[Crash-utility] Re: [PATCH v3] kmem: fix the determination for slab page

On Fri, Sep 20, 2024 at 9:30 AM <devel-request(a)lists.crash-utility.osci.io&gt; wrote: > > Date: Fri, 20 Sep 2024 01:28:32 -0000 > From: qiwu.chen(a)transsion.com > Subject: [Crash-utility] [PATCH v3] kmem: fix the determination for > slab page > To: devel(a)lists.crash-utility.osci.io > Message-ID: <20240920012832.29184.28326(a)lists.crash-utility.osci.io&gt; > Content-Type: text/plain; charset="utf-8" > > The determination for a slab page has changed due to changing > PG_slab from a page flag to a page type since kernel commit > 46df8e73a4a3. > > Before apply this patch: > crash> kmem -s ffff000002aa4100 > kmem: address is not allocated in slab subsystem: ffff000002aa4100 > > After apply this patch: > crash> kmem -s ffff000002aa4100 > CACHE OBJSIZE ALLOCATED TOTAL SLABS SSIZE NAME > ffff00000140f900 4096 94 126 18 32k task_struct > SLAB MEMORY NODE TOTAL ALLOCATED FREE > fffffdffc00aa800 ffff000002aa0000 0 7 5 2 > FREE / [ALLOCATED] > [ffff000002aa4100] > > Signed-off-by: qiwu.chen <qiwu.chen(a)transsion.com&gt; > --- > defs.h | 7 ++++++ > memory.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++--------- > symbols.c | 2 ++ > 3 files changed, 66 insertions(+), 11 deletions(-) > Thank you for the update, qiwu. I have no other issues, for the v3: Ack Thanks Lianbo > > 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..8befe8c 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; > > +/* > + * Before kernel commit ff202303c398e, the value is defined as a macro, so copy it here; > + * After this commit, the value is defined as an enum, which can be evaluated at runtime. > + */ > +#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) > +{ > + 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 page, 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(page+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 +541,7 @@ 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"); > + MEMBER_OFFSET_INIT(page_page_type, "page", "page_type"); > > MEMBER_OFFSET_INIT(mm_struct_pgd, "mm_struct", "pgd"); > > @@ -1278,6 +1316,8 @@ vm_init(void) > > page_flags_init(); > > + page_type_init(); > + > rss_page_types_init(); > > vt->flags |= VM_INIT; > @@ -5931,7 +5971,7 @@ 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 +6421,7 @@ 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) > @@ -6694,7 +6734,6 @@ dump_hstates() > FREEBUF(hstate); > } > > - > static void > page_flags_init(void) > { > @@ -6775,6 +6814,9 @@ 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, > @@ -6835,8 +6877,9 @@ 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]); > - > + vt->pageflags_data[p].mask = 1 << atoi(arglist[2]); > + if (!strncmp(nameptr, "slab", 4)) > + vt->flags |= SLAB_PAGEFLAGS; > p++; > } > } else > @@ -9736,14 +9779,14 @@ 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; > @@ -14108,6 +14151,8 @@ dump_vm_table(int verbose) > fprintf(fp, "%sNODELISTS_IS_PTR", others++ ? "|" : "");\ > if (vt->flags & VM_INIT) > fprintf(fp, "%sVM_INIT", others++ ? "|" : "");\ > + if (vt->flags & SLAB_PAGEFLAGS) > + fprintf(fp, "%sSLAB_PAGEFLAGS", others++ ? "|" : "");\ > > fprintf(fp, ")\n"); > if (vt->kernel_pgd[0] == vt->kernel_pgd[1]) > @@ -14237,6 +14282,7 @@ dump_vm_table(int verbose) > vt->pageflags_data[i].mask, > vt->pageflags_data[i].name); > } > + fprintf(fp, " page_type_base: %x\n", vt->page_type_base); > > dump_vma_cache(VERBOSE); > } > @@ -20195,7 +20241,7 @@ 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 +20256,11 @@ 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 +20268,7 @@ 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)) > diff --git a/symbols.c b/symbols.c > index 69a1fbb..014cd29 100644 > --- a/symbols.c > +++ b/symbols.c > @@ -10339,6 +10339,8 @@ dump_offset_table(char *spec, ulong makestruct) > fprintf(fp, " page_compound_head: %ld\n", > OFFSET(page_compound_head)); > fprintf(fp, " page_private: %ld\n", OFFSET(page_private)); > + fprintf(fp, " page_page_type: %ld\n", > + OFFSET(page_page_type)); > > fprintf(fp, " trace_print_flags_mask: %ld\n", > OFFSET(trace_print_flags_mask)); > -- > 2.25.1 -- Crash-utility mailing list -- devel(a)lists.crash-utility.osci.io To unsubscribe send an email to devel-leave(a)lists.crash-utility.osci.io https://${domain_name}/admin/lists/devel.lists.crash-utility.osci.io/ Contribution Guidelines: https://github.com/crash-utility/crash/wiki