Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull RCU updates from Ingo Molnar:
"The biggest RCU changes in this cycle were:
- Convert RCU's BUG_ON() and similar calls to WARN_ON() and similar.
- Replace calls of RCU-bh and RCU-sched update-side functions to
their vanilla RCU counterparts. This series is a step towards
complete removal of the RCU-bh and RCU-sched update-side functions.
( Note that some of these conversions are going upstream via their
respective maintainers. )
- Documentation updates, including a number of flavor-consolidation
updates from Joel Fernandes.
- Miscellaneous fixes.
- Automate generation of the initrd filesystem used for rcutorture
testing.
- Convert spin_is_locked() assertions to instead use lockdep.
( Note that some of these conversions are going upstream via their
respective maintainers. )
- SRCU updates, especially including a fix from Dennis Krein for a
bag-on-head-class bug.
- RCU torture-test updates"
* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (112 commits)
rcutorture: Don't do busted forward-progress testing
rcutorture: Use 100ms buckets for forward-progress callback histograms
rcutorture: Recover from OOM during forward-progress tests
rcutorture: Print forward-progress test age upon failure
rcutorture: Print time since GP end upon forward-progress failure
rcutorture: Print histogram of CB invocation at OOM time
rcutorture: Print GP age upon forward-progress failure
rcu: Print per-CPU callback counts for forward-progress failures
rcu: Account for nocb-CPU callback counts in RCU CPU stall warnings
rcutorture: Dump grace-period diagnostics upon forward-progress OOM
rcutorture: Prepare for asynchronous access to rcu_fwd_startat
torture: Remove unnecessary "ret" variables
rcutorture: Affinity forward-progress test to avoid housekeeping CPUs
rcutorture: Break up too-long rcu_torture_fwd_prog() function
rcutorture: Remove cbflood facility
torture: Bring any extra CPUs online during kernel startup
rcutorture: Add call_rcu() flooding forward-progress tests
rcutorture/formal: Replace synchronize_sched() with synchronize_rcu()
tools/kernel.h: Replace synchronize_sched() with synchronize_rcu()
net/decnet: Replace rcu_barrier_bh() with rcu_barrier()
...
This commit is contained in:
Linus Torvalds
@@ -194,6 +194,14 @@ do
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shift
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done
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if test -z "$TORTURE_INITRD" || tools/testing/selftests/rcutorture/bin/mkinitrd.sh
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then
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:
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else
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echo No initrd and unable to create one, aborting test >&2
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exit 1
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fi
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CONFIGFRAG=${KVM}/configs/${TORTURE_SUITE}; export CONFIGFRAG
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if test -z "$configs"
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136
tools/testing/selftests/rcutorture/bin/mkinitrd.sh
Executable file
136
tools/testing/selftests/rcutorture/bin/mkinitrd.sh
Executable file
@@ -0,0 +1,136 @@
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#!/bin/bash
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#
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# Create an initrd directory if one does not already exist.
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, you can access it online at
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# http://www.gnu.org/licenses/gpl-2.0.html.
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#
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# Copyright (C) IBM Corporation, 2013
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#
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# Author: Connor Shu <Connor.Shu@ibm.com>
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D=tools/testing/selftests/rcutorture
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# Prerequisite checks
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[ -z "$D" ] && echo >&2 "No argument supplied" && exit 1
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if [ ! -d "$D" ]; then
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echo >&2 "$D does not exist: Malformed kernel source tree?"
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exit 1
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fi
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if [ -s "$D/initrd/init" ]; then
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echo "$D/initrd/init already exists, no need to create it"
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exit 0
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fi
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T=${TMPDIR-/tmp}/mkinitrd.sh.$$
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trap 'rm -rf $T' 0 2
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mkdir $T
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cat > $T/init << '__EOF___'
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#!/bin/sh
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# Run in userspace a few milliseconds every second. This helps to
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# exercise the NO_HZ_FULL portions of RCU.
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while :
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do
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q=
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for i in \
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a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a \
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a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a \
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a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a \
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a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a \
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a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a \
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a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a
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do
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q="$q $i"
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done
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sleep 1
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done
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__EOF___
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# Try using dracut to create initrd
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if command -v dracut >/dev/null 2>&1
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then
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echo Creating $D/initrd using dracut.
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# Filesystem creation
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dracut --force --no-hostonly --no-hostonly-cmdline --module "base" $T/initramfs.img
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cd $D
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mkdir -p initrd
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cd initrd
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zcat $T/initramfs.img | cpio -id
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cp $T/init init
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chmod +x init
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echo Done creating $D/initrd using dracut
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exit 0
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fi
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# No dracut, so create a C-language initrd/init program and statically
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# link it. This results in a very small initrd, but might be a bit less
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# future-proof than dracut.
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echo "Could not find dracut, attempting C initrd"
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cd $D
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mkdir -p initrd
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cd initrd
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cat > init.c << '___EOF___'
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#ifndef NOLIBC
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#include <unistd.h>
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#include <sys/time.h>
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#endif
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volatile unsigned long delaycount;
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int main(int argc, int argv[])
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{
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int i;
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struct timeval tv;
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struct timeval tvb;
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for (;;) {
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sleep(1);
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/* Need some userspace time. */
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if (gettimeofday(&tvb, NULL))
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continue;
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do {
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for (i = 0; i < 1000 * 100; i++)
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delaycount = i * i;
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if (gettimeofday(&tv, NULL))
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break;
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tv.tv_sec -= tvb.tv_sec;
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if (tv.tv_sec > 1)
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break;
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tv.tv_usec += tv.tv_sec * 1000 * 1000;
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tv.tv_usec -= tvb.tv_usec;
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} while (tv.tv_usec < 1000);
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}
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return 0;
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}
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___EOF___
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# build using nolibc on supported archs (smaller executable) and fall
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# back to regular glibc on other ones.
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if echo -e "#if __x86_64__||__i386__||__i486__||__i586__||__i686__" \
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"||__ARM_EABI__||__aarch64__\nyes\n#endif" \
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| ${CROSS_COMPILE}gcc -E -nostdlib -xc - \
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| grep -q '^yes'; then
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# architecture supported by nolibc
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${CROSS_COMPILE}gcc -fno-asynchronous-unwind-tables -fno-ident \
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-nostdlib -include ../bin/nolibc.h -lgcc -s -static -Os \
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-o init init.c
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else
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${CROSS_COMPILE}gcc -s -static -Os -o init init.c
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fi
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rm init.c
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echo "Done creating a statically linked C-language initrd"
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exit 0
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2197
tools/testing/selftests/rcutorture/bin/nolibc.h
Normal file
2197
tools/testing/selftests/rcutorture/bin/nolibc.h
Normal file
File diff suppressed because it is too large
Load Diff
@@ -1,9 +1,12 @@
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This document describes one way to create the initrd directory hierarchy
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in order to allow an initrd to be built into your kernel. The trick
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here is to steal the initrd file used on your Linux laptop, Ubuntu in
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this case. There are probably much better ways of doing this.
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The rcutorture scripting tools automatically create the needed initrd
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directory using dracut. Failing that, this tool will create an initrd
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containing a single statically linked binary named "init" that loops
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over a very long sleep() call. In both cases, this creation is done
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by tools/testing/selftests/rcutorture/bin/mkinitrd.sh.
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That said, here are the commands:
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However, if you are attempting to run rcutorture on a system that does
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not have dracut installed, and if you don't like the notion of static
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linking, you might wish to press an existing initrd into service:
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------------------------------------------------------------------------
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cd tools/testing/selftests/rcutorture
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@@ -11,22 +14,7 @@ zcat /initrd.img > /tmp/initrd.img.zcat
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mkdir initrd
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cd initrd
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cpio -id < /tmp/initrd.img.zcat
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------------------------------------------------------------------------
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Another way to create an initramfs image is using "dracut"[1], which is
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available on many distros, however the initramfs dracut generates is a cpio
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archive with another cpio archive in it, so an extra step is needed to create
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the initrd directory hierarchy.
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Here are the commands to create a initrd directory for rcutorture using
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dracut:
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------------------------------------------------------------------------
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dracut --no-hostonly --no-hostonly-cmdline --module "base bash shutdown" /tmp/initramfs.img
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cd tools/testing/selftests/rcutorture
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mkdir initrd
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cd initrd
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/usr/lib/dracut/skipcpio /tmp/initramfs.img | zcat | cpio -id < /tmp/initramfs.img
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# Manually verify that initrd contains needed binaries and libraries.
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------------------------------------------------------------------------
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Interestingly enough, if you are running rcutorture, you don't really
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@@ -39,75 +27,12 @@ with 0755 mode.
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------------------------------------------------------------------------
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#!/bin/sh
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[ -d /dev ] || mkdir -m 0755 /dev
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[ -d /root ] || mkdir -m 0700 /root
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[ -d /sys ] || mkdir /sys
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[ -d /proc ] || mkdir /proc
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[ -d /tmp ] || mkdir /tmp
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mkdir -p /var/lock
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mount -t sysfs -o nodev,noexec,nosuid sysfs /sys
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mount -t proc -o nodev,noexec,nosuid proc /proc
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# Some things don't work properly without /etc/mtab.
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ln -sf /proc/mounts /etc/mtab
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# Note that this only becomes /dev on the real filesystem if udev's scripts
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# are used; which they will be, but it's worth pointing out
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if ! mount -t devtmpfs -o mode=0755 udev /dev; then
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echo "W: devtmpfs not available, falling back to tmpfs for /dev"
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mount -t tmpfs -o mode=0755 udev /dev
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[ -e /dev/console ] || mknod --mode=600 /dev/console c 5 1
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[ -e /dev/kmsg ] || mknod --mode=644 /dev/kmsg c 1 11
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[ -e /dev/null ] || mknod --mode=666 /dev/null c 1 3
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fi
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mkdir /dev/pts
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mount -t devpts -o noexec,nosuid,gid=5,mode=0620 devpts /dev/pts || true
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mount -t tmpfs -o "nosuid,size=20%,mode=0755" tmpfs /run
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mkdir /run/initramfs
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# compatibility symlink for the pre-oneiric locations
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ln -s /run/initramfs /dev/.initramfs
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# Export relevant variables
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export ROOT=
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export ROOTDELAY=
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export ROOTFLAGS=
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export ROOTFSTYPE=
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export IP=
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export BOOT=
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export BOOTIF=
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export UBIMTD=
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export break=
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export init=/sbin/init
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export quiet=n
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export readonly=y
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export rootmnt=/root
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export debug=
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export panic=
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export blacklist=
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export resume=
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export resume_offset=
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export recovery=
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for i in /sys/devices/system/cpu/cpu*/online
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do
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case $i in
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'/sys/devices/system/cpu/cpu0/online')
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;;
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'/sys/devices/system/cpu/cpu*/online')
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;;
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*)
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echo 1 > $i
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;;
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esac
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done
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while :
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do
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sleep 10
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done
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------------------------------------------------------------------------
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References:
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[1]: https://dracut.wiki.kernel.org/index.php/Main_Page
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[2]: http://blog.elastocloud.org/2015/06/rapid-linux-kernel-devtest-with-qemu.html
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[3]: https://www.centos.org/forums/viewtopic.php?t=51621
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This approach also allows most of the binaries and libraries in the
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initrd filesystem to be dispensed with, which can save significant
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space in rcutorture's "res" directory.
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@@ -131,8 +131,8 @@ struct hlist_node {
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* weird ABI and we need to ask it explicitly.
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*
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* The alignment is required to guarantee that bits 0 and 1 of @next will be
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* clear under normal conditions -- as long as we use call_rcu(),
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* call_rcu_bh(), call_rcu_sched(), or call_srcu() to queue callback.
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* clear under normal conditions -- as long as we use call_rcu() or
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* call_srcu() to queue callback.
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*
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* This guarantee is important for few reasons:
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* - future call_rcu_lazy() will make use of lower bits in the pointer;
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Reference in New Issue
Block a user