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Nicholas Piggin 5d5e4522a7 printk: restore flushing of NMI buffers on remote CPUs after NMI backtraces
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
2021-11-10 16:12:00 +01:00
arch printk: restore flushing of NMI buffers on remote CPUs after NMI backtraces 2021-11-10 16:12:00 +01:00
block sched: Change task_struct::state 2021-06-18 11:43:09 +02:00
certs Kbuild updates for v5.13 (2nd) 2021-05-08 10:00:11 -07:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2021-06-28 16:04:56 -07:00
Documentation Merge branch 'akpm' (patches from Andrew) 2021-06-29 17:29:11 -07:00
drivers Merge branch 'akpm' (patches from Andrew) 2021-06-29 17:29:11 -07:00
fs Merge branch 'akpm' (patches from Andrew) 2021-06-29 17:29:11 -07:00
include printk: restore flushing of NMI buffers on remote CPUs after NMI backtraces 2021-11-10 16:12:00 +01:00
init printk: remove NMI tracking 2021-07-26 15:09:44 +02:00
ipc Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2021-06-28 20:39:26 -07:00
kernel printk: restore flushing of NMI buffers on remote CPUs after NMI backtraces 2021-11-10 16:12:00 +01:00
lib printk: restore flushing of NMI buffers on remote CPUs after NMI backtraces 2021-11-10 16:12:00 +01:00
LICENSES LICENSES: Add the CC-BY-4.0 license 2020-12-08 10:33:27 -07:00
mm Merge branch 'akpm' (patches from Andrew) 2021-06-29 17:29:11 -07:00
net Merge branch 'akpm' (patches from Andrew) 2021-06-29 17:29:11 -07:00
samples This was a reasonably active cycle for documentation; this pull includes: 2021-06-28 16:53:05 -07:00
scripts Merge branch 'akpm' (patches from Andrew) 2021-06-29 17:29:11 -07:00
security integrity-v5.14 2021-06-28 16:15:50 -07:00
sound spi: Updates for v5.14 2021-06-28 11:10:20 -07:00
tools Merge branch 'akpm' (patches from Andrew) 2021-06-29 17:29:11 -07:00
usr .gitignore: prefix local generated files with a slash 2021-05-02 00:43:35 +09:00
virt Merge branch 'akpm' (patches from Andrew) 2021-06-29 17:29:11 -07:00
.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 m68k updates for v5.14 2021-06-28 14:01:03 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: move Murali Karicheri to credits 2021-04-29 15:47:30 -07:00
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 printk changes for 5.14 2021-06-29 12:07:18 -07:00
Makefile arm64 updates for 5.14 2021-06-28 14:04:24 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.