On Fri, Aug 30, 2024 at 7:39 PM <devel-requ...@lists.crash-utility.osci.io>
wrote:
> Date: Fri, 30 Aug 2024 10:33:03 -0000
> From: qiwu.c...@transsion.com
> Subject: [Crash-utility] [PATCH] kmem: fix the determination for slab
> page
> To: devel@lists.crash-utility.osci.io
> Message-ID: <20240830103303.2824.23...@lists.crash-utility.osci.io>
> Content-Type: text/plain; charset="utf-8"
>
> The determination for a slab page is changed since kernel commit
> 8db00ad564617 which migrates PG_slab flag from page flags to the
> lower 16 bit of the page type.
>
>
Thank you for the fix, qiwu.
Can you help double check if the code related to PG_* flags in the crash
tool needs to be changed accordingly?
Thanks
Lianbo
> 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.c...@transsion.com>
> ---
> defs.h | 1 +
> memory.c | 23 +++++++++++++++++++----
> 2 files changed, 20 insertions(+), 4 deletions(-)
>
> diff --git a/defs.h b/defs.h
> index e9eb9e3..9ef7f97 100644
> --- a/defs.h
> +++ b/defs.h
> @@ -2289,6 +2289,7 @@ struct offset_table { /* stash of
> commonly-used offsets */
> long track_cpu;
> long track_when;
> long track_handle;
> + long page_page_type;
> };
>
> struct size_table { /* stash of commonly-used sizes */
> diff --git a/memory.c b/memory.c
> index 7bf8f86..f9ad6e4 100644
> --- a/memory.c
> +++ b/memory.c
> @@ -509,6 +509,8 @@ 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");
>
> MEMBER_OFFSET_INIT(mm_struct_pgd, "mm_struct", "pgd");
>
> @@ -10114,7 +10116,7 @@ static char *
> vaddr_to_kmem_cache(ulong vaddr, char *buf, int verbose)
> {
> physaddr_t paddr;
> - ulong page, cache, page_flags;
> + ulong page, cache, page_flags, page_type;
>
> if (!kvtop(NULL, vaddr, &paddr, 0)) {
> if (verbose)
> @@ -10143,7 +10145,10 @@ vaddr_to_kmem_cache(ulong vaddr, char *buf, int
> verbose)
>
> readmem(compound_head(page)+OFFSET(page_flags), KVADDR,
> &page_flags, sizeof(ulong),
> "page.flags",
> FAULT_ON_ERROR);
> - if (!(page_flags & (1 << vt->PG_slab)))
> + readmem(page + OFFSET(page_page_type),
> KVADDR, &page_type,
> + sizeof(ulong), "page type",
> FAULT_ON_ERROR);
> + if (!(page_flags & (1 << vt->PG_slab)) &&
> + !(page_type & (1 << vt->PG_slab)))
> return NULL;
> } else
> return NULL;
> @@ -20688,7 +20693,7 @@ char *
> is_slab_page(struct meminfo *si, char *buf)
> {
> int i, cnt;
> - ulong page_slab, page_flags, name;
> + ulong page_slab, page_flags, page_type, name;
> ulong *cache_list;
> char *retval;
>
> @@ -20703,7 +20708,17 @@ is_slab_page(struct meminfo *si, char *buf)
> RETURN_ON_ERROR|QUIET))
> return NULL;
>
> - if (!(page_flags & (1 << vt->PG_slab)))
> + if (!readmem(si->spec_addr + OFFSET(page_page_type), KVADDR,
> + &page_type, sizeof(ulong), "page.page_type",
> + RETURN_ON_ERROR|QUIET))
> + return NULL;
> +
> + /*
> + * PG_slab is migrated from the page flags to the lower 16 bit
> + * of the page type since linux commit 8db00ad564617.
> + */
> + if (!(page_flags & (1 << vt->PG_slab)) &&
> + !(page_type & (1 << vt->PG_slab)))
> return NULL;
>
> if (!readmem(si->spec_addr + OFFSET(page_slab), KVADDR,
> --
> 2.25.1
>
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