Hi Tao,
Thanks for your review.
>
> Thanks for the fix, however there are several issues:
>
> On Mon, Sep 2, 2024 at 2:30 AM <qiwu.chen(a)transsion.com> wrote:
>
> The new members for the offset_table should always be appended to the
> end of the struct.
>
>
> 1. The function naming better be page_slab() instead of PageSlab.
>
> 2. For the 1st "if", the page_type is not used, only used in the
> "else" branch. But page_type will always be readmem() previously, also
> page_type may not exist for older kernels. Can you rewrite the
> function?
>
>
> There is a problem for readmem(page_page_type), the page_type member
> of struct page is not introduced for kernels such as v4.17 and prior.
> E.g for 3.10:
>
> crash> kmem -s ffff880169b30000
>
> kmem: invalid structure member offset: page_page_type
> FILE: memory.c LINE: 9780 FUNCTION: vaddr_to_kmem_cache()
>
> [/root/crash-dev/crash] error trace: 530063 => 55e269 => 53f5d8 => 63740e
>
> 63740e: OFFSET_verify+164
> 53f5d8: vaddr_to_kmem_cache+299
> 55e269: dump_kmem_cache_slub+688
> 530063: cmd_kmem+3017
>
> kmem: invalid structure member offset: page_page_type
> FILE: memory.c LINE: 9780 FUNCTION: vaddr_to_kmem_cache()
>
> Also see the comment for function PageSlab.
>
I make a improvement in the following change as your comments. The page_slab() function will resolve the problem for readmem(page_page_type), since it will test the page_type member of struct page exist before readmem(page_page_type).
diff --git a/defs.h b/defs.h
index 2231cb6..e2a9278 100644
--- a/defs.h
+++ b/defs.h
@@ -2243,6 +2243,7 @@ struct offset_table { /* stash of commonly-used offsets */
long vmap_node_busy;
long rb_list_head;
long file_f_inode;
+ long page_page_type;
};
struct size_table { /* stash of commonly-used sizes */
@@ -2651,6 +2652,7 @@ struct vm_table { /* kernel VM-related data */
ulong max_mem_section_nr;
ulong zero_paddr;
ulong huge_zero_paddr;
+ uint page_type_base;
};
#define NODES (0x1)
@@ -2684,6 +2686,11 @@ struct vm_table { /* kernel VM-related data */
#define SLAB_CPU_CACHE (0x10000000)
#define SLAB_ROOT_CACHES (0x20000000)
#define USE_VMAP_NODES (0x40000000)
+/*
+ * The SLAB_PAGEFLAGS flag is introduced to detect the change of
+ * PG_slab's type from a page flag to a page type.
+ */
+#define SLAB_PAGEFLAGS (0x80000000)
#define IS_FLATMEM() (vt->flags & FLATMEM)
#define IS_DISCONTIGMEM() (vt->flags & DISCONTIGMEM)
diff --git a/memory.c b/memory.c
index 967a9cf..a2885bd 100644
--- a/memory.c
+++ b/memory.c
@@ -351,6 +351,43 @@ static ulong handle_each_vm_area(struct handle_each_vm_area_args *);
static ulong DISPLAY_DEFAULT;
+#define PAGE_TYPE_BASE 0xf0000000
+#define PageType(page_type, flag) \
+ ((page_type & (vt->page_type_base | flag)) == vt->page_type_base)
+
+static void page_type_init(void)
+{
+ /*
+ * The page type macros covert into enum since kernel commit ff202303c398e,
+ * use the default macro value if the vmcoreinfo without enum pagetype.
+ */
+ if (!enumerator_value("PAGE_TYPE_BASE", (long *)&vt->page_type_base))
+ vt->page_type_base = PAGE_TYPE_BASE;
+}
+
+/*
+ * The PG_slab's type has changed from a page flag to a page type
+ * since kernel commit 46df8e73a4a3.
+ */
+static bool page_slab(ulong pp, ulong flags)
+{
+ if (vt->flags & SLAB_PAGEFLAGS) {
+ if ((flags >> vt->PG_slab) & 1)
+ return TRUE;
+ }
+
+ if (VALID_MEMBER(page_page_type)) {
+ uint page_type;
+
+ readmem(pp+OFFSET(page_page_type), KVADDR, &page_type,
+ sizeof(page_type), "page_type", FAULT_ON_ERROR);
+ if (PageType(page_type, (uint)vt->PG_slab))
+ return TRUE;
+ }
+
+ return FALSE;
+}
+
/*
* Verify that the sizeof the primitive types are reasonable.
*/
@@ -504,6 +541,10 @@ vm_init(void)
ANON_MEMBER_OFFSET_INIT(page_compound_head, "page", "compound_head");
MEMBER_OFFSET_INIT(page_private, "page", "private");
MEMBER_OFFSET_INIT(page_freelist, "page", "freelist");
+ if (MEMBER_EXISTS("page", "page_type")) {
+ MEMBER_OFFSET_INIT(page_page_type, "page", "page_type");
+ page_type_init();
+ }
MEMBER_OFFSET_INIT(mm_struct_pgd, "mm_struct", "pgd");
@@ -5931,7 +5972,7 @@ dump_mem_map_SPARSEMEM(struct meminfo *mi)
if ((flags >> v22_PG_Slab) & 1)
slabs++;
} else if (vt->PG_slab) {
- if ((flags >> vt->PG_slab) & 1)
+ if (page_slab(pp, flags))
slabs++;
} else {
if ((flags >> v24_PG_slab) & 1)
@@ -6381,7 +6422,7 @@ dump_mem_map(struct meminfo *mi)
if ((flags >> v22_PG_Slab) & 1)
slabs++;
} else if (vt->PG_slab) {
- if ((flags >> vt->PG_slab) & 1)
+ if (page_slab(pp, flags))
slabs++;
} else {
if ((flags >> v24_PG_slab) & 1)
@@ -6775,6 +6816,9 @@ page_flags_init_from_pageflag_names(void)
vt->pageflags_data[i].name = nameptr;
vt->pageflags_data[i].mask = mask;
+ if (!strncmp(nameptr, "slab", 4))
+ vt->flags |= SLAB_PAGEFLAGS;
+
if (CRASHDEBUG(1)) {
fprintf(fp, " %08lx %s\n",
vt->pageflags_data[i].mask,
@@ -6836,7 +6880,8 @@ page_flags_init_from_pageflags_enum(void)
strcpy(nameptr, arglist[0] + strlen("PG_"));
vt->pageflags_data[p].name = nameptr;
vt->pageflags_data[p].mask = 1 << atoi(arglist[2]);
-
+ if (!strncmp(nameptr, "slab", 4))
+ vt->flags |= SLAB_PAGEFLAGS;
p++;
}
} else
@@ -9736,14 +9781,14 @@ vaddr_to_kmem_cache(ulong vaddr, char *buf, int verbose)
readmem(page+OFFSET(page_flags), KVADDR,
&page_flags, sizeof(ulong), "page.flags",
FAULT_ON_ERROR);
- if (!(page_flags & (1 << vt->PG_slab))) {
+ if (!page_slab(page, page_flags)) {
if (((vt->flags & KMALLOC_SLUB) || VALID_MEMBER(page_compound_head)) ||
((vt->flags & KMALLOC_COMMON) &&
VALID_MEMBER(page_slab) && VALID_MEMBER(page_first_page))) {
readmem(compound_head(page)+OFFSET(page_flags), KVADDR,
&page_flags, sizeof(ulong), "page.flags",
FAULT_ON_ERROR);
- if (!(page_flags & (1 << vt->PG_slab)))
+ if (!page_slab(compound_head(page), page_flags))
return NULL;
} else
return NULL;
@@ -20195,7 +20240,7 @@ char *
is_slab_page(struct meminfo *si, char *buf)
{
int i, cnt;
- ulong page_slab, page_flags, name;
+ ulong pg_slab, page_flags, name;
ulong *cache_list;
char *retval;
@@ -20210,11 +20255,11 @@ is_slab_page(struct meminfo *si, char *buf)
RETURN_ON_ERROR|QUIET))
return NULL;
- if (!(page_flags & (1 << vt->PG_slab)))
+ if (!page_slab(si->spec_addr, page_flags))
return NULL;
if (!readmem(si->spec_addr + OFFSET(page_slab), KVADDR,
- &page_slab, sizeof(ulong), "page.slab",
+ &pg_slab, sizeof(ulong), "page.slab",
RETURN_ON_ERROR|QUIET))
return NULL;
@@ -20222,7 +20267,7 @@ is_slab_page(struct meminfo *si, char *buf)
cnt = get_kmem_cache_list(&cache_list);
for (i = 0; i < cnt; i++) {
- if (page_slab == cache_list[i]) {
+ if (pg_slab == cache_list[i]) {
if (!readmem(cache_list[i] + OFFSET(kmem_cache_name),
KVADDR, &name, sizeof(char *),
"kmem_cache.name", QUIET|RETURN_ON_ERROR))
--
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