[Crash-utility] [PATCH 1/2] Revert "Fix "kmem -s|-S" not working properly on RHEL8.6 and later"
This reverts commit 9253b40a0ecb2d365f89f0a5ebc28a01735c1d24.
The commit 9253b40a0ecb only handles the current issue on X86 64/X86
architectures, furthermore the freelist_ptr_bswap_x86() depends on
disassembling a static symbol which might not be available, depending on
how the compiler decides to optimize the code, that is to say, the
compiler might generate different code eventually.
More importantly, a subsequent patch can cover the current issue on
various architectures. Given that, revert the commit.
Signed-off-by: Lianbo Jiang <lijiang(a)redhat.com>
---
defs.h | 1 -
memory.c | 49 +------------------------------------------------
2 files changed, 1 insertion(+), 49 deletions(-)
diff --git a/defs.h b/defs.h
index 5ee60f1eb3a5..b7d2382cb314 100644
--- a/defs.h
+++ b/defs.h
@@ -2662,7 +2662,6 @@ struct vm_table { /* kernel VM-related data */
#define SLAB_OVERLOAD_PAGE (0x8000000)
#define SLAB_CPU_CACHE (0x10000000)
#define SLAB_ROOT_CACHES (0x20000000)
-#define FREELIST_PTR_BSWAP (0x40000000)
#define IS_FLATMEM() (vt->flags & FLATMEM)
#define IS_DISCONTIGMEM() (vt->flags & DISCONTIGMEM)
diff --git a/memory.c b/memory.c
index acbee6389472..626c6039c6d9 100644
--- a/memory.c
+++ b/memory.c
@@ -320,7 +320,6 @@ static void dump_per_cpu_offsets(void);
static void dump_page_flags(ulonglong);
static ulong kmem_cache_nodelists(ulong);
static void dump_hstates(void);
-static void freelist_ptr_init(void);
static ulong freelist_ptr(struct meminfo *, ulong, ulong);
static ulong handle_each_vm_area(struct handle_each_vm_area_args *);
@@ -791,8 +790,6 @@ vm_init(void)
MEMBER_OFFSET_INIT(kmem_cache_name, "kmem_cache", "name");
MEMBER_OFFSET_INIT(kmem_cache_flags, "kmem_cache", "flags");
MEMBER_OFFSET_INIT(kmem_cache_random, "kmem_cache", "random");
- if (VALID_MEMBER(kmem_cache_random))
- freelist_ptr_init();
MEMBER_OFFSET_INIT(kmem_cache_cpu_freelist, "kmem_cache_cpu",
"freelist");
MEMBER_OFFSET_INIT(kmem_cache_cpu_page, "kmem_cache_cpu", "page");
if (INVALID_MEMBER(kmem_cache_cpu_page))
@@ -13965,8 +13962,6 @@ dump_vm_table(int verbose)
fprintf(fp, "%sSLAB_CPU_CACHE", others++ ? "|" : "");\
if (vt->flags & SLAB_ROOT_CACHES)
fprintf(fp, "%sSLAB_ROOT_CACHES", others++ ? "|" : "");\
- if (vt->flags & FREELIST_PTR_BSWAP)
- fprintf(fp, "%sFREELIST_PTR_BSWAP", others++ ? "|" :
"");\
if (vt->flags & USE_VMAP_AREA)
fprintf(fp, "%sUSE_VMAP_AREA", others++ ? "|" : "");\
if (vt->flags & CONFIG_NUMA)
@@ -19653,55 +19648,13 @@ count_free_objects(struct meminfo *si, ulong freelist)
return c;
}
-/*
- * With CONFIG_SLAB_FREELIST_HARDENED, freelist_ptr's are crypted with xor's,
- * and for recent release with an additionnal bswap. Some releases prio to 5.7.0
- * may be using the additionnal bswap. The only easy and reliable way to tell is
- * to inspect assembly code (eg. "__slab_free") for a bswap instruction.
- */
-static int
-freelist_ptr_bswap_x86(void)
-{
- char buf1[BUFSIZE];
- char buf2[BUFSIZE];
- char *arglist[MAXARGS];
- int found;
-
- sprintf(buf1, "disassemble __slab_free");
- open_tmpfile();
- if (!gdb_pass_through(buf1, pc->tmpfile, GNU_RETURN_ON_ERROR)) {
- close_tmpfile();
- return FALSE;
- }
- rewind(pc->tmpfile);
- found = FALSE;
- while (fgets(buf2, BUFSIZE, pc->tmpfile)) {
- if (parse_line(buf2, arglist) < 3)
- continue;
- if (STREQ(arglist[2], "bswap")) {
- found = TRUE;
- break;
- }
- }
- close_tmpfile();
- return found;
-}
-
-static void
-freelist_ptr_init(void)
-{
- if (THIS_KERNEL_VERSION >= LINUX(5,7,0) ||
- ((machine_type("X86_64") || machine_type("X86")) &&
freelist_ptr_bswap_x86()))
- vt->flags |= FREELIST_PTR_BSWAP;
-}
-
static ulong
freelist_ptr(struct meminfo *si, ulong ptr, ulong ptr_addr)
{
if (VALID_MEMBER(kmem_cache_random)) {
/* CONFIG_SLAB_FREELIST_HARDENED */
- if (vt->flags & FREELIST_PTR_BSWAP)
+ 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);
--
2.37.1