linux.git/kernel/power, branch v5.15.185

PM: hibernate: Add error handling for syscore_suspend()

2025-03-13T11:50:12+00:00

[ Upstream commit e20a70c572539a486dbd91b225fa6a194a5e2122 ]

In hibernation_platform_enter(), the code did not check the
return value of syscore_suspend(), potentially leading to a
situation where syscore_resume() would be called even if
syscore_suspend() failed. This could cause unpredictable
behavior or system instability.

Modify the code sequence in question to properly handle errors returned
by syscore_suspend(). If an error occurs in the suspend path, the code
now jumps to label 'Enable_irqs' skipping the syscore_resume() call and
only enabling interrupts after setting the system state to SYSTEM_RUNNING.

Fixes: 40dc166cb5dd ("PM / Core: Introduce struct syscore_ops for core subsystems PM")
Signed-off-by: Wentao Liang 
Link: https://patch.msgid.link/20250119143205.2103-1-vulab@iscas.ac.cn
[ rjw: Changelog edits ]
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Sasha Levin

PM: suspend: Set mem_sleep_current during kernel command line setup

2024-04-10T14:18:36+00:00

[ Upstream commit 9bc4ffd32ef8943f5c5a42c9637cfd04771d021b ]

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: faf7ec4a92c0 ("drivers: firmware: psci: add system suspend support")
CC: stable@vger.kernel.org # 5.4+
Signed-off-by: Maulik Shah 
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Sasha Levin

PM: hibernate: Enforce ordering during image compression/decompression

2024-02-23T07:54:23+00:00

commit 71cd7e80cfde548959952eac7063aeaea1f2e1c6 upstream.

An S4 (suspend to disk) test on the LoongArch 3A6000 platform sometimes
fails with the following error messaged in the dmesg log:

	Invalid LZO compressed length

That happens because when compressing/decompressing the image, the
synchronization between the control thread and the compress/decompress/crc
thread is based on a relaxed ordering interface, which is unreliable, and the
following situation may occur:

CPU 0					CPU 1
save_image_lzo				lzo_compress_threadfn
					  atomic_set(&d->stop, 1);
  atomic_read(&data[thr].stop)
  data[thr].cmp = data[thr].cmp_len;
	  				  WRITE data[thr].cmp_len

Then CPU0 gets a stale cmp_len and writes it to disk. During resume from S4,
wrong cmp_len is loaded.

To maintain data consistency between the two threads, use the acquire/release
variants of atomic set and read operations.

Fixes: 081a9d043c98 ("PM / Hibernate: Improve performance of LZO/plain hibernation, checksum image")
Cc: All applicable 
Signed-off-by: Hongchen Zhang 
Co-developed-by: Weihao Li 
Signed-off-by: Weihao Li 
[ rjw: Subject rewrite and changelog edits ]
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Greg Kroah-Hartman

PM: hibernate: Clean up sync_read handling in snapshot_write_next()

2023-11-28T16:56:29+00:00

commit d08970df1980476f27936e24d452550f3e9e92e1 upstream.

In snapshot_write_next(), sync_read is set and unset in three different
spots unnecessiarly. As a result there is a subtle bug where the first
page after the meta data has been loaded unconditionally sets sync_read
to 0. If this first PFN was actually a highmem page, then the returned
buffer will be the global "buffer," and the page needs to be loaded
synchronously.

That is, I'm not sure we can always assume the following to be safe:

	handle->buffer = get_buffer(&orig_bm, &ca);
	handle->sync_read = 0;

Because get_buffer() can call get_highmem_page_buffer() which can
return 'buffer'.

The easiest way to address this is just set sync_read before
snapshot_write_next() returns if handle->buffer == buffer.

Signed-off-by: Brian Geffon 
Fixes: 8357376d3df2 ("[PATCH] swsusp: Improve handling of highmem")
Cc: All applicable 
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Greg Kroah-Hartman

PM: hibernate: Use __get_safe_page() rather than touching the list

2023-11-28T16:56:29+00:00

commit f0c7183008b41e92fa676406d87f18773724b48b upstream.

We found at least one situation where the safe pages list was empty and
get_buffer() would gladly try to use a NULL pointer.

Signed-off-by: Brian Geffon 
Fixes: 8357376d3df2 ("[PATCH] swsusp: Improve handling of highmem")
Cc: All applicable 
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Greg Kroah-Hartman

workqueue: Introduce show_one_worker_pool and show_one_workqueue.

2023-05-11T14:00:35+00:00

[ Upstream commit 55df0933be74bd2e52aba0b67eb743ae0feabe7e ]

Currently show_workqueue_state shows the state of all workqueues and of
all worker pools. In certain cases we may need to dump state of only a
specific workqueue or worker pool. For example in destroy_workqueue we
only need to show state of the workqueue which is getting destroyed.

So rename show_workqueue_state to show_all_workqueues(to signify it
dumps state of all busy workqueues) and divide it into more granular
functions (show_one_workqueue and show_one_worker_pool), that would show
states of individual workqueues and worker pools and can be used in
cases such as the one mentioned above.

Also, as mentioned earlier, make destroy_workqueue dump data pertaining
to only the workqueue that is being destroyed and make user(s) of
earlier interface(show_workqueue_state), use new interface
(show_all_workqueues).

Signed-off-by: Imran Khan 
Signed-off-by: Tejun Heo 
Stable-dep-of: 335a42ebb0ca ("workqueue: Fix hung time report of worker pools")
Signed-off-by: Sasha Levin

PM: EM: fix memory leak with using debugfs_lookup()

2023-03-10T08:39:51+00:00

[ Upstream commit a0e8c13ccd6a9a636d27353da62c2410c4eca337 ]

When calling debugfs_lookup() the result must have dput() called on it,
otherwise the memory will leak over time.  To make things simpler, just
call debugfs_lookup_and_remove() instead which handles all of the logic
at once.

Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Sasha Levin

PM: hibernate: Fix mistake in kerneldoc comment

2022-12-31T12:14:01+00:00

[ Upstream commit 6e5d7300cbe7c3541bc31f16db3e9266e6027b4b ]

The actual maximum image size formula in hibernate_preallocate_memory()
is as follows:

max_size = (count - (size + PAGES_FOR_IO)) / 2
	    - 2 * DIV_ROUND_UP(reserved_size, PAGE_SIZE);

but the one in the kerneldoc comment of the function is different and
incorrect.

Fixes: ddeb64870810 ("PM / Hibernate: Add sysfs knob to control size of memory for drivers")
Signed-off-by: xiongxin 
[ rjw: Subject and changelog rewrite ]
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Sasha Levin

PM: hibernate: Allow hybrid sleep to work with s2idle

2022-11-03T14:59:17+00:00

[ Upstream commit 85850af4fc47132f3f2f0dd698b90f67906600b4 ]

Hybrid sleep is currently hardcoded to only operate with S3 even
on systems that might not support it.

Instead of assuming this mode is what the user wants to use, for
hybrid sleep follow the setting of `mem_sleep_current` which
will respect mem_sleep_default kernel command line and policy
decisions made by the presence of the FADT low power idle bit.

Fixes: 81d45bdf8913 ("PM / hibernate: Untangle power_down()")
Reported-and-tested-by: kolAflash 
Link: https://bugzilla.kernel.org/show_bug.cgi?id=216574
Signed-off-by: Mario Limonciello 
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Sasha Levin

PM: hibernate: defer device probing when resuming from hibernation

2022-08-17T12:23:04+00:00

[ Upstream commit 8386c414e27caba8501119948e9551e52b527f59 ]

syzbot is reporting hung task at misc_open() [1], for there is a race
window of AB-BA deadlock which involves probe_count variable. Currently
wait_for_device_probe() from snapshot_open() from misc_open() can sleep
forever with misc_mtx held if probe_count cannot become 0.

When a device is probed by hub_event() work function, probe_count is
incremented before the probe function starts, and probe_count is
decremented after the probe function completed.

There are three cases that can prevent probe_count from dropping to 0.

  (a) A device being probed stopped responding (i.e. broken/malicious
      hardware).

  (b) A process emulating a USB device using /dev/raw-gadget interface
      stopped responding for some reason.

  (c) New device probe requests keeps coming in before existing device
      probe requests complete.

The phenomenon syzbot is reporting is (b). A process which is holding
system_transition_mutex and misc_mtx is waiting for probe_count to become
0 inside wait_for_device_probe(), but the probe function which is called
 from hub_event() work function is waiting for the processes which are
blocked at mutex_lock(&misc_mtx) to respond via /dev/raw-gadget interface.

This patch mitigates (b) by deferring wait_for_device_probe() from
snapshot_open() to snapshot_write() and snapshot_ioctl(). Please note that
the possibility of (b) remains as long as any thread which is emulating a
USB device via /dev/raw-gadget interface can be blocked by uninterruptible
blocking operations (e.g. mutex_lock()).

Please also note that (a) and (c) are not addressed. Regarding (c), we
should change the code to wait for only one device which contains the
image for resuming from hibernation. I don't know how to address (a), for
use of timeout for wait_for_device_probe() might result in loss of user
data in the image. Maybe we should require the userland to wait for the
image device before opening /dev/snapshot interface.

Link: https://syzkaller.appspot.com/bug?extid=358c9ab4c93da7b7238c [1]
Reported-by: syzbot 
Signed-off-by: Tetsuo Handa 
Tested-by: syzbot 
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Sasha Levin