在 2023/12/19 13:29, Yuntao Wang 写道:
On Tue, 19 Dec 2023 11:50:32 +0800, fuqiang wang <fuqiang.wang@xxxxxxxxxxxx> wrote:
在 2023/12/19 10:47, Yuntao Wang 写道:
Hi fuqiang,
Yesterday, I posted two patches that happen to address the bugs you an Baoquan
are currently discussing here, I wasn't aware that you both were also working
on fixing these issues.
Baoquan suggested I talk to you about it.
If you're interested, you can take a look at my patches and review them to see
if there are any issues. If everything is fine, and if you're willing, you can
also add a 'Reviewed-by' tag there.
The following link is for the two patches I posted yesterday:
https://lore.kernel.org/lkml/20231218081915.24120-3-ytcoode@xxxxxxxxx/t/#u
Sincerely,
Yuntao
Hi Yuntao,
I'm glad you've also noticed this issue. But I'm sorry, I want to solve this
problem myself because this is my first time posting a patch in the community,
and I cherish this opportunity very much.
I can truly understand your feelings because I still remember how thrilled I
was when my first patch got merged. So keep it up!
Hi Yuntao,
Thanks for your understanding and encourage. :)
I have carefully reviewed your patch. There is some changes where my views differ
from yours:
diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
index c92d88680dbf..3be46f4b441e 100644
--- a/arch/x86/kernel/crash.c
+++ b/arch/x86/kernel/crash.c
@@ -282,10 +282,6 @@ int crash_setup_memmap_entries(struct kimage *image, struct boot_params *params)
struct crash_memmap_data cmd;
struct crash_mem *cmem;
- cmem = vzalloc(struct_size(cmem, ranges, 1));
- if (!cmem)
- return -ENOMEM;
-
memset(&cmd, 0, sizeof(struct crash_memmap_data));
cmd.params = params;
@@ -321,6 +317,11 @@ int crash_setup_memmap_entries(struct kimage *image, struct boot_params *params)
}
/* Exclude some ranges from crashk_res and add rest to memmap */
+ cmem = vzalloc(struct_size(cmem, ranges, 1));
+ if (!cmem)
+ return -ENOMEM;
+ cmem->max_nr_ranges = 1;
+
ret = memmap_exclude_ranges(image, cmem, crashk_res.start, crashk_res.end);
if (ret)
goto out;
1. I don't feel very good that you have moved vzalloc() to in front of
memmap_exclude_ranges. Because if memory allocation fails, there is no need to
do anything else afterwards.
I moved it here because only memmap_exclude_ranges() and the code below it use cmem.
I think it is a good practice to put related code together, which also improves
code readability.
Thank you very much for your patient comment. This change does indeed improve
readability. But as a combination of these two, how do you feel about moving
crash_setup_memmap_entries() behind vzalloc().
2. The cmem->max_nr_ranges should be set to 2. Because in
memmap_exclude_ranges, a cmem->ranges[] will be filled in and if a split occurs
later, another one will be added.
With the current code, image->elf_load_addr should be equal to crashk_res.start,
so split will not occur in crash_exclude_mem_range(). Therefore, setting
cmem->max_nr_ranges to 1 is safe.
The image->elf_load_addr is determined by arch_kexec_locate_mem_hole(), this
function can ensure that the value is within the range of [crashk_res.start,
crashk_res.end), but it seems that it cannot guarantee that its value will
always be equal to crashk_res.start. Perhaps I have some omissions, please
point them out.
Thanks
fuqiang
Thanks
fuqiang
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