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Nicholas Piggin c3b0ab956d printk: restore flushing of NMI buffers on remote CPUs after NMI backtraces
commit 5d5e4522a7 upstream.

printk from NMI context relies on irq work being raised on the local CPU
to print to console. This can be a problem if the NMI was raised by a
lockup detector to print lockup stack and regs, because the CPU may not
enable irqs (because it is locked up).

Introduce printk_trigger_flush() that can be called another CPU to try
to get those messages to the console, call that where printk_safe_flush
was previously called.

Fixes: 93d102f094 ("printk: remove safe buffers")
Cc: stable@vger.kernel.org # 5.15
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: John Ogness <john.ogness@linutronix.de>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20211107045116.1754411-1-npiggin@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-11-25 09:48:45 +01:00
Documentation fscrypt: allow 256-bit master keys with AES-256-XTS 2021-11-18 19:16:11 +01:00
LICENSES LICENSES/dual/CC-BY-4.0: Git rid of "smart quotes" 2021-07-15 06:31:24 -06:00
arch printk: restore flushing of NMI buffers on remote CPUs after NMI backtraces 2021-11-25 09:48:45 +01:00
block block: Check ADMIN before NICE for IOPRIO_CLASS_RT 2021-11-25 09:48:45 +01:00
certs certs: Add support for using elliptic curve keys for signing modules 2021-08-23 19:55:42 +03:00
crypto crypto: pcrypt - Delay write to padata->info 2021-11-18 19:16:44 +01:00
drivers drm/cma-helper: Release non-coherent memory with dma_free_noncoherent() 2021-11-25 09:48:45 +01:00
fs pstore/blk: Use "%lu" to format unsigned long 2021-11-25 09:48:42 +01:00
include printk: restore flushing of NMI buffers on remote CPUs after NMI backtraces 2021-11-25 09:48:45 +01:00
init init: make unknown command line param message clearer 2021-11-18 19:17:11 +01:00
ipc shm: extend forced shm destroy to support objects from several IPC nses 2021-11-25 09:48:42 +01:00
kernel printk: restore flushing of NMI buffers on remote CPUs after NMI backtraces 2021-11-25 09:48:45 +01:00
lib printk: restore flushing of NMI buffers on remote CPUs after NMI backtraces 2021-11-25 09:48:45 +01:00
mm mm/damon/dbgfs: fix missed use of damon_dbgfs_lock 2021-11-25 09:48:43 +01:00
net tipc: check for null after calling kmemdup 2021-11-25 09:48:42 +01:00
samples samples/bpf: Fix incorrect use of strlen in xdp_redirect_cpu 2021-11-25 09:48:33 +01:00
scripts leaking_addresses: Always print a trailing newline 2021-11-18 19:16:16 +01:00
security fortify: Explicitly disable Clang support 2021-11-21 13:44:13 +01:00
sound ALSA: usb-audio: fix null pointer dereference on pointer cs_desc 2021-11-25 09:48:30 +01:00
tools tools build: Fix removal of feature-sync-compare-and-swap feature detection 2021-11-25 09:48:40 +01:00
usr .gitignore: prefix local generated files with a slash 2021-05-02 00:43:35 +09:00
virt KVM: Remove tlbs_dirty 2021-09-23 11:01:12 -04:00
.clang-format clang-format: Update with the latest for_each macro list 2021-05-12 23:32:39 +02:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.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 drm fixes for 5.15 final 2021-10-28 12:17:01 -07:00
Makefile Linux 5.15.4 2021-11-21 13:44:15 +01:00
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.