[Crash-utility] [PATCH v3 3/3] Let kmem print task context when physical address is vmalloced stack
Tao Liu
ltao at redhat.com
Thu Sep 8 00:55:48 UTC 2022
Hi Kazu,
On Tue, Sep 6, 2022 at 1:32 PM HAGIO KAZUHITO(萩尾 一仁) <k-hagio-ab at nec.com> wrote:
>
>
> On 2022/09/05 16:09, Tao Liu wrote:
> > Patch [1] enables kmem to print task context if the given virtual
> > address is a vmalloced stack.
> >
> > This patch handles the same issue except the given address is
> > physical address.
>
> If we do this, it would be better to support a kernel without
> CONFIG_VMAP_STACK, too. Any reason not to support?
>
I will support it in the v4 patch. Sorry for the late reply, I was
busy working on the maple tree support for crash, which is in a final
stage and code refactoring/testing. Maybe it will take a few days
before I work on the v4.
Thanks,
Tao Liu
> crash> sys
> KERNEL: vmlinux-3.10.0-957.el7.x86_64
> ...
> crash> kmem ffff88007cfdbf80
> PID: 1
> COMMAND: "systemd"
> TASK: ffff88007cfd0000 [THREAD_INFO: ffff88007cfd8000]
> CPU: 0
> STATE: TASK_INTERRUPTIBLE
>
> PAGE PHYSICAL MAPPING INDEX CNT FLAGS
> ffffea0001f3f6c0 7cfdb000 0 0 0 1fffff00000000
>
> crash> kmem 7cfdbf80
> PAGE PHYSICAL MAPPING INDEX CNT FLAGS
> ffffea0001f3f6c0 7cfdb000 0 0 0 1fffff00000000
>
>
> Thanks,
> Kazu
>
> >
> > Before:
> > crash> kmem 1883700e28
> > 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 1883700e28
> > 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
> >
> > [1]: https://listman.redhat.com/archives/crash-utility/2022-August/010074.html
> >
> > Signed-off-by: Tao Liu <ltao at redhat.com>
> > ---
> > memory.c | 4 ++++
> > 1 file changed, 4 insertions(+)
> >
> > diff --git a/memory.c b/memory.c
> > index 1b6f9ba..eac8262 100644
> > --- a/memory.c
> > +++ b/memory.c
> > @@ -13506,6 +13506,10 @@ kmem_search(struct meminfo *mi)
> > mi->flags &= ~GET_PHYS_TO_VMALLOC;
> >
> > if (mi->retval) {
> > + if ((task = stkptr_to_task(mi->retval)) && (tc = task_to_context(task))) {
> > + show_context(tc);
> > + fprintf(fp, "\n");
> > + }
> > if ((sp = value_search(mi->retval, &offset))) {
> > show_symbol(sp, offset,
> > SHOW_LINENUM | SHOW_RADIX());
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