On 2022/08/25 15:42, Tao Liu wrote:
> When kernel enabled CONFIG_VMAP_STACK, stack can be allocated to
> vmalloced area. Currently crash didn't handle the case, as a result,
> kmem will not print the task context as expected. This patch fix the
> bug by checking if the address is a vmalloced stack first.
>
> Before:
> crash> kmem ffffb7efce9bbe28
> VMAP_AREA VM_STRUCT ADDRESS RANGE
> SIZE
> ffff94eb9102c640 ffff94eb9102b140 ffffb7efce9b8000 - ffffb7efce9bd000
> 20480
>
> PAGE PHYSICAL MAPPING INDEX CNT FLAGS
> ffffdd28220dc000 1883700000 0 0 1 50000000000000
>
> After:
> crash> kmem ffffb7efce9bbe28
> PID: 847
> COMMAND: "khungtaskd"
> TASK: ffff94f8038f4000 [THREAD_INFO: ffff94f8038f4000]
> CPU: 72
> STATE: TASK_RUNNING (PANIC)
>
> VMAP_AREA VM_STRUCT ADDRESS RANGE
> SIZE
> ffff94eb9102c640 ffff94eb9102b140 ffffb7efce9b8000 - ffffb7efce9bd000
> 20480
>
> PAGE PHYSICAL MAPPING INDEX CNT FLAGS
> ffffdd28220dc000 1883700000 0 0 1 50000000000000
>
> Signed-off-by: Tao Liu <l...@redhat.com>
> ---
>
> v1 -> v2: 1) Remove goto to print task context and vmlist.
> 2) Update commit log to show the change.
Thanks for the update, looks good to me.
Acked-by: Kazuhito Hagio <k-hagio...@nec.com>
Thanks,
Kazu
>
> ---
> memory.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/memory.c b/memory.c
> index 7339f0c..9ab5781 100644
> --- a/memory.c
> +++ b/memory.c
> @@ -13477,6 +13477,10 @@ kmem_search(struct meminfo *mi)
> * Check for a valid mapped address.
> */
> if ((mi->memtype == KVADDR) && IS_VMALLOC_ADDR(mi->spec_addr)) {
> + if ((task = stkptr_to_task(vaddr)) && (tc =
> task_to_context(task))) {
> + show_context(tc);
> + fprintf(fp, "\n");
> + }
> if (kvtop(NULL, mi->spec_addr, &paddr, 0)) {
> mi->flags = orig_flags | VMLIST_VERIFY;
> dump_vmlist(mi);
--
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