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Valentin Schneider d29bca49de kexec: turn all kexec_mutex acquisitions into trylocks
commit 7bb5da0d49 upstream.

Patch series "kexec, panic: Making crash_kexec() NMI safe", v4.

This patch (of 2):

Most acquistions of kexec_mutex are done via mutex_trylock() - those were
a direct "translation" from:

  8c5a1cf0ad ("kexec: use a mutex for locking rather than xchg()")

there have however been two additions since then that use mutex_lock():
crash_get_memory_size() and crash_shrink_memory().

A later commit will replace said mutex with an atomic variable, and
locking operations will become atomic_cmpxchg().  Rather than having those
mutex_lock() become while (atomic_cmpxchg(&lock, 0, 1)), turn them into
trylocks that can return -EBUSY on acquisition failure.

This does halve the printable size of the crash kernel, but that's still
neighbouring 2G for 32bit kernels which should be ample enough.

Link: https://lkml.kernel.org/r/20220630223258.4144112-1-vschneid@redhat.com
Link: https://lkml.kernel.org/r/20220630223258.4144112-2-vschneid@redhat.com
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: "Eric W . Biederman" <ebiederm@xmission.com>
Cc: Juri Lelli <jlelli@redhat.com>
Cc: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Baoquan He <bhe@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Wen Yang <wenyang.linux@foxmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-06-06 18:05:31 +08:00
arch x86/rtc: Remove __init for runtime functions 2023-06-06 18:05:22 +08:00
block block: don't allow multiple bios for IOCB_NOWAIT issue 2023-04-19 18:00:13 +08:00
certs certs/blacklist_hashes.c: fix const confusion in certs blacklist 2023-04-19 17:50:34 +08:00
crypto asymmetric_keys: log on fatal failures in PE/pkcs7 2023-06-06 18:05:06 +08:00
Documentation tcp: restrict net.ipv4.tcp_app_win 2023-06-06 18:04:54 +08:00
drivers nvme-pci: add NVME_QUIRK_BOGUS_NID for T-FORCE Z330 SSD 2023-06-06 18:05:30 +08:00
fs btrfs: fix fast csum implementation detection 2023-06-06 18:04:41 +08:00
include kexec: turn all kexec_mutex acquisitions into trylocks 2023-06-06 18:05:31 +08:00
init kbuild: Add CONFIG_PAHOLE_VERSION 2023-04-19 17:59:33 +08:00
io_uring io_uring: avoid null-ptr-deref in io_arm_poll_handler 2023-04-19 18:00:57 +08:00
ipc ipc/sem: Fix dangling sem_array access in semtimedop race 2023-04-19 17:56:54 +08:00
kernel kexec: turn all kexec_mutex acquisitions into trylocks 2023-06-06 18:05:31 +08:00
lib kobject: Fix slab-out-of-bounds in fill_kobj_path() 2023-04-19 18:00:00 +08:00
LICENSES LICENSES/dual/CC-BY-4.0: Git rid of "smart quotes" 2021-07-15 06:31:24 -06:00
mm mm: take a page reference when removing device exclusive entries 2023-04-19 18:01:24 +08:00
net mptcp: stricter state check in mptcp_worker 2023-06-06 18:05:18 +08:00
samples samples: vfio-mdev: Fix missing pci_disable_device() in mdpy_fb_probe() 2023-04-19 17:57:46 +08:00
scripts kconfig: Update config changed flag before calling callback 2023-04-19 18:00:53 +08:00
security keys: Do not cache key in task struct if key is requested from kernel thread 2023-04-19 18:01:01 +08:00
sound ALSA: hda/sigmatel: fix S/PDIF out on Intel D*45* motherboards 2023-06-06 18:04:38 +08:00
tools libbpf: Fix single-line struct definition output in btf_dump 2023-06-06 18:05:01 +08:00
usr usr/include/Makefile: add linux/nfc.h to the compile-test coverage 2023-04-19 17:44:58 +08:00
virt KVM: fix memoryleak in kvm_init() 2023-04-19 18:00:47 +08:00
.clang-format clang-format: Update with the latest for_each macro list 2021-05-12 23:32:39 +02:00
.cocciconfig
.get_maintainer.ignore
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap mailmap: add Andrej Shadura 2021-10-18 20:22:03 -10:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Daniel Drake to credits 2021-09-21 08:34:58 +03:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS counter: Internalize sysfs interface code 2023-06-06 18:05:09 +08:00
Makefile Linux 5.15.107 2023-04-19 18:01:24 +08:00
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.