Christian Brauner Cc: Martin Wilck Signed-off-by: Andrew Morton

initramfs: add INITRAMFS_PRESERVE_MTIME Kconfig option

2022-05-10T01:29:19Z

initramfs cpio mtime preservation, as implemented in commit 889d51a10712 ("initramfs: add option to preserve mtime from initramfs cpio images"), uses a linked list to defer directory mtime processing until after all other items in the cpio archive have been processed. This is done to ensure that parent directory mtimes aren't overwritten via subsequent child creation. The lkml link below indicates that the mtime retention use case was for embedded devices with applications running exclusively out of initramfs, where the 32-bit mtime value provided a rough file version identifier. Linux distributions which discard an extracted initramfs immediately after the root filesystem has been mounted may want to avoid the unnecessary overhead. This change adds a new INITRAMFS_PRESERVE_MTIME Kconfig option, which can be used to disable on-by-default mtime retention and in turn speed up initramfs extraction, particularly for cpio archives with large directory counts. Benchmarks with a one million directory cpio archive extracted 20 times demonstrated: mean extraction time (s) std dev INITRAMFS_PRESERVE_MTIME=y 3.808 0.006 INITRAMFS_PRESERVE_MTIME unset 3.056 0.004 The above extraction times were measured using ftrace (initcall_finish - initcall_start) values for populate_rootfs() with initramfs_async disabled. [ddiss@suse.de: rebase atop dir_entry.name flexible array member and drop separate initramfs_mtime.h header] Link: https://lkml.org/lkml/2008/9/3/424 Link: https://lkml.kernel.org/r/20220404093429.27570-4-ddiss@suse.de Signed-off-by: David Disseldorp Reviewed-by: Martin Wilck Cc: Al Viro Cc: Christian Brauner Cc: Matthew Wilcox (Oracle) Signed-off-by: Andrew Morton

initramfs: make dir_entry.name a flexible array member

2022-05-10T01:29:19Z

dir_entry.name is currently allocated via a separate kstrdup(). Change it to a flexible array member and allocate it along with struct dir_entry. Link: https://lkml.kernel.org/r/20220404093429.27570-3-ddiss@suse.de Signed-off-by: David Disseldorp Acked-by: Christian Brauner Cc: Al Viro Cc: Martin Wilck Cc: Matthew Wilcox (Oracle) Signed-off-by: Andrew Morton