From 38d921a2ef50ebd36258097553626443ffe27496 Mon Sep 17 00:00:00 2001 From: Coiby Xu Date: Tue, 15 Jun 2021 18:26:31 +0800 Subject: [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 Signed-off-by: Coiby Xu --- elf_info.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/makedumpfile-1.6.8/elf_info.c b/makedumpfile-1.6.8/elf_info.c index e8affb7..bc24083 100644 --- a/makedumpfile-1.6.8/elf_info.c +++ b/makedumpfile-1.6.8/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; -- 2.29.2