File 0001-Fix-for-kmem-s-S-option-on-Linux-5.7-and-l... of Package crash.28010

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File 0001-Fix-for-kmem-s-S-option-on-Linux-5.7-and-later-kerne.patch of Package crash.28010

From 647a5c33e1c94054d7b63168cd6c12901591cb77 Mon Sep 17 00:00:00 2001
From: Lianbo Jiang <lijiang@redhat.com>
Date: Thu, 27 May 2021 18:02:11 +0800
Subject: [PATCH] Fix for "kmem -s|-S" option on Linux 5.7 and later kernels

Linux 5.7 and later kernels that contain kernel commit 1ad53d9fa3f6
("slub: improve bit diffusion for freelist ptr obfuscation") changed
the calculation formula in the freelist_ptr(), which added a swab()
call to mix bits a little more.  When kernel is configured with the
"CONFIG_SLAB_FREELIST_HARDENED=y", without the patch, the "kmem -s|-S"
options display wrong statistics and state whether slab objects are
in use or free and can print the following errors:

crash> kmem -s
  CACHE             OBJSIZE  ALLOCATED     TOTAL  SLABS  SSIZE  NAME
  87201e00              528          0         0      0     8k  xfs_dqtrx
  87201f00              496          0         0      0     8k  xfs_dquot
  kmem: xfs_buf: slab: 37202e6e900 invalid freepointer: b844bab900001d70
  kmem: xfs_buf: slab: 3720250fd80 invalid freepointer: b8603f9400001370
  ...

Signed-off-by: Lianbo Jiang <lijiang@redhat.com>
---
 memory.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/memory.c b/memory.c
index 8c6bbe4..a3cf8a8 100644
--- a/memory.c
+++ b/memory.c
@@ -20,6 +20,7 @@
 #include <sys/mman.h>
 #include <ctype.h>
 #include <netinet/in.h>
+#include <byteswap.h>
 
 struct meminfo {           /* general purpose memory information structure */
         ulong cache;       /* used by the various memory searching/dumping */
@@ -19336,10 +19337,14 @@ count_free_objects(struct meminfo *si, ulong freelist)
 static ulong
 freelist_ptr(struct meminfo *si, ulong ptr, ulong ptr_addr)
 {
-	if (VALID_MEMBER(kmem_cache_random))
+	if (VALID_MEMBER(kmem_cache_random)) {
 		/* CONFIG_SLAB_FREELIST_HARDENED */
+
+		if (THIS_KERNEL_VERSION >= LINUX(5,7,0))
+			ptr_addr = (sizeof(long) == 8) ? bswap_64(ptr_addr)
+						       : bswap_32(ptr_addr);
 		return (ptr ^ si->random ^ ptr_addr);
-	else
+	} else
 		return ptr;
 }
 
-- 
2.33.1

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File 0001-Fix-for-kmem-s-S-option-on-Linux-5.7-and-later-kerne.patch of Package crash.28010

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