linux.git/kernel/power/snapshot.c, branch v7.0 Linux kernel source tree PM: hibernate: Drain trailing zero pages on userspace restore 2026-03-23T12:33:06+00:00 Alberto Garcia berto@igalia.com 2026-03-09T17:39:41+00:00 734eba62cd32cb9ceffa09e57cdc03d761528525 Commit 005e8dddd497 ("PM: hibernate: don't store zero pages in the image file") added an optimization to skip zero-filled pages in the hibernation image. On restore, zero pages are handled internally by snapshot_write_next() in a loop that processes them without returning to the caller. With the userspace restore interface, writing the last non-zero page to /dev/snapshot is followed by the SNAPSHOT_ATOMIC_RESTORE ioctl. At this point there are no more calls to snapshot_write_next() so any trailing zero pages are not processed, snapshot_image_loaded() fails because handle->cur is smaller than expected, the ioctl returns -EPERM and the image is not restored. The in-kernel restore path is not affected by this because the loop in load_image() in swap.c calls snapshot_write_next() until it returns 0. It is this final call that drains any trailing zero pages. Fixed by calling snapshot_write_next() in snapshot_write_finalize(), giving the kernel the chance to drain any trailing zero pages. Fixes: 005e8dddd497 ("PM: hibernate: don't store zero pages in the image file") Signed-off-by: Alberto Garcia <berto@igalia.com> Acked-by: Brian Geffon <bgeffon@google.com> Link: https://patch.msgid.link/ef5a7c5e3e3dbd17dcb20efaa0c53a47a23498bb.1773075892.git.berto@igalia.com Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> 
Commit 005e8dddd497 ("PM: hibernate: don't store zero pages in the
image file") added an optimization to skip zero-filled pages in the
hibernation image. On restore, zero pages are handled internally by
snapshot_write_next() in a loop that processes them without returning
to the caller.

With the userspace restore interface, writing the last non-zero page
to /dev/snapshot is followed by the SNAPSHOT_ATOMIC_RESTORE ioctl. At
this point there are no more calls to snapshot_write_next() so any
trailing zero pages are not processed, snapshot_image_loaded() fails
because handle->cur is smaller than expected, the ioctl returns -EPERM
and the image is not restored.

The in-kernel restore path is not affected by this because the loop in
load_image() in swap.c calls snapshot_write_next() until it returns 0.
It is this final call that drains any trailing zero pages.

Fixed by calling snapshot_write_next() in snapshot_write_finalize(),
giving the kernel the chance to drain any trailing zero pages.

Fixes: 005e8dddd497 ("PM: hibernate: don't store zero pages in the image file")
Signed-off-by: Alberto Garcia <berto@igalia.com>
Acked-by: Brian Geffon <bgeffon@google.com>
Link: https://patch.msgid.link/ef5a7c5e3e3dbd17dcb20efaa0c53a47a23498bb.1773075892.git.berto@igalia.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-22T01:09:51+00:00 Linus Torvalds torvalds@linux-foundation.org 2026-02-22T00:37:42+00:00 bf4afc53b77aeaa48b5409da5c8da6bb4eff7f43 This was done entirely with mindless brute force, using git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' | xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/' to convert the new alloc_obj() users that had a simple GFP_KERNEL argument to just drop that argument. Note that due to the extreme simplicity of the scripting, any slightly more complex cases spread over multiple lines would not be triggered: they definitely exist, but this covers the vast bulk of the cases, and the resulting diff is also then easier to check automatically. For the same reason the 'flex' versions will be done as a separate conversion. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
This was done entirely with mindless brute force, using

    git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' |
        xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/'

to convert the new alloc_obj() users that had a simple GFP_KERNEL
argument to just drop that argument.

Note that due to the extreme simplicity of the scripting, any slightly
more complex cases spread over multiple lines would not be triggered:
they definitely exist, but this covers the vast bulk of the cases, and
the resulting diff is also then easier to check automatically.

For the same reason the 'flex' versions will be done as a separate
conversion.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
treewide: Replace kmalloc with kmalloc_obj for non-scalar types 2026-02-21T09:02:28+00:00 Kees Cook kees@kernel.org 2026-02-21T07:49:23+00:00 69050f8d6d075dc01af7a5f2f550a8067510366f This is the result of running the Coccinelle script from scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to avoid scalar types (which need careful case-by-case checking), and instead replace kmalloc-family calls that allocate struct or union object instances: Single allocations: kmalloc(sizeof(TYPE), ...) are replaced with: kmalloc_obj(TYPE, ...) Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...) are replaced with: kmalloc_objs(TYPE, COUNT, ...) Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...) are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...) (where TYPE may also be *VAR) The resulting allocations no longer return "void *", instead returning "TYPE *". Signed-off-by: Kees Cook <kees@kernel.org> 
This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:

Single allocations:	kmalloc(sizeof(TYPE), ...)
are replaced with:	kmalloc_obj(TYPE, ...)

Array allocations:	kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with:	kmalloc_objs(TYPE, COUNT, ...)

Flex array allocations:	kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with:	kmalloc_flex(*PTR, FAM, COUNT, ...)

(where TYPE may also be *VAR)

The resulting allocations no longer return "void *", instead returning
"TYPE *".

Signed-off-by: Kees Cook <kees@kernel.org>
PM: hibernate: Rework message printing in swsusp_save() 2025-10-20T18:43:09+00:00 Rafael J. Wysocki rafael.j.wysocki@intel.com 2025-10-09T19:34:16+00:00 d3db87f89c71c34f4a6a0ee9de3dfab5eee18b22 The messages printed by swsusp_save() are basically only useful for debug, so printing them every time a hibernation image is created at the "info" log level is not particularly useful. Also printing a message on a failing memory allocation is redundant. Use pm_deferred_pr_dbg() for printing those messages so they will only be printed when requested and the "deferred" variant is used because this code runs in a deeply atomic context (one CPU with interrupts off, no functional devices). Also drop the useless message printed when memory allocations fails. While at it, extend one of the messages in question so it is less cryptic. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> [ rjw: Dropped a useless colon at the end of one of the messages ] Link: https://patch.msgid.link/10750389.nUPlyArG6x@rafael.j.wysocki 
The messages printed by swsusp_save() are basically only useful for
debug, so printing them every time a hibernation image is created at
the "info" log level is not particularly useful.  Also printing a
message on a failing memory allocation is redundant.

Use pm_deferred_pr_dbg() for printing those messages so they will only
be printed when requested and the "deferred" variant is used because
this code runs in a deeply atomic context (one CPU with interrupts
off, no functional devices).  Also drop the useless message printed
when memory allocations fails.

While at it, extend one of the messages in question so it is less
cryptic.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
[ rjw: Dropped a useless colon at the end of one of the messages ]
Link: https://patch.msgid.link/10750389.nUPlyArG6x@rafael.j.wysocki
PM: hibernate: Fix typo in memory bitmaps description comment 2025-09-01T09:55:53+00:00 Li Jun lijun01@kylinos.cn 2025-08-19T10:40:38+00:00 98da8a4aecf584af011cdc67d9581deb21088f24 Correct 'leave' to 'leaf' in memory bitmaps description comment. Signed-off-by: Li Jun <lijun01@kylinos.cn> Link: https://patch.msgid.link/20250819104038.1596952-1-lijun01@kylinos.cn [ rjw: Subject and changelog edits ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> 
Correct 'leave' to 'leaf' in memory bitmaps description comment.

Signed-off-by: Li Jun <lijun01@kylinos.cn>
Link: https://patch.msgid.link/20250819104038.1596952-1-lijun01@kylinos.cn
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
PM: hibernate: Fix up white space that does not follow coding style 2025-07-17T18:30:52+00:00 Darshan Rathod darshanrathod475@gmail.com 2025-07-16T12:42:16+00:00 f633c1a236df95ab927f1919b3be2619c8cc6733 Fix up white space usage that does not follow the kernel coding style rules in several places in snapshot.c. Signed-off-by: Darshan Rathod <darshanrathod475@gmail.com> Link: https://patch.msgid.link/20250716124216.64329-1-darshanrathod475@gmail.com [ rjw: New subject and changelog ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> 
Fix up white space usage that does not follow the kernel coding style
rules in several places in snapshot.c.

Signed-off-by: Darshan Rathod <darshanrathod475@gmail.com>
Link: https://patch.msgid.link/20250716124216.64329-1-darshanrathod475@gmail.com
[ rjw: New subject and changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
mm, PM: use for_each_valid_pfn() in kernel/power/snapshot.c 2025-05-13T06:50:44+00:00 David Woodhouse dwmw@amazon.co.uk 2025-04-23T13:33:40+00:00 312eca8a14c5f58de62692517afd4738099e6fac Link: https://lkml.kernel.org/r/20250423133821.789413-5-dwmw2@infradead.org Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Ard Biesheuvel <ardb@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: David Hildenbrand <david@redhat.com> Cc: Marc Rutland <mark.rutland@arm.com> Cc: Marc Zyngier <maz@kernel.org> Cc: Ruihan Li <lrh2000@pku.edu.cn> Cc: Will Deacon <will@kernel.org> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> 
Link: https://lkml.kernel.org/r/20250423133821.789413-5-dwmw2@infradead.org
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Marc Rutland <mark.rutland@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Ruihan Li <lrh2000@pku.edu.cn>
Cc: Will Deacon <will@kernel.org>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
PM: hibernate: Replace deprecated kmap_atomic() with kmap_local_page() 2025-02-18T19:39:24+00:00 David Reaver me@davidreaver.com 2025-01-12T15:26:55+00:00 d42044aad6528e0c9533dbaf836d1b0fbb19fe2d kmap_atomic() is deprecated and should be replaced with kmap_local_page() [1][2]. kmap_local_page() is faster in kernels with HIGHMEM enabled, can take page faults, and allows preemption. According to [2], this replacement is safe as long as the code between kmap_atomic() and kunmap_atomic() does not implicitly depend on disabling page faults or preemption. In all of the call sites in this patch, the only thing happening between mapping and unmapping pages is copy_page() calls, and I don't suspect they depend on disabling page faults or preemption. Link: https://lwn.net/Articles/836144/ [1] Link: https://docs.kernel.org/mm/highmem.html#temporary-virtual-mappings [2] Signed-off-by: David Reaver <me@davidreaver.com> Link: https://patch.msgid.link/20250112152658.20132-1-me@davidreaver.com Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> 
kmap_atomic() is deprecated and should be replaced with kmap_local_page()
[1][2]. kmap_local_page() is faster in kernels with HIGHMEM enabled, can
take page faults, and allows preemption.

According to [2], this replacement is safe as long as the code between
kmap_atomic() and kunmap_atomic() does not implicitly depend on disabling
page faults or preemption. In all of the call sites in this patch, the only
thing happening between mapping and unmapping pages is copy_page() calls,
and I don't suspect they depend on disabling page faults or preemption.

Link: https://lwn.net/Articles/836144/ [1]
Link: https://docs.kernel.org/mm/highmem.html#temporary-virtual-mappings [2]
Signed-off-by: David Reaver <me@davidreaver.com>
Link: https://patch.msgid.link/20250112152658.20132-1-me@davidreaver.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
mm/memblock: add memblock_alloc_or_panic interface 2025-01-26T04:22:38+00:00 Guo Weikang guoweikang.kernel@gmail.com 2025-01-02T07:25:28+00:00 c6f239796b55dbc4225a6fca9f96232092b9df83 Before SLUB initialization, various subsystems used memblock_alloc to allocate memory. In most cases, when memory allocation fails, an immediate panic is required. To simplify this behavior and reduce repetitive checks, introduce `memblock_alloc_or_panic`. This function ensures that memory allocation failures result in a panic automatically, improving code readability and consistency across subsystems that require this behavior. [guoweikang.kernel@gmail.com: arch/s390: save_area_alloc default failure behavior changed to panic] Link: https://lkml.kernel.org/r/20250109033136.2845676-1-guoweikang.kernel@gmail.com Link: https://lore.kernel.org/lkml/Z2fknmnNtiZbCc7x@kernel.org/ Link: https://lkml.kernel.org/r/20250102072528.650926-1-guoweikang.kernel@gmail.com Signed-off-by: Guo Weikang <guoweikang.kernel@gmail.com> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> [m68k] Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com> [s390] Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> 
Before SLUB initialization, various subsystems used memblock_alloc to
allocate memory.  In most cases, when memory allocation fails, an
immediate panic is required.  To simplify this behavior and reduce
repetitive checks, introduce `memblock_alloc_or_panic`.  This function
ensures that memory allocation failures result in a panic automatically,
improving code readability and consistency across subsystems that require
this behavior.

[guoweikang.kernel@gmail.com: arch/s390: save_area_alloc default failure behavior changed to panic]
  Link: https://lkml.kernel.org/r/20250109033136.2845676-1-guoweikang.kernel@gmail.com
  Link: https://lore.kernel.org/lkml/Z2fknmnNtiZbCc7x@kernel.org/
Link: https://lkml.kernel.org/r/20250102072528.650926-1-guoweikang.kernel@gmail.com
Signed-off-by: Guo Weikang <guoweikang.kernel@gmail.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>	[m68k]
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>	[s390]
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
PM: hibernate: Remove unused stub for saveable_highmem_page() 2024-09-10T18:11:40+00:00 Andy Shevchenko andriy.shevchenko@linux.intel.com 2024-09-05T18:48:48+00:00 c3565a35d97102fbea69e324086d5e33ee2ab34e When saveable_highmem_page() is unused, it prevents kernel builds with clang, `make W=1` and CONFIG_WERROR=y: kernel/power/snapshot.c:1369:21: error: unused function 'saveable_highmem_page' [-Werror,-Wunused-function] 1369 | static inline void *saveable_highmem_page(struct zone *z, unsigned long p) | ^~~~~~~~~~~~~~~~~~~~~ Fix this by removing unused stub. See also commit 6863f5643dd7 ("kbuild: allow Clang to find unused static inline functions for W=1 build"). Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://patch.msgid.link/20240905184848.318978-1-andriy.shevchenko@linux.intel.com Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> 
When saveable_highmem_page() is unused, it prevents kernel builds
with clang, `make W=1` and CONFIG_WERROR=y:

kernel/power/snapshot.c:1369:21: error: unused function 'saveable_highmem_page' [-Werror,-Wunused-function]
 1369 | static inline void *saveable_highmem_page(struct zone *z, unsigned long p)
      |                     ^~~~~~~~~~~~~~~~~~~~~

Fix this by removing unused stub.

See also commit 6863f5643dd7 ("kbuild: allow Clang to find unused static
inline functions for W=1 build").

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://patch.msgid.link/20240905184848.318978-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>