This series includes some bug fixes and cleanups for kexec.
This v5 series introduces no changes to any patches. I just reorganize the
patches and repost them.
Yuntao Wang (3):
kexec: modify the meaning of the end parameter in
kimage_is_destination_range()
kexec_file: fix incorrect temp_start value in
locate_mem_hole_top_down()
x86/kexec: use pr_err() instead of pr_debug() when an error occurs
arch/x86/kernel/kexec-bzimage64.c | 2 +-
kernel/kexec_core.c | 8 ++++----
kernel/kexec_file.c | 4 ++--
mm/highmem.c | 2 --
4 files changed, 7 insertions(+), 9 deletions(-)
--
2.43.0
The end parameter received by kimage_is_destination_range() should be the
last valid byte address of the target memory segment plus 1. However, in
the locate_mem_hole_bottom_up() and locate_mem_hole_top_down() functions,
the corresponding value passed to kimage_is_destination_range() is the last
valid byte address of the target memory segment, which is 1 less.
There are two ways to fix this bug. We can either correct the logic of the
locate_mem_hole_bottom_up() and locate_mem_hole_top_down() functions, or we
can fix kimage_is_destination_range() by making the end parameter represent
the last valid byte address of the target memory segment. Here, we choose
the second approach.
Due to the modification to kimage_is_destination_range(), we also need to
adjust its callers, such as kimage_alloc_normal_control_pages() and
kimage_alloc_page().
Signed-off-by: Yuntao Wang <[email protected]>
Acked-by: Baoquan He <[email protected]>
---
v1->v2:
Fix this issue using the approach suggested by Eric and Baoquan.
v2->v3:
Modify the assignment of eaddr as suggested by Baoquan.
v3->v4:
`eaddr = epfn << PAGE_SHIFT - 1` causes a compilation warning, fix it.
v4->v5:
No changes.
kernel/kexec_core.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
index be5642a4ec49..e3b1a699f087 100644
--- a/kernel/kexec_core.c
+++ b/kernel/kexec_core.c
@@ -276,8 +276,8 @@ int kimage_is_destination_range(struct kimage *image,
unsigned long mstart, mend;
mstart = image->segment[i].mem;
- mend = mstart + image->segment[i].memsz;
- if ((end > mstart) && (start < mend))
+ mend = mstart + image->segment[i].memsz - 1;
+ if ((end >= mstart) && (start <= mend))
return 1;
}
@@ -370,7 +370,7 @@ static struct page *kimage_alloc_normal_control_pages(struct kimage *image,
pfn = page_to_boot_pfn(pages);
epfn = pfn + count;
addr = pfn << PAGE_SHIFT;
- eaddr = epfn << PAGE_SHIFT;
+ eaddr = (epfn << PAGE_SHIFT) - 1;
if ((epfn >= (KEXEC_CONTROL_MEMORY_LIMIT >> PAGE_SHIFT)) ||
kimage_is_destination_range(image, addr, eaddr)) {
list_add(&pages->lru, &extra_pages);
@@ -716,7 +716,7 @@ static struct page *kimage_alloc_page(struct kimage *image,
/* If the page is not a destination page use it */
if (!kimage_is_destination_range(image, addr,
- addr + PAGE_SIZE))
+ addr + PAGE_SIZE - 1))
break;
/*
--
2.43.0
temp_end represents the address of the last available byte. Therefore, the
starting address of the memory segment with temp_end as its last available
byte and a size of `kbuf->memsz`, that is, the value of temp_start, should
be `temp_end - kbuf->memsz + 1` instead of `temp_end - kbuf->memsz`.
Additionally, use the ALIGN_DOWN macro instead of open-coding it directly
in locate_mem_hole_top_down() to improve code readability.
Signed-off-by: Yuntao Wang <[email protected]>
---
kernel/kexec_file.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index f9a419cd22d4..336d085cbc47 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -426,11 +426,11 @@ static int locate_mem_hole_top_down(unsigned long start, unsigned long end,
unsigned long temp_start, temp_end;
temp_end = min(end, kbuf->buf_max);
- temp_start = temp_end - kbuf->memsz;
+ temp_start = temp_end - kbuf->memsz + 1;
do {
/* align down start */
- temp_start = temp_start & (~(kbuf->buf_align - 1));
+ temp_start = ALIGN_DOWN(temp_start, kbuf->buf_align);
if (temp_start < start || temp_start < kbuf->buf_min)
return 0;
--
2.43.0
When an error is detected, use pr_err() instead of pr_debug() to output
log message.
In addition, remove the unnecessary return from set_page_address().
Signed-off-by: Yuntao Wang <[email protected]>
---
arch/x86/kernel/kexec-bzimage64.c | 2 +-
mm/highmem.c | 2 --
2 files changed, 1 insertion(+), 3 deletions(-)
diff --git a/arch/x86/kernel/kexec-bzimage64.c b/arch/x86/kernel/kexec-bzimage64.c
index a61c12c01270..472a45dbc79a 100644
--- a/arch/x86/kernel/kexec-bzimage64.c
+++ b/arch/x86/kernel/kexec-bzimage64.c
@@ -424,7 +424,7 @@ static void *bzImage64_load(struct kimage *image, char *kernel,
* command line. Make sure it does not overflow
*/
if (cmdline_len + MAX_ELFCOREHDR_STR_LEN > header->cmdline_size) {
- pr_debug("Appending elfcorehdr=<addr> to command line exceeds maximum allowed length\n");
+ pr_err("Appending elfcorehdr=<addr> to command line exceeds maximum allowed length\n");
return ERR_PTR(-EINVAL);
}
diff --git a/mm/highmem.c b/mm/highmem.c
index e19269093a93..bd48ba445dd4 100644
--- a/mm/highmem.c
+++ b/mm/highmem.c
@@ -799,8 +799,6 @@ void set_page_address(struct page *page, void *virtual)
}
spin_unlock_irqrestore(&pas->lock, flags);
}
-
- return;
}
void __init page_address_init(void)
--
2.43.0
On 12/17/23 at 11:35am, Yuntao Wang wrote:
> This series includes some bug fixes and cleanups for kexec.
>
> This v5 series introduces no changes to any patches. I just reorganize the
> patches and repost them.
LGTM, thx.
Acked-by: Baoquan He <[email protected]>
>
> Yuntao Wang (3):
> kexec: modify the meaning of the end parameter in
> kimage_is_destination_range()
> kexec_file: fix incorrect temp_start value in
> locate_mem_hole_top_down()
> x86/kexec: use pr_err() instead of pr_debug() when an error occurs
>
> arch/x86/kernel/kexec-bzimage64.c | 2 +-
> kernel/kexec_core.c | 8 ++++----
> kernel/kexec_file.c | 4 ++--
> mm/highmem.c | 2 --
> 4 files changed, 7 insertions(+), 9 deletions(-)
>
> --
> 2.43.0
>
On Sun, 17 Dec 2023 11:35:28 +0800 Yuntao Wang <[email protected]> wrote:
> When an error is detected, use pr_err() instead of pr_debug() to output
> log message.
>
> In addition, remove the unnecessary return from set_page_address().
>
> ...
>
> --- a/arch/x86/kernel/kexec-bzimage64.c
> +++ b/arch/x86/kernel/kexec-bzimage64.c
> @@ -424,7 +424,7 @@ static void *bzImage64_load(struct kimage *image, char *kernel,
> * command line. Make sure it does not overflow
> */
> if (cmdline_len + MAX_ELFCOREHDR_STR_LEN > header->cmdline_size) {
> - pr_debug("Appending elfcorehdr=<addr> to command line exceeds maximum allowed length\n");
> + pr_err("Appending elfcorehdr=<addr> to command line exceeds maximum allowed length\n");
> return ERR_PTR(-EINVAL);
> }
https://lkml.kernel.org/r/[email protected] has
already changed this to call kexec_dprintk(). I'll skip this patch.
When an error is detected, use pr_err() instead of kexec_dprintk() to
output log message.
In addition, remove the unnecessary return from set_page_address().
Signed-off-by: Yuntao Wang <[email protected]>
---
arch/x86/kernel/kexec-bzimage64.c | 2 +-
mm/highmem.c | 2 --
2 files changed, 1 insertion(+), 3 deletions(-)
diff --git a/arch/x86/kernel/kexec-bzimage64.c b/arch/x86/kernel/kexec-bzimage64.c
index e9ae0eac6bf9..4a77d5dd4bce 100644
--- a/arch/x86/kernel/kexec-bzimage64.c
+++ b/arch/x86/kernel/kexec-bzimage64.c
@@ -429,7 +429,7 @@ static void *bzImage64_load(struct kimage *image, char *kernel,
* command line. Make sure it does not overflow
*/
if (cmdline_len + MAX_ELFCOREHDR_STR_LEN > header->cmdline_size) {
- kexec_dprintk("Appending elfcorehdr=<addr> to command line exceeds maximum allowed length\n");
+ pr_err("Appending elfcorehdr=<addr> to command line exceeds maximum allowed length\n");
return ERR_PTR(-EINVAL);
}
diff --git a/mm/highmem.c b/mm/highmem.c
index e19269093a93..bd48ba445dd4 100644
--- a/mm/highmem.c
+++ b/mm/highmem.c
@@ -799,8 +799,6 @@ void set_page_address(struct page *page, void *virtual)
}
spin_unlock_irqrestore(&pas->lock, flags);
}
-
- return;
}
void __init page_address_init(void)
--
2.43.0
On Tue, 19 Dec 2023 15:29:01 +0800 Yuntao Wang <[email protected]> wrote:
> When an error is detected, use pr_err() instead of kexec_dprintk() to
> output log message.
>
> In addition, remove the unnecessary return from set_page_address().
The above describes what the code does, which is already quite clear
from looking at the code.
Please write changelogs and code comments which describe *why* the code
does something, rather than *what* it does.
>
>
> --- a/arch/x86/kernel/kexec-bzimage64.c
> +++ b/arch/x86/kernel/kexec-bzimage64.c
> @@ -429,7 +429,7 @@ static void *bzImage64_load(struct kimage *image, char *kernel,
> * command line. Make sure it does not overflow
> */
> if (cmdline_len + MAX_ELFCOREHDR_STR_LEN > header->cmdline_size) {
> - kexec_dprintk("Appending elfcorehdr=<addr> to command line exceeds maximum allowed length\n");
> + pr_err("Appending elfcorehdr=<addr> to command line exceeds maximum allowed length\n");
ie, what are the reasons for this change?
> return ERR_PTR(-EINVAL);
> }
>
> diff --git a/mm/highmem.c b/mm/highmem.c
> index e19269093a93..bd48ba445dd4 100644
> --- a/mm/highmem.c
> +++ b/mm/highmem.c
> @@ -799,8 +799,6 @@ void set_page_address(struct page *page, void *virtual)
> }
> spin_unlock_irqrestore(&pas->lock, flags);
> }
> -
> - return;
> }
>
> void __init page_address_init(void)
> --
> 2.43.0
When detecting an error, the current code uses kexec_dprintk() to output
log message. This is not quite appropriate as kexec_dprintk() is mainly
used for outputting debugging messages, rather than error messages.
Replace kexec_dprintk() with pr_err(). This also makes the output method
for this error log align with the output method for other error logs in
this function.
Additionally, the last return statement in set_page_address() is
unnecessary, remove it.
Signed-off-by: Yuntao Wang <[email protected]>
---
v1 -> v2: Rewrite changelogs
arch/x86/kernel/kexec-bzimage64.c | 2 +-
mm/highmem.c | 2 --
2 files changed, 1 insertion(+), 3 deletions(-)
diff --git a/arch/x86/kernel/kexec-bzimage64.c b/arch/x86/kernel/kexec-bzimage64.c
index e9ae0eac6bf9..4a77d5dd4bce 100644
--- a/arch/x86/kernel/kexec-bzimage64.c
+++ b/arch/x86/kernel/kexec-bzimage64.c
@@ -429,7 +429,7 @@ static void *bzImage64_load(struct kimage *image, char *kernel,
* command line. Make sure it does not overflow
*/
if (cmdline_len + MAX_ELFCOREHDR_STR_LEN > header->cmdline_size) {
- kexec_dprintk("Appending elfcorehdr=<addr> to command line exceeds maximum allowed length\n");
+ pr_err("Appending elfcorehdr=<addr> to command line exceeds maximum allowed length\n");
return ERR_PTR(-EINVAL);
}
diff --git a/mm/highmem.c b/mm/highmem.c
index e19269093a93..bd48ba445dd4 100644
--- a/mm/highmem.c
+++ b/mm/highmem.c
@@ -799,8 +799,6 @@ void set_page_address(struct page *page, void *virtual)
}
spin_unlock_irqrestore(&pas->lock, flags);
}
-
- return;
}
void __init page_address_init(void)
--
2.43.0