Merge updates related to system suspend and hibernation for 6.19-rc1:
- Replace snprintf() with scnprintf() in show_trace_dev_match()
(Kaushlendra Kumar)
- Fix memory allocation error handling in pm_vt_switch_required()
(Malaya Kumar Rout)
- Introduce CALL_PM_OP() macro and use it to simplify code in
generic PM operations (Kaushlendra Kumar)
- Add module param to backtrace all CPUs in the device power management
watchdog (Sergey Senozhatsky)
- Rework message printing in swsusp_save() (Rafael Wysocki)
- Make it possible to change the number of hibernation compression
threads (Xueqin Luo)
- Clarify that only cgroup1 freezer uses PM freezer (Tejun Heo)
- Add document on debugging shutdown hangs to PM documentation and
correct a mistaken configuration option in it (Mario Limonciello)
- Shut down wakeup source timer before removing the wakeup source from
the list (Kaushlendra Kumar, Rafael Wysocki)
- Introduce new PMSG_POWEROFF event for system shutdown handling with
the help of PM device callbacks (Mario Limonciello)
- Make pm_test delay interruptible by wakeup events (Riwen Lu)
- Clean up kernel-doc comment style usage in the core hibernation
code and remove unuseful comments from it (Sunday Adelodun, Rafael
Wysocki)
- Add support for handling wakeup events and aborting the suspend
process while it is syncing file systems (Samuel Wu, Rafael Wysocki)
* pm-sleep: (21 commits)
PM: hibernate: Extra cleanup of comments in swap handling code
PM: sleep: Call pm_sleep_fs_sync() instead of ksys_sync_helper()
PM: sleep: Add support for wakeup during filesystem sync
PM: hibernate: Clean up kernel-doc comment style usage
PM: suspend: Make pm_test delay interruptible by wakeup events
usb: sl811-hcd: Add PM_EVENT_POWEROFF into suspend callbacks
scsi: Add PM_EVENT_POWEROFF into suspend callbacks
PM: Introduce new PMSG_POWEROFF event
PM: wakeup: Update after recent wakeup source removal ordering change
PM: wakeup: Delete timer before removing wakeup source from list
Documentation: power: Correct a mistaken configuration option
Documentation: power: Add document on debugging shutdown hangs
freezer: Clarify that only cgroup1 freezer uses PM freezer
PM: hibernate: add sysfs interface for hibernate_compression_threads
PM: hibernate: make compression threads configurable
PM: hibernate: dynamically allocate crc->unc_len/unc for configurable threads
PM: hibernate: Rework message printing in swsusp_save()
PM: dpm_watchdog: add module param to backtrace all CPUs
PM: sleep: Introduce CALL_PM_OP() macro to simplify code
PM: console: Fix memory allocation error handling in pm_vt_switch_required()
...
Pull vfs fixes from Christian Brauner:
- Fix unitialized variable in statmount_string()
- Fix hostfs mounting when passing host root during boot
- Fix dynamic lookup to fail on cell lookup failure
- Fix missing file type when reading bfs inodes from disk
- Enforce checking of sb_min_blocksize() calls and update all callers
accordingly
- Restore write access before closing files opened by open_exec() in
binfmt_misc
- Always freeze efivarfs during suspend/hibernate cycles
- Fix statmount()'s and listmount()'s grab_requested_mnt_ns() helper to
actually allow mount namespace file descriptor in addition to mount
namespace ids
- Fix tmpfs remount when noswap is specified
- Switch Landlock to iput_not_last() to remove false-positives from
might_sleep() annotations in iput()
- Remove dead node_to_mnt_ns() code
- Ensure that per-queue kobjects are successfully created
* tag 'vfs-6.18-rc7.fixes' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs:
landlock: fix splats from iput() after it started calling might_sleep()
fs: add iput_not_last()
shmem: fix tmpfs reconfiguration (remount) when noswap is set
fs/namespace: correctly handle errors returned by grab_requested_mnt_ns
power: always freeze efivarfs
binfmt_misc: restore write access before closing files opened by open_exec()
block: add __must_check attribute to sb_min_blocksize()
virtio-fs: fix incorrect check for fsvq->kobj
xfs: check the return value of sb_min_blocksize() in xfs_fs_fill_super
isofs: check the return value of sb_min_blocksize() in isofs_fill_super
exfat: check return value of sb_min_blocksize in exfat_read_boot_sector
vfat: fix missing sb_min_blocksize() return value checks
mnt: Remove dead code which might prevent from building
bfs: Reconstruct file type when loading from disk
afs: Fix dynamic lookup to fail on cell lookup failure
hostfs: Fix only passing host root in boot stage with new mount
fs: Fix uninitialized 'offp' in statmount_string()
Modify the suspend_test() function to allow the test delay to be
interrupted by wakeup events.
This improves the responsiveness of the system during suspend testing
when wakeup events occur, allowing the suspend process to proceed
without waiting for the full test delay to complete when wakeup events
are detected.
Additionally, using msleep() instead of mdelay() avoids potential soft
lockup "CPU stuck" issues when long test delays are configured.
Co-developed-by: xiongxin <xiongxin@kylinos.cn>
Signed-off-by: xiongxin <xiongxin@kylinos.cn>
Signed-off-by: Riwen Lu <luriwen@kylinos.cn>
[ rjw: Changelog edits ]
Link: https://patch.msgid.link/20251113012638.1362013-1-luriwen@kylinos.cn
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Move pm_wakeup_clear() to the same location as other functions that do
bookkeeping prior to suspend_prepare().
Since calling pm_wakeup_clear() is a prerequisite to setting up for
suspend and enabling functionalities of suspend (like aborting during
suspend), moving pm_wakeup_clear() higher up the call stack makes its
intent more clear and obvious that it is called prior to
suspend_prepare().
After this change, there is a slightly larger window when abort events
can be registered, but otherwise suspend functionality is the same.
Suggested-by: Saravana Kannan <saravanak@google.com>
Signed-off-by: Samuel Wu <wusamuel@google.com>
Link: https://patch.msgid.link/20250821004237.2712312-2-wusamuel@google.com
Reviewed-by: Saravana Kannan <saravanak@google.com>
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The recently introduced support for freezing filesystems during system
suspend included calls to filesystems_freeze() in both suspend_prepare()
and enter_state(), as well as calls to filesystems_thaw() in both
suspend_finish() and the Unlock path in enter_state(). These are
redundant.
Moreover, calling filesystems_freeze() twice, from both suspend_prepare()
and enter_state(), leads to a black screen and makes the system unable
to resume in some cases.
Address this as follows:
- filesystems_freeze() is already called in suspend_prepare(), which
is the proper and consistent place to handle pre-suspend operations.
The second call in enter_state() is unnecessary and so remove it.
- filesystems_thaw() is invoked in suspend_finish(), which covers
successful suspend/resume paths. In the failure case, add a call
to filesystems_thaw() only when needed, avoiding the duplicate call
in the general Unlock path.
This change simplifies the suspend code and avoids repeated freeze/thaw
calls, while preserving correct ordering and behavior.
Fixes: eacfbf7419 ("power: freeze filesystems during suspend/resume")
Signed-off-by: Zihuan Zhang <zhangzihuan@kylinos.cn>
Link: https://patch.msgid.link/20250712030824.81474-1-zhangzihuan@kylinos.cn
[ rjw: Changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The pm_restore_gfp_mask() call added by commit 12ffc3b151 ("PM:
Restrict swap use to later in the suspend sequence") to
suspend_devices_and_enter() is done too early because it takes
place before calling dpm_resume() in dpm_resume_end() and some
swap-backing devices may not be ready at that point. Moreover,
dpm_resume_end() called subsequently in the same code path invokes
pm_restore_gfp_mask() again and calling it twice in a row is
pointless.
Drop the misplaced pm_restore_gfp_mask() call from
suspend_devices_and_enter() to address this issue.
Fixes: 12ffc3b151 ("PM: Restrict swap use to later in the suspend sequence")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Link: https://patch.msgid.link/2810409.mvXUDI8C0e@rjwysocki.net
[ rjw: Changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Now all the pieces are in place to actually allow the power subsystem
to freeze/thaw filesystems during suspend/resume. Filesystems are only
frozen and thawed if the power subsystem does actually own the freeze.
We could bubble up errors and fail suspend/resume if the error isn't
EBUSY (aka it's already frozen) but I don't think that this is worth it.
Filesystem freezing during suspend/resume is best-effort. If the user
has 500 ext4 filesystems mounted and 4 fail to freeze for whatever
reason then we simply skip them.
What we have now is already a big improvement and let's see how we fare
with it before making our lives even harder (and uglier) than we have
to.
We add a new sysctl know /sys/power/freeze_filesystems that will allow
userspace to freeze filesystems during suspend/hibernate. For now it
defaults to off. The thaw logic doesn't require checking whether
freezing is enabled because the power subsystem exclusively owns frozen
filesystems for the duration of suspend/hibernate and is able to skip
filesystems it doesn't need to freeze.
Also it is technically possible that filesystem
filesystem_freeze_enabled is true and power freezes the filesystems but
before freezing all processes another process disables
filesystem_freeze_enabled. If power were to place the filesystems_thaw()
call under filesystems_freeze_enabled it would fail to thaw the
fileystems it frozw. The exclusive holder mechanism makes it possible to
iterate through the list without any concern making sure that no
filesystems are left frozen.
Link: https://lore.kernel.org/r/20250402-work-freeze-v2-3-6719a97b52ac@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
Pull printk updates from Petr Mladek:
- New option "printk.debug_non_panic_cpus" allows to store printk
messages from non-panic CPUs during panic. It might be useful when
panic() fails. It is disabled by default because it increases the
chance to see the messages printed before panic() and on the
panic-CPU.
- New build option "CONFIG_NULL_TTY_DEFAULT_CONSOLE" allows to build
kernel without the virtual terminal support which prefers ttynull
over serial console.
- Do not unblank suspended consoles.
- Some code clean up.
* tag 'printk-for-6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux:
printk/panic: Add option to allow non-panic CPUs to write to the ring buffer.
printk: Add an option to allow ttynull to be a default console device
printk: Check CON_SUSPEND when unblanking a console
printk: Rename console_start to console_resume
printk: Rename console_stop to console_suspend
printk: Rename resume_console to console_resume_all
printk: Rename suspend_console to console_suspend_all
The calls to cpus_read_lock|unlock() protects us from getting CPUS
hotplugged, while entering suspend-to-idle. However, when s2idle_enter() is
called we should be far beyond the point when CPUs may be hotplugged.
Let's therefore simplify the code and drop the use of the lock.
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://patch.msgid.link/20250311160827.1129643-2-ulf.hansson@linaro.org
[ rjw: Rewrote the new comment ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
s2idle works like a regular suspend with freezing processes and freezing
devices. All CPUs except the control CPU go into idle. Once this is
completed the control CPU kicks all other CPUs out of idle, so that they
reenter the idle loop and then enter s2idle state. The control CPU then
issues an swait() on the suspend state and therefore enters the idle loop
as well.
Due to being kicked out of idle, the other CPUs leave their NOHZ states,
which means the tick is active and the corresponding hrtimer is programmed
to the next jiffie.
On entering s2idle the CPUs shut down their local clockevent device to
prevent wakeups. The last CPU which enters s2idle shuts down its local
clockevent and freezes timekeeping.
On resume, one of the CPUs receives the wakeup interrupt, unfreezes
timekeeping and its local clockevent and starts the resume process. At that
point all other CPUs are still in s2idle with their clockevents switched
off. They only resume when they are kicked by another CPU or after resuming
devices and then receiving a device interrupt.
That means there is no guarantee that all CPUs will wakeup directly on
resume. As a consequence there is no guarantee that timers which are queued
on those CPUs and should expire directly after resume, are handled. Also
timer list timers which are remotely queued to one of those CPUs after
resume will not result in a reprogramming IPI as the tick is
active. Queueing a hrtimer will also not result in a reprogramming IPI
because the first hrtimer event is already in the past.
The recent introduction of the timer pull model (7ee9887703 ("timers:
Implement the hierarchical pull model")) amplifies this problem, if the
current migrator is one of the non woken up CPUs. When a non pinned timer
list timer is queued and the queuing CPU goes idle, it relies on the still
suspended migrator CPU to expire the timer which will happen by chance.
The problem exists since commit 8d89835b04 ("PM: suspend: Do not pause
cpuidle in the suspend-to-idle path"). There the cpuidle_pause() call which
in turn invoked a wakeup for all idle CPUs was moved to a later point in
the resume process. This might not be reached or reached very late because
it waits on a timer of a still suspended CPU.
Address this by kicking all CPUs out of idle after the control CPU returns
from swait() so that they resume their timers and restore consistent system
state.
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218641
Fixes: 8d89835b04 ("PM: suspend: Do not pause cpuidle in the suspend-to-idle path")
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Mario Limonciello <mario.limonciello@amd.com>
Cc: 5.16+ <stable@kernel.org> # 5.16+
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
psci_init_system_suspend() invokes suspend_set_ops() very early during
bootup even before kernel command line for mem_sleep_default is setup.
This leads to kernel command line mem_sleep_default=s2idle not working
as mem_sleep_current gets changed to deep via suspend_set_ops() and never
changes back to s2idle.
Set mem_sleep_current along with mem_sleep_default during kernel command
line setup as default suspend mode.
Fixes: faf7ec4a92 ("drivers: firmware: psci: add system suspend support")
CC: stable@vger.kernel.org # 5.4+
Signed-off-by: Maulik Shah <quic_mkshah@quicinc.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
It is not necessary to define struct suspend_stats in a header file and the
suspend_stats variable in the core device system-wide PM code. They both
can be defined in kernel/power/main.c, next to the sysfs and debugfs code
accessing suspend_stats, which can be static.
Modify the code in question in accordance with the above observation and
replace the static inline functions manipulating suspend_stats with
regular ones defined in kernel/power/main.c.
While at it, move the enum suspend_stat_step to the end of suspend.h which
is a more suitable place for it.
No intentional functional impact.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Instead of using a set of individual struct suspend_stats fields
representing suspend step failure counters, use an array of counters
indexed by enum suspend_stat_step for this purpose, which allows
dpm_save_failed_step() to increment the appropriate counter
automatically, so that its callers don't need to do that directly.
It also allows suspend_stats_show() to carry out a loop over the
counters array to print their values.
Because the counters cannot become negative, use unsigned int for
representing them.
The only user-observable impact of this change is a different
ordering of entries in the suspend_stats debugfs file which is not
expected to matter.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Pull scheduler updates from Ingo Molnar:
"Debuggability:
- Change most occurances of BUG_ON() to WARN_ON_ONCE()
- Reorganize & fix TASK_ state comparisons, turn it into a bitmap
- Update/fix misc scheduler debugging facilities
Load-balancing & regular scheduling:
- Improve the behavior of the scheduler in presence of lot of
SCHED_IDLE tasks - in particular they should not impact other
scheduling classes.
- Optimize task load tracking, cleanups & fixes
- Clean up & simplify misc load-balancing code
Freezer:
- Rewrite the core freezer to behave better wrt thawing and be
simpler in general, by replacing PF_FROZEN with TASK_FROZEN &
fixing/adjusting all the fallout.
Deadline scheduler:
- Fix the DL capacity-aware code
- Factor out dl_task_is_earliest_deadline() &
replenish_dl_new_period()
- Relax/optimize locking in task_non_contending()
Cleanups:
- Factor out the update_current_exec_runtime() helper
- Various cleanups, simplifications"
* tag 'sched-core-2022-10-07' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (41 commits)
sched: Fix more TASK_state comparisons
sched: Fix TASK_state comparisons
sched/fair: Move call to list_last_entry() in detach_tasks
sched/fair: Cleanup loop_max and loop_break
sched/fair: Make sure to try to detach at least one movable task
sched: Show PF_flag holes
freezer,sched: Rewrite core freezer logic
sched: Widen TAKS_state literals
sched/wait: Add wait_event_state()
sched/completion: Add wait_for_completion_state()
sched: Add TASK_ANY for wait_task_inactive()
sched: Change wait_task_inactive()s match_state
freezer,umh: Clean up freezer/initrd interaction
freezer: Have {,un}lock_system_sleep() save/restore flags
sched: Rename task_running() to task_on_cpu()
sched/fair: Cleanup for SIS_PROP
sched/fair: Default to false in test_idle_cores()
sched/fair: Remove useless check in select_idle_core()
sched/fair: Avoid double search on same cpu
sched/fair: Remove redundant check in select_idle_smt()
...
Rafael explained that the reason for having both PF_NOFREEZE and
PF_FREEZER_SKIP is that {,un}lock_system_sleep() is callable from
kthread context that has previously called set_freezable().
In preparation of merging the flags, have {,un}lock_system_slee() save
and restore current->flags.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/20220822114648.725003428@infradead.org
The CXL specification claims S3 support at a hardware level, but at a
system software level there are some missing pieces. Section 9.4 (CXL
2.0) rightly claims that "CXL mem adapters may need aux power to retain
memory context across S3", but there is no enumeration mechanism for the
OS to determine if a given adapter has that support. Moreover the save
state and resume image for the system may inadvertantly end up in a CXL
device that needs to be restored before the save state is recoverable.
I.e. a circular dependency that is not resolvable without a third party
save-area.
Arrange for the cxl_mem driver to fail S3 attempts. This still nominaly
allows for suspend, but requires unbinding all CXL memory devices before
the suspend to ensure the typical DRAM flow is taken. The cxl_mem unbind
flow is intended to also tear down all CXL memory regions associated
with a given cxl_memdev.
It is reasonable to assume that any device participating in a System RAM
range published in the EFI memory map is covered by aux power and
save-area outside the device itself. So this restriction can be
minimized in the future once pre-existing region enumeration support
arrives, and perhaps a spec update to clarify if the EFI memory map is
sufficent for determining the range of devices managed by
platform-firmware for S3 support.
Per Rafael, if the CXL configuration prevents suspend then it should
fail early before tasks are frozen, and mem_sleep should stop showing
'mem' as an option [1]. Effectively CXL augments the platform suspend
->valid() op since, for example, the ACPI ops are not aware of the CXL /
PCI dependencies. Given the split role of platform firmware vs OS
provisioned CXL memory it is up to the cxl_mem driver to determine if
the CXL configuration has elements that platform firmware may not be
prepared to restore.
Link: https://lore.kernel.org/r/CAJZ5v0hGVN_=3iU8OLpHY3Ak35T5+JcBM-qs8SbojKrpd0VXsA@mail.gmail.com [1]
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Len Brown <len.brown@intel.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/165066828317.3907920.5690432272182042556.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
