Kernel commit 130d4df57390 ("mm/sl[au]b: rearrange struct slab fields to allow larger rcu_head"), which is contained in Linux 6.2-rc1 and later kernels, changed the offset of slab.slab_list and now it's not equal to the offset of page.lru.
Without the patch, "kmem -s|-S" options print errors and zeros for slab counters like this for kernels configured with CONFIG_SLAB=y. crash> kmem -s CACHE OBJSIZE ALLOCATED TOTAL SLABS SSIZE NAME kmem: rpc_inode_cache: partial list: page/slab: fffff31ac4125190 bad active counter: 99476865 kmem: rpc_inode_cache: partial list: page/slab: fffff31ac4125190 bad s_mem pointer: 100000003 kmem: rpc_inode_cache: full list: page/slab: fffff31ac4125150 bad active counter: 99476225 kmem: rpc_inode_cache: full list: page/slab: fffff31ac4125150 bad active counter: 99476225 kmem: rpc_inode_cache: full list: page/slab: fffff31ac4125150 bad s_mem pointer: 100000005 ffff930202adfb40 704 0 0 0 4k rpc_inode_cache ... Signed-off-by: Kazuhito Hagio <k-hagio...@nec.com> --- memory.c | 45 +++++++++++++++++++++++++-------------------- 1 file changed, 25 insertions(+), 20 deletions(-) diff --git a/memory.c b/memory.c index 71ded688206f..156de2f7b5a3 100644 --- a/memory.c +++ b/memory.c @@ -78,6 +78,7 @@ struct meminfo { /* general purpose memory information structure */ int *freelist; int freelist_index_size; ulong random; + ulong list_offset; }; /* @@ -553,6 +554,8 @@ vm_init(void) MEMBER_OFFSET_INIT(page_freelist, "slab", "freelist"); if (INVALID_MEMBER(page_active)) MEMBER_OFFSET_INIT(page_active, "slab", "active"); + + MEMBER_OFFSET_INIT(slab_slab_list, "slab", "slab_list"); } if (!VALID_STRUCT(kmem_slab_s) && VALID_STRUCT(slab_s)) { @@ -10767,6 +10770,8 @@ dump_kmem_cache_percpu_v2(struct meminfo *si) if (vt->flags & SLAB_OVERLOAD_PAGE) { si->freelist = si->kmem_bufctl; si->freelist_index_size = slab_freelist_index_size(); + si->list_offset = VALID_MEMBER(slab_slab_list) ? + OFFSET(slab_slab_list) : OFFSET(page_lru); } for (i = 0; i < vt->kmem_max_cpus; i++) si->cpudata[i] = (ulong *) @@ -11983,7 +11988,7 @@ do_slab_chain_slab_overload_page(long cmd, struct meminfo *si) } last = si->slab; - readmem(si->slab - OFFSET(page_lru), KVADDR, page_buf, + readmem(si->slab - si->list_offset, KVADDR, page_buf, SIZE(page), "page (slab) buffer", FAULT_ON_ERROR); @@ -11996,8 +12001,7 @@ do_slab_chain_slab_overload_page(long cmd, struct meminfo *si) si->num_slabs++; - si->slab = ULONG(page_buf + - OFFSET(page_lru)); + si->slab = ULONG(page_buf + si->list_offset); /* * Check for slab transition. (Tony Dziedzic) @@ -12024,11 +12028,11 @@ do_slab_chain_slab_overload_page(long cmd, struct meminfo *si) case SLAB_WALKTHROUGH: if (si->flags & SLAB_OVERLOAD_PAGE_PTR) { specified_slab = si->spec_addr; - si->slab = si->spec_addr + OFFSET(page_lru); + si->slab = si->spec_addr + si->list_offset; } else { specified_slab = si->slab; if (si->slab) - si->slab += OFFSET(page_lru); + si->slab += si->list_offset; } si->flags |= (SLAB_WALKTHROUGH|SLAB_FIRST_NODE); si->flags &= ~SLAB_GET_COUNTS; @@ -12082,7 +12086,7 @@ do_slab_chain_slab_overload_page(long cmd, struct meminfo *si) if (si->slab == slab_chains[s]) continue; - readmem(si->slab - OFFSET(page_lru), KVADDR, page_buf, + readmem(si->slab - si->list_offset, KVADDR, page_buf, SIZE(page), "page (slab) buffer", FAULT_ON_ERROR); @@ -12242,7 +12246,7 @@ verify_slab_overload_page(struct meminfo *si, ulong last, int s) errcnt = 0; - if (!readmem(si->slab - OFFSET(page_lru), KVADDR, page_buf, + if (!readmem(si->slab - si->list_offset, KVADDR, page_buf, SIZE(page), "page (slab) buffer", QUIET|RETURN_ON_ERROR)) { error(INFO, "%s: %s list: bad slab pointer: %lx\n", si->curname, list, si->slab); @@ -12250,7 +12254,7 @@ verify_slab_overload_page(struct meminfo *si, ulong last, int s) return FALSE; } - list_head = (struct kernel_list_head *)(page_buf + OFFSET(page_lru)); + list_head = (struct kernel_list_head *)(page_buf + si->list_offset); if (!IS_KVADDR((ulong)list_head->next) || !accessible((ulong)list_head->next)) { error(INFO, "%s: %s list: page/slab: %lx bad next pointer: %lx\n", @@ -12569,7 +12573,7 @@ dump_slab_overload_page(struct meminfo *si) int tmp; ulong slab_overload_page, freelist; - slab_overload_page = si->slab - OFFSET(page_lru); + slab_overload_page = si->slab - si->list_offset; readmem(slab_overload_page + OFFSET(page_s_mem), KVADDR, &si->s_mem, sizeof(ulong), @@ -12796,12 +12800,12 @@ gather_slab_free_list_slab_overload_page(struct meminfo *si) if (CRASHDEBUG(1)) fprintf(fp, "slab page: %lx active: %ld si->c_num: %ld\n", - si->slab - OFFSET(page_lru), si->s_inuse, si->c_num); + si->slab - si->list_offset, si->s_inuse, si->c_num); if (si->s_inuse == si->c_num ) return; - slab_overload_page = si->slab - OFFSET(page_lru); + slab_overload_page = si->slab - si->list_offset; readmem(slab_overload_page + OFFSET(page_freelist), KVADDR, &freelist, sizeof(void *), "page freelist", FAULT_ON_ERROR); @@ -13099,7 +13103,7 @@ dump_slab_objects_percpu(struct meminfo *si) if ((si->flags & ADDRESS_SPECIFIED) && (vt->flags & SLAB_OVERLOAD_PAGE)) { - readmem(si->slab - OFFSET(page_lru) + OFFSET(page_freelist), + readmem(si->slab - si->list_offset + OFFSET(page_freelist), KVADDR, &freelist, sizeof(ulong), "page.freelist", FAULT_ON_ERROR); @@ -18713,6 +18717,9 @@ dump_kmem_cache_slub(struct meminfo *si) si->cache_buf = GETBUF(SIZE(kmem_cache)); + si->list_offset = VALID_MEMBER(slab_slab_list) ? + OFFSET(slab_slab_list) : OFFSET(page_lru); + if (VALID_MEMBER(page_objects) && OFFSET(page_objects) == OFFSET(page_inuse)) si->flags |= SLAB_BITFIELD; @@ -19484,7 +19491,6 @@ do_node_lists_slub(struct meminfo *si, ulong node_ptr, int node) { ulong next, last, list_head, flags; int first; - long list_off = VALID_MEMBER(slab_slab_list) ? OFFSET(slab_slab_list) : OFFSET(page_lru); if (!node_ptr) return; @@ -19498,7 +19504,7 @@ do_node_lists_slub(struct meminfo *si, ulong node_ptr, int node) next == list_head ? " (empty)\n" : ""); first = 0; while (next != list_head) { - si->slab = last = next - list_off; + si->slab = last = next - si->list_offset; if (first++ == 0) fprintf(fp, " %s", slab_hdr); @@ -19521,7 +19527,7 @@ do_node_lists_slub(struct meminfo *si, ulong node_ptr, int node) if (!IS_KVADDR(next) || ((next != list_head) && - !is_page_ptr(next - list_off, NULL))) { + !is_page_ptr(next - si->list_offset, NULL))) { error(INFO, "%s: partial list slab: %lx invalid page.lru.next: %lx\n", si->curname, last, next); @@ -19548,7 +19554,7 @@ do_node_lists_slub(struct meminfo *si, ulong node_ptr, int node) next == list_head ? " (empty)\n" : ""); first = 0; while (next != list_head) { - si->slab = next - list_off; + si->slab = next - si->list_offset; if (first++ == 0) fprintf(fp, " %s", slab_hdr); @@ -19765,7 +19771,6 @@ count_partial(ulong node, struct meminfo *si, ulong *free) short inuse, objects; ulong total_inuse; ulong count = 0; - long list_off = VALID_MEMBER(slab_slab_list) ? OFFSET(slab_slab_list) : OFFSET(page_lru); count = 0; total_inuse = 0; @@ -19777,12 +19782,12 @@ count_partial(ulong node, struct meminfo *si, ulong *free) hq_open(); while (next != list_head) { - if (!readmem(next - list_off + OFFSET(page_inuse), + if (!readmem(next - si->list_offset + OFFSET(page_inuse), KVADDR, &inuse, sizeof(ushort), "page.inuse", RETURN_ON_ERROR)) { hq_close(); return -1; } - last = next - list_off; + last = next - si->list_offset; if (inuse == -1) { error(INFO, @@ -19808,7 +19813,7 @@ count_partial(ulong node, struct meminfo *si, ulong *free) } if (!IS_KVADDR(next) || ((next != list_head) && - !is_page_ptr(next - list_off, NULL))) { + !is_page_ptr(next - si->list_offset, NULL))) { error(INFO, "%s: partial list slab: %lx invalid page.lru.next: %lx\n", si->curname, last, next); break; -- 2.31.1 -- Crash-utility mailing list Crash-utility@redhat.com https://listman.redhat.com/mailman/listinfo/crash-utility Contribution Guidelines: https://github.com/crash-utility/crash/wiki