From: Akinobu Mita <amgta@yacht.ocn.ne.jp>
To: Badari Pulavarty <pbadari@us.ibm.com>,
Hariprasad Nellitheertha <hari@in.ibm.com>
Cc: Andrew Morton <akpm@osdl.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
varap@us.ibm.com
Subject: Re: [PATCH] kdump: Fix for boot problems on SMP
Date: Fri, 26 Nov 2004 02:21:49 +0900 [thread overview]
Message-ID: <200411260221.49888.amgta@yacht.ocn.ne.jp> (raw)
In-Reply-To: <1101170617.4987.268.camel@dyn318077bld.beaverton.ibm.com>
On Tuesday 23 November 2004 09:43, Badari Pulavarty wrote:
> gdb is not showing the stack info properly, on my saved vmcore.
> I thought vmlinux is not matching the vmcore, so I verified that
> vmcore and vmlinux matchup. But still no luck...
>
> # gdb ../linux-2.6.9/vmlinux vmcore.2
[...]
> (gdb) bt
> #0 default_idle () at arch/i386/kernel/process.c:108
> #1 0xc04cdff8 in init_thread_union ()
> #2 0xc0101b86 in cpu_idle () at arch/i386/kernel/process.c:196
> #3 0xc04cea20 in start_kernel () at init/main.c:523
> #4 0xc0100211 in L6 () at /tmp/cch2z2jk.s:2054
> Cannot access memory at address 0x550007
I think the panic was happened on the CPU except for CPU#0.
Currently vmcore contains only CPU#0's register contents.
Therefore, GDB always shows backtrace of CPU#0.
fs/proc/vmcore.c:
static void elf_vmcore_store_hdr(char *bufp, int nphdr, int dataoff)
{
...
/* 1 - Get the registers from the reserved memory area */
reg_ppos = BACKUP_END + CRASH_RELOCATE_SIZE;
read_from_oldmem(reg_buf, REG_SIZE, ®_ppos, 0);
elf_core_copy_regs(&prstatus.pr_reg, (struct pt_regs *)reg_buf);
buf = storenote(¬es[0], buf);
In this place, "reg_ppos" is the pointer to the copy of relocated
crash_smp_regs[0].
kdump should save the "crash_smp_regs[**panic_cpu**]".
Or, it is better to save all crash_smp_regs[NR_CPUS].
In other words:
# readelf --note /proc/vmcore
Notes at offset 0x00000074 with length 0x0000069c:
Owner Data size Description
CORE 0x00000090 NT_PRSTATUS (prstatus structure)
CORE 0x0000007c NT_PRPSINFO (prpsinfo structure)
CORE 0x00000560 NT_TASKSTRUCT (task structure)
:
:
:
...(repeat NR_CPU times)
next prev parent reply other threads:[~2004-11-26 21:56 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-11-18 14:08 [PATCH] kdump: Fix for boot problems on SMP Hariprasad Nellitheertha
2004-11-18 15:34 ` Badari Pulavarty
2004-11-19 17:56 ` Akinobu Mita
2004-11-19 23:30 ` Andrew Morton
2004-11-19 23:29 ` Badari Pulavarty
2004-11-20 1:05 ` Badari Pulavarty
2004-11-20 3:04 ` Akinobu Mita
2004-11-22 16:03 ` Hariprasad Nellitheertha
2004-11-22 22:34 ` Badari Pulavarty
2004-11-23 0:43 ` Badari Pulavarty
2004-11-23 18:15 ` Hariprasad Nellitheertha
2004-11-24 20:07 ` Badari Pulavarty
2004-11-25 15:13 ` Hariprasad Nellitheertha
2004-11-25 17:21 ` Akinobu Mita [this message]
2004-11-26 11:57 ` Hariprasad Nellitheertha
2004-11-20 3:46 ` Akinobu Mita
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