On 09/17/2018 07:36 PM, Daniel Thompson wrote:
> On Mon, Sep 17, 2018 at 07:08:44PM -0400, Prarit Bhargava wrote:
>>
>>
>> On 09/17/2018 06:46 PM, Daniel Thompson wrote:
>>> On Tue, Sep 11, 2018 at 01:29:42PM -0400, Prarit Bhargava wrote:
>>>> As a test I hacked the buffer size to 16 and entered kdb:
>>>>
>>>> [16]kdb>
>>>> 117661 symbols are found. But only first 30 symbols will be printed.
>>>> You can change the environment variable DTABCOUNT.
>>>> irq_stack_union __per_cpu_start cpu_debug_store cpu_tss_rw gdt_page
>>>> exception_stack... entry_stack_sto... espfix_waddr espfix_stack cpu_llc_id
>>>> cpu_llc_shared_... cpu_core_map cpu_sibling_map cpu_info cpu_number
>>>> this_cpu_off x86_cpu_to_acpi... x86_cpu_to_apic... x86_bios_cpu_ap...
>>>> sched_core_prio... cpu_loops_per_j... pmc_prev_left cpu_hw_events bts_ctx
>>>> insn_buffer pt_ctx xen_vcpu_info xen_vcpu_id xen_vcpu mc_buffer ...
>>>
>>> I don't quite understand what is being tested here (I thought the code
>>> you changed was only reached after tab is pressed twice) and you haven't
>>> shared what conclusion you have drawn from this test.
>>>
>> Hi Daniel, my apologies. Here's a more detailed explanation.
>>
>> I didn't feel comfortable submitting the code without testing and the
>> problem is
>> that I couldn't think of a kernel symbol that was 128 bytes in size that
>> would
>> be truncated so that ellipses would be printed out. What I decided to do is
>> apply my patch *and* change the buffer size to 16, then rebuilt the kernel,
>> booted the kernel, and selected the ttyS0 as the buffer console. I entered
>> kdb
>> using "echo g > /proc/sysrq-trigger" and hit tab twice to test the code.
>>
>> The above output confirms that the code is working as expected. Any symbol
>> larger than 15 is truncated and appended with ellipses, for example
>> "cpu_llc_shared_...". Symbols smaller than 15 are fully output, for example,
>> cpu_llc_id.
>>
>> IOW, it looks like the code works as expected.
>
> I cannot replicate the ellipsis behaviour my filling the read buffer
> until it is full (256 character command) and then deleting a few
> characters and then trying to tab complete.
>
> I'm not sure if I have misunderstood the code or your test! Can you
> share the change you made for testing as a patch?
>
Sure ... sorry for the cut-and-paste but it's a one line patch.
diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c
index 6a4b41484afe..51c38922f2ba 100644
--- a/kernel/debug/kdb/kdb_io.c
+++ b/kernel/debug/kdb/kdb_io.c
@@ -209,7 +209,7 @@ static char *kdb_read(char *buffer, size_t bufsize)
char *lastchar;
char *p_tmp;
char tmp;
- static char tmpbuffer[CMD_BUFLEN];
+ static char tmpbuffer[16]; /* ellipses for symbols larger than 15 */
int len = strlen(buffer);
int len_tmp;
int tab = 0;
P.
>
> Daniel.
>
>>
>> P.
>>
>>>
>>> Daniel.
>>>
_______________________________________________
Kgdb-bugreport mailing list
Kgdb-bugreport@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/kgdb-bugreport
