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Creating 2**32 tasks to wait in D-state is impossible and wasteful.
Return "unsigned int" and save on REX prefixes.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210422200228.1423391-2-adobriyan@gmail.com
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Creating 2**32 tasks is impossible due to futex pid limits and wasteful
anyway. Nobody has done it.
Bring nr_running() into 32-bit world to save on REX prefixes.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210422200228.1423391-1-adobriyan@gmail.com
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Add "continue;" for switch/case block according to Doc[1]
[1] https://www.kernel.org/doc/html/latest/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through
Signed-off-by: Wei Ming Chen <jj251510319013@gmail.com>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
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A few snuck through.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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A few more snuck in. Also capitalize 'CPU' while at it.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Last users of blk_account_rq gone with patch commit a1ce35fa49852db
("block: remove dead elevator code") and now it gets no caller, it can
be safely removed.
Signed-off-by: Lin Feng <linf@wangsu.com>
Link: https://lore.kernel.org/r/20210512100124.173769-1-linf@wangsu.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Have jump_label_init() set jump_entry::key bit1 to either 0 ot 1
unconditionally. This makes it available for build-time games.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210506194157.906893264@infradead.org
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This allows architectures to have variable sized jumps.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210506194157.786777050@infradead.org
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This patch provides support for setting and copying core scheduling
'task cookies' between threads (PID), processes (TGID), and process
groups (PGID).
The value of core scheduling isn't that tasks don't share a core,
'nosmt' can do that. The value lies in exploiting all the sharing
opportunities that exist to recover possible lost performance and that
requires a degree of flexibility in the API.
From a security perspective (and there are others), the thread,
process and process group distinction is an existent hierarchal
categorization of tasks that reflects many of the security concerns
about 'data sharing'. For example, protecting against cache-snooping
by a thread that can just read the memory directly isn't all that
useful.
With this in mind, subcommands to CREATE/SHARE (TO/FROM) provide a
mechanism to create and share cookies. CREATE/SHARE_TO specify a
target pid with enum pidtype used to specify the scope of the targeted
tasks. For example, PIDTYPE_TGID will share the cookie with the
process and all of it's threads as typically desired in a security
scenario.
API:
prctl(PR_SCHED_CORE, PR_SCHED_CORE_GET, tgtpid, pidtype, &cookie)
prctl(PR_SCHED_CORE, PR_SCHED_CORE_CREATE, tgtpid, pidtype, NULL)
prctl(PR_SCHED_CORE, PR_SCHED_CORE_SHARE_TO, tgtpid, pidtype, NULL)
prctl(PR_SCHED_CORE, PR_SCHED_CORE_SHARE_FROM, srcpid, pidtype, NULL)
where 'tgtpid/srcpid == 0' implies the current process and pidtype is
kernel enum pid_type {PIDTYPE_PID, PIDTYPE_TGID, PIDTYPE_PGID, ...}.
For return values, EINVAL, ENOMEM are what they say. ESRCH means the
tgtpid/srcpid was not found. EPERM indicates lack of PTRACE permission
access to tgtpid/srcpid. ENODEV indicates your machines lacks SMT.
[peterz: complete rewrite]
Signed-off-by: Chris Hyser <chris.hyser@oracle.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Don Hiatt <dhiatt@digitalocean.com>
Tested-by: Hongyu Ning <hongyu.ning@linux.intel.com>
Tested-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lkml.kernel.org/r/20210422123309.039845339@infradead.org
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Note that sched_core_fork() is called from under tasklist_lock, and
not from sched_fork() earlier. This avoids a few races later.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Don Hiatt <dhiatt@digitalocean.com>
Tested-by: Hongyu Ning <hongyu.ning@linux.intel.com>
Tested-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lkml.kernel.org/r/20210422123308.980003687@infradead.org
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In order to not have to use pid_struct, create a new, smaller,
structure to manage task cookies for core scheduling.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Don Hiatt <dhiatt@digitalocean.com>
Tested-by: Hongyu Ning <hongyu.ning@linux.intel.com>
Tested-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lkml.kernel.org/r/20210422123308.919768100@infradead.org
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When a sibling is forced-idle to match the core-cookie; search for
matching tasks to fill the core.
rcu_read_unlock() can incur an infrequent deadlock in
sched_core_balance(). Fix this by using the RCU-sched flavor instead.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Don Hiatt <dhiatt@digitalocean.com>
Tested-by: Hongyu Ning <hongyu.ning@linux.intel.com>
Tested-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lkml.kernel.org/r/20210422123308.800048269@infradead.org
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Introduce task_struct::core_cookie as an opaque identifier for core
scheduling. When enabled; core scheduling will only allow matching
task to be on the core; where idle matches everything.
When task_struct::core_cookie is set (and core scheduling is enabled)
these tasks are indexed in a second RB-tree, first on cookie value
then on scheduling function, such that matching task selection always
finds the most elegible match.
NOTE: *shudder* at the overhead...
NOTE: *sigh*, a 3rd copy of the scheduling function; the alternative
is per class tracking of cookies and that just duplicates a lot of
stuff for no raisin (the 2nd copy lives in the rt-mutex PI code).
[Joel: folded fixes]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Don Hiatt <dhiatt@digitalocean.com>
Tested-by: Hongyu Ning <hongyu.ning@linux.intel.com>
Tested-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lkml.kernel.org/r/20210422123308.496975854@infradead.org
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Just like sched_schedstats, allow runtime enabling (and disabling) of
delayacct. This is useful if one forgot to add the delayacct boot time
option.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/YJkhebGJAywaZowX@hirez.programming.kicks-ass.net
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Assuming this stuff isn't actually used much; disable it by default
and avoid allocating and tracking the task_delay_info structure.
taskstats is changed to still report the regular sched and sched_info
and only skip the missing task_delay_info fields instead of not
reporting anything.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Link: https://lkml.kernel.org/r/20210505111525.308018373@infradead.org
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Cheaper when delayacct is disabled.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Link: https://lkml.kernel.org/r/20210505111525.248028369@infradead.org
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The situation around sched_info is somewhat complicated, it is used by
sched_stats and delayacct and, indirectly, kvm.
If SCHEDSTATS=Y (but disabled by default) sched_info_on() is
unconditionally true -- this is the case for all distro kernel configs
I checked.
If for some reason SCHEDSTATS=N, but TASK_DELAY_ACCT=Y, then
sched_info_on() can return false when delayacct is disabled,
presumably because there would be no other users left; except kvm is.
Instead of complicating matters further by accurately accounting
sched_stat and kvm state, simply unconditionally enable when
SCHED_INFO=Y, matching the common distro case.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Link: https://lkml.kernel.org/r/20210505111525.121458839@infradead.org
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The WWAN framework provides a unified way to handle WWAN/modems and its
control port(s). It has initially been introduced to support MHI/PCI
modems, offering the same control protocols as the USB variants such as
MBIM, QMI, AT... The WWAN framework exposes these control protocols as
character devices, similarly to cdc-wdm, but in a bus agnostic fashion.
This change adds registration of the USB modem cdc-wdm control endpoints
to the WWAN framework as standard control ports (wwanXpY...).
Exposing cdc-wdm through WWAN framework normally maintains backward
compatibility, e.g:
$ qmicli --device-open-qmi -d /dev/wwan0p1QMI --dms-get-ids
instead of
$ qmicli --device-open-qmi -d /dev/cdc-wdm0 --dms-get-ids
However, some tools may rely on cdc-wdm driver/device name for device
detection. It is then safer to keep the 'legacy' cdc-wdm character
device to prevent any breakage. This is handled in this change by
API mutual exclusion, only one access method can be used at a time,
either cdc-wdm chardev or WWAN API.
Note that unknown channel types (other than MBIM, AT or MBIM) are not
registered to the WWAN framework.
Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Some devices may have ports with unknown type/protocol which need to
be tagged (though not supported by WWAN core). This will be the case
for cdc-wdm based drivers.
Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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__blk_mq_sched_bio_merge() gets the ctx and hctx for the current CPU and
passes the hctx to ->bio_merge(). kyber_bio_merge() then gets the ctx
for the current CPU again and uses that to get the corresponding Kyber
context in the passed hctx. However, the thread may be preempted between
the two calls to blk_mq_get_ctx(), and the ctx returned the second time
may no longer correspond to the passed hctx. This "works" accidentally
most of the time, but it can cause us to read garbage if the second ctx
came from an hctx with more ctx's than the first one (i.e., if
ctx->index_hw[hctx->type] > hctx->nr_ctx).
This manifested as this UBSAN array index out of bounds error reported
by Jakub:
UBSAN: array-index-out-of-bounds in ../kernel/locking/qspinlock.c:130:9
index 13106 is out of range for type 'long unsigned int [128]'
Call Trace:
dump_stack+0xa4/0xe5
ubsan_epilogue+0x5/0x40
__ubsan_handle_out_of_bounds.cold.13+0x2a/0x34
queued_spin_lock_slowpath+0x476/0x480
do_raw_spin_lock+0x1c2/0x1d0
kyber_bio_merge+0x112/0x180
blk_mq_submit_bio+0x1f5/0x1100
submit_bio_noacct+0x7b0/0x870
submit_bio+0xc2/0x3a0
btrfs_map_bio+0x4f0/0x9d0
btrfs_submit_data_bio+0x24e/0x310
submit_one_bio+0x7f/0xb0
submit_extent_page+0xc4/0x440
__extent_writepage_io+0x2b8/0x5e0
__extent_writepage+0x28d/0x6e0
extent_write_cache_pages+0x4d7/0x7a0
extent_writepages+0xa2/0x110
do_writepages+0x8f/0x180
__writeback_single_inode+0x99/0x7f0
writeback_sb_inodes+0x34e/0x790
__writeback_inodes_wb+0x9e/0x120
wb_writeback+0x4d2/0x660
wb_workfn+0x64d/0xa10
process_one_work+0x53a/0xa80
worker_thread+0x69/0x5b0
kthread+0x20b/0x240
ret_from_fork+0x1f/0x30
Only Kyber uses the hctx, so fix it by passing the request_queue to
->bio_merge() instead. BFQ and mq-deadline just use that, and Kyber can
map the queues itself to avoid the mismatch.
Fixes: a6088845c2bf ("block: kyber: make kyber more friendly with merging")
Reported-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Link: https://lore.kernel.org/r/c7598605401a48d5cfeadebb678abd10af22b83f.1620691329.git.osandov@fb.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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For some reason we never added a description for the clk_stop
callback.
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Reviewed-by: Rander Wang <rander.wang@intel.com>
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Link: https://lore.kernel.org/r/20210511030048.25622-3-yung-chuan.liao@linux.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
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Existing devices and implementations only support the required
CLOCK_STOP_MODE0. All the code related to CLOCK_STOP_MODE1 has not
been tested and is highly questionable, with a clear confusion between
CLOCK_STOP_MODE1 and the simple clock stop state machine.
This patch removes all usages of CLOCK_STOP_MODE1 - which has no
impact on any solution - and fixes the use of the simple clock stop
state machine. The resulting code should be a lot more symmetrical and
easier to maintain.
Note that CLOCK_STOP_MODE1 is not supported in the SoundWire Device
Class specification so it's rather unlikely that we need to re-add
this mode later.
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Reviewed-by: Rander Wang <rander.wang@intel.com>
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Link: https://lore.kernel.org/r/20210511030048.25622-2-yung-chuan.liao@linux.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
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While fixing undefined behaviour the commit f60d7270c8a3 ("spi: Avoid
undefined behaviour when counting unused native CSs") missed the case
when all CSs are GPIOs and thus unused_native_cs will be evaluated to
-1 in unsigned representation. This will falsely trigger a condition
in the spi_get_gpio_descs().
Switch to signed types for *_native_cs SPI controller fields to fix above.
Fixes: f60d7270c8a3 ("spi: Avoid undefined behaviour when counting unused native CSs")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210510131242.49455-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
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Intel Merrifield SPI is actually more closer to PXA3xx. It has extended FIFO
(32 bytes) and additional registers to get or set FIFO thresholds.
Introduce new type for Intel Merrifield SPI host controllers and handle bigger
FIFO size.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210510124134.24638-15-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
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There are few places that repeat the logic of pxa_ssp_enable() and
pxa_ssp_disable(). Use them instead of open coded variants.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210510124134.24638-10-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
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"o" isn't a common asm() constraint to use; it triggers an assertion in
assert-enabled builds of LLVM that it's not recognized when targeting
aarch64 (though it appears to fall back to "m"). It's fixed in LLVM 13 now,
but there isn't really a good reason to use "o" in particular here. To
avoid causing build issues for those using assert-enabled builds of earlier
LLVM versions, the constraint needs changing.
Instead, if the point is to retain the __builtin_alloca(), make ptr appear
to "escape" via being an input to an empty inline asm block. This is
preferable anyways, since otherwise this looks like a dead store.
While the use of "r" was considered in
https://lore.kernel.org/lkml/202104011447.2E7F543@keescook/
it was only tested as an output (which looks like a dead store, and wasn't
sufficient).
Use "r" as an input constraint instead, which behaves correctly across
compilers and architectures.
Fixes: 39218ff4c625 ("stack: Optionally randomize kernel stack offset each syscall")
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Kees Cook <keescook@chromium.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Link: https://reviews.llvm.org/D100412
Link: https://bugs.llvm.org/show_bug.cgi?id=49956
Link: https://lore.kernel.org/r/20210419231741.4084415-1-keescook@chromium.org
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seliunx_xfrm_policy_lookup() is hooks of security_xfrm_policy_lookup().
The dir argument is uselss in security_xfrm_policy_lookup(). So
remove the dir argument from selinux_xfrm_policy_lookup() and
security_xfrm_policy_lookup().
Signed-off-by: Zhongjun Tan <tanzhongjun@yulong.com>
[PM: reformat the subject line]
Signed-off-by: Paul Moore <paul@paul-moore.com>
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After the introduction of the cgroup.kill there is only one call site
of cgroup_task_freeze() left: cgroup_exit(). cgroup_task_freeze() is
currently taking rcu_read_lock() to read task's cgroup flags, but
because it's always called with css_set_lock locked, the rcu protection
is excessive.
Simplify the code by inlining cgroup_task_freeze().
v2: fix build
Signed-off-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Tejun Heo <tj@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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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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func_states_equal makes a very short lived allocation for idmap,
probably because it's too large to fit on the stack. However the
function is called quite often, leading to a lot of alloc / free
churn. Replace the temporary allocation with dedicated scratch
space in struct bpf_verifier_env.
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Edward Cree <ecree.xilinx@gmail.com>
Link: https://lore.kernel.org/bpf/20210429134656.122225-4-lmb@cloudflare.com
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Once srcu_init() is called, the SRCU core will make use of delayed
workqueues, which rely on timers. However init_timers() is called
several steps after rcu_init(). This means that a call_srcu() after
rcu_init() but before init_timers() would find itself within a dangerously
uninitialized timer core.
This commit therefore creates a separate call to srcu_init() after
init_timer() completes, which ensures that we stay in early SRCU mode
until timers are safe(r).
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Uladzislau Rezki <urezki@gmail.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Neeraj Upadhyay <neeraju@codeaurora.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Joel Fernandes <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
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Since struct lockdep_map has zero size when CONFIG_DEBUG_LOCK_ALLOC=n,
this commit removes the #ifdef from the srcu_struct structure's ->dep_map.
This change will simplify further manipulations of this field.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Uladzislau Rezki <urezki@gmail.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Neeraj Upadhyay <neeraju@codeaurora.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Joel Fernandes <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
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This reverts commit dcd42591ebb8a25895b551a5297ea9c24414ba54.
The only user was RCU/nocb.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Neeraj Upadhyay <neeraju@codeaurora.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
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Make scaled_ppm_to_ppb static inline to be able to build drivers that
use this function even with PTP_1588_CLOCK disabled.
Signed-off-by: Radu Pirea (NXP OSS) <radu-nicolae.pirea@oss.nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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As pm_runtime_need_not_resume() relies also on usage_count, it can return
a different value in pm_runtime_force_suspend() compared to when called in
pm_runtime_force_resume(). Different return values can happen if anything
calls PM runtime functions in between, and causes the parent child_count
to increase on every resume.
So far I've seen the issue only for omapdrm that does complicated things
with PM runtime calls during system suspend for legacy reasons:
omap_atomic_commit_tail() for omapdrm.0
dispc_runtime_get()
wakes up 58000000.dss as it's the dispc parent
dispc_runtime_resume()
rpm_resume() increases parent child_count
dispc_runtime_put() won't idle, PM runtime suspend blocked
pm_runtime_force_suspend() for 58000000.dss, !pm_runtime_need_not_resume()
__update_runtime_status()
system suspended
pm_runtime_force_resume() for 58000000.dss, pm_runtime_need_not_resume()
pm_runtime_enable() only called because of pm_runtime_need_not_resume()
omap_atomic_commit_tail() for omapdrm.0
dispc_runtime_get()
wakes up 58000000.dss as it's the dispc parent
dispc_runtime_resume()
rpm_resume() increases parent child_count
dispc_runtime_put() won't idle, PM runtime suspend blocked
...
rpm_suspend for 58000000.dss but parent child_count is now unbalanced
Let's fix the issue by adding a flag for needs_force_resume and use it in
pm_runtime_force_resume() instead of pm_runtime_need_not_resume().
Additionally omapdrm system suspend could be simplified later on to avoid
lots of unnecessary PM runtime calls and the complexity it adds. The
driver can just use internal functions that are shared between the PM
runtime and system suspend related functions.
Fixes: 4918e1f87c5f ("PM / runtime: Rework pm_runtime_force_suspend/resume()")
Signed-off-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Tested-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Cc: 4.16+ <stable@vger.kernel.org> # 4.16+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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As found by Vineet Gupta and Linus Torvalds, gcc has somewhat unexpected
behavior when faced with overlapping unaligned pointers. The kernel's
unaligned/access-ok.h header technically invokes undefined behavior
that happens to usually work on the architectures using it, but if the
compiler optimizes code based on the assumption that undefined behavior
doesn't happen, it can create output that actually causes data corruption.
A related problem was previously found on 32-bit ARMv7, where most
instructions can be used on unaligned data, but 64-bit ldrd/strd causes
an exception. The workaround was to always use the unaligned/le_struct.h
helper instead of unaligned/access-ok.h, in commit 1cce91dfc8f7 ("ARM:
8715/1: add a private asm/unaligned.h").
The same solution should work on all other architectures as well, so
remove the access-ok.h variant and use the other one unconditionally on
all architectures, picking either the big-endian or little-endian version.
With this, the arm specific header can be removed as well, and the
only file including linux/unaligned/access_ok.h gets moved to including
the normal file.
Fortunately, this made almost no difference to the object code produced
by gcc-11. On x86, s390, powerpc, and arc, the resulting binary appears
to be identical to the previous version, while on arm64 and m68k there
are minimal differences that looks like an optimization pass went into
a different direction, usually using fewer stack spills on the new
version.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100363
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In theory, compilers should be able to work this out themselves so we
can use a simpler version based on the swab() helpers.
I have verified that this works on all supported compiler versions
(gcc-4.9 and up, clang-10 and up). Looking at the object code produced by
gcc-11, I found that the impact is mostly a change in inlining decisions
that lead to slightly larger code.
In other cases, this version produces explicit byte swaps in place of
separate byte access, or comparing against pre-swapped constants.
While the source code is clearly simpler, I have not seen an indication
of the new version actually producing better code on Arm, so maybe
we want to skip this after all. From what I can tell, gcc recognizes
the byteswap pattern in the byteshift.h header and can turn it into
explicit instructions, but it does not turn a __builtin_bswap32() back
into individual bytes when that would result in better output, e.g.
when storing a byte-reversed constant.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
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openrisc is the only architecture using the linux/unaligned/*memmove
infrastructure. There is a comment saying that this version is more
efficient, but this was added in 2011 before the openrisc gcc port
was merged upstream.
I checked a couple of files to see what the actual difference is with
the mainline gcc (9.4 and 11.1), and found that the generic header
seems to produce better code now, regardless of the gcc version.
Specifically, the be_memmove leads to allocating a stack slot and
copying the data one byte at a time, then reading the whole word
from the stack:
00000000 <test_get_unaligned_memmove>:
0: 9c 21 ff f4 l.addi r1,r1,-12
4: d4 01 10 04 l.sw 4(r1),r2
8: 8e 63 00 00 l.lbz r19,0(r3)
c: 9c 41 00 0c l.addi r2,r1,12
10: 8e 23 00 01 l.lbz r17,1(r3)
14: db e2 9f f4 l.sb -12(r2),r19
18: db e2 8f f5 l.sb -11(r2),r17
1c: 8e 63 00 02 l.lbz r19,2(r3)
20: 8e 23 00 03 l.lbz r17,3(r3)
24: d4 01 48 08 l.sw 8(r1),r9
28: db e2 9f f6 l.sb -10(r2),r19
2c: db e2 8f f7 l.sb -9(r2),r17
30: 85 62 ff f4 l.lwz r11,-12(r2)
34: 85 21 00 08 l.lwz r9,8(r1)
38: 84 41 00 04 l.lwz r2,4(r1)
3c: 44 00 48 00 l.jr r9
40: 9c 21 00 0c l.addi r1,r1,12
while the be_struct version reads each byte into a register
and does a shift to the right position:
00000000 <test_get_unaligned_struct>:
0: 9c 21 ff f8 l.addi r1,r1,-8
4: 8e 63 00 00 l.lbz r19,0(r3)
8: aa 20 00 18 l.ori r17,r0,0x18
c: e2 73 88 08 l.sll r19,r19,r17
10: 8d 63 00 01 l.lbz r11,1(r3)
14: aa 20 00 10 l.ori r17,r0,0x10
18: e1 6b 88 08 l.sll r11,r11,r17
1c: e1 6b 98 04 l.or r11,r11,r19
20: 8e 23 00 02 l.lbz r17,2(r3)
24: aa 60 00 08 l.ori r19,r0,0x8
28: e2 31 98 08 l.sll r17,r17,r19
2c: d4 01 10 00 l.sw 0(r1),r2
30: d4 01 48 04 l.sw 4(r1),r9
34: 9c 41 00 08 l.addi r2,r1,8
38: e2 31 58 04 l.or r17,r17,r11
3c: 8d 63 00 03 l.lbz r11,3(r3)
40: e1 6b 88 04 l.or r11,r11,r17
44: 84 41 00 00 l.lwz r2,0(r1)
48: 85 21 00 04 l.lwz r9,4(r1)
4c: 44 00 48 00 l.jr r9
50: 9c 21 00 08 l.addi r1,r1,8
According to Stafford Horne, the new version should in fact perform
better.
In the trivial example, the struct version is a few instructions longer,
but building a whole kernel shows an overall reduction in code size,
presumably because it now has to manage fewer stack slots:
text data bss dec hex filename
4792010 181480 82324 5055814 4d2546 vmlinux-unaligned-memmove
4790642 181480 82324 5054446 4d1fee vmlinux-unaligned-struct
Remove the memmove version completely and let openrisc use the same
code as everyone else, as a simplification.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Stafford Horne <shorne@gmail.com>
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Introduce the cgroup.kill file. It does what it says on the tin and
allows a caller to kill a cgroup by writing "1" into cgroup.kill.
The file is available in non-root cgroups.
Killing cgroups is a process directed operation, i.e. the whole
thread-group is affected. Consequently trying to write to cgroup.kill in
threaded cgroups will be rejected and EOPNOTSUPP returned. This behavior
aligns with cgroup.procs where reads in threaded-cgroups are rejected
with EOPNOTSUPP.
The cgroup.kill file is write-only since killing a cgroup is an event
not which makes it different from e.g. freezer where a cgroup
transitions between the two states.
As with all new cgroup features cgroup.kill is recursive by default.
Killing a cgroup is protected against concurrent migrations through the
cgroup mutex. To protect against forkbombs and to mitigate the effect of
racing forks a new CGRP_KILL css set lock protected flag is introduced
that is set prior to killing a cgroup and unset after the cgroup has
been killed. We can then check in cgroup_post_fork() where we hold the
css set lock already whether the cgroup is currently being killed. If so
we send the child a SIGKILL signal immediately taking it down as soon as
it returns to userspace. To make the killing of the child semantically
clean it is killed after all cgroup attachment operations have been
finalized.
There are various use-cases of this interface:
- Containers usually have a conservative layout where each container
usually has a delegated cgroup. For such layouts there is a 1:1
mapping between container and cgroup. If the container in addition
uses a separate pid namespace then killing a container usually becomes
a simple kill -9 <container-init-pid> from an ancestor pid namespace.
However, there are quite a few scenarios where that isn't true. For
example, there are containers that share the cgroup with other
processes on purpose that are supposed to be bound to the lifetime of
the container but are not in the same pidns of the container.
Containers that are in a delegated cgroup but share the pid namespace
with the host or other containers.
- Service managers such as systemd use cgroups to group and organize
processes belonging to a service. They usually rely on a recursive
algorithm now to kill a service. With cgroup.kill this becomes a
simple write to cgroup.kill.
- Userspace OOM implementations can make good use of this feature to
efficiently take down whole cgroups quickly.
- The kill program can gain a new
kill --cgroup /sys/fs/cgroup/delegated
flag to take down cgroups.
A few observations about the semantics:
- If parent and child are in the same cgroup and CLONE_INTO_CGROUP is
not specified we are not taking cgroup mutex meaning the cgroup can be
killed while a process in that cgroup is forking.
If the kill request happens right before cgroup_can_fork() and before
the parent grabs its siglock the parent is guaranteed to see the
pending SIGKILL. In addition we perform another check in
cgroup_post_fork() whether the cgroup is being killed and is so take
down the child (see above). This is robust enough and protects gainst
forkbombs. If userspace really really wants to have stricter
protection the simple solution would be to grab the write side of the
cgroup threadgroup rwsem which will force all ongoing forks to
complete before killing starts. We concluded that this is not
necessary as the semantics for concurrent forking should simply align
with freezer where a similar check as cgroup_post_fork() is performed.
For all other cases CLONE_INTO_CGROUP is required. In this case we
will grab the cgroup mutex so the cgroup can't be killed while we
fork. Once we're done with the fork and have dropped cgroup mutex we
are visible and will be found by any subsequent kill request.
- We obviously don't kill kthreads. This means a cgroup that has a
kthread will not become empty after killing and consequently no
unpopulated event will be generated. The assumption is that kthreads
should be in the root cgroup only anyway so this is not an issue.
- We skip killing tasks that already have pending fatal signals.
- Freezer doesn't care about tasks in different pid namespaces, i.e. if
you have two tasks in different pid namespaces the cgroup would still
be frozen. The cgroup.kill mechanism consequently behaves the same
way, i.e. we kill all processes and ignore in which pid namespace they
exist.
- If the caller is located in a cgroup that is killed the caller will
obviously be killed as well.
Link: https://lore.kernel.org/r/20210503143922.3093755-1-brauner@kernel.org
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: cgroups@vger.kernel.org
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Serge Hallyn <serge@hallyn.com>
Acked-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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fw_devlink expects DT device nodes with "compatible" property to have
struct devices created for them. Since the connector node might not be
populated as a device, mark it as such so that fw_devlink knows not to
wait on this fwnode being populated as a struct device.
Without this patch, USB functionality can be broken on some boards.
Fixes: f7514a663016 ("of: property: fw_devlink: Add support for remote-endpoint")
Reported-by: John Stultz <john.stultz@linaro.org>
Tested-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20210506004423.345199-1-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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DDS_RATE is Intel Quark specific definition. Move it to the rest
Intel Quark related.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210423182441.50272-7-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
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The two headers have quite different ifdeffery to prevent multiple inclusion.
Unify them with the pattern that in particular reflects their location.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210423182441.50272-6-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
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When the data structure is only referred by pointer, compiler may not need
to see the contents of the data type. Thus, we may replace header inclusions
by respective forward declarations. Due to above add missed headers as well.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210423182441.50272-5-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
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Flash OTP regions can already be read via user space. Some boards have
their serial number or MAC addresses stored in the OTP regions. Add
support for them being a (read-only) nvmem provider.
The API to read the OTP data is already in place. It distinguishes
between factory and user OTP, thus there are up to two different
providers.
Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20210424110608.15748-6-michael@walle.cc
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Until now, the of_node of the parent device is used. Some devices
provide more than just the nvmem provider. To avoid name space clashes,
add a way to allow specifying the nvmem cells in subnodes. Consider the
following example:
flash@0 {
compatible = "jedec,spi-nor";
partitions {
compatible = "fixed-partitions";
#address-cells = <1>;
#size-cells = <1>;
partition@0 {
reg = <0x000000 0x010000>;
};
};
otp {
compatible = "user-otp";
#address-cells = <1>;
#size-cells = <1>;
serial-number@0 {
reg = <0x0 0x8>;
};
};
};
There the nvmem provider might be the MTD partition or the OTP region of
the flash.
Add a new config->of_node parameter, which if set, will be used instead
of the parent's of_node.
Signed-off-by: Michael Walle <michael@walle.cc>
Acked-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20210424110608.15748-2-michael@walle.cc
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Pull block fix from Jens Axboe:
"Turns out the bio max size change still has issues, so let's get it
reverted for 5.13-rc1. We'll shake out the issues there and defer it
to 5.14 instead"
* tag 'block-5.13-2021-05-09' of git://git.kernel.dk/linux-block:
Revert "bio: limit bio max size"
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
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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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Borislav Petkov:
"A bunch of things accumulated for x86 in the last two weeks:
- Fix guest vtime accounting so that ticks happening while the guest
is running can also be accounted to it. Along with a consolidation
to the guest-specific context tracking helpers.
- Provide for the host NMI handler running after a VMX VMEXIT to be
able to run on the kernel stack correctly.
- Initialize MSR_TSC_AUX when RDPID is supported and not RDTSCP (virt
relevant - real hw supports both)
- A code generation improvement to TASK_SIZE_MAX through the use of
alternatives
- The usual misc and related cleanups and improvements"
* tag 'x86_urgent_for_v5.13_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
KVM: x86: Consolidate guest enter/exit logic to common helpers
context_tracking: KVM: Move guest enter/exit wrappers to KVM's domain
context_tracking: Consolidate guest enter/exit wrappers
sched/vtime: Move guest enter/exit vtime accounting to vtime.h
sched/vtime: Move vtime accounting external declarations above inlines
KVM: x86: Defer vtime accounting 'til after IRQ handling
context_tracking: Move guest exit vtime accounting to separate helpers
context_tracking: Move guest exit context tracking to separate helpers
KVM/VMX: Invoke NMI non-IST entry instead of IST entry
x86/cpu: Remove write_tsc() and write_rdtscp_aux() wrappers
x86/cpu: Initialize MSR_TSC_AUX if RDTSCP *or* RDPID is supported
x86/resctrl: Fix init const confusion
x86: Delete UD0, UD1 traces
x86/smpboot: Remove duplicate includes
x86/cpu: Use alternative to generate the TASK_SIZE_MAX constant
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This reverts commit cd2c7545ae1beac3b6aae033c7f31193b3255946.
Alex reports that the commit causes corruption with LUKS on ext4. Revert
it for now so that this can be investigated properly.
Link: https://lore.kernel.org/linux-block/1620493841.bxdq8r5haw.none@localhost/
Reported-by: Alex Xu (Hello71) <alex_y_xu@yahoo.ca>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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