Hi,
I found that from gdb 7.1 to gdb-cvs-head cannot analyze the core file
that get from kdump.
What I got:
[New <main task>]
[New Thread 2719]
../../src/gdb/thread.c:884: internal-error: switch_to_thread:
Assertion `inf != NULL' failed.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n)
That is because:
objdump -h ./vmcore
./vmcore: file format elf64-x86-64
Sections:
Idx Name Size VMA LMA File off Algn
0 note0 00000a48 0000000000000000 0000000000000000 00000238 2**0
CONTENTS, READONLY
1 .reg/0 000000d8 0000000000000000 0000000000000000 000002bc 2**2
CONTENTS
2 .reg 000000d8 0000000000000000 0000000000000000 000002bc 2**2
CONTENTS
3 .reg/2719 000000d8 0000000000000000 0000000000000000 00000420 2**2
CONTENTS
4 .reg/0 000000d8 0000000000000000 0000000000000000 00000584 2**2
CONTENTS
5 .reg/0 000000d8 0000000000000000 0000000000000000 000006e8 2**2
CONTENTS
Each of reg/n is a cpu core note. It will be a GDB thread. n is the
prstatus.pr_pid that will be the thread lwpid. Because the 3 threads
pid is same, so GDB get error.
current->pid is 0 because this cpu is in idle. So I add a check, set
prstatus.pr_pid to cpu id when current->pid is 0. Then GDB work OK
with the core.
Thanks,
Hui
Signed-off-by: Hui Zhu <teawater at gmail.com>
---
kernel/kexec.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -1191,7 +1191,10 @@ void crash_save_cpu(struct pt_regs *regs
if (!buf)
return;
memset(&prstatus, 0, sizeof(prstatus));
- prstatus.pr_pid = current->pid;
+ if (current->pid)
+ prstatus.pr_pid = current->pid;
+ else
+ prstatus.pr_pid = cpu;
elf_core_copy_kernel_regs(&prstatus.pr_reg, regs);
buf = append_elf_note(buf, KEXEC_CORE_NOTE_NAME, NT_PRSTATUS,
&prstatus, sizeof(prstatus));
