linux.git/kernel/power, branch v6.6.23

PM: hibernate: Enforce ordering during image compression/decompression

2024-02-01T00:18:49+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()

2023-11-28T17:20:02+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

2023-11-28T17:20:02+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

PM: hibernate: Fix copying the zero bitmap to safe pages

2023-10-04T18:43:44+00:00

The following crash is observed 100% of the time during resume from
the hibernation on a x86 QEMU system.

[   12.931887]  ? __die_body+0x1a/0x60
[   12.932324]  ? page_fault_oops+0x156/0x420
[   12.932824]  ? search_exception_tables+0x37/0x50
[   12.933389]  ? fixup_exception+0x21/0x300
[   12.933889]  ? exc_page_fault+0x69/0x150
[   12.934371]  ? asm_exc_page_fault+0x26/0x30
[   12.934869]  ? get_buffer.constprop.0+0xac/0x100
[   12.935428]  snapshot_write_next+0x7c/0x9f0
[   12.935929]  ? submit_bio_noacct_nocheck+0x2c2/0x370
[   12.936530]  ? submit_bio_noacct+0x44/0x2c0
[   12.937035]  ? hib_submit_io+0xa5/0x110
[   12.937501]  load_image+0x83/0x1a0
[   12.937919]  swsusp_read+0x17f/0x1d0
[   12.938355]  ? create_basic_memory_bitmaps+0x1b7/0x240
[   12.938967]  load_image_and_restore+0x45/0xc0
[   12.939494]  software_resume+0x13c/0x180
[   12.939994]  resume_store+0xa3/0x1d0

The commit being fixed introduced a bug in copying the zero bitmap
to safe pages. A temporary bitmap is allocated with PG_ANY flag in
prepare_image() to make a copy of zero bitmap after the unsafe pages
are marked. Freeing this temporary bitmap with PG_UNSAFE_KEEP later
results in an inconsistent state of unsafe pages. Since free bit is
left as is for this temporary bitmap after free, these pages are
treated as unsafe pages when they are allocated again. This results
in incorrect calculation of the number of pages pre-allocated for the
image.

nr_pages = (nr_zero_pages + nr_copy_pages) - nr_highmem - allocated_unsafe_pages;

The allocate_unsafe_pages is estimated to be higher than the actual
which results in running short of pages in safe_pages_list. Hence the
crash is observed in get_buffer() due to NULL pointer access of
safe_pages_list.

Fix this issue by creating the temporary zero bitmap from safe pages
(free bit not set) so that the corresponding free bits can be cleared
while freeing this bitmap.

Fixes: 005e8dddd497 ("PM: hibernate: don't store zero pages in the image file")
Suggested-by:: Brian Geffon 
Signed-off-by: Pavankumar Kondeti 
Reviewed-by: Brian Geffon 
Signed-off-by: Rafael J. Wysocki

PM: hibernate: Fix the exclusive get block device in test_resume mode

2023-09-12T09:45:15+00:00

Commit 5904de0d735b ("PM: hibernate: Do not get block device exclusively
in test_resume mode") fixes a hibernation issue under test_resume mode.
That commit is supposed to open the block device in non-exclusive mode
when in test_resume. However the code does the opposite, which is against
its description.

In summary, the swap device is only opened exclusively by swsusp_check()
with its corresponding *close(), and must be in non test_resume mode.
This is to avoid the race condition that different processes scribble the
device at the same time. All the other cases should use non-exclusive mode.

Fix it by really disabling exclusive mode under test_resume.

Fixes: 5904de0d735b ("PM: hibernate: Do not get block device exclusively in test_resume mode")
Closes: https://lore.kernel.org/lkml/000000000000761f5f0603324129@google.com/
Reported-by: Pengfei Xu 
Signed-off-by: Chen Yu 
Tested-by: Chenzhou Feng 
Signed-off-by: Rafael J. Wysocki

PM: hibernate: Rename function parameter from snapshot_test to exclusive

2023-09-12T09:45:15+00:00

Several functions reply on snapshot_test to decide whether to
open the resume device exclusively. However there is no strict
connection between the snapshot_test and the open mode. Rename
the 'snapshot_test' input parameter to 'exclusive' to better reflect
the use case.

No functional change is expected.

Signed-off-by: Chen Yu 
Signed-off-by: Rafael J. Wysocki

Merge tag 'tty-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

2023-09-01T16:38:00+00:00

Pull tty/serial driver updates from Greg KH:
 "Here is the big set of tty and serial driver changes for 6.6-rc1.

  Lots of cleanups in here this cycle, and some driver updates. Short
  summary is:

   - Jiri's continued work to make the tty code and apis be a bit more
     sane with regards to modern kernel coding style and types

   - cpm_uart driver updates

   - n_gsm updates and fixes

   - meson driver updates

   - sc16is7xx driver updates

   - 8250 driver updates for different hardware types

   - qcom-geni driver fixes

   - tegra serial driver change

   - stm32 driver updates

   - synclink_gt driver cleanups

   - tty structure size reduction

  All of these have been in linux-next this week with no reported
  issues. The last bit of cleanups from Jiri and the tty structure size
  reduction came in last week, a bit late but as they were just style
  changes and size reductions, I figured they should get into this merge
  cycle so that others can work on top of them with no merge conflicts"

* tag 'tty-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (199 commits)
  tty: shrink the size of struct tty_struct by 40 bytes
  tty: n_tty: deduplicate copy code in n_tty_receive_buf_real_raw()
  tty: n_tty: extract ECHO_OP processing to a separate function
  tty: n_tty: unify counts to size_t
  tty: n_tty: use u8 for chars and flags
  tty: n_tty: simplify chars_in_buffer()
  tty: n_tty: remove unsigned char casts from character constants
  tty: n_tty: move newline handling to a separate function
  tty: n_tty: move canon handling to a separate function
  tty: n_tty: use MASK() for masking out size bits
  tty: n_tty: make n_tty_data::num_overrun unsigned
  tty: n_tty: use time_is_before_jiffies() in n_tty_receive_overrun()
  tty: n_tty: use 'num' for writes' counts
  tty: n_tty: use output character directly
  tty: n_tty: make flow of n_tty_receive_buf_common() a bool
  Revert "tty: serial: meson: Add a earlycon for the T7 SoC"
  Documentation: devices.txt: Fix minors for ttyCPM*
  Documentation: devices.txt: Remove ttySIOC*
  Documentation: devices.txt: Remove ttyIOC*
  serial: 8250_bcm7271: improve bcm7271 8250 port
  ...

Merge branches 'pm-sleep', 'pm-qos' and 'powercap'

2023-08-25T19:23:30+00:00

Merge system-wide power management changes and power capping updates
for 6.6-rc1:

 - Add device PM helpers to allow a device to remain powered-on during
   system-wide transitions (Ulf Hansson).

 - Rework hibernation memory snapshotting to avoid storing pages filled
   with zeros in hibernation image files (Brian Geffon).

 - Add check to make sure that CPU latency QoS constraints do not use
   negative values (Clive Lin).

 - Optimize rp->domains memory allocation in the Intel RAPL power
   capping driver (xiongxin).

 - Remove recursion while parsing zones in the arm_scmi power capping
   driver (Cristian Marussi).

* pm-sleep:
  PM: sleep: Add helpers to allow a device to remain powered-on
  PM: hibernate: don't store zero pages in the image file

* pm-qos:
  PM: QoS: Add check to make sure CPU latency is non-negative

* powercap:
  powercap: intel_rapl: Optimize rp->domains memory allocation
  powercap: arm_scmi: Remove recursion while parsing zones

PM: QoS: Add check to make sure CPU latency is non-negative

2023-08-22T19:37:29+00:00

CPU latency should never be negative, which will be incorrectly high
when converted to unsigned data type.

Commit 8d36694245f2 ("PM: QoS: Add check to make sure CPU freq is
non-negative") makes sure CPU frequency is non-negative to fix incorrect
behavior in freqency QoS.

Add an analogous check to make sure CPU latency is non-negative so as to
prevent this problem from happening in CPU latency QoS.

Signed-off-by: Clive Lin 
[ rjw: Changelog edits ]
Signed-off-by: Rafael J. Wysocki

Merge commit b320441c04c9 ("Merge tag 'tty-6.5-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty") into tty-next

2023-08-20T12:29:37+00:00

We need the serial-core fixes in here as well.

Signed-off-by: Greg Kroah-Hartman