Re: [PATCH v3 3/3] Let kmem print task context when physical address is vmalloced stack

[lijiang <lijiang@xxxxxxxxxx>]

Hi, Tao

Thank you for the update.

On Mon, Sep 5, 2022 at 8:00 PM <crash-utility-request@xxxxxxxxxx> wrote:

Date: Mon,  5 Sep 2022 15:09:22 +0800
From: Tao Liu <ltao@xxxxxxxxxx>
To: crash-utility@xxxxxxxxxx
Subject: [PATCH v3 3/3] Let kmem print task context
        when physical address is vmalloced stack
Message-ID: <20220905070922.14426-4-ltao@xxxxxxxxxx>
Content-Type: text/plain; charset="US-ASCII"; x-default=true

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.

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

 

I did the test and got different results with yours as below. Did I miss anything else?

crash> kmem ffff94e088110000
CACHE             OBJSIZE  ALLOCATED     TOTAL  SLABS  SSIZE  NAME
ffff94e080c22a00    12040       3126      3129   3129    16k  task_struct
  SLAB              MEMORY            NODE  TOTAL  ALLOCATED  FREE
  ffffdd27c4204400  ffff94e088110000     0      1          1     0
  FREE / [ALLOCATED]
  [ffff94e088110000]

    PID: 0
COMMAND: "swapper/2"
   TASK: ffff94e088110000  (1 of 96)  [THREAD_INFO: ffff94e088110000]
    CPU: 2
  STATE: TASK_RUNNING (ACTIVE)

      PAGE         PHYSICAL      MAPPING       INDEX CNT FLAGS
ffffdd27c4204400  108110000 ffff94e080c22a00        0  1 10000000008100 slab,head

crash> kmem 108110000
CACHE             OBJSIZE  ALLOCATED     TOTAL  SLABS  SSIZE  NAME
ffff94e080c22a00    12040       3126      3129   3129    16k  task_struct
  SLAB              MEMORY            NODE  TOTAL  ALLOCATED  FREE
  ffffdd27c4204400  ffff94e088110000     0      1          1     0
  FREE / [ALLOCATED]
  [ffff94e088110000]

      PAGE         PHYSICAL      MAPPING       INDEX CNT FLAGS
ffffdd27c4204400  108110000 ffff94e080c22a00        0  1 10000000008100 slab,head
crash>

 

Thanks

Lianbo

Signed-off-by: Tao Liu <ltao@xxxxxxxxxx>
---
 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());
--
2.33.1

--
Crash-utility mailing list
Crash-utility@xxxxxxxxxx
https://listman.redhat.com/mailman/listinfo/crash-utility
Contribution Guidelines: https://github.com/crash-utility/crash/wiki