[MAKEDUMPFILE PATCH] makedumpfile: elf_info: check for invalid physical address when finding max_paddr
Coiby Xu
coxu at redhat.com
Tue Jun 15 03:10:47 PDT 2021
Kernel commit 464920104bf7adac12722035bfefb3d772eb04d8
"/proc/kcore: update physical address for kcore ram and text" sets an
invalid paddr (-1=0xffffffffffffffff) for PT_LOAD segments of not direct
mapped regions,
$ readelf -l /proc/kcore
Elf file type is CORE (Core file)
Entry point 0x0
There are 4 program headers, starting at offset 64
Program Headers:
Type Offset VirtAddr PhysAddr
FileSiz MemSiz Flags Align
NOTE 0x0000000000000120 0x0000000000000000 0x0000000000000000
0x0000000000002320 0x0000000000000000 0x0
LOAD 0x1000000000010000 0xd000000000000000 0xffffffffffffffff
^^^^^^^^^^^^^^^^^^
0x0001f80000000000 0x0001f80000000000 RWE 0x10000
LOAD 0x0000000000010000 0xc000000000000000 0x0000000000000000
0x00000003f0000000 0x00000003f0000000 RWE 0x10000
LOAD 0x3000000000010000 0xf000000000000000 0xffffffffffffffff
^^^^^^^^^^^^^^^^^^
0x0000000000fc0000 0x0000000000fc0000 RWE 0x10000
makedumple uses max_paddr to calculate the number of sections for sparse
memory model thus wrong number is obtained based on max_paddr=-1. This
error could lead to the failure of copying /proc/kcore for RHEL-8.5 on
ppc64le machine [1],
$ uname -r
4.18.0-312.el8.ppc64le
$ makedumpfile /proc/kcore vmcore1
get_mem_section: Could not validate mem_section.
get_mm_sparsemem: Can't get the address of mem_section.
makedumpfile Failed.
Let's check if the phys_start of the segment is a valid physical address
to fix this problem.
[1] https://bugzilla.redhat.com/show_bug.cgi?id=1965267
Reported-by: Xiaoying Yan <yiyan at redhat.com>
Signed-off-by: Coiby Xu <coxu at redhat.com>
---
elf_info.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/elf_info.c b/elf_info.c
index e8affb7..9444847 100644
--- a/elf_info.c
+++ b/elf_info.c
@@ -628,7 +628,7 @@ get_max_paddr(void)
for (i = 0; i < num_pt_loads; i++) {
pls = &pt_loads[i];
- if (max_paddr < pls->phys_end)
+ if (pls->phys_start != NOT_PADDR && max_paddr < pls->phys_end)
max_paddr = pls->phys_end;
}
return max_paddr;
--
2.31.1
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