linux.git/kernel/kexec_core.c, branch v7.2-rc1

liveupdate: skip serialization for context-preserving kexec

2026-06-01T06:19:38+00:00

A preserve_context kexec returns to the current kernel, which is
unrelated to live update where the state is passed to the next kernel.
Skip liveupdate_reboot() in this case to avoid serialization and prevent
sessions from being left in a frozen state upon return.

Fixes: db8bed8082dc ("kexec: call liveupdate_reboot() before kexec")
Reported-by: Oskar Gerlicz Kowalczuk 
Reviewed-by: Pratyush Yadav (Google) 
Acked-by: Mike Rapoport (Microsoft) 
Signed-off-by: Pasha Tatashin 
Link: https://patch.msgid.link/20260527202737.1345192-2-pasha.tatashin@soleen.com
Signed-off-by: Mike Rapoport (Microsoft)

kernel/kexec: remove inclusion of crypto/hash.h

2026-03-28T04:19:46+00:00

kexec_core.c does not do any cryptographic hashing, so the header
crypto/hash.h is not needed at all.

Link: https://lkml.kernel.org/r/20260314204144.44884-1-ebiggers@kernel.org
Signed-off-by: Eric Biggers 
Cc: Baoquan He 
Signed-off-by: Andrew Morton

Convert 'alloc_obj' family to use the new default GFP_KERNEL argument

2026-02-22T01:09:51+00:00

This was done entirely with mindless brute force, using

    git grep -l '\

treewide: Replace kmalloc with kmalloc_obj for non-scalar types

2026-02-21T09:02:28+00:00

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

kernel/kexec: fix IMA when allocation happens in CMA area

2025-12-23T19:23:14+00:00

*** Bug description ***

When I tested kexec with the latest kernel, I ran into the following warning:

[   40.712410] ------------[ cut here ]------------
[   40.712576] WARNING: CPU: 2 PID: 1562 at kernel/kexec_core.c:1001 kimage_map_segment+0x144/0x198
[...]
[   40.816047] Call trace:
[   40.818498]  kimage_map_segment+0x144/0x198 (P)
[   40.823221]  ima_kexec_post_load+0x58/0xc0
[   40.827246]  __do_sys_kexec_file_load+0x29c/0x368
[...]
[   40.855423] ---[ end trace 0000000000000000 ]---

*** How to reproduce ***

This bug is only triggered when the kexec target address is allocated in
the CMA area. If no CMA area is reserved in the kernel, use the "cma="
option in the kernel command line to reserve one.

*** Root cause ***
The commit 07d24902977e ("kexec: enable CMA based contiguous
allocation") allocates the kexec target address directly on the CMA area
to avoid copying during the jump. In this case, there is no IND_SOURCE
for the kexec segment.  But the current implementation of
kimage_map_segment() assumes that IND_SOURCE pages exist and map them
into a contiguous virtual address by vmap().

*** Solution ***
If IMA segment is allocated in the CMA area, use its page_address()
directly.

Link: https://lkml.kernel.org/r/20251216014852.8737-2-piliu@redhat.com
Fixes: 07d24902977e ("kexec: enable CMA based contiguous allocation")
Signed-off-by: Pingfan Liu 
Acked-by: Baoquan He 
Cc: Alexander Graf 
Cc: Steven Chen 
Cc: Mimi Zohar 
Cc: Roberto Sassu 
Cc: 
Signed-off-by: Andrew Morton

kernel/kexec: change the prototype of kimage_map_segment()

2025-12-23T19:23:13+00:00

The kexec segment index will be required to extract the corresponding
information for that segment in kimage_map_segment().  Additionally,
kexec_segment already holds the kexec relocation destination address and
size.  Therefore, the prototype of kimage_map_segment() can be changed.

Link: https://lkml.kernel.org/r/20251216014852.8737-1-piliu@redhat.com
Fixes: 07d24902977e ("kexec: enable CMA based contiguous allocation")
Signed-off-by: Pingfan Liu 
Acked-by: Baoquan He 
Cc: Mimi Zohar 
Cc: Roberto Sassu 
Cc: Alexander Graf 
Cc: Steven Chen 
Cc: 
Signed-off-by: Andrew Morton

kexec: move sysfs entries to /sys/kernel/kexec

2025-11-27T22:24:42+00:00

Patch series "kexec: reorganize kexec and kdump sysfs", v6.

All existing kexec and kdump sysfs entries are moved to a new location,
/sys/kernel/kexec, to keep /sys/kernel/ clean and better organized.
Symlinks are created at the old locations for backward compatibility and
can be removed in the future [01/03].

While doing this cleanup, the old kexec and kdump sysfs entries are
marked as deprecated in the existing ABI documentation [02/03]. This
makes it clear that these older interfaces should no longer be used.
New ABI documentation is added to describe the reorganized interfaces
[03/03], so users and tools can rely on the updated sysfs interfaces
going forward.


This patch (of 3):

Several kexec and kdump sysfs entries are currently placed directly under
/sys/kernel/, which clutters the directory and makes it harder to identify
unrelated entries.  To improve organization and readability, these entries
are now moved under a dedicated directory, /sys/kernel/kexec.

The following sysfs moved under new kexec sysfs node
+------------------------------------+------------------+
|    Old sysfs name         |     New sysfs name        |
|  (under /sys/kernel)      | (under /sys/kernel/kexec) |
+---------------------------+---------------------------+
| kexec_loaded              | loaded                    |
+---------------------------+---------------------------+
| kexec_crash_loaded        | crash_loaded              |
+---------------------------+---------------------------+
| kexec_crash_size          | crash_size                |
+---------------------------+---------------------------+
| crash_elfcorehdr_size     | crash_elfcorehdr_size     |
+---------------------------+---------------------------+
| kexec_crash_cma_ranges    | crash_cma_ranges          |
+---------------------------+---------------------------+

For backward compatibility, symlinks are created at the old locations so
that existing tools and scripts continue to work.  These symlinks can be
removed in the future once users have switched to the new path.

While creating symlinks, entries are added in /sys/kernel/ that point to
their new locations under /sys/kernel/kexec/.  If an error occurs while
adding a symlink, it is logged but does not stop initialization of the
remaining kexec sysfs symlinks.

The /sys/kernel/
entry is now controlled by CONFIG_CRASH_DUMP instead of
CONFIG_VMCORE_INFO, as CONFIG_CRASH_DUMP also enables CONFIG_VMCORE_INFO.

Link: https://lkml.kernel.org/r/20251118114507.1769455-1-sourabhjain@linux.ibm.com
Link: https://lkml.kernel.org/r/20251118114507.1769455-2-sourabhjain@linux.ibm.com
Signed-off-by: Sourabh Jain 
Acked-by: Baoquan He 
Cc: Aditya Gupta 
Cc: Dave Young 
Cc: Hari Bathini 
Cc: Jiri Bohac 
Cc: Madhavan Srinivasan 
Cc: Mahesh J Salgaonkar 
Cc: Pingfan Liu 
Cc: Ritesh Harjani (IBM) 
Cc: Shivang Upadhyay 
Cc: Vivek Goyal 
Signed-off-by: Andrew Morton

kexec: call liveupdate_reboot() before kexec

2025-11-27T22:24:38+00:00

Modify the kernel_kexec() to call liveupdate_reboot().

This ensures that the Live Update Orchestrator is notified just before the
kernel executes the kexec jump.  The liveupdate_reboot() function triggers
the final freeze event, allowing participating FDs perform last-minute
check or state saving within the blackout window.

If liveupdate_reboot() returns an error (indicating a failure during LUO
finalization), the kexec operation is aborted to prevent proceeding with
an inconsistent state.  An error is returned to user.

Link: https://lkml.kernel.org/r/20251125165850.3389713-4-pasha.tatashin@soleen.com
Signed-off-by: Pasha Tatashin 
Reviewed-by: Mike Rapoport (Microsoft) 
Reviewed-by: Pratyush Yadav 
Tested-by: David Matlack 
Cc: Aleksander Lobakin 
Cc: Alexander Graf 
Cc: Alice Ryhl 
Cc: Andriy Shevchenko 
Cc: anish kumar 
Cc: Anna Schumaker 
Cc: Bartosz Golaszewski 
Cc: Bjorn Helgaas 
Cc: Borislav Betkov 
Cc: Chanwoo Choi 
Cc: Chen Ridong 
Cc: Chris Li 
Cc: Christian Brauner 
Cc: Daniel Wagner 
Cc: Danilo Krummrich 
Cc: Dan Williams 
Cc: David Hildenbrand 
Cc: David Jeffery 
Cc: David Rientjes 
Cc: Greg Kroah-Hartman 
Cc: Guixin Liu 
Cc: "H. Peter Anvin" 
Cc: Hugh Dickins 
Cc: Ilpo Järvinen 
Cc: Ingo Molnar 
Cc: Ira Weiny 
Cc: Jann Horn 
Cc: Jason Gunthorpe 
Cc: Jens Axboe 
Cc: Joanthan Cameron 
Cc: Joel Granados 
Cc: Johannes Weiner 
Cc: Jonathan Corbet 
Cc: Lennart Poettering 
Cc: Leon Romanovsky 
Cc: Leon Romanovsky 
Cc: Lukas Wunner 
Cc: Marc Rutland 
Cc: Masahiro Yamada 
Cc: Matthew Maurer 
Cc: Miguel Ojeda 
Cc: Myugnjoo Ham 
Cc: Parav Pandit 
Cc: Pratyush Yadav 
Cc: Randy Dunlap 
Cc: Roman Gushchin 
Cc: Saeed Mahameed 
Cc: Samiullah Khawaja 
Cc: Song Liu 
Cc: Steven Rostedt 
Cc: Stuart Hayes 
Cc: Tejun Heo 
Cc: Thomas Gleinxer 
Cc: Thomas Weißschuh 
Cc: Vincent Guittot 
Cc: William Tu 
Cc: Yoann Congal 
Cc: Zhu Yanjun 
Cc: Zijun Hu 
Signed-off-by: Andrew Morton

kexec_core: remove superfluous page offset handling in segment loading

2025-11-12T18:00:13+00:00

During kexec_segment loading, when copying the content of the segment
(i.e.  kexec_segment::kbuf or kexec_segment::buf) to its associated pages,
kimage_load_{cma,normal,crash}_segment handle the case where the physical
address of the segment is not page aligned, e.g.  in
kimage_load_normal_segment:

	page = kimage_alloc_page(image, GFP_HIGHUSER, maddr);
	// ...
	ptr = kmap_local_page(page);
	// ...
	ptr += maddr & ~PAGE_MASK;
	mchunk = min_t(size_t, mbytes,
		PAGE_SIZE - (maddr & ~PAGE_MASK));
	// ^^^^ Non page-aligned segments handled here ^^^
	// ...
	if (image->file_mode)
		memcpy(ptr, kbuf, uchunk);
	else
		result = copy_from_user(ptr, buf, uchunk);

(similar logic is present in kimage_load_{cma,crash}_segment).

This is actually not needed because, prior to their loading, all
kexec_segments first go through a vetting step in
`sanity_check_segment_list`, which rejects any segment that is not
page-aligned:

	for (i = 0; i < nr_segments; i++) {
		unsigned long mstart, mend;
		mstart = image->segment[i].mem;
		mend   = mstart + image->segment[i].memsz;
		// ...
		if ((mstart & ~PAGE_MASK) || (mend & ~PAGE_MASK))
			return -EADDRNOTAVAIL;
		// ...
	}

In case `sanity_check_segment_list` finds a non-page aligned the whole
kexec load is aborted and no segment is loaded.

This means that `kimage_load_{cma,normal,crash}_segment` never actually
have to handle non page-aligned segments and `(maddr & ~PAGE_MASK) == 0`
is always true no matter if the segment is coming from a file (i.e. 
`kexec_file_load` syscall), from a user-space buffer (i.e.  `kexec_load`
syscall) or created by the kernel through `kexec_add_buffer`.  In the
latter case, `kexec_add_buffer` actually enforces the page alignment:

	/* Ensure minimum alignment needed for segments. */
	kbuf->memsz = ALIGN(kbuf->memsz, PAGE_SIZE);
	kbuf->buf_align = max(kbuf->buf_align, PAGE_SIZE);

[jbouron@amazon.com: v3]
  Link: https://lkml.kernel.org/r/20251024155009.39502-1-jbouron@amazon.com
Link: https://lkml.kernel.org/r/20250929160220.47616-1-jbouron@amazon.com
Signed-off-by: Justinien Bouron 
Reviewed-by: Gunnar Kudrjavets 
Reviewed-by: Andy Shevchenko 
Acked-by: Baoquan He 
Cc: Alexander Graf 
Cc: Marcos Paulo de Souza 
Cc: Mario Limonciello 
Cc: Petr Mladek 
Cc: Yan Zhao 
Signed-off-by: Andrew Morton

kexec_core: remove redundant 0 value initialization

2025-09-14T00:32:49+00:00

The kimage struct is already zeroed by kzalloc(). It's redundant to
initialize image->head to 0.

Link: https://lkml.kernel.org/r/20250825123307.306634-1-liaoyuanhong@vivo.com
Signed-off-by: Liao Yuanhong 
Signed-off-by: Andrew Morton