Backport from upstream.
commit 38d921a2ef50ebd36258097553626443ffe27496
Author: Coiby Xu <coxu@redhat.com>
Date: Tue Jun 15 18:26:31 2021 +0800
[PATCH] check for invalid physical address of /proc/kcore when finding max_paddr
Kernel commit 464920104bf7adac12722035bfefb3d772eb04d8 ("/proc/kcore:
update physical address for kcore ram and text") sets an invalid paddr
(0xffffffffffffffff = -1) for PT_LOAD segments of not direct mapped
regions:
$ readelf -l /proc/kcore
...
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
makedumpfile 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]:
$ 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@redhat.com>
Signed-off-by: Coiby Xu <coxu@redhat.com>
Signed-off-by: Tao Liu <ltao@redhat.com>
Acked-by: Kairui Song <kasong@redhat.com>
