* [PATCH v2 1/4] kexec: Replace the goto out_unlock with out
2025-12-19 9:31 [PATCH v2 0/4] kexec: add kexec flag to control debug printing Qiang Ma
@ 2025-12-19 9:31 ` Qiang Ma
2025-12-19 9:31 ` [PATCH v2 2/4] kexec: add kexec flag to control debug printing Qiang Ma
` (3 subsequent siblings)
4 siblings, 0 replies; 8+ messages in thread
From: Qiang Ma @ 2025-12-19 9:31 UTC (permalink / raw)
To: akpm, bhe, catalin.marinas, will
Cc: kexec, linux-arm-kernel, linux-kernel, Qiang Ma
The image is initialized to NULL. Then, after calling kimage_alloc_init,
we can directly goto 'out' because at this time, the kimage_free will
determine whether image is a NULL pointer.
This will prepare for the subsequent patch to reset the variable in
kimage_free.
Signed-off-by: Qiang Ma <maqianga@uniontech.com>
---
kernel/kexec.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/kernel/kexec.c b/kernel/kexec.c
index 28008e3d462e..9bb1f2b6b268 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -95,6 +95,8 @@ static int do_kexec_load(unsigned long entry, unsigned long nr_segments,
unsigned long i;
int ret;
+ image = NULL;
+
/*
* Because we write directly to the reserved memory region when loading
* crash kernels we need a serialization here to prevent multiple crash
@@ -129,7 +131,7 @@ static int do_kexec_load(unsigned long entry, unsigned long nr_segments,
ret = kimage_alloc_init(&image, entry, nr_segments, segments, flags);
if (ret)
- goto out_unlock;
+ goto out;
if (flags & KEXEC_PRESERVE_CONTEXT)
image->preserve_context = 1;
--
2.20.1
^ permalink raw reply related [flat|nested] 8+ messages in thread* [PATCH v2 2/4] kexec: add kexec flag to control debug printing
2025-12-19 9:31 [PATCH v2 0/4] kexec: add kexec flag to control debug printing Qiang Ma
2025-12-19 9:31 ` [PATCH v2 1/4] kexec: Replace the goto out_unlock with out Qiang Ma
@ 2025-12-19 9:31 ` Qiang Ma
2025-12-19 9:31 ` [PATCH v2 3/4] kexec: print out debugging message if required for kexec_load Qiang Ma
` (2 subsequent siblings)
4 siblings, 0 replies; 8+ messages in thread
From: Qiang Ma @ 2025-12-19 9:31 UTC (permalink / raw)
To: akpm, bhe, catalin.marinas, will
Cc: kexec, linux-arm-kernel, linux-kernel, Qiang Ma
The commit cbc2fe9d9cb2 ("kexec_file: add kexec_file flag to control
debug printing") added the kexec_file flag to control debug printing.
However, for arm64, after commit 6f8c1da071a4 ("kexec_file, arm64: print
out debugging message if required"), when using the kexec_load interface,
the kexec_image_info function is called to print debug message, but
it uses kexec_dprintk, which is only available under kexec_file,
then when specifying 'kexec -d', kexec_load interface will print nothing.
For riscv, commit eb7622d908a09 ("kexec_file, riscv: print out debugging
message if required") remove kexec_image_info(), because the content has
been printed out in generic code in kexec_file_load, but not in kexec_load.
Therefore, in order to solve the two problems mentioned above, for this
patchset, several things need to be done:
1. Enabling kexec_dprintk is available for kexec_load.
2. Add some debugging message of the deleted kexec_image_info
to generic code.
3. Remove duplicate debugging prints for arm64
Since kexec_load and kexec_file_load are not triggered simultaneously,
we can unify the debug flag of kexec and kexec_file as kexec_dbg_print.
In this way, kexec_dprintk is available for kexec_load and kexec_file_load.
The following are the key points of the specific changes:
1. rename kexec_file_dbg_print to kexec_dbg_print
2. Add KEXEC_DEBUG
3. Initialize kexec_dbg_print for kexec
4. Set the reset of kexec_dbg_print to kimage_free
Signed-off-by: Qiang Ma <maqianga@uniontech.com>
---
include/linux/kexec.h | 9 +++++----
include/uapi/linux/kexec.h | 1 +
kernel/kexec.c | 1 +
kernel/kexec_core.c | 4 +++-
kernel/kexec_file.c | 4 +---
5 files changed, 11 insertions(+), 8 deletions(-)
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index ff7e231b0485..23f10aec0b34 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -455,10 +455,11 @@ bool kexec_load_permitted(int kexec_image_type);
/* List of defined/legal kexec flags */
#ifndef CONFIG_KEXEC_JUMP
-#define KEXEC_FLAGS (KEXEC_ON_CRASH | KEXEC_UPDATE_ELFCOREHDR | KEXEC_CRASH_HOTPLUG_SUPPORT)
+#define KEXEC_FLAGS (KEXEC_ON_CRASH | KEXEC_UPDATE_ELFCOREHDR | KEXEC_CRASH_HOTPLUG_SUPPORT | \
+ KEXEC_DEBUG)
#else
#define KEXEC_FLAGS (KEXEC_ON_CRASH | KEXEC_PRESERVE_CONTEXT | KEXEC_UPDATE_ELFCOREHDR | \
- KEXEC_CRASH_HOTPLUG_SUPPORT)
+ KEXEC_CRASH_HOTPLUG_SUPPORT | KEXEC_DEBUG)
#endif
/* List of defined/legal kexec file flags */
@@ -525,10 +526,10 @@ static inline int arch_kexec_post_alloc_pages(void *vaddr, unsigned int pages, g
static inline void arch_kexec_pre_free_pages(void *vaddr, unsigned int pages) { }
#endif
-extern bool kexec_file_dbg_print;
+extern bool kexec_dbg_print;
#define kexec_dprintk(fmt, arg...) \
- do { if (kexec_file_dbg_print) pr_info(fmt, ##arg); } while (0)
+ do { if (kexec_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_unmap_segment(void *buffer);
diff --git a/include/uapi/linux/kexec.h b/include/uapi/linux/kexec.h
index 55749cb0b81d..819c600af125 100644
--- a/include/uapi/linux/kexec.h
+++ b/include/uapi/linux/kexec.h
@@ -14,6 +14,7 @@
#define KEXEC_PRESERVE_CONTEXT 0x00000002
#define KEXEC_UPDATE_ELFCOREHDR 0x00000004
#define KEXEC_CRASH_HOTPLUG_SUPPORT 0x00000008
+#define KEXEC_DEBUG 0x00000010
#define KEXEC_ARCH_MASK 0xffff0000
/*
diff --git a/kernel/kexec.c b/kernel/kexec.c
index 9bb1f2b6b268..f6c58c767eb0 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -42,6 +42,7 @@ static int kimage_alloc_init(struct kimage **rimage, unsigned long entry,
if (!image)
return -ENOMEM;
+ kexec_dbg_print = !!(flags & KEXEC_DEBUG);
image->start = entry;
image->nr_segments = nr_segments;
memcpy(image->segment, segments, nr_segments * sizeof(*segments));
diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
index 0f92acdd354d..d7c2a2b79214 100644
--- a/kernel/kexec_core.c
+++ b/kernel/kexec_core.c
@@ -55,7 +55,7 @@ atomic_t __kexec_lock = ATOMIC_INIT(0);
/* Flag to indicate we are going to kexec a new kernel */
bool kexec_in_progress = false;
-bool kexec_file_dbg_print;
+bool kexec_dbg_print;
/*
* When kexec transitions to the new kernel there is a one-to-one
@@ -578,6 +578,8 @@ void kimage_free(struct kimage *image)
kimage_entry_t *ptr, entry;
kimage_entry_t ind = 0;
+ kexec_dbg_print = false;
+
if (!image)
return;
diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index eb62a9794242..3f1d6c4e8ff2 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -138,8 +138,6 @@ void kimage_file_post_load_cleanup(struct kimage *image)
*/
kfree(image->image_loader_data);
image->image_loader_data = NULL;
-
- kexec_file_dbg_print = false;
}
#ifdef CONFIG_KEXEC_SIG
@@ -314,7 +312,7 @@ kimage_file_alloc_init(struct kimage **rimage, int kernel_fd,
if (!image)
return -ENOMEM;
- kexec_file_dbg_print = !!(flags & KEXEC_FILE_DEBUG);
+ kexec_dbg_print = !!(flags & KEXEC_FILE_DEBUG);
image->file_mode = 1;
#ifdef CONFIG_CRASH_DUMP
--
2.20.1
^ permalink raw reply related [flat|nested] 8+ messages in thread* [PATCH v2 3/4] kexec: print out debugging message if required for kexec_load
2025-12-19 9:31 [PATCH v2 0/4] kexec: add kexec flag to control debug printing Qiang Ma
2025-12-19 9:31 ` [PATCH v2 1/4] kexec: Replace the goto out_unlock with out Qiang Ma
2025-12-19 9:31 ` [PATCH v2 2/4] kexec: add kexec flag to control debug printing Qiang Ma
@ 2025-12-19 9:31 ` Qiang Ma
2025-12-19 9:31 ` [PATCH v2 4/4] arm64: kexec: Adjust the debug print of kexec_image_info Qiang Ma
2026-01-19 23:49 ` [PATCH v2 0/4] kexec: add kexec flag to control debug printing Andrew Morton
4 siblings, 0 replies; 8+ messages in thread
From: Qiang Ma @ 2025-12-19 9:31 UTC (permalink / raw)
To: akpm, bhe, catalin.marinas, will
Cc: kexec, linux-arm-kernel, linux-kernel, Qiang Ma
The commit a85ee18c7900 ("kexec_file: print out debugging message
if required") has added general code printing in kexec_file_load(),
but not in kexec_load().
As a result, when using '-d' for the kexec_load interface,
print nothing in the kernel space.
Since the segments debugging message has already been printed by the
user-space tool kexec-tools, it will not be printed here in the
kernel space.
And print out type/start/head of kimage and flags to help debug.
Signed-off-by: Qiang Ma <maqianga@uniontech.com>
---
kernel/kexec.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/kernel/kexec.c b/kernel/kexec.c
index f6c58c767eb0..37e4ac8af9f3 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -166,6 +166,9 @@ static int do_kexec_load(unsigned long entry, unsigned long nr_segments,
if (ret)
goto out;
+ kexec_dprintk("kexec_load: type:%u, start:0x%lx head:0x%lx flags:0x%lx\n",
+ image->type, image->start, image->head, flags);
+
/* Install the new kernel and uninstall the old */
image = xchg(dest_image, image);
--
2.20.1
^ permalink raw reply related [flat|nested] 8+ messages in thread* [PATCH v2 4/4] arm64: kexec: Adjust the debug print of kexec_image_info
2025-12-19 9:31 [PATCH v2 0/4] kexec: add kexec flag to control debug printing Qiang Ma
` (2 preceding siblings ...)
2025-12-19 9:31 ` [PATCH v2 3/4] kexec: print out debugging message if required for kexec_load Qiang Ma
@ 2025-12-19 9:31 ` Qiang Ma
2026-01-05 20:41 ` Will Deacon
2026-01-19 23:49 ` [PATCH v2 0/4] kexec: add kexec flag to control debug printing Andrew Morton
4 siblings, 1 reply; 8+ messages in thread
From: Qiang Ma @ 2025-12-19 9:31 UTC (permalink / raw)
To: akpm, bhe, catalin.marinas, will
Cc: kexec, linux-arm-kernel, linux-kernel, Qiang Ma
In the previous patch, we move start/head of kimage to the
generic code, so, we remove them to avoid duplicate printing.
Signed-off-by: Qiang Ma <maqianga@uniontech.com>
---
arch/arm64/kernel/machine_kexec.c | 2 --
1 file changed, 2 deletions(-)
diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c
index 239c16e3d02f..0896e3e6a811 100644
--- a/arch/arm64/kernel/machine_kexec.c
+++ b/arch/arm64/kernel/machine_kexec.c
@@ -34,8 +34,6 @@ static void _kexec_image_info(const char *func, int line,
{
kexec_dprintk("%s:%d:\n", func, line);
kexec_dprintk(" kexec kimage info:\n");
- kexec_dprintk(" type: %d\n", kimage->type);
- kexec_dprintk(" head: %lx\n", kimage->head);
kexec_dprintk(" kern_reloc: %pa\n", &kimage->arch.kern_reloc);
kexec_dprintk(" el2_vectors: %pa\n", &kimage->arch.el2_vectors);
}
--
2.20.1
^ permalink raw reply related [flat|nested] 8+ messages in thread* Re: [PATCH v2 4/4] arm64: kexec: Adjust the debug print of kexec_image_info
2025-12-19 9:31 ` [PATCH v2 4/4] arm64: kexec: Adjust the debug print of kexec_image_info Qiang Ma
@ 2026-01-05 20:41 ` Will Deacon
0 siblings, 0 replies; 8+ messages in thread
From: Will Deacon @ 2026-01-05 20:41 UTC (permalink / raw)
To: Qiang Ma
Cc: akpm, bhe, catalin.marinas, kexec, linux-arm-kernel, linux-kernel
On Fri, Dec 19, 2025 at 05:31:34PM +0800, Qiang Ma wrote:
> In the previous patch, we move start/head of kimage to the
> generic code, so, we remove them to avoid duplicate printing.
>
> Signed-off-by: Qiang Ma <maqianga@uniontech.com>
> ---
> arch/arm64/kernel/machine_kexec.c | 2 --
> 1 file changed, 2 deletions(-)
>
> diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c
> index 239c16e3d02f..0896e3e6a811 100644
> --- a/arch/arm64/kernel/machine_kexec.c
> +++ b/arch/arm64/kernel/machine_kexec.c
> @@ -34,8 +34,6 @@ static void _kexec_image_info(const char *func, int line,
> {
> kexec_dprintk("%s:%d:\n", func, line);
> kexec_dprintk(" kexec kimage info:\n");
> - kexec_dprintk(" type: %d\n", kimage->type);
> - kexec_dprintk(" head: %lx\n", kimage->head);
> kexec_dprintk(" kern_reloc: %pa\n", &kimage->arch.kern_reloc);
> kexec_dprintk(" el2_vectors: %pa\n", &kimage->arch.el2_vectors);
> }
> --
> 2.20.1
Acked-by: Will Deacon <will@kernel.org>
Will
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v2 0/4] kexec: add kexec flag to control debug printing
2025-12-19 9:31 [PATCH v2 0/4] kexec: add kexec flag to control debug printing Qiang Ma
` (3 preceding siblings ...)
2025-12-19 9:31 ` [PATCH v2 4/4] arm64: kexec: Adjust the debug print of kexec_image_info Qiang Ma
@ 2026-01-19 23:49 ` Andrew Morton
2026-01-20 10:15 ` Baoquan He
4 siblings, 1 reply; 8+ messages in thread
From: Andrew Morton @ 2026-01-19 23:49 UTC (permalink / raw)
To: Qiang Ma
Cc: bhe, catalin.marinas, will, kexec, linux-arm-kernel, linux-kernel
On Fri, 19 Dec 2025 17:31:30 +0800 Qiang Ma <maqianga@uniontech.com> wrote:
> The commit cbc2fe9d9cb2 ("kexec_file: add kexec_file flag to control
> debug printing") added the kexec_file flag to control debug printing.
> However, for arm64, after commit 6f8c1da071a4 ("kexec_file, arm64: print
> out debugging message if required"), when using the kexec_load interface,
> the kexec_image_info function is called to print debug message, but
> it uses kexec_dprintk, which is only available under kexec_file,
> then when specifying 'kexec -d', kexec_load interface will print nothing.
>
> For riscv, commit eb7622d908a09 ("kexec_file, riscv: print out debugging
> message if required") remove kexec_image_info(), because the content has
> been printed out in generic code in kexec_file_load, but not in kexec_load.
>
> Therefore, in order to solve the two problems mentioned above, for this
> patchset, several things need to be done:
>
> 1. Enabling kexec_dprintk is available for kexec_load.
> 2. Add some debugging message of the deleted kexec_image_info
> to generic code.
> 3. Remove duplicate debugging prints for arm64.
Some additional review input on this series would be good, if someone
has the time.
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH v2 0/4] kexec: add kexec flag to control debug printing
2026-01-19 23:49 ` [PATCH v2 0/4] kexec: add kexec flag to control debug printing Andrew Morton
@ 2026-01-20 10:15 ` Baoquan He
0 siblings, 0 replies; 8+ messages in thread
From: Baoquan He @ 2026-01-20 10:15 UTC (permalink / raw)
To: Andrew Morton, Qiang Ma
Cc: catalin.marinas, will, kexec, linux-arm-kernel, linux-kernel
On 01/19/26 at 03:49pm, Andrew Morton wrote:
> On Fri, 19 Dec 2025 17:31:30 +0800 Qiang Ma <maqianga@uniontech.com> wrote:
>
> > The commit cbc2fe9d9cb2 ("kexec_file: add kexec_file flag to control
> > debug printing") added the kexec_file flag to control debug printing.
> > However, for arm64, after commit 6f8c1da071a4 ("kexec_file, arm64: print
> > out debugging message if required"), when using the kexec_load interface,
> > the kexec_image_info function is called to print debug message, but
> > it uses kexec_dprintk, which is only available under kexec_file,
> > then when specifying 'kexec -d', kexec_load interface will print nothing.
> >
> > For riscv, commit eb7622d908a09 ("kexec_file, riscv: print out debugging
> > message if required") remove kexec_image_info(), because the content has
> > been printed out in generic code in kexec_file_load, but not in kexec_load.
> >
> > Therefore, in order to solve the two problems mentioned above, for this
> > patchset, several things need to be done:
> >
> > 1. Enabling kexec_dprintk is available for kexec_load.
> > 2. Add some debugging message of the deleted kexec_image_info
> > to generic code.
> > 3. Remove duplicate debugging prints for arm64.
>
> Some additional review input on this series would be good, if someone
> has the time.
As I have said before, I am not fan of this patchset becuase I think
it's not necessary, even though it has no much harm except of adding code.
Leave this to those who like it.
^ permalink raw reply [flat|nested] 8+ messages in thread