[PATCH] makedumpfile: sadump, kaslr: fix failure of calculating kaslr_offset

[Tao Liu]

Resolves: bz2055498
Upstream: github.com/makedumpfile/makedumpfile.git

commit 59b1726fbcc251155140c8a1972384498fee4daf
Author: HATAYAMA Daisuke 
Date:   Tue Jan 25 12:55:15 2022 +0000

[PATCH] sadump, kaslr: fix failure of calculating kaslr_offset

On kernels v5.8 or later, makedumpfile fails for memory dumps in the
    sadump-related formats as follows:

# makedumpfile -f -l -d 31 -x ./vmlinux /dev/sdd4 /root/vmcore-ld31
    __vtop4_x86_64: Can't get a valid pud_pte.
    ...110 lines of the same message...
    __vtop4_x86_64: Can't get a valid pud_pte.
    calc_kaslr_offset: failed to calculate kaslr_offset and phys_base; default to 0
    readmem: type_addr: 1, addr:ffffffff85411858, size:8
    __vtop4_x86_64: Can't get pgd (page_dir:ffffffff85411858).
    readmem: Can't convert a virtual address(ffffffff059be980) to physical address.
    readmem: type_addr: 0, addr:ffffffff059be980, size:1024
    cpu_online_mask_init: Can't read cpu_online_mask memory.

makedumpfile Failed.

This is caused by the kernel commit 9d06c4027f21 ("x86/entry: Convert
    Divide Error to IDTENTRY") that renamed divide_error to
    asm_exc_divide_error, breaking logic for calculating kaslr offset.

Fix this by adding initialization of asm_exc_divide_error.

Signed-off-by: HATAYAMA Daisuke

Signed-off-by: Tao Liu 
---
 ...lr-fix-failure-of-calculating-kaslr_.patch | 49 +++++++++++++++++++
 kexec-tools.spec                              |  2 +
 2 files changed, 51 insertions(+)
 create mode 100644 kexec-tools-2.0.23-makedumpfile-sadump-kaslr-fix-failure-of-calculating-kaslr_.patch

diff --git a/kexec-tools-2.0.23-makedumpfile-sadump-kaslr-fix-failure-of-calculating-kaslr_.patch b/kexec-tools-2.0.23-makedumpfile-sadump-kaslr-fix-failure-of-calculating-kaslr_.patch
new file mode 100644
index 0000000..e7a47b5
--- /dev/null
+++ b/kexec-tools-2.0.23-makedumpfile-sadump-kaslr-fix-failure-of-calculating-kaslr_.patch
@@ -0,0 +1,49 @@
+From 59b1726fbcc251155140c8a1972384498fee4daf Mon Sep 17 00:00:00 2001
+From: HATAYAMA Daisuke 
+Date: Tue, 25 Jan 2022 12:55:15 +0000
+Subject: [PATCH] [PATCH] sadump, kaslr: fix failure of calculating
+ kaslr_offset
+
+On kernels v5.8 or later, makedumpfile fails for memory dumps in the
+sadump-related formats as follows:
+
+    # makedumpfile -f -l -d 31 -x ./vmlinux /dev/sdd4 /root/vmcore-ld31
+    __vtop4_x86_64: Can't get a valid pud_pte.
+    ...110 lines of the same message...
+    __vtop4_x86_64: Can't get a valid pud_pte.
+    calc_kaslr_offset: failed to calculate kaslr_offset and phys_base; default to 0
+    readmem: type_addr: 1, addr:ffffffff85411858, size:8
+    __vtop4_x86_64: Can't get pgd (page_dir:ffffffff85411858).
+    readmem: Can't convert a virtual address(ffffffff059be980) to physical address.
+    readmem: type_addr: 0, addr:ffffffff059be980, size:1024
+    cpu_online_mask_init: Can't read cpu_online_mask memory.
+
+    makedumpfile Failed.
+
+This is caused by the kernel commit 9d06c4027f21 ("x86/entry: Convert
+Divide Error to IDTENTRY") that renamed divide_error to
+asm_exc_divide_error, breaking logic for calculating kaslr offset.
+
+Fix this by adding initialization of asm_exc_divide_error.
+
+Signed-off-by: HATAYAMA Daisuke 
+---
+ makedumpfile.c | 2 ++
+ 1 file changed, 2 insertions(+)
+
+diff --git a/makedumpfile-1.7.0/makedumpfile.c b/makedumpfile-1.7.0/makedumpfile.c
+index a51bdaf..7ed9756 100644
+--- a/makedumpfile-1.7.0/makedumpfile.c
++++ b/makedumpfile-1.7.0/makedumpfile.c
+@@ -1667,6 +1667,8 @@ get_symbol_info(void)
+ 	SYMBOL_INIT(cur_cpu_spec, "cur_cpu_spec");
+ 
+ 	SYMBOL_INIT(divide_error, "divide_error");
++	if (SYMBOL(divide_error) == NOT_FOUND_SYMBOL)
++		SYMBOL_INIT(divide_error, "asm_exc_divide_error");
+ 	SYMBOL_INIT(idt_table, "idt_table");
+ 	SYMBOL_INIT(saved_command_line, "saved_command_line");
+ 	SYMBOL_INIT(pti_init, "pti_init");
+-- 
+2.33.1
+
diff --git a/kexec-tools.spec b/kexec-tools.spec
index 6b7ef14..182662e 100644
--- a/kexec-tools.spec
+++ b/kexec-tools.spec
@@ -112,6 +112,7 @@ Patch401: ./kexec-tools-2.0.23-s390_handle_R_390_PLT32DBL_reloc_entries_in_machi
 #
 # Patches 601 onward are generic patches
 #
+Patch601: ./kexec-tools-2.0.23-makedumpfile-sadump-kaslr-fix-failure-of-calculating-kaslr_.patch

%description
 kexec-tools provides /sbin/kexec binary that facilitates a new
@@ -128,6 +129,7 @@ tar -z -x -v -f %{SOURCE9}
 tar -z -x -v -f %{SOURCE19}

%patch401 -p1
+%patch601 -p1

%ifarch ppc
 %define archdef ARCH=ppc