Re: [Crash-utility] [PATCH v2] Fix kmem failing to print task context when address is vmalloced stack
On 2022/09/01 14:52, Tao Liu wrote:
Hi Kazu,
I see 3 out of 4 patches I posted upstream have been merged, could you
please help to merge this patch as well? Thank you very much!
This patch is waiting for Lianbo's review.
Did I miss it?
Thanks,
Kazu
>
> Thanks,
> Tao Liu
>
> On Mon, Aug 29, 2022 at 3:21 PM HAGIO KAZUHITO(萩尾 一仁)
> <k-hagio-ab(a)nec.com> wrote:
>>
>> 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 <ltao(a)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-ab(a)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);