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Jason A. Donenfeld 2c60d7f38d random: do crng pre-init loading in worker rather than irq 
commit c2a7de4feb upstream.

Taking spinlocks from IRQ context is generally problematic for
PREEMPT_RT. That is, in part, why we take trylocks instead. However, a
spin_try_lock() is also problematic since another spin_lock() invocation
can potentially PI-boost the wrong task, as the spin_try_lock() is
invoked from an IRQ-context, so the task on CPU (random task or idle) is
not the actual owner.

Additionally, by deferring the crng pre-init loading to the worker, we
can use the cryptographic hash function rather than xor, which is
perhaps a meaningful difference when considering this data has only been
through the relatively weak fast_mix() function.

The biggest downside of this approach is that the pre-init loading is
now deferred until later, which means things that need random numbers
after interrupts are enabled, but before workqueues are running -- or
before this particular worker manages to run -- are going to get into
trouble. Hopefully in the real world, this window is rather small,
especially since this code won't run until 64 interrupts had occurred.

Cc: Sultan Alsawaf <sultan@kerneltoast.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Eric Biggers <ebiggers@kernel.org>
Cc: Theodore Ts'o <tytso@mit.edu>
Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-05-30 09:29:10 +02:00
arch random: remove unused irq_flags argument from add_interrupt_randomness() 2022-05-30 09:29:00 +02:00
block iocost: don't reset the inuse weight of under-weighted debtors 2022-05-09 09:14:31 +02:00
certs certs: Add support for using elliptic curve keys for signing modules 2021-08-23 19:55:42 +03:00
crypto lib/crypto: blake2s: avoid indirect calls to compression function for Clang CFI 2022-05-30 09:28:59 +02:00
Documentation random: remove ifdef'd out interrupt bench 2022-05-30 09:29:06 +02:00
drivers random: do crng pre-init loading in worker rather than irq 2022-05-30 09:29:10 +02:00
fs afs: Fix afs_getattr() to refetch file status if callback break occurred 2022-05-25 09:57:37 +02:00
include random: clear fast pool, crng, and batches in cpuhp bring up 2022-05-30 09:29:09 +02:00
init init/main.c: return 1 from handled __setup() functions 2022-04-13 20:59:10 +02:00
ipc ipc/sem: do not sleep with a spin lock held 2022-02-08 18:34:03 +01:00
kernel random: clear fast pool, crng, and batches in cpuhp bring up 2022-05-30 09:29:09 +02:00
lib random: remove unused tracepoints 2022-05-30 09:29:06 +02:00
LICENSES LICENSES/dual/CC-BY-4.0: Git rid of "smart quotes" 2021-07-15 06:31:24 -06:00
mm mm/kfence: reset PG_slab and memcg_data before freeing __kfence_pool 2022-05-25 09:57:23 +02:00
net mptcp: Do TCP fallback on early DSS checksum failure 2022-05-25 14:42:07 +02:00
samples x86: Prepare inline-asm for straight-line-speculation 2022-05-15 20:18:50 +02:00
scripts x86: Add straight-line-speculation mitigation 2022-05-15 20:18:51 +02:00
security lockdown: also lock down previous kgdb use 2022-05-25 09:57:37 +02:00
sound ALSA: hda - fix unused Realtek function when PM is not enabled 2022-05-25 09:57:30 +02:00
tools selftests: add ping test with ping_group_range tuned 2022-05-25 09:57:35 +02:00
usr usr/include/Makefile: add linux/nfc.h to the compile-test coverage 2022-02-01 17:27:15 +01:00
virt KVM: avoid NULL pointer dereference in kvm_dirty_ring_push 2022-04-13 20:59:26 +02:00
.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
.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 MAINTAINERS: add git tree for random.c 2022-05-30 09:28:59 +02:00
Makefile Linux 5.15.43 2022-05-25 14:42:07 +02:00
README

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.