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Although there are trace events for RCU grace periods, these are only
enabled in CONFIG_RCU_TRACE=y kernels. This commit therefore marks
rcu_gp_cleanup() noinline in order to provide a function that can be
traced that is invoked near the end of each grace period.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
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Kernels built with CONFIG_RCU_STRICT_GRACE_PERIOD=y can experience
significant lock contention due to RCU's resulting focus on ending grace
periods as soon as possible. This is OK, but only if there are not very
many CPUs. This commit therefore puts this Kconfig option off-limits
to systems with more than four CPUs.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
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Currently, show_rcu_gp_kthreads() only dumps rcu_node structures that
have outdated ideas of the current grace-period number. This commit
also dumps those that are in any way blocking the current grace period.
This helps diagnose RCU priority boosting failures.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
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When any CPU comes online, it checks to see if an RCU-boost kthread has
already been created for that CPU's leaf rcu_node structure, and if
not, it creates one. Unfortunately, it also verifies that this leaf
rcu_node structure actually has at least one online CPU, and if not,
it declines to create the kthread. Although this behavior makes sense
during early boot, especially on systems that claim far more CPUs than
they actually have, it makes no sense for the first CPU to come online
for a given rcu_node structure. There is no point in checking because
we know there is a CPU on its way in.
The problem is that timing differences can cause this incoming CPU to not
yet be reflected in the various bit masks even at rcutree_online_cpu()
time, and there is no chance at rcutree_prepare_cpu() time. Plus it
would be better to create the RCU-boost kthread at rcutree_prepare_cpu()
to handle the case where the CPU is involved in an RCU priority inversion
very shortly after it comes online.
This commit therefore moves the checking to rcu_prepare_kthreads(), which
is called only at early boot, when the check is appropriate. In addition,
it makes rcutree_prepare_cpu() invoke rcu_spawn_one_boost_kthread(), which
no longer does any checking for online CPUs.
With this change, RCU priority boosting tests now pass for short rcutorture
runs, even with single-CPU leaf rcu_node structures.
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Scott Wood <swood@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
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This commit adds each rcu_node structure's ->qsmask and "bBEG" output
indicating whether: (1) There is a boost kthread, (2) A reader needs
to be (or is in the process of being) boosted, (3) A reader is blocking
an expedited grace period, and (4) A reader is blocking a normal grace
period. This helps diagnose RCU priority boosting failures.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
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If another lockdep report runs concurrently with an RCU lockdep report
from RCU_LOCKDEP_WARN(), the following sequence of events can occur:
1. debug_lockdep_rcu_enabled() sees that lockdep is enabled
when called from (say) synchronize_rcu().
2. Lockdep is disabled by a concurrent lockdep report.
3. debug_lockdep_rcu_enabled() evaluates its lockdep-expression
argument, for example, lock_is_held(&rcu_bh_lock_map).
4. Because lockdep is now disabled, lock_is_held() plays it safe and
returns the constant 1.
5. But in this case, the constant 1 is not safe, because invoking
synchronize_rcu() under rcu_read_lock_bh() is disallowed.
6. debug_lockdep_rcu_enabled() wrongly invokes lockdep_rcu_suspicious(),
resulting in a false-positive splat.
This commit therefore changes RCU_LOCKDEP_WARN() to check
debug_lockdep_rcu_enabled() after checking the lockdep expression,
so that any "safe" returns from lock_is_held() are rejected by
debug_lockdep_rcu_enabled(). This requires memory ordering, which is
supplied by READ_ONCE(debug_locks). The resulting volatile accesses
prevent the compiler from reordering and the fact that only one variable
is being accessed prevents the underlying hardware from reordering.
The combination works for IA64, which can reorder reads to the same
location, but this is defeated by the volatile accesses, which compile
to load instructions that provide ordering.
Reported-by: syzbot+dde0cc33951735441301@syzkaller.appspotmail.com
Reported-by: Matthew Wilcox <willy@infradead.org>
Reported-by: syzbot+88e4f02896967fe1ab0d@syzkaller.appspotmail.com
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Suggested-by: Boqun Feng <boqun.feng@gmail.com>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
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The reason that lockdep_rcu_suspicious() prints the value of debug_locks
is because a value of zero indicates a likely false positive. This can
work, but is a bit obtuse. This commit therefore explicitly calls out
the possibility of a false positive.
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
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This commit adds ->gp_max to show_rcu_gp_kthreads() output in order to
better diagnose RCU priority boosting failures.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
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This commit adds ->rt_priority and ->gp_start to show_rcu_gp_kthreads()
output in order to better diagnose RCU priority boosting failures.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
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Currently, rcu_spawn_core_kthreads() is invoked via an early_initcall(),
which works, except that rcu_spawn_gp_kthread() is also invoked via an
early_initcall() and rcu_spawn_core_kthreads() relies on adjustments to
kthread_prio that are carried out by rcu_spawn_gp_kthread(). There is
no guaranttee of ordering among early_initcall() handlers, and thus no
guarantee that kthread_prio will be properly checked and range-limited
at the time that rcu_spawn_core_kthreads() needs it.
In most cases, this bug is harmless. After all, the only reason that
rcu_spawn_gp_kthread() adjusts the value of kthread_prio is if the user
specified a nonsensical value for this boot parameter, which experience
indicates is rare.
Nevertheless, a bug is a bug. This commit therefore causes the
rcu_spawn_core_kthreads() function to be invoked directly from
rcu_spawn_gp_kthread() after any needed adjustments to kthread_prio have
been carried out.
Fixes: 48d07c04b4cc ("rcu: Enable elimination of Tree-RCU softirq processing")
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
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This commit cleans up some comments and code in kernel/rcu/tree.c.
Signed-off-by: Zhouyi Zhou <zhouzhouyi@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
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Commit 9ee01e0f69a9 ("x86/entry: Clean up idtentry_enter/exit()
leftovers") left the rcu_irq_exit_preempt() in place in order to avoid
conflicts with the -rcu tree. Now that this change has long since hit
mainline, this commit removes the no-longer-used rcu_irq_exit_preempt()
function.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
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Signed-off-by: Rolf Eike Beer <eb@emlix.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
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Pull scheduler fixes from Thomas Gleixner:
"A set of scheduler updates:
- Prevent PSI state corruption when schedule() races with cgroup
move.
A recent commit combined two PSI callbacks to reduce the number of
cgroup tree updates, but missed that schedule() can drop rq::lock
for load balancing, which opens the race window for
cgroup_move_task() which then observes half updated state.
The fix is to solely use task::ps_flags instead of looking at the
potentially mismatching scheduler state
- Prevent an out-of-bounds access in uclamp caused bu a rounding
division which can lead to an off-by-one error exceeding the
buckets array size.
- Prevent unfairness caused by missing load decay when a task is
attached to a cfs runqueue.
The old load of the task was attached to the runqueue and never
removed. Fix it by enforcing the load update through the hierarchy
for unthrottled run queue instances.
- A documentation fix fot the 'sched_verbose' command line option"
* tag 'sched-urgent-2021-05-09' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/fair: Fix unfairness caused by missing load decay
sched: Fix out-of-bound access in uclamp
psi: Fix psi state corruption when schedule() races with cgroup move
sched,doc: sched_debug_verbose cmdline should be sched_verbose
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Pull locking fixes from Thomas Gleixner:
"A set of locking related fixes and updates:
- Two fixes for the futex syscall related to the timeout handling.
FUTEX_LOCK_PI does not support the FUTEX_CLOCK_REALTIME bit and
because it's not set the time namespace adjustment for clock
MONOTONIC is applied wrongly.
FUTEX_WAIT cannot support the FUTEX_CLOCK_REALTIME bit because its
always a relative timeout.
- Cleanups in the futex syscall entry points which became obvious
when the two timeout handling bugs were fixed.
- Cleanup of queued_write_lock_slowpath() as suggested by Linus
- Fixup of the smp_call_function_single_async() prototype"
* tag 'locking-urgent-2021-05-09' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
futex: Make syscall entry points less convoluted
futex: Get rid of the val2 conditional dance
futex: Do not apply time namespace adjustment on FUTEX_LOCK_PI
Revert 337f13046ff0 ("futex: Allow FUTEX_CLOCK_REALTIME with FUTEX_WAIT op")
locking/qrwlock: Cleanup queued_write_lock_slowpath()
smp: Fix smp_call_function_single_async prototype
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Pull more Kbuild updates from Masahiro Yamada:
- Convert sh and sparc to use generic shell scripts to generate the
syscall headers
- refactor .gitignore files
- Update kernel/config_data.gz only when the content of the .config
is really changed, which avoids the unneeded re-link of vmlinux
- move "remove stale files" workarounds to scripts/remove-stale-files
- suppress unused-but-set-variable warnings by default for Clang
as well
- fix locale setting LANG=C to LC_ALL=C
- improve 'make distclean'
- always keep intermediate objects from scripts/link-vmlinux.sh
- move IF_ENABLED out of <linux/kconfig.h> to make it self-contained
- misc cleanups
* tag 'kbuild-v5.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (25 commits)
linux/kconfig.h: replace IF_ENABLED() with PTR_IF() in <linux/kernel.h>
kbuild: Don't remove link-vmlinux temporary files on exit/signal
kbuild: remove the unneeded comments for external module builds
kbuild: make distclean remove tag files in sub-directories
kbuild: make distclean work against $(objtree) instead of $(srctree)
kbuild: refactor modname-multi by using suffix-search
kbuild: refactor fdtoverlay rule
kbuild: parameterize the .o part of suffix-search
arch: use cross_compiling to check whether it is a cross build or not
kbuild: remove ARCH=sh64 support from top Makefile
.gitignore: prefix local generated files with a slash
kbuild: replace LANG=C with LC_ALL=C
Makefile: Move -Wno-unused-but-set-variable out of GCC only block
kbuild: add a script to remove stale generated files
kbuild: update config_data.gz only when the content of .config is changed
.gitignore: ignore only top-level modules.builtin
.gitignore: move tags and TAGS close to other tag files
kernel/.gitgnore: remove stale timeconst.h and hz.bc
usr/include: refactor .gitignore
genksyms: fix stale comment
...
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Pull networking fixes from Jakub Kicinski:
"Networking fixes for 5.13-rc1, including fixes from bpf, can and
netfilter trees. Self-contained fixes, nothing risky.
Current release - new code bugs:
- dsa: ksz: fix a few bugs found by static-checker in the new driver
- stmmac: fix frame preemption handshake not triggering after
interface restart
Previous releases - regressions:
- make nla_strcmp handle more then one trailing null character
- fix stack OOB reads while fragmenting IPv4 packets in openvswitch
and net/sched
- sctp: do asoc update earlier in sctp_sf_do_dupcook_a
- sctp: delay auto_asconf init until binding the first addr
- stmmac: clear receive all(RA) bit when promiscuous mode is off
- can: mcp251x: fix resume from sleep before interface was brought up
Previous releases - always broken:
- bpf: fix leakage of uninitialized bpf stack under speculation
- bpf: fix masking negation logic upon negative dst register
- netfilter: don't assume that skb_header_pointer() will never fail
- only allow init netns to set default tcp cong to a restricted algo
- xsk: fix xp_aligned_validate_desc() when len == chunk_size to avoid
false positive errors
- ethtool: fix missing NLM_F_MULTI flag when dumping
- can: m_can: m_can_tx_work_queue(): fix tx_skb race condition
- sctp: fix a SCTP_MIB_CURRESTAB leak in sctp_sf_do_dupcook_b
- bridge: fix NULL-deref caused by a races between assigning
rx_handler_data and setting the IFF_BRIDGE_PORT bit
Latecomer:
- seg6: add counters support for SRv6 Behaviors"
* tag 'net-5.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (73 commits)
atm: firestream: Use fallthrough pseudo-keyword
net: stmmac: Do not enable RX FIFO overflow interrupts
mptcp: fix splat when closing unaccepted socket
i40e: Remove LLDP frame filters
i40e: Fix PHY type identifiers for 2.5G and 5G adapters
i40e: fix the restart auto-negotiation after FEC modified
i40e: Fix use-after-free in i40e_client_subtask()
i40e: fix broken XDP support
netfilter: nftables: avoid potential overflows on 32bit arches
netfilter: nftables: avoid overflows in nft_hash_buckets()
tcp: Specify cmsgbuf is user pointer for receive zerocopy.
mlxsw: spectrum_mr: Update egress RIF list before route's action
net: ipa: fix inter-EE IRQ register definitions
can: m_can: m_can_tx_work_queue(): fix tx_skb race condition
can: mcp251x: fix resume from sleep before interface was brought up
can: mcp251xfd: mcp251xfd_probe(): add missing can_rx_offload_del() in error path
can: mcp251xfd: mcp251xfd_probe(): fix an error pointer dereference in probe
netfilter: nftables: Fix a memleak from userdata error path in new objects
netfilter: remove BUG_ON() after skb_header_pointer()
netfilter: nfnetlink_osf: Fix a missing skb_header_pointer() NULL check
...
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Merge yet more updates from Andrew Morton:
"This is everything else from -mm for this merge window.
90 patches.
Subsystems affected by this patch series: mm (cleanups and slub),
alpha, procfs, sysctl, misc, core-kernel, bitmap, lib, compat,
checkpatch, epoll, isofs, nilfs2, hpfs, exit, fork, kexec, gcov,
panic, delayacct, gdb, resource, selftests, async, initramfs, ipc,
drivers/char, and spelling"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (90 commits)
mm: fix typos in comments
mm: fix typos in comments
treewide: remove editor modelines and cruft
ipc/sem.c: spelling fix
fs: fat: fix spelling typo of values
kernel/sys.c: fix typo
kernel/up.c: fix typo
kernel/user_namespace.c: fix typos
kernel/umh.c: fix some spelling mistakes
include/linux/pgtable.h: few spelling fixes
mm/slab.c: fix spelling mistake "disired" -> "desired"
scripts/spelling.txt: add "overflw"
scripts/spelling.txt: Add "diabled" typo
scripts/spelling.txt: add "overlfow"
arm: print alloc free paths for address in registers
mm/vmalloc: remove vwrite()
mm: remove xlate_dev_kmem_ptr()
drivers/char: remove /dev/kmem for good
mm: fix some typos and code style problems
ipc/sem.c: mundane typo fixes
...
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change 'infite' to 'infinite'
change 'concurent' to 'concurrent'
change 'memvers' to 'members'
change 'decendants' to 'descendants'
change 'argumets' to 'arguments'
Link: https://lkml.kernel.org/r/20210316112904.10661-1-cxfcosmos@gmail.com
Signed-off-by: Xiaofeng Cao <caoxiaofeng@yulong.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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s/condtions/conditions/
Link: https://lkml.kernel.org/r/20210317032732.3260835-1-unixbhaskar@gmail.com
Signed-off-by: Bhaskar Chowdhury <unixbhaskar@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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change 'verifing' to 'verifying'
change 'certaint' to 'certain'
change 'approprpiate' to 'appropriate'
Link: https://lkml.kernel.org/r/20210317100129.12440-1-caoxiaofeng@yulong.com
Signed-off-by: Xiaofeng Cao <caoxiaofeng@yulong.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Fix some spelling mistakes, and modify the order of the parameter comments
to be consistent with the order of the parameters passed to the function.
Link: https://lkml.kernel.org/r/1615636139-4076-1-git-send-email-zhouchuangao@vivo.com
Signed-off-by: zhouchuangao <zhouchuangao@vivo.com>
Acked-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Patch series "drivers/char: remove /dev/kmem for good".
Exploring /dev/kmem and /dev/mem in the context of memory hot(un)plug and
memory ballooning, I started questioning the existence of /dev/kmem.
Comparing it with the /proc/kcore implementation, it does not seem to be
able to deal with things like
a) Pages unmapped from the direct mapping (e.g., to be used by secretmem)
-> kern_addr_valid(). virt_addr_valid() is not sufficient.
b) Special cases like gart aperture memory that is not to be touched
-> mem_pfn_is_ram()
Unless I am missing something, it's at least broken in some cases and might
fault/crash the machine.
Looks like its existence has been questioned before in 2005 and 2010 [1],
after ~11 additional years, it might make sense to revive the discussion.
CONFIG_DEVKMEM is only enabled in a single defconfig (on purpose or by
mistake?). All distributions disable it: in Ubuntu it has been disabled
for more than 10 years, in Debian since 2.6.31, in Fedora at least
starting with FC3, in RHEL starting with RHEL4, in SUSE starting from
15sp2, and OpenSUSE has it disabled as well.
1) /dev/kmem was popular for rootkits [2] before it got disabled
basically everywhere. Ubuntu documents [3] "There is no modern user of
/dev/kmem any more beyond attackers using it to load kernel rootkits.".
RHEL documents in a BZ [5] "it served no practical purpose other than to
serve as a potential security problem or to enable binary module drivers
to access structures/functions they shouldn't be touching"
2) /proc/kcore is a decent interface to have a controlled way to read
kernel memory for debugging puposes. (will need some extensions to
deal with memory offlining/unplug, memory ballooning, and poisoned
pages, though)
3) It might be useful for corner case debugging [1]. KDB/KGDB might be a
better fit, especially, to write random memory; harder to shoot
yourself into the foot.
4) "Kernel Memory Editor" [4] hasn't seen any updates since 2000 and seems
to be incompatible with 64bit [1]. For educational purposes,
/proc/kcore might be used to monitor value updates -- or older
kernels can be used.
5) It's broken on arm64, and therefore, completely disabled there.
Looks like it's essentially unused and has been replaced by better
suited interfaces for individual tasks (/proc/kcore, KDB/KGDB). Let's
just remove it.
[1] https://lwn.net/Articles/147901/
[2] https://www.linuxjournal.com/article/10505
[3] https://wiki.ubuntu.com/Security/Features#A.2Fdev.2Fkmem_disabled
[4] https://sourceforge.net/projects/kme/
[5] https://bugzilla.redhat.com/show_bug.cgi?id=154796
Link: https://lkml.kernel.org/r/20210324102351.6932-1-david@redhat.com
Link: https://lkml.kernel.org/r/20210324102351.6932-2-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Alexander A. Klimov" <grandmaster@al2klimov.de>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Andrey Zhizhikin <andrey.zhizhikin@leica-geosystems.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Chris Zankel <chris@zankel.net>
Cc: Corentin Labbe <clabbe@baylibre.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Gregory Clement <gregory.clement@bootlin.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Hillf Danton <hdanton@sina.com>
Cc: huang ying <huang.ying.caritas@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: James Troup <james.troup@canonical.com>
Cc: Jiaxun Yang <jiaxun.yang@flygoat.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kairui Song <kasong@redhat.com>
Cc: Krzysztof Kozlowski <krzk@kernel.org>
Cc: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Cc: Liviu Dudau <liviu.dudau@arm.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Mikulas Patocka <mpatocka@redhat.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Niklas Schnelle <schnelle@linux.ibm.com>
Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sonymobile.com>
Cc: openrisc@lists.librecores.org
Cc: Palmer Dabbelt <palmerdabbelt@google.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: "Pavel Machek (CIP)" <pavel@denx.de>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Cc: Pierre Morel <pmorel@linux.ibm.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Rich Felker <dalias@libc.org>
Cc: Robert Richter <rric@kernel.org>
Cc: Rob Herring <robh@kernel.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Cc: sparclinux@vger.kernel.org
Cc: Stafford Horne <shorne@gmail.com>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Theodore Dubois <tblodt@icloud.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: William Cohen <wcohen@redhat.com>
Cc: Xiaoming Ni <nixiaoming@huawei.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Allow the developer to specifiy the initial value of the modprobe_path[]
string. This can be used to set it to the empty string initially, thus
effectively disabling request_module() during early boot until userspace
writes a new value via the /proc/sys/kernel/modprobe interface. [1]
When building a custom kernel (often for an embedded target), it's normal
to build everything into the kernel that is needed for booting, and indeed
the initramfs often contains no modules at all, so every such
request_module() done before userspace init has mounted the real rootfs is
a waste of time.
This is particularly useful when combined with the previous patch, which
made the initramfs unpacking asynchronous - for that to work, it had to
make any usermodehelper call wait for the unpacking to finish before
attempting to invoke the userspace helper. By eliminating all such
(known-to-be-futile) calls of usermodehelper, the initramfs unpacking and
the {device,late}_initcalls can proceed in parallel for much longer.
For a relatively slow ppc board I'm working on, the two patches combined
lead to 0.2s faster boot - but more importantly, the fact that the
initramfs unpacking proceeds completely in the background while devices
get probed means I get to handle the gpio watchdog in time without getting
reset.
[1] __request_module() already has an early -ENOENT return when
modprobe_path is the empty string.
Link: https://lkml.kernel.org/r/20210313212528.2956377-3-linux@rasmusvillemoes.dk
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Jessica Yu <jeyu@kernel.org>
Acked-by: Luis Chamberlain <mcgrof@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Patch series "background initramfs unpacking, and CONFIG_MODPROBE_PATH", v3.
These two patches are independent, but better-together.
The second is a rather trivial patch that simply allows the developer to
change "/sbin/modprobe" to something else - e.g. the empty string, so
that all request_module() during early boot return -ENOENT early, without
even spawning a usermode helper, needlessly synchronizing with the
initramfs unpacking.
The first patch delegates decompressing the initramfs to a worker thread,
allowing do_initcalls() in main.c to proceed to the device_ and late_
initcalls without waiting for that decompression (and populating of
rootfs) to finish. Obviously, some of those later calls may rely on the
initramfs being available, so I've added synchronization points in the
firmware loader and usermodehelper paths - there might be other places
that would need this, but so far no one has been able to think of any
places I have missed.
There's not much to win if most of the functionality needed during boot is
only available as modules. But systems with a custom-made .config and
initramfs can boot faster, partly due to utilizing more than one cpu
earlier, partly by avoiding known-futile modprobe calls (which would still
trigger synchronization with the initramfs unpacking, thus eliminating
most of the first benefit).
This patch (of 2):
Most of the boot process doesn't actually need anything from the
initramfs, until of course PID1 is to be executed. So instead of doing
the decompressing and populating of the initramfs synchronously in
populate_rootfs() itself, push that off to a worker thread.
This is primarily motivated by an embedded ppc target, where unpacking
even the rather modest sized initramfs takes 0.6 seconds, which is long
enough that the external watchdog becomes unhappy that it doesn't get
attention soon enough. By doing the initramfs decompression in a worker
thread, we get to do the device_initcalls and hence start petting the
watchdog much sooner.
Normal desktops might benefit as well. On my mostly stock Ubuntu kernel,
my initramfs is a 26M xz-compressed blob, decompressing to around 126M.
That takes almost two seconds:
[ 0.201454] Trying to unpack rootfs image as initramfs...
[ 1.976633] Freeing initrd memory: 29416K
Before this patch, these lines occur consecutively in dmesg. With this
patch, the timestamps on these two lines is roughly the same as above, but
with 172 lines inbetween - so more than one cpu has been kept busy doing
work that would otherwise only happen after the populate_rootfs()
finished.
Should one of the initcalls done after rootfs_initcall time (i.e., device_
and late_ initcalls) need something from the initramfs (say, a kernel
module or a firmware blob), it will simply wait for the initramfs
unpacking to be done before proceeding, which should in theory make this
completely safe.
But if some driver pokes around in the filesystem directly and not via one
of the official kernel interfaces (i.e. request_firmware*(),
call_usermodehelper*) that theory may not hold - also, I certainly might
have missed a spot when sprinkling wait_for_initramfs(). So there is an
escape hatch in the form of an initramfs_async= command line parameter.
Link: https://lkml.kernel.org/r/20210313212528.2956377-1-linux@rasmusvillemoes.dk
Link: https://lkml.kernel.org/r/20210313212528.2956377-2-linux@rasmusvillemoes.dk
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
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No callers in the tree.
Link: https://lkml.kernel.org/r/20210309151723.1907838-2-linux@rasmusvillemoes.dk
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
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It's currently nigh impossible to get these pr_debug()s to print
something. Being guarded by initcall_debug means one has to enable tons
of other debug output during boot, and the system_state condition further
means it's impossible to get them when loading modules later.
Also, the compiler can't know that these global conditions do not change,
so there are W=2 warnings
kernel/async.c:125:9: warning: `calltime' may be used uninitialized in this function [-Wmaybe-uninitialized]
kernel/async.c:300:9: warning: `starttime' may be used uninitialized in this function [-Wmaybe-uninitialized]
Make it possible, for a DYNAMIC_DEBUG kernel, to get these to print their
messages by booting with appropriate 'dyndbg="file async.c +p"' command
line argument. For a non-DYNAMIC_DEBUG kernel, pr_debug() compiles to
nothing.
This does cost doing an unconditional ktime_get() for the starttime value,
but the corresponding ktime_get for the end time can be elided by
factoring it into a function which only gets called if the printk()
arguments end up being evaluated.
Link: https://lkml.kernel.org/r/20210309151723.1907838-1-linux@rasmusvillemoes.dk
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
request_free_mem_region() is used to find an empty range of physical
addresses for hotplugging ZONE_DEVICE memory. It does this by iterating
over the range of possible addresses using region_intersects() to see if
the range is free before calling request_mem_region() to allocate the
region.
However the resource_lock is dropped between these two calls meaning by
the time request_mem_region() is called in request_free_mem_region()
another thread may have already reserved the requested region. This
results in unexpected failures and a message in the kernel log from
hitting this condition:
/*
* mm/hmm.c reserves physical addresses which then
* become unavailable to other users. Conflicts are
* not expected. Warn to aid debugging if encountered.
*/
if (conflict->desc == IORES_DESC_DEVICE_PRIVATE_MEMORY) {
pr_warn("Unaddressable device %s %pR conflicts with %pR",
conflict->name, conflict, res);
These unexpected failures can be corrected by holding resource_lock across
the two calls. This also requires memory allocation to be performed prior
to taking the lock.
Link: https://lkml.kernel.org/r/20210419070109.4780-3-apopple@nvidia.com
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Muchun Song <smuchun@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
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Refactor the portion of __request_region() done whilst holding the
resource_lock into a separate function to allow callers to hold the lock.
Link: https://lkml.kernel.org/r/20210419070109.4780-2-apopple@nvidia.com
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Muchun Song <smuchun@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Introduce a version of region_intersects() that can be called with the
resource_lock already held.
This will be used in a future fix to __request_free_mem_region().
[akpm@linux-foundation.org: make __region_intersects static]
Link: https://lkml.kernel.org/r/20210419070109.4780-1-apopple@nvidia.com
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Muchun Song <smuchun@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
All functions that search for IORESOURCE_SYSTEM_RAM or IORESOURCE_MEM
resources now properly consider the whole resource tree, not just the
first level. Let's drop the unused first_lvl / siblings_only logic.
Remove documentation that indicates that some functions behave differently,
all consider the full resource tree now.
Link: https://lkml.kernel.org/r/20210325115326.7826-4-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Cc: Dave Young <dyoung@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Qian Cai <cai@lca.pw>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
It used to be true that we can have system RAM (IORESOURCE_SYSTEM_RAM |
IORESOURCE_BUSY) only on the first level in the resource tree. However,
this is no longer holds for driver-managed system RAM (i.e., added via
dax/kmem and virtio-mem), which gets added on lower levels, for example,
inside device containers.
IORESOURCE_SYSTEM_RAM is defined as IORESOURCE_MEM | IORESOURCE_SYSRAM and
just a special type of IORESOURCE_MEM.
The function walk_mem_res() only considers the first level and is used in
arch/x86/mm/ioremap.c:__ioremap_check_mem() only. We currently fail to
identify System RAM added by dax/kmem and virtio-mem as
"IORES_MAP_SYSTEM_RAM", for example, allowing for remapping of such
"normal RAM" in __ioremap_caller().
Let's find all IORESOURCE_MEM | IORESOURCE_BUSY resources, making the
function behave similar to walk_system_ram_res().
Link: https://lkml.kernel.org/r/20210325115326.7826-3-david@redhat.com
Fixes: ebf71552bb0e ("virtio-mem: Add parent resource for all added "System RAM"")
Fixes: c221c0b0308f ("device-dax: "Hotplug" persistent memory for use like normal RAM")
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Cc: Dave Young <dyoung@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Qian Cai <cai@lca.pw>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Patch series "kernel/resource: make walk_system_ram_res() and walk_mem_res() search the whole tree", v2.
Playing with kdump+virtio-mem I noticed that kexec_file_load() does not
consider System RAM added via dax/kmem and virtio-mem when preparing the
elf header for kdump. Looking into the details, the logic used in
walk_system_ram_res() and walk_mem_res() seems to be outdated.
walk_system_ram_range() already does the right thing, let's change
walk_system_ram_res() and walk_mem_res(), and clean up.
Loading a kdump kernel via "kexec -p -s" ... will result in the kdump
kernel to also dump dax/kmem and virtio-mem added System RAM now.
Note: kexec-tools on x86-64 also have to be updated to consider this
memory in the kexec_load() case when processing /proc/iomem.
This patch (of 3):
It used to be true that we can have system RAM (IORESOURCE_SYSTEM_RAM |
IORESOURCE_BUSY) only on the first level in the resource tree. However,
this is no longer holds for driver-managed system RAM (i.e., added via
dax/kmem and virtio-mem), which gets added on lower levels, for example,
inside device containers.
We have two users of walk_system_ram_res(), which currently only
consideres the first level:
a) kernel/kexec_file.c:kexec_walk_resources() -- We properly skip
IORESOURCE_SYSRAM_DRIVER_MANAGED resources via
locate_mem_hole_callback(), so even after this change, we won't be
placing kexec images onto dax/kmem and virtio-mem added memory. No
change.
b) arch/x86/kernel/crash.c:fill_up_crash_elf_data() -- we're currently
not adding relevant ranges to the crash elf header, resulting in them
not getting dumped via kdump.
This change fixes loading a crashkernel via kexec_file_load() and
including dax/kmem and virtio-mem added System RAM in the crashdump on
x86-64. Note that e.g,, arm64 relies on memblock data and, therefore,
always considers all added System RAM already.
Let's find all IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY resources, making
the function behave like walk_system_ram_range().
Link: https://lkml.kernel.org/r/20210325115326.7826-1-david@redhat.com
Link: https://lkml.kernel.org/r/20210325115326.7826-2-david@redhat.com
Fixes: ebf71552bb0e ("virtio-mem: Add parent resource for all added "System RAM"")
Fixes: c221c0b0308f ("device-dax: "Hotplug" persistent memory for use like normal RAM")
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Cc: Dave Young <dyoung@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Qian Cai <cai@lca.pw>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
LLVM changed the expected function signatures for llvm_gcda_start_file()
and llvm_gcda_emit_function() in the clang-11 release. Drop the older
implementations and require folks to upgrade their compiler if they're
interested in GCOV support.
Link: https://reviews.llvm.org/rGcdd683b516d147925212724b09ec6fb792a40041
Link: https://reviews.llvm.org/rG13a633b438b6500ecad9e4f936ebadf3411d0f44
Link: https://lkml.kernel.org/r/20210312224132.3413602-3-ndesaulniers@google.com
Link: https://lkml.kernel.org/r/20210413183113.2977432-1-ndesaulniers@google.com
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Suggested-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Fangrui Song <maskray@google.com>
Cc: Prasad Sodagudi <psodagud@quicinc.com>
Cc: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Using vmalloc() in gcov is really quite wasteful, many of the objects
allocated are really small (e.g. I've seen 24 bytes.) Use kvmalloc() to
automatically pick the better of kmalloc() or vmalloc() depending on the
size.
[johannes.berg@intel.com: fix clang-11+ build]
Link: https://lkml.kernel.org/r/20210412214210.6e1ecca9cdc5.I24459763acf0591d5e6b31c7e3a59890d802f79c@changeid
Link: https://lkml.kernel.org/r/20210315235453.799e7a9d627d.I741d0db096c6f312910f7f1bcdfde0fda20801a4@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Cc: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Use just a single vmalloc() with struct_size() instead of a separate
kmalloc() for the iter struct.
Link: https://lkml.kernel.org/r/20210315235453.b6de4a92096e.Iac40a5166589cefbff8449e466bd1b38ea7a17af@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Cc: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
There's a lot of duplicated code between gcc and clang implementations,
move it over to fs.c to simplify the code, there's no reason to believe
that for small data like this one would not just implement the simple
convert_to_gcda() function.
Link: https://lkml.kernel.org/r/20210315235453.e3fbb86e99a0.I08a3ee6dbe47ea3e8024956083f162884a958e40@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
kmsg_dump(KMSG_DUMP_SHUTDOWN) is called before machine_restart(),
machine_halt(), and machine_power_off(). The only one that is missing
is machine_kexec().
The dmesg output that it contains can be used to study the shutdown
performance of both kernel and systemd during kexec reboot.
Here is example of dmesg data collected after kexec:
root@dplat-cp22:~# cat /sys/fs/pstore/dmesg-ramoops-0 | tail
...
[ 70.914592] psci: CPU3 killed (polled 0 ms)
[ 70.915705] CPU4: shutdown
[ 70.916643] psci: CPU4 killed (polled 4 ms)
[ 70.917715] CPU5: shutdown
[ 70.918725] psci: CPU5 killed (polled 0 ms)
[ 70.919704] CPU6: shutdown
[ 70.920726] psci: CPU6 killed (polled 4 ms)
[ 70.921642] CPU7: shutdown
[ 70.922650] psci: CPU7 killed (polled 0 ms)
Link: https://lkml.kernel.org/r/20210319192326.146000-2-pasha.tatashin@soleen.com
Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Bhupesh Sharma <bhsharma@redhat.com>
Acked-by: Baoquan He <bhe@redhat.com>
Reviewed-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Cc: James Morris <jmorris@namei.org>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Anton Vorontsov <anton@enomsg.org>
Cc: Colin Cross <ccross@android.com>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
When vzalloc() returns NULL to sha_regions, no error return code of
kexec_calculate_store_digests() is assigned. To fix this bug, ret is
assigned with -ENOMEM in this case.
Link: https://lkml.kernel.org/r/20210309083904.24321-1-baijiaju1990@gmail.com
Fixes: a43cac0d9dc2 ("kexec: split kexec_file syscall code to kexec_file.c")
Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Reported-by: TOTE Robot <oslab@tsinghua.edu.cn>
Acked-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The purpose is to notify the kernel module for fast reboot.
Upstream a patch from the SONiC network operating system [1].
[1]: https://github.com/Azure/sonic-linux-kernel/pull/46
Link: https://lkml.kernel.org/r/20210304124626.13927-1-pmenzel@molgen.mpg.de
Signed-off-by: Joe LeVeque <jolevequ@microsoft.com>
Signed-off-by: Paul Menzel <pmenzel@molgen.mpg.de>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Guohan Lu <lguohan@gmail.com>
Cc: Joe LeVeque <jolevequ@microsoft.com>
Cc: Paul Menzel <pmenzel@molgen.mpg.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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change 'ancestoral' to 'ancestral'
change 'reuseable' to 'reusable'
delete 'do' grammatically
Link: https://lkml.kernel.org/r/20210317082031.11692-1-caoxiaofeng@yulong.com
Signed-off-by: Xiaofeng Cao <caoxiaofeng@yulong.com>
Reviewed-by: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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All this can happen without a single goto.
Link: https://lkml.kernel.org/r/2072685.XptgVkyDqn@devpool47
Signed-off-by: Rolf Eike Beer <eb@emlix.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Add a special-case when waiting on a pid (via waitpid, waitid, wait4, etc)
to avoid doing an O(n) scan of children and tracees, and instead do an
O(1) lookup. This improves performance when waiting on a pid from a
thread group with many children and/or tracees.
Time to fork and then call waitpid on the child, from a task that already
has N children [1]:
N | Before | After
-----|---------|------
1 | 74 us | 74 us
20 | 72 us | 75 us
100 | 83 us | 77 us
500 | 99 us | 74 us
1000 | 179 us | 75 us
5000 | 804 us | 79 us
8000 | 1268 us | 78 us
[1]: https://lkml.org/lkml/2021/3/12/1567
This can make a substantial performance improvement for applications with
a thread that has many children or tracees and frequently needs to wait on
them. Tools that use ptrace to intercept syscalls for a large number of
processes are likely to fall into this category. In particular this patch
was developed while building a ptrace-based second generation of the
Shadow emulator [2], for which it allows us to avoid quadratic scaling
(without having to use a workaround that introduces a ~40% performance
penalty) [3]. Other examples of tools that fall into this category which
this patch may help include User Mode Linux [4] and DetTrace [5].
[2]: https://shadow.github.io/
[3]: https://github.com/shadow/shadow/issues/1134#issuecomment-798992292
[4]: https://en.wikipedia.org/wiki/User-mode_Linux
[5]: https://github.com/dettrace/dettrace
Link: https://lkml.kernel.org/r/20210314231544.9379-1-jnewsome@torproject.org
Signed-off-by: James Newsome <jnewsome@torproject.org>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Cc: "Eric W . Biederman" <ebiederm@xmission.com>
Cc: Christian Brauner <christian@brauner.io>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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init_groups is declared in both cred.h and init_task.h, but it is not
actually referenced anywhere outside of cred.c where it is defined. So
make it static and remove the declarations.
Link: https://lkml.kernel.org/r/20210310220102.2484201-1-linux@rasmusvillemoes.dk
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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An async_func_t returns void - any errors encountered it has to stash
somewhere for consumers to discover later.
Link: https://lkml.kernel.org/r/20210226124355.2503524-1-linux@rasmusvillemoes.dk
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The futex and the compat syscall entry points do pretty much the same
except for the timespec data types and the corresponding copy from
user function.
Split out the rest into inline functions and share the functionality.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210422194705.244476369@linutronix.de
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There is no point in checking which FUTEX operand treats the utime pointer
as 'val2' argument because that argument to do_futex() is only used by
exactly these operands.
So just handing it in unconditionally is not making any difference, but
removes a lot of pointless gunk.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210422194705.125957049@linutronix.de
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FUTEX_LOCK_PI does not require to have the FUTEX_CLOCK_REALTIME bit set
because it has been using CLOCK_REALTIME based absolute timeouts
forever. Due to that, the time namespace adjustment which is applied when
FUTEX_CLOCK_REALTIME is not set, will wrongly take place for FUTEX_LOCK_PI
and wreckage the timeout.
Exclude it from that procedure.
Fixes: c2f7d08cccf4 ("futex: Adjust absolute futex timeouts with per time namespace offset")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210422194704.984540159@linutronix.de
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The FUTEX_WAIT operand has historically a relative timeout which means that
the clock id is irrelevant as relative timeouts on CLOCK_REALTIME are not
subject to wall clock changes and therefore are mapped by the kernel to
CLOCK_MONOTONIC for simplicity.
If a caller would set FUTEX_CLOCK_REALTIME for FUTEX_WAIT the timeout is
still treated relative vs. CLOCK_MONOTONIC and then the wait arms that
timeout based on CLOCK_REALTIME which is broken and obviously has never
been used or even tested.
Reject any attempt to use FUTEX_CLOCK_REALTIME with FUTEX_WAIT again.
The desired functionality can be achieved with FUTEX_WAIT_BITSET and a
FUTEX_BITSET_MATCH_ANY argument.
Fixes: 337f13046ff0 ("futex: Allow FUTEX_CLOCK_REALTIME with FUTEX_WAIT op")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210422194704.834797921@linutronix.de
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Pull tracing fix from Steven Rostedt:
"Fix probes written to the set_ftrace_filter file
Now that there's a library that accesses the tracefs file system
(libtracefs), the way the files are interacted with is slightly
different than the command line. For instance, the write() system call
is used directly instead of an echo. This exposes some old bugs.
If a probe is written to "set_ftrace_filter" without any white space
after it, it will be ignored. This is because the write expects that a
string written to it that does not end with white spaces thinks there
is more to come. But if the file is closed, the release function needs
to finish it. The "set_ftrace_filter" release function handles the
filter part of the "set_ftrace_filter" file, but did not handle the
probe part"
* tag 'trace-v5.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
ftrace: Handle commands when closing set_ftrace_filter file
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Paul E. McKenney
Zhouyi Zhou
Rolf Eike Beer
Linus Torvalds
Xiaofeng Cao
Bhaskar Chowdhury
Xiaofeng Cao
zhouchuangao
David Hildenbrand
Rasmus Villemoes
Alistair Popple
Nick Desaulniers
Johannes Berg
Pavel Tatashin
Jia-Ju Bai
Joe LeVeque
Jim Newsome
Thomas Gleixner