On 2024/07/20 16:38, Lichen Liu wrote:
>> This will work only for 4.19 and later kernels, but might reduce users
>> that hit the issue. Does this work for you?
> That works for me because I'm testing for the 6.x kernel.
Thanks for the check. Is the issue a segmentation fault?
I've made a patch below, is this OK?
From 084742cba5b81da563074454ab8c879e8e411cb0 Mon Sep 17 00:00:00 2001
From: Kazuhito Hagio <k-hagio-ab@xxxxxxx>
Date: Mon, 22 Jul 2024 14:31:43 +0900
Subject: [PATCH] Workaround for segfault by "makedumpfile --mem-usage" on PPC64
"makedumpfile --mem-usage /proc/kcore" can cause a segmentation fault on
PPC64, because the readmem() of the following code path uses cache
before it's initialized in initial().
show_mem_usage
get_page_offset
get_versiondep_info_ppc64
readmem
...
initial
cache_init
The get_page_offset() is needed to get vmcoreinfo from /proc/kcore data,
so we can avoid calling it when a vmcoreinfo exists in the ELF NOTE
segment of /proc/kcore, i.e. on Linux 4.19 and later.
(Note: for older kernels, we will need another way to fix it.)
Reported-by: Lichen Liu <lichliu@xxxxxxxxxx>
Signed-off-by: Kazuhito Hagio <k-hagio-ab@xxxxxxx>
---
makedumpfile.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/makedumpfile.c b/makedumpfile.c
index 5b347126db76..7d1dfcca50d8 100644
--- a/makedumpfile.c
+++ b/makedumpfile.c
@@ -12019,14 +12019,14 @@ int show_mem_usage(void)
DEBUG_MSG("Read vmcoreinfo from NOTE segment: %d\n", vmcoreinfo);
}
- if (!get_page_offset())
- return FALSE;
+ if (!vmcoreinfo) {
+ if (!get_page_offset())
+ return FALSE;
- /* paddr_to_vaddr() on arm64 needs phys_base. */
- if (!get_phys_base())
- return FALSE;
+ /* paddr_to_vaddr() on arm64 needs phys_base. */
+ if (!get_phys_base())
+ return FALSE;
- if (!vmcoreinfo) {
if (!get_sys_kernel_vmcoreinfo(&vmcoreinfo_addr, &vmcoreinfo_len))
return FALSE;
--
2.31.1
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