2020-09-24 14:22:41

by George Prekas

Subject: [PATCH v2] scripts/gdb: fix list_for_each

If the list is uninitialized (next pointer is NULL), list_for_each gets
stuck in an infinite loop. Print a message and treat list as empty.

Signed-off-by: George Prekas <[email protected]>
---
 scripts/gdb/linux/lists.py | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/scripts/gdb/linux/lists.py b/scripts/gdb/linux/lists.py
index c487ddf09d38..bae4d70b7eae 100644
--- a/scripts/gdb/linux/lists.py
+++ b/scripts/gdb/linux/lists.py
@@ -27,6 +27,11 @@ def list_for_each(head):
         raise TypeError("Must be struct list_head not {}"
                            .format(head.type))

+    if head['next'] == 0:
+        gdb.write("list_for_each: Uninitialized list '{}' treated as
empty\n"
+                     .format(head.address))
+        return
+
     node = head['next'].dereference()
     while node.address != head.address:
         yield node.address
--
2.16.6

2021-01-05 16:55:14

by George Prekas

Subject: Re: [PATCH v2] scripts/gdb: fix list_for_each

On 9/24/2020 9:20 AM, George Prekas wrote:
> If the list is uninitialized (next pointer is NULL), list_for_each gets
> stuck in an infinite loop. Print a message and treat list as empty.
>
> Signed-off-by: George Prekas <[email protected]>
> ---
>  scripts/gdb/linux/lists.py | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/scripts/gdb/linux/lists.py b/scripts/gdb/linux/lists.py
> index c487ddf09d38..bae4d70b7eae 100644
> --- a/scripts/gdb/linux/lists.py
> +++ b/scripts/gdb/linux/lists.py
> @@ -27,6 +27,11 @@ def list_for_each(head):
>          raise TypeError("Must be struct list_head not {}"
>                             .format(head.type))
>
> +    if head['next'] == 0:
> +        gdb.write("list_for_each: Uninitialized list '{}' treated as
> empty\n"
> +                     .format(head.address))
> +        return
> +
>      node = head['next'].dereference()
>      while node.address != head.address:
>          yield node.address

Happy New Year!

Any updates on this?

Thanks,
George

2021-01-05 19:11:05

by Jan Kiszka

Subject: Re: [PATCH v2] scripts/gdb: fix list_for_each

On 05.01.21 17:51, George Prekas wrote:
> On 9/24/2020 9:20 AM, George Prekas wrote:
>> If the list is uninitialized (next pointer is NULL), list_for_each gets
>> stuck in an infinite loop. Print a message and treat list as empty.
>>
>> Signed-off-by: George Prekas <[email protected]>
>> ---
>>  scripts/gdb/linux/lists.py | 5 +++++
>>  1 file changed, 5 insertions(+)
>>
>> diff --git a/scripts/gdb/linux/lists.py b/scripts/gdb/linux/lists.py
>> index c487ddf09d38..bae4d70b7eae 100644
>> --- a/scripts/gdb/linux/lists.py
>> +++ b/scripts/gdb/linux/lists.py
>> @@ -27,6 +27,11 @@ def list_for_each(head):
>>          raise TypeError("Must be struct list_head not {}"
>>                             .format(head.type))
>>
>> +    if head['next'] == 0:
>> +        gdb.write("list_for_each: Uninitialized list '{}' treated as
>> empty\n"
>> +                     .format(head.address))
>> +        return
>> +
>>      node = head['next'].dereference()
>>      while node.address != head.address:
>>          yield node.address
>
> Happy New Year!

Same to you!

>
> Any updates on this?
>

Sorry, slipped through.

Reviewed-by: Jan Kiszka <[email protected]>

Andrew, please pick this up.

Jan

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