[PATCHv3 1/2] kernel/kexec: Change the prototype of kimage_map_segment()

[PATCHv3 1/2] kernel/kexec: Change the prototype of kimage_map_segment()

[Pingfan Liu]

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.

Fixes: 07d24902977e ("kexec: enable CMA based contiguous allocation")
Signed-off-by: Pingfan Liu <piliu@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Mimi Zohar <zohar@linux.ibm.com>
Cc: Roberto Sassu <roberto.sassu@huawei.com>
Cc: Alexander Graf <graf@amazon.com>
Cc: Steven Chen <chenste@linux.microsoft.com>
Cc: linux-kernel@vger.kernel.org
Cc: <stable@vger.kernel.org>
To: kexec@lists.infradead.org
To: linux-integrity@vger.kernel.org
---
 include/linux/kexec.h              | 4 ++--
 kernel/kexec_core.c                | 9 ++++++---
 security/integrity/ima/ima_kexec.c | 4 +---
 3 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index ff7e231b0485..8a22bc9b8c6c 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -530,7 +530,7 @@ extern bool kexec_file_dbg_print;
 #define kexec_dprintk(fmt, arg...) \
         do { if (kexec_file_dbg_print) pr_info(fmt, ##arg); } while (0)
 
-extern void *kimage_map_segment(struct kimage *image, unsigned long addr, unsigned long size);
+extern void *kimage_map_segment(struct kimage *image, int idx);
 extern void kimage_unmap_segment(void *buffer);
 #else /* !CONFIG_KEXEC_CORE */
 struct pt_regs;
@@ -540,7 +540,7 @@ static inline void __crash_kexec(struct pt_regs *regs) { }
 static inline void crash_kexec(struct pt_regs *regs) { }
 static inline int kexec_should_crash(struct task_struct *p) { return 0; }
 static inline int kexec_crash_loaded(void) { return 0; }
-static inline void *kimage_map_segment(struct kimage *image, unsigned long addr, unsigned long size)
+static inline void *kimage_map_segment(struct kimage *image, int idx)
 { return NULL; }
 static inline void kimage_unmap_segment(void *buffer) { }
 #define kexec_in_progress false
diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
index 0f92acdd354d..1a79c5b18d8f 100644
--- a/kernel/kexec_core.c
+++ b/kernel/kexec_core.c
@@ -953,17 +953,20 @@ int kimage_load_segment(struct kimage *image, int idx)
 	return result;
 }
 
-void *kimage_map_segment(struct kimage *image,
-			 unsigned long addr, unsigned long size)
+void *kimage_map_segment(struct kimage *image, int idx)
 {
+	unsigned long addr, size, eaddr;
 	unsigned long src_page_addr, dest_page_addr = 0;
-	unsigned long eaddr = addr + size;
 	kimage_entry_t *ptr, entry;
 	struct page **src_pages;
 	unsigned int npages;
 	void *vaddr = NULL;
 	int i;
 
+	addr = image->segment[idx].mem;
+	size = image->segment[idx].memsz;
+	eaddr = addr + size;
+
 	/*
 	 * Collect the source pages and map them in a contiguous VA range.
 	 */
diff --git a/security/integrity/ima/ima_kexec.c b/security/integrity/ima/ima_kexec.c
index 7362f68f2d8b..5beb69edd12f 100644
--- a/security/integrity/ima/ima_kexec.c
+++ b/security/integrity/ima/ima_kexec.c
@@ -250,9 +250,7 @@ void ima_kexec_post_load(struct kimage *image)
 	if (!image->ima_buffer_addr)
 		return;
 
-	ima_kexec_buffer = kimage_map_segment(image,
-					      image->ima_buffer_addr,
-					      image->ima_buffer_size);
+	ima_kexec_buffer = kimage_map_segment(image, image->ima_segment_index);
 	if (!ima_kexec_buffer) {
 		pr_err("Could not map measurements buffer.\n");
 		return;
-- 
2.49.0

[PATCHv3 2/2] kernel/kexec: Fix IMA when allocation happens in CMA area

[Pingfan Liu]

*** 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.

Fixes: 07d24902977e ("kexec: enable CMA based contiguous allocation")
Signed-off-by: Pingfan Liu <piliu@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Alexander Graf <graf@amazon.com>
Cc: Steven Chen <chenste@linux.microsoft.com>
Cc: Mimi Zohar <zohar@linux.ibm.com>
Cc: linux-integrity@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: <stable@vger.kernel.org>
To: kexec@lists.infradead.org
---
v2 -> v3
  improve commit log

 kernel/kexec_core.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
index 1a79c5b18d8f..95c585c6ddc3 100644
--- a/kernel/kexec_core.c
+++ b/kernel/kexec_core.c
@@ -960,13 +960,17 @@ void *kimage_map_segment(struct kimage *image, int idx)
 	kimage_entry_t *ptr, entry;
 	struct page **src_pages;
 	unsigned int npages;
+	struct page *cma;
 	void *vaddr = NULL;
 	int i;
 
+	cma = image->segment_cma[idx];
+	if (cma)
+		return page_address(cma);
+
 	addr = image->segment[idx].mem;
 	size = image->segment[idx].memsz;
 	eaddr = addr + size;
-
 	/*
 	 * Collect the source pages and map them in a contiguous VA range.
 	 */
@@ -1007,7 +1011,8 @@ void *kimage_map_segment(struct kimage *image, int idx)
 
 void kimage_unmap_segment(void *segment_buffer)
 {
-	vunmap(segment_buffer);
+	if (is_vmalloc_addr(segment_buffer))
+		vunmap(segment_buffer);
 }
 
 struct kexec_load_limit {
-- 
2.49.0

Re: [PATCHv3 1/2] kernel/kexec: Change the prototype of kimage_map_segment()

[Baoquan He]

On 12/16/25 at 09:48am, Pingfan Liu wrote:
> 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.
> 
> Fixes: 07d24902977e ("kexec: enable CMA based contiguous allocation")
> Signed-off-by: Pingfan Liu <piliu@redhat.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Baoquan He <bhe@redhat.com>
> Cc: Mimi Zohar <zohar@linux.ibm.com>
> Cc: Roberto Sassu <roberto.sassu@huawei.com>
> Cc: Alexander Graf <graf@amazon.com>
> Cc: Steven Chen <chenste@linux.microsoft.com>
> Cc: linux-kernel@vger.kernel.org
> Cc: <stable@vger.kernel.org>
> To: kexec@lists.infradead.org
> To: linux-integrity@vger.kernel.org
> ---
>  include/linux/kexec.h              | 4 ++--
>  kernel/kexec_core.c                | 9 ++++++---
>  security/integrity/ima/ima_kexec.c | 4 +---
>  3 files changed, 9 insertions(+), 8 deletions(-)

Ack the series:

Acked-by: Baoquan He <bhe@redhat.com>