File makedumpfile-sadump-Fix-failure-of-reading.patch of Package makedumpfile

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File makedumpfile-sadump-Fix-failure-of-reading.patch of Package makedumpfile

From: "saito.kazuya@fujitsu.com" <saito.kazuya@fujitsu.com>
Date: Thu, 21 May 2020 07:15:19 +0000
Subject: sadump: Fix failure of reading __per_cpu_load memory
References: bsc#1168798
Upstream: merged
Git-commit: c9e078531efaffbe6f780221d40bdac21a84855b

Creating vmcore from sadump by makedumpfile fails with the following
error messages since kernel-4.19 with PTI (Page Table Isolation)
enabled:

__vtop4_x86_64: Can't get a valid pte.
  readmem: Can't convert a virtual address(ffffffffb2986000) to physical address.
  readmem: type_addr: 0, addr:ffffffffb2986000, size:8
  per_cpu_init: Can't read __per_cpu_load memory.

This is caused by the following patch:
https://github.com/torvalds/linux/commit/c40a56a7818cfe735fc93a69e1875f8bba834483

The above patch clears _PAGE_PRESENT bit of __per_cpu_load memory, so
__vtop4_x86_64 fails to convert the virtual address of the
__per_cpu_load.

To fix this issue, this patch changes sanity check of per_cpu_ptr()
to use address of the __per_cpu_load instead of data of the memory.

Signed-off-by: Kazuya Saito <saito.kazuya@fujitsu.com>
Signed-off-by: Kiyotaka Nakamura <kiyo@fujitsu.com>
---
 sadump_info.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/sadump_info.c b/sadump_info.c
index 46867ce..72a077b 100644
--- a/sadump_info.c
+++ b/sadump_info.c
@@ -1732,11 +1732,11 @@ per_cpu_init(void)
 		return FALSE;
 	}
 
-	if (!readmem(VADDR, SYMBOL(__per_cpu_load), &si->__per_cpu_load,
-		     sizeof(unsigned long))) {
-		ERRMSG("Can't read __per_cpu_load memory.\n");
+	if (SYMBOL(__per_cpu_load) == NOT_FOUND_SYMBOL) {
+		ERRMSG("Can't find __per_cpu_load symbol.\n");
 		return FALSE;
 	}
+	si->__per_cpu_load = SYMBOL(__per_cpu_load);
 
 	DEBUG_MSG("sadump: __per_cpu_load: %#lx\n", si->__per_cpu_load);
 	DEBUG_MSG("sadump: __per_cpu_offset: LENGTH: %ld\n",
-- 
2.26.2

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File makedumpfile-sadump-Fix-failure-of-reading.patch of Package makedumpfile

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