Commit Graph

1336759 Commits

Author SHA1 Message Date
Michael Jeanson
d047e32b8d rseq/selftests: Fix namespace collision with rseq UAPI header
When the rseq UAPI header is included, 'union rseq' clashes with 'struct
rseq'. It's not the case in the rseq selftests but it does break the KVM
selftests that also include this file.

Rename 'union rseq' to 'union rseq_tls' to fix this.

Fixes: e6644c967d ("rseq/selftests: Ensure the rseq ABI TLS is actually 1024 bytes")
Reported-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/r/20250319202144.1141542-1-mjeanson@efficios.com
2025-03-19 21:26:24 +01:00
Juri Lelli
34929a070b include/{topology,cpuset}: Move dl_rebuild_rd_accounting to cpuset.h
dl_rebuild_rd_accounting() is defined in cpuset.c, so it makes more
sense to move related declarations to cpuset.h.

Implement the move.

Suggested-by: Waiman Long <llong@redhat.com>
Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Waiman Long <llong@redhat.com>
Reviewed-by: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Tested-by: Waiman Long <longman@redhat.com>
Tested-by: Jon Hunter <jonathanh@nvidia.com>
Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Link: https://lore.kernel.org/r/Z9MSOVMpU7jpVrMU@jlelli-thinkpadt14gen4.remote.csb
2025-03-17 11:23:43 +01:00
Juri Lelli
d128130f48 sched/topology: Stop exposing partition_sched_domains_locked
The are no callers of partition_sched_domains_locked() outside
topology.c.

Stop exposing such function.

Suggested-by: Waiman Long <llong@redhat.com>
Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Tested-by: Waiman Long <longman@redhat.com>
Tested-by: Jon Hunter <jonathanh@nvidia.com>
Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Link: https://lore.kernel.org/r/Z9MSC96a8FcqWV3G@jlelli-thinkpadt14gen4.remote.csb
2025-03-17 11:23:43 +01:00
Juri Lelli
ce9b3f93d7 cgroup/cpuset: Remove partition_and_rebuild_sched_domains
partition_and_rebuild_sched_domains() and partition_sched_domains() are
now equivalent.

Remove the former as a nice clean up.

Suggested-by: Waiman Long <llong@redhat.com>
Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Waiman Long <llong@redhat.com>
Reviewed-by: Shrikanth Hegde <sshegde@linux.ibm.com>
Reviewed-by: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Tested-by: Waiman Long <longman@redhat.com>
Tested-by: Jon Hunter <jonathanh@nvidia.com>
Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Link: https://lore.kernel.org/r/Z9MR4ryNDJZDzsSG@jlelli-thinkpadt14gen4.remote.csb
2025-03-17 11:23:42 +01:00
Juri Lelli
d735bab3d5 sched/topology: Remove redundant dl_clear_root_domain call
We completely clean and restore root domains bandwidth accounting after
every root domains change, so the dl_clear_root_domain() call in
partition_sched_domains_locked() is redundant.

Remove it.

Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Waiman Long <llong@redhat.com>
Reviewed-by: Shrikanth Hegde <sshegde@linux.ibm.com>
Reviewed-by: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Tested-by: Waiman Long <longman@redhat.com>
Tested-by: Jon Hunter <jonathanh@nvidia.com>
Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Link: https://lore.kernel.org/r/Z9MRtcX4tz4tcLRR@jlelli-thinkpadt14gen4.remote.csb
2025-03-17 11:23:42 +01:00
Juri Lelli
2ff899e351 sched/deadline: Rebuild root domain accounting after every update
Rebuilding of root domains accounting information (total_bw) is
currently broken on some cases, e.g. suspend/resume on aarch64. Problem
is that the way we keep track of domain changes and try to add bandwidth
back is convoluted and fragile.

Fix it by simplify things by making sure bandwidth accounting is cleared
and completely restored after root domains changes (after root domains
are again stable).

To be sure we always call dl_rebuild_rd_accounting while holding
cpuset_mutex we also add cpuset_reset_sched_domains() wrapper.

Fixes: 53916d5fd3 ("sched/deadline: Check bandwidth overflow earlier for hotplug")
Reported-by: Jon Hunter <jonathanh@nvidia.com>
Co-developed-by: Waiman Long <llong@redhat.com>
Signed-off-by: Waiman Long <llong@redhat.com>
Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Link: https://lore.kernel.org/r/Z9MRfeJKJUOyUSto@jlelli-thinkpadt14gen4.remote.csb
2025-03-17 11:23:42 +01:00
Juri Lelli
45007c6fb5 sched/deadline: Generalize unique visiting of root domains
Bandwidth checks and updates that work on root domains currently employ
a cookie mechanism for efficiency. This mechanism is very much tied to
when root domains are first created and initialized.

Generalize the cookie mechanism so that it can be used also later at
runtime while updating root domains. Also, additionally guard it with
sched_domains_mutex, since domains need to be stable while updating them
(and it will be required for further dynamic changes).

Fixes: 53916d5fd3 ("sched/deadline: Check bandwidth overflow earlier for hotplug")
Reported-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Tested-by: Waiman Long <longman@redhat.com>
Tested-by: Jon Hunter <jonathanh@nvidia.com>
Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Link: https://lore.kernel.org/r/Z9MQaiXPvEeW_v7x@jlelli-thinkpadt14gen4.remote.csb
2025-03-17 11:23:41 +01:00
Juri Lelli
56209334dd sched/topology: Wrappers for sched_domains_mutex
Create wrappers for sched_domains_mutex so that it can transparently be
used on both CONFIG_SMP and !CONFIG_SMP, as some function will need to
do.

Fixes: 53916d5fd3 ("sched/deadline: Check bandwidth overflow earlier for hotplug")
Reported-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Tested-by: Waiman Long <longman@redhat.com>
Tested-by: Jon Hunter <jonathanh@nvidia.com>
Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Link: https://lore.kernel.org/r/Z9MP5Oq9RB8jBs3y@jlelli-thinkpadt14gen4.remote.csb
2025-03-17 11:23:41 +01:00
Juri Lelli
f6147af176 sched/deadline: Ignore special tasks when rebuilding domains
SCHED_DEADLINE special tasks get a fake bandwidth that is only used to
make sure sleeping and priority inheritance 'work', but it is ignored
for runtime enforcement and admission control.

Be consistent with it also when rebuilding root domains.

Fixes: 53916d5fd3 ("sched/deadline: Check bandwidth overflow earlier for hotplug")
Reported-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Tested-by: Waiman Long <longman@redhat.com>
Tested-by: Jon Hunter <jonathanh@nvidia.com>
Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Link: https://lore.kernel.org/r/20250313170011.357208-2-juri.lelli@redhat.com
2025-03-17 11:23:41 +01:00
Sebastian Andrzej Siewior
3bffa47a02 tracing: Use preempt_model_str()
Use preempt_model_str() instead of manually conducting the preemption
model.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: "Steven Rostedt (Google)" <rostedt@goodmis.org>
Link: https://lore.kernel.org/r/20250314160810.2373416-10-bigeasy@linutronix.de
2025-03-17 11:23:41 +01:00
Sebastian Andrzej Siewior
6966cd46f6 xtensa: Rely on generic printing of preemption model
die() invokes later show_regs() -> show_regs_print_info() which prints
the current preemption model.

Remove it from the initial line.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Max Filippov <jcmvbkbc@gmail.com>
Link: https://lore.kernel.org/r/20250314160810.2373416-9-bigeasy@linutronix.de
2025-03-17 11:23:40 +01:00
Sebastian Andrzej Siewior
96389cf365 x86: Rely on generic printing of preemption model
After __die_header(), __die_body() is always invoked. There we have
show_regs() -> show_regs_print_info() which prints the current
preemption model.
Remove it from the initial line.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250314160810.2373416-8-bigeasy@linutronix.de
2025-03-17 11:23:40 +01:00
Sebastian Andrzej Siewior
b70f50be0c s390: Rely on generic printing of preemption model
die() invokes later show_regs() -> show_regs_print_info() which prints
the current preemption model.
Remove it from the initial line.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Link: https://lore.kernel.org/r/20250314160810.2373416-7-bigeasy@linutronix.de
2025-03-17 11:23:40 +01:00
Sebastian Andrzej Siewior
732ed149f7 powerpc: Rely on generic printing of preemption model
After the first printk in __die() there is show_regs() ->
show_regs_print_info() which prints the current
preemption model.

Remove the preempion model from the arch code.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Shrikanth Hegde <sshegde@linux.ibm.com>
Link: https://lore.kernel.org/r/20250314160810.2373416-6-bigeasy@linutronix.de
2025-03-17 11:23:39 +01:00
Sebastian Andrzej Siewior
4769437de0 arm64: Rely on generic printing of preemption model
__die() invokes later show_regs() -> show_regs_print_info() which prints
the current preemption model.
Remove it from the initial line.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20250314160810.2373416-5-bigeasy@linutronix.de
2025-03-17 11:23:39 +01:00
Sebastian Andrzej Siewior
03288138ba arm: Rely on generic printing of preemption model
__die() invokes later __show_regs() -> show_regs_print_info() which
prints the current preemption model.
Remove it from the initial line.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: "Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>
Link: https://lore.kernel.org/r/20250314160810.2373416-4-bigeasy@linutronix.de
2025-03-17 11:23:39 +01:00
Sebastian Andrzej Siewior
d167706f68 lib/dump_stack: Use preempt_model_str()
Use preempt_model_str() to print the current preemption model. Use
pr_warn() instead of printk() to pass a loglevel. This makes it part of
generic WARN/ BUG traces.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250314160810.2373416-3-bigeasy@linutronix.de
2025-03-17 11:23:39 +01:00
Sebastian Andrzej Siewior
8bdc5daaa0 sched: Add a generic function to return the preemption string
The individual architectures often add the preemption model to the begin
of the backtrace. This is the case on X86 or ARM64 for the "die" case
but not for regular warning. With the addition of DYNAMIC_PREEMPT for
PREEMPT_RT we end up with CONFIG_PREEMPT and CONFIG_PREEMPT_RT set
simultaneously. That means that everyone who tried to add that piece of
information gets it wrong for PREEMPT_RT because PREEMPT is checked
first.

Provide a generic function which returns the current scheduling model
considering LAZY preempt and the current state of PREEMPT_DYNAMIC.

The resulting strings are:
┏━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━┓
┃   Model   ┃  -RT -DYN    ┃     +RT -DYN      ┃     -RT +DYN       ┃     +RT +DYN      ┃
┡━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━┩
│NONE       │ NONE         │ n/a               │ PREEMPT(none)      │ n/a               │
├───────────┼──────────────┼───────────────────┼────────────────────┼───────────────────┤
│VOLUNTARY  │ VOLUNTARY    │ n/a               │ PREEMPT(voluntary) │ n/a               │
├───────────┼──────────────┼───────────────────┼────────────────────┼───────────────────┤
│FULL       │ PREEMPT      │ PREEMPT_RT        │ PREEMPT(full)      │ PREEMPT_{RT,full} │
├───────────┼──────────────┼───────────────────┼────────────────────┼───────────────────┤
│LAZY       │ PREEMPT_LAZY │ PREEMPT_{RT,LAZY} │ PREEMPT(lazy)      │ PREEMPT_{RT,lazy} │
└───────────┴──────────────┴───────────────────┴────────────────────┴───────────────────┘

[ The dynamic building of the string can lead to an empty string if the
  function is invoked simultaneously on two CPUs. ]

Co-developed-by: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Signed-off-by: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Co-developed-by: "Steven Rostedt (Google)" <rostedt@goodmis.org>
Signed-off-by: "Steven Rostedt (Google)" <rostedt@goodmis.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Shrikanth Hegde <sshegde@linux.ibm.com>
Link: https://lore.kernel.org/r/20250314160810.2373416-2-bigeasy@linutronix.de
2025-03-17 11:23:38 +01:00
Xuewen Yan
4bc4582414 sched/uclamp: Optimize sched_uclamp_used static key enabling
Repeat calls of static_branch_enable() to an already enabled
static key introduce overhead, because it calls cpus_read_lock().

Users may frequently set the uclamp value of tasks, triggering
the repeat enabling of the sched_uclamp_used static key.

Optimize this and avoid repeat calls to static_branch_enable()
by checking whether it's enabled already.

[ mingo: Rewrote the changelog for legibility ]

Signed-off-by: Xuewen Yan <xuewen.yan@unisoc.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Christian Loehle <christian.loehle@arm.com>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lore.kernel.org/r/20250219093747.2612-2-xuewen.yan@unisoc.com
2025-03-15 10:28:50 +01:00
Xuewen Yan
5fca5a4cf9 sched/uclamp: Use the uclamp_is_used() helper instead of open-coding it
Don't open-code static_branch_unlikely(&sched_uclamp_used), we have
the uclamp_is_used() wrapper around it.

[ mingo: Clean up the changelog ]

Signed-off-by: Xuewen Yan <xuewen.yan@unisoc.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Hongyan Xia <hongyan.xia2@arm.com>
Reviewed-by: Christian Loehle <christian.loehle@arm.com>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lore.kernel.org/r/20250219093747.2612-1-xuewen.yan@unisoc.com
2025-03-15 10:26:37 +01:00
Michael Jeanson
e6644c967d rseq/selftests: Ensure the rseq ABI TLS is actually 1024 bytes
Adding the aligned(1024) attribute to the definition of __rseq_abi did
not increase its size to 1024, for this attribute to impact the size of
__rseq_abi it would need to be added to the declaration of 'struct
rseq_abi'. We only want to increase the size of the TLS allocation to
ensure registration will succeed with future extended ABI. Use a union
with a dummy member to ensure we allocate 1024 bytes.

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/r/20250311192222.323453-1-mjeanson@efficios.com
2025-03-12 13:19:47 +01:00
Michael Jeanson
fd881d0a08 rseq: Fix segfault on registration when rseq_cs is non-zero
The rseq_cs field is documented as being set to 0 by user-space prior to
registration, however this is not currently enforced by the kernel. This
can result in a segfault on return to user-space if the value stored in
the rseq_cs field doesn't point to a valid struct rseq_cs.

The correct solution to this would be to fail the rseq registration when
the rseq_cs field is non-zero. However, some older versions of glibc
will reuse the rseq area of previous threads without clearing the
rseq_cs field and will also terminate the process if the rseq
registration fails in a secondary thread. This wasn't caught in testing
because in this case the leftover rseq_cs does point to a valid struct
rseq_cs.

What we can do is clear the rseq_cs field on registration when it's
non-zero which will prevent segfaults on registration and won't break
the glibc versions that reuse rseq areas on thread creation.

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20250306211223.109455-1-mjeanson@efficios.com
2025-03-06 22:26:49 +01:00
Ingo Molnar
82354fce16 Merge branch 'sched/urgent' into sched/core, to pick up dependent commits
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2025-03-06 22:26:36 +01:00
Shrikanth Hegde
b1536481c8 sched/rt: Update limit of sched_rt sysctl in documentation
By default fair_server dl_server allocates 5% of the bandwidth to the root
domain. Due to this writing any value less than 5% fails due to -EBUSY:

  $ cat /proc/sys/kernel/sched_rt_period_us
  1000000

  $ echo 49999 > /proc/sys/kernel/sched_rt_runtime_us
  -bash: echo: write error: Device or resource busy

  $ echo 50000 > /proc/sys/kernel/sched_rt_runtime_us
  $

Since the sched_rt_runtime_us allows -1 as the minimum, put this
restriction in the documentation.

One should check average of runtime/period in
/sys/kernel/debug/sched/fair_server/cpuX/* for exact value.

Signed-off-by: Shrikanth Hegde <sshegde@linux.ibm.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Juri Lelli <juri.lelli@redhat.com>
Link: https://lore.kernel.org/r/20250306052954.452005-3-sshegde@linux.ibm.com
2025-03-06 10:21:31 +01:00
Shrikanth Hegde
14672f059d sched/deadline: Use online cpus for validating runtime
The ftrace selftest reported a failure because writing -1 to
sched_rt_runtime_us returns -EBUSY. This happens when the possible
CPUs are different from active CPUs.

Active CPUs are part of one root domain, while remaining CPUs are part
of def_root_domain. Since active cpumask is being used, this results in
cpus=0 when a non active CPUs is used in the loop.

Fix it by looping over the online CPUs instead for validating the
bandwidth calculations.

Signed-off-by: Shrikanth Hegde <sshegde@linux.ibm.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Juri Lelli <juri.lelli@redhat.com>
Link: https://lore.kernel.org/r/20250306052954.452005-2-sshegde@linux.ibm.com
2025-03-06 10:21:31 +01:00
Zecheng Li
3b4035ddbf sched/fair: Fix potential memory corruption in child_cfs_rq_on_list
child_cfs_rq_on_list attempts to convert a 'prev' pointer to a cfs_rq.
This 'prev' pointer can originate from struct rq's leaf_cfs_rq_list,
making the conversion invalid and potentially leading to memory
corruption. Depending on the relative positions of leaf_cfs_rq_list and
the task group (tg) pointer within the struct, this can cause a memory
fault or access garbage data.

The issue arises in list_add_leaf_cfs_rq, where both
cfs_rq->leaf_cfs_rq_list and rq->leaf_cfs_rq_list are added to the same
leaf list. Also, rq->tmp_alone_branch can be set to rq->leaf_cfs_rq_list.

This adds a check `if (prev == &rq->leaf_cfs_rq_list)` after the main
conditional in child_cfs_rq_on_list. This ensures that the container_of
operation will convert a correct cfs_rq struct.

This check is sufficient because only cfs_rqs on the same CPU are added
to the list, so verifying the 'prev' pointer against the current rq's list
head is enough.

Fixes a potential memory corruption issue that due to current struct
layout might not be manifesting as a crash but could lead to unpredictable
behavior when the layout changes.

Fixes: fdaba61ef8 ("sched/fair: Ensure that the CFS parent is added after unthrottling")
Signed-off-by: Zecheng Li <zecheng@google.com>
Reviewed-and-tested-by: K Prateek Nayak <kprateek.nayak@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lore.kernel.org/r/20250304214031.2882646-1-zecheng@google.com
2025-03-05 17:30:54 +01:00
Nysal Jan K.A.
7ab02bd36e sched/membarrier: Fix redundant load of membarrier_state
On architectures where ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
is not selected, sync_core_before_usermode() is a no-op.
In membarrier_mm_sync_core_before_usermode() the compiler does not
eliminate redundant branches and load of mm->membarrier_state
for this case as the atomic_read() cannot be optimized away.

Here's a snippet of the code generated for finish_task_switch() on powerpc
prior to this change:

  1b786c:   ld      r26,2624(r30)   # mm = rq->prev_mm;
  .......
  1b78c8:   cmpdi   cr7,r26,0
  1b78cc:   beq     cr7,1b78e4 <finish_task_switch+0xd0>
  1b78d0:   ld      r9,2312(r13)    # current
  1b78d4:   ld      r9,1888(r9)     # current->mm
  1b78d8:   cmpd    cr7,r26,r9
  1b78dc:   beq     cr7,1b7a70 <finish_task_switch+0x25c>
  1b78e0:   hwsync
  1b78e4:   cmplwi  cr7,r27,128
  .......
  1b7a70:   lwz     r9,176(r26)     # atomic_read(&mm->membarrier_state)
  1b7a74:   b       1b78e0 <finish_task_switch+0xcc>

This was found while analyzing "perf c2c" reports on kernels prior
to commit c1753fd02a ("mm: move mm_count into its own cache line")
where mm_count was false sharing with membarrier_state.

There is a minor improvement in the size of finish_task_switch().
The following are results from bloat-o-meter for ppc64le:

  GCC 7.5.0
  ---------
  add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-32 (-32)
  Function                                     old     new   delta
  finish_task_switch                           884     852     -32

  GCC 12.2.1
  ----------
  add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-32 (-32)
  Function                                     old     new   delta
  finish_task_switch.isra                      852     820     -32

  LLVM 17.0.6
  -----------
  add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-36 (-36)
  Function                                     old     new   delta
  rt_mutex_schedule                            120     104     -16
  finish_task_switch                           792     772     -20

Results on aarch64:

  GCC 14.1.1
  ----------
  add/remove: 0/2 grow/shrink: 1/1 up/down: 4/-60 (-56)
  Function                                     old     new   delta
  get_nohz_timer_target                        352     356      +4
  e843419@0b02_0000d7e7_408                      8       -      -8
  e843419@01bb_000021d2_868                      8       -      -8
  finish_task_switch.isra                      592     548     -44

Signed-off-by: Nysal Jan K.A. <nysal@linux.ibm.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reviewed-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Segher Boessenkool <segher@kernel.crashing.org>
Link: https://lore.kernel.org/r/20250303060457.531293-1-nysal@linux.ibm.com
2025-03-03 11:25:40 +01:00
Linus Torvalds
7eb172143d Linux 6.14-rc5 v6.14-rc5 2025-03-02 11:48:20 -08:00
Linus Torvalds
b91872c569 Merge tag 'dmaengine-fix-6.14' of git://git.kernel.org/pub/scm/linux/kernel/git/vkoul/dmaengine
Pull dmaengine fixes from Vinod Koul:

 - tegra210 div_u64 divison and max page fixes

 - revert Qualcomm unavailable register workaround which is causing
   regression, fixes have been proposed but still gaps are present so
   revert this for now

* tag 'dmaengine-fix-6.14' of git://git.kernel.org/pub/scm/linux/kernel/git/vkoul/dmaengine:
  dmaengine: Revert "dmaengine: qcom: bam_dma: Avoid writing unavailable register"
  dmaengine: tegra210-adma: check for adma max page
  dmaengine: tegra210-adma: Use div_u64 for 64 bit division
2025-03-02 10:08:45 -08:00
Linus Torvalds
a760b10147 Merge tag 'phy-fixes-6.14' of git://git.kernel.org/pub/scm/linux/kernel/git/phy/linux-phy
Pull phy fixes from Vinod Koul:

 - rockchip phy kconfig dependency fix with USB_COMMON and regression
   fix for old DT

 - stm32 phy overflow assertion fix

 - exonysfs phy refclk masks fix and power gate on exit fix

 - freescale fix for clock dividor valid range

 - TI regmap syscon register fix

 - tegra reset registers on init fix

* tag 'phy-fixes-6.14' of git://git.kernel.org/pub/scm/linux/kernel/git/phy/linux-phy:
  phy: tegra: xusb: reset VBUS & ID OVERRIDE
  phy: ti: gmii-sel: Do not use syscon helper to build regmap
  phy: exynos5-usbdrd: gs101: ensure power is gated to SS phy in phy_exit()
  phy: freescale: fsl-samsung-hdmi: Limit PLL lock detection clock divider to valid range
  phy: exynos5-usbdrd: fix MPLL_MULTIPLIER and SSC_REFCLKSEL masks in refclk
  phy: stm32: Fix constant-value overflow assertion
  phy: rockchip: naneng-combphy: compatible reset with old DT
  phy: rockchip: fix Kconfig dependency more
2025-03-02 09:54:25 -08:00
Linus Torvalds
1973160c90 Merge tag 'gpio-fixes-for-v6.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux
Pull gpio fix from Bartosz Golaszewski:

 - fix a buggy get_direction() retval check

* tag 'gpio-fixes-for-v6.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux:
  gpiolib: Fix Oops in gpiod_direction_input_nonotify()
2025-03-02 04:35:39 -08:00
Linus Torvalds
ebb7d37abf Merge tag 'mips-fixes_6.14_2' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux
Pull MIPS fix from Thomas Bogendoerfer:
 "Fix fallout of /scripts/sorttable cleanup"

* tag 'mips-fixes_6.14_2' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux:
  MIPS: Ignore relocs against __ex_table for relocatable kernel
2025-03-02 04:33:15 -08:00
Linus Torvalds
ece144f151 Merge tag 'v6.14-rc4-smb3-client-fix' of git://git.samba.org/sfrench/cifs-2.6
Pull smb client fix from Steve French:
 "Fix SMB1 netfs client regression"

* tag 'v6.14-rc4-smb3-client-fix' of git://git.samba.org/sfrench/cifs-2.6:
  cifs: Fix the smb1 readv callback to correctly call netfs
2025-03-01 16:10:31 -08:00
Linus Torvalds
9d20040d71 Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 fixes from Will Deacon:
 "Ryan's been hard at work finding and fixing mm bugs in the arm64 code,
  so here's a small crop of fixes for -rc5.

  The main changes are to fix our zapping of non-present PTEs for
  hugetlb entries created using the contiguous bit in the page-table
  rather than a block entry at the level above. Prior to these fixes, we
  were pulling the contiguous bit back out of the PTE in order to
  determine the size of the hugetlb page but this is clearly bogus if
  the thing isn't present and consequently both the clearing of the
  PTE(s) and the TLB invalidation were unreliable.

  Although the problem was found by code inspection, we really don't
  want this sitting around waiting to trigger and the changes are CC'd
  to stable accordingly.

  Note that the diffstat looks a lot worse than it really is;
  huge_ptep_get_and_clear() now takes a size argument from the core code
  and so all the arch implementations of that have been updated in a
  pretty mechanical fashion.

   - Fix a sporadic boot failure due to incorrect randomization of the
     linear map on systems that support it

   - Fix the zapping (both clearing the entries *and* invalidating the
     TLB) of hugetlb PTEs constructed using the contiguous bit"

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: hugetlb: Fix flush_hugetlb_tlb_range() invalidation level
  arm64: hugetlb: Fix huge_ptep_get_and_clear() for non-present ptes
  mm: hugetlb: Add huge page size param to huge_ptep_get_and_clear()
  arm64/mm: Fix Boot panic on Ampere Altra
2025-03-01 13:44:51 -08:00
Linus Torvalds
b4b215cf33 Merge tag 'i2c-for-6.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux
Pull i2c fixes from Wolfram Sang:
 "All driver fixes this time:

   - fix interrupt initialization sequence (npcm)

   - fix frequency setting (ls2x)

   - re-enable interrupts properly at irq handler's exit (amd-asf)"

* tag 'i2c-for-6.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  i2c: amd-asf: Fix EOI register write to enable successive interrupts
  i2c: ls2x: Fix frequency division register access
  i2c: npcm: disable interrupt enable bit before devm_request_irq
2025-03-01 12:43:11 -08:00
Linus Torvalds
df87d843c6 Merge tag 'ata-6.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/libata/linux
Pull ata fixes from Niklas Cassel:

 - Fix a regression where the enablement of the PHYs would be skipped
   for device trees without any port child nodes (me)

 - Revert ATA_QUIRK_NOLPM for Samsung SSD 870 QVO drives, as it stops
   systems from entering lower package states. LPM works on newer
   firmware versions. We will need a more refined quirk that only
   targets the older firmware versions (me)

* tag 'ata-6.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/libata/linux:
  Revert "ata: libata-core: Add ATA_QUIRK_NOLPM for Samsung SSD 870 QVO drives"
  ata: ahci: Make ahci_ignore_port() handle empty mask_port_map
2025-03-01 08:59:29 -08:00
Linus Torvalds
209cd6f2ca Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull kvm fixes from Paolo Bonzini:
 "ARM:

   - Fix TCR_EL2 configuration to not use the ASID in TTBR1_EL2 and not
     mess-up T1SZ/PS by using the HCR_EL2.E2H==0 layout.

   - Bring back the VMID allocation to the vcpu_load phase, ensuring
     that we only setup VTTBR_EL2 once on VHE. This cures an ugly race
     that would lead to running with an unallocated VMID.

  RISC-V:

   - Fix hart status check in SBI HSM extension

   - Fix hart suspend_type usage in SBI HSM extension

   - Fix error returned by SBI IPI and TIME extensions for unsupported
     function IDs

   - Fix suspend_type usage in SBI SUSP extension

   - Remove unnecessary vcpu kick after injecting interrupt via IMSIC
     guest file

  x86:

   - Fix an nVMX bug where KVM fails to detect that, after nested
     VM-Exit, L1 has a pending IRQ (or NMI).

   - To avoid freeing the PIC while vCPUs are still around, which would
     cause a NULL pointer access with the previous patch, destroy vCPUs
     before any VM-level destruction.

   - Handle failures to create vhost_tasks"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  kvm: retry nx_huge_page_recovery_thread creation
  vhost: return task creation error instead of NULL
  KVM: nVMX: Process events on nested VM-Exit if injectable IRQ or NMI is pending
  KVM: x86: Free vCPUs before freeing VM state
  riscv: KVM: Remove unnecessary vcpu kick
  KVM: arm64: Ensure a VMID is allocated before programming VTTBR_EL2
  KVM: arm64: Fix tcr_el2 initialisation in hVHE mode
  riscv: KVM: Fix SBI sleep_type use
  riscv: KVM: Fix SBI TIME error generation
  riscv: KVM: Fix SBI IPI error generation
  riscv: KVM: Fix hart suspend_type use
  riscv: KVM: Fix hart suspend status check
2025-03-01 08:48:53 -08:00
Niklas Cassel
a2f925a2f6 Revert "ata: libata-core: Add ATA_QUIRK_NOLPM for Samsung SSD 870 QVO drives"
This reverts commit cc77e2ce18.

It was reported that adding ATA_QUIRK_NOLPM for Samsung SSD 870 QVO drives
breaks entering lower package states for certain systems.

It turns out that Samsung SSD 870 QVO actually has working LPM when using
a recent SSD firmware version.

The author of commit cc77e2ce18 ("ata: libata-core: Add ATA_QUIRK_NOLPM
for Samsung SSD 870 QVO drives") reported himself that only older SSD
firmware versions have broken LPM:
https://lore.kernel.org/stable/93c10d38-718c-459d-84a5-4d87680b4da7@debian.org/

Unfortunately, he did not specify which older firmware version he was using
which had broken LPM.

Let's revert this quirk, which has FW version field specified as NULL
(which means that it applies for all Samsung SSD 870 QVO firmware versions)
for now. Once the author reports which older firmware version(s) that are
broken, we can create a more fine grained quirk, which populates the FW
version field accordingly.

Fixes: cc77e2ce18 ("ata: libata-core: Add ATA_QUIRK_NOLPM for Samsung SSD 870 QVO drives")
Reported-by: Dieter Mummenschanz <dmummenschanz@web.de>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=219747
Link: https://lore.kernel.org/r/20250228122603.91814-2-cassel@kernel.org
Signed-off-by: Niklas Cassel <cassel@kernel.org>
2025-03-01 10:18:25 +01:00
Keith Busch
916b7f42b3 kvm: retry nx_huge_page_recovery_thread creation
A VMM may send a non-fatal signal to its threads, including vCPU tasks,
at any time, and thus may signal vCPU tasks during KVM_RUN.  If a vCPU
task receives the signal while its trying to spawn the huge page recovery
vhost task, then KVM_RUN will fail due to copy_process() returning
-ERESTARTNOINTR.

Rework call_once() to mark the call complete if and only if the called
function succeeds, and plumb the function's true error code back to the
call_once() invoker.  This provides userspace with the correct, non-fatal
error code so that the VMM doesn't terminate the VM on -ENOMEM, and allows
subsequent KVM_RUN a succeed by virtue of retrying creation of the NX huge
page task.

Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
[implemented the kvm user side]
Signed-off-by: Keith Busch <kbusch@kernel.org>
Message-ID: <20250227230631.303431-3-kbusch@meta.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2025-03-01 02:54:18 -05:00
Keith Busch
cb380909ae vhost: return task creation error instead of NULL
Lets callers distinguish why the vhost task creation failed. No one
currently cares why it failed, so no real runtime change from this
patch, but that will not be the case for long.

Signed-off-by: Keith Busch <kbusch@kernel.org>
Message-ID: <20250227230631.303431-2-kbusch@meta.com>
Reviewed-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2025-03-01 02:52:52 -05:00
Linus Torvalds
03d38806a9 Merge tag 'thermal-6.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull thermal control fixes from Rafael Wysocki:
 "These fix the processing of DT thermal properties and the Power
  Allocator thermal governor:

   - Fix parsing cooling-maps in DT for trip points with more than one
     cooling device (Rafael Wysocki)

   - Fix granted_power computation in the Power Allocator thermal
     governor and make it update total_weight on configuration changes
     after the thermal zone has been registered (Yu-Che Cheng)"

* tag 'thermal-6.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  thermal: gov_power_allocator: Update total_weight on bind and cdev updates
  thermal/of: Fix cdev lookup in thermal_of_should_bind()
  thermal: gov_power_allocator: Fix incorrect calculation in divvy_up_power()
2025-02-28 18:02:23 -08:00
Linus Torvalds
14ebe69091 Merge tag 'pm-6.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management fix from Rafael Wysocki:
 "Fix the handling of processors that stop the TSC in deeper C-states in
  the intel_idle driver (Thomas Gleixner)"

* tag 'pm-6.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  intel_idle: Handle older CPUs, which stop the TSC in deeper C states, correctly
2025-02-28 17:40:27 -08:00
Linus Torvalds
7a5668899f Merge tag 'x86-urgent-2025-02-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Ingo Molnar:

 - Fix conflicts between devicetree and ACPI SMP discovery & setup

 - Fix a warm-boot lockup on AMD SC1100 SoC systems

 - Fix a W=1 build warning related to x86 IRQ trace event setup

 - Fix a kernel-doc warning

* tag 'x86-urgent-2025-02-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/entry: Fix kernel-doc warning
  x86/irq: Define trace events conditionally
  x86/CPU: Fix warm boot hang regression on AMD SC1100 SoC systems
  x86/of: Don't use DTB for SMP setup if ACPI is enabled
2025-02-28 17:05:22 -08:00
Linus Torvalds
d203484f25 Merge tag 'sched-urgent-2025-02-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fix from Ingo Molnar:
 "Prevent cond_resched() based preemption when interrupts are disabled,
  on PREEMPT_NONE and PREEMPT_VOLUNTARY kernels"

* tag 'sched-urgent-2025-02-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/core: Prevent rescheduling when interrupts are disabled
2025-02-28 17:00:16 -08:00
Linus Torvalds
766331f286 Merge tag 'perf-urgent-2025-02-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf event fixes from Ingo Molnar:
 "Miscellaneous perf events fixes and a minor HW enablement change:

   - Fix missing RCU protection in perf_iterate_ctx()

   - Fix pmu_ctx_list ordering bug

   - Reject the zero page in uprobes

   - Fix a family of bugs related to low frequency sampling

   - Add Intel Arrow Lake U CPUs to the generic Arrow Lake RAPL support
     table

   - Fix a lockdep-assert false positive in uretprobes"

* tag 'perf-urgent-2025-02-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  uprobes: Remove too strict lockdep_assert() condition in hprobe_expire()
  perf/x86/rapl: Add support for Intel Arrow Lake U
  perf/x86/intel: Use better start period for frequency mode
  perf/core: Fix low freq setting via IOC_PERIOD
  perf/x86: Fix low freqency setting issue
  uprobes: Reject the shared zeropage in uprobe_write_opcode()
  perf/core: Order the PMU list to fix warning about unordered pmu_ctx_list
  perf/core: Add RCU read lock protection to perf_iterate_ctx()
2025-02-28 16:52:10 -08:00
Linus Torvalds
ad69e02128 Merge tag 'objtool-urgent-2025-02-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull objtool fixes from Ingo Molnar:
 "Fix an objtool false positive, and objtool related build warnings that
  happens on PIE-enabled architectures such as LoongArch"

* tag 'objtool-urgent-2025-02-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  objtool: Add bch2_trans_unlocked_or_in_restart_error() to bcachefs noreturns
  objtool: Fix C jump table annotations for Clang
  vmlinux.lds: Ensure that const vars with relocations are mapped R/O
2025-02-28 16:45:36 -08:00
Linus Torvalds
405a41d759 Merge tag 'locking-urgent-2025-02-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking fix from Ingo Molnar:
 "Fix an rcuref_put() slowpath race"

* tag 'locking-urgent-2025-02-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  rcuref: Plug slowpath race in rcuref_put()
2025-02-28 16:07:18 -08:00
Linus Torvalds
5c44ddaf7d Merge tag 'trace-v6.14-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull tracing fixes from Steven Rostedt:

 - Fix crash from bad histogram entry

   An error path in the histogram creation could leave an entry in a
   link list that gets freed. Then when a new entry is added it can
   cause a u-a-f bug. This is fixed by restructuring the code so that
   the histogram is consistent on failure and everything is cleaned up
   appropriately.

 - Fix fprobe self test

   The fprobe self test relies on no function being attached by ftrace.
   BPF programs can attach to functions via ftrace and systemd now does
   so. This causes those functions to appear in the enabled_functions
   list which holds all functions attached by ftrace. The selftest also
   uses that file to see if functions are being connected correctly. It
   counts the functions in the file, but if there's already functions in
   the file, it fails. Instead, add the number of functions in the file
   at the start of the test to all the calculations during the test.

 - Fix potential division by zero of the function profiler stddev

   The calculated divisor that calculates the standard deviation of the
   function times can overflow. If the overflow happens to land on zero,
   that can cause a division by zero. Check for zero from the
   calculation before doing the division.

   TODO: Catch when it ever overflows and report it accordingly. For
   now, just prevent the system from crashing.

* tag 'trace-v6.14-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ftrace: Avoid potential division by zero in function_stat_show()
  selftests/ftrace: Let fprobe test consider already enabled functions
  tracing: Fix bad hist from corrupting named_triggers list
2025-02-28 15:43:32 -08:00
Linus Torvalds
3d7dc86581 Merge tag 'iommu-fixes-v6.14-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/iommu/linux
Pull iommu fixes from Joerg Roedel:

 - Intel VT-d fixes:
     - Fix suspicious RCU usage splat
     - Fix passthrough for devices under PCIe-PCI bridge

 - AMD-Vi fix:
     - Fix to preserve bits when updating device table entries

* tag 'iommu-fixes-v6.14-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/iommu/linux:
  iommu/vt-d: Fix suspicious RCU usage
  iommu/vt-d: Remove device comparison in context_setup_pass_through_cb
  iommu/amd: Preserve default DTE fields when updating Host Page Table Root
2025-02-28 15:39:17 -08:00
Thomas Gleixner
c157d35146 intel_idle: Handle older CPUs, which stop the TSC in deeper C states, correctly
The Intel idle driver is preferred over the ACPI processor idle driver,
but fails to implement the work around for Core2 generation CPUs, where
the TSC stops in C2 and deeper C-states. This causes stalls and boot
delays, when the clocksource watchdog does not catch the unstable TSC
before the CPU goes deep idle for the first time.

The ACPI driver marks the TSC unstable when it detects that the CPU
supports C2 or deeper and the CPU does not have a non-stop TSC.

Add the equivivalent work around to the Intel idle driver to cure that.

Fixes: 18734958e9 ("intel_idle: Use ACPI _CST for processor models without C-state tables")
Reported-by: Fab Stz <fabstz-it@yahoo.fr>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Fab Stz <fabstz-it@yahoo.fr>
Cc: All applicable <stable@vger.kernel.org>
Closes: https://lore.kernel.org/all/10cf96aa-1276-4bd4-8966-c890377030c3@yahoo.fr
Link: https://patch.msgid.link/87bjupfy7f.ffs@tglx
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2025-02-28 22:04:26 +01:00