Subject: Re: [BUG] 2.6.25-rc8-mm1 kernel panic while bootup on powerpc

From: Andrew Morton <[email-masked]>
Date: Tue, 1 Apr 2008 23:39:09 -0700

On Wed, 02 Apr 2008 11:55:36 +0530 Kamalesh Babulal <[email-masked]> wrote:

> Hi Andrew,
> 
> The 2.6.25-rc8-mm1 kernel panic's while bootup on the power machine(s).
> 
> [    0.000000] ------------[ cut here ]------------
> [    0.000000] kernel BUG at arch/powerpc/mm/init_64.c:240!
> [    0.000000] Oops: Exception in kernel mode, sig: 5 [#1]
> [    0.000000] SMP NR_CPUS=32 NUMA PowerMac
> [    0.000000] Modules linked in:
> [    0.000000] NIP: c0000000003d1dcc LR: c0000000003d1dc4 CTR: c00000000002b6ac
> [    0.000000] REGS: c00000000049b960 TRAP: 0700   Not tainted  (2.6.25-rc8-mm1-autokern1)
> [    0.000000] MSR: 9000000000021032 <ME,IR,DR>  CR: 44000088  XER: 20000000
> [    0.000000] TASK = c0000000003f9c90[0] 'swapper' THREAD: c000000000498000 CPU: 0
> [    0.000000] GPR00: c0000000003d1dc4 c00000000049bbe0 c0000000004989d0 0000000000000001 
> [    0.000000] GPR04: d59aca40f0000000 000000000b000000 0000000000000010 0000000000000000 
> [    0.000000] GPR08: 0000000000000004 0000000000000001 c00000027e520800 c0000000004bf0f0 
> [    0.000000] GPR12: c0000000004bf020 c0000000003fa900 0000000000000000 0000000000000000 
> [    0.000000] GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 
> [    0.000000] GPR20: 0000000000000000 0000000000000000 0000000000000000 4000000001400000 
> [    0.000000] GPR24: 00000000017d64b0 c0000000003d6250 0000000000000000 c000000000504000 
> [    0.000000] GPR28: 0000000000000000 cf000000001f8000 0000000001000000 cf00000000000000 
> [    0.000000] NIP [c0000000003d1dcc] .vmemmap_populate+0xb8/0xf4
> [    0.000000] LR [c0000000003d1dc4] .vmemmap_populate+0xb0/0xf4
> [    0.000000] Call Trace:
> [    0.000000] [c00000000049bbe0] [c0000000003d1dc4] .vmemmap_populate+0xb0/0xf4 (unreliable)
> [    0.000000] [c00000000049bc70] [c0000000003d2ee8] .sparse_mem_map_populate+0x38/0x60
> [    0.000000] [c00000000049bd00] [c0000000003c242c] .sparse_early_mem_map_alloc+0x54/0x94
> [    0.000000] [c00000000049bd90] [c0000000003c250c] .sparse_init+0xa0/0x20c
> [    0.000000] [c00000000049be50] [c0000000003ab7d0] .setup_arch+0x1ac/0x218
> [    0.000000] [c00000000049bee0] [c0000000003a36ac] .start_kernel+0xe0/0x3fc
> [    0.000000] [c00000000049bf90] [c000000000008594] .start_here_common+0x54/0xc0
> [    0.000000] Instruction dump:
> [    0.000000] 7fe3fb78 7ca02a14 4082000c 3860fff4 4800003c e92289c8 e96289c0 e9090002 
> [    0.000000] e8eb0002 4bc575cd 60000000 78630fe0 <0b030000> 7ffff214 7fbfe840 7fe3fb78 
> [    0.000000] ---[ end trace 31fd0ba7d8756001 ]---
> [    0.000000] Kernel panic - not syncing: Attempted to kill the idle task!
> 

int __meminit vmemmap_populate(struct page *start_page,
					unsigned long nr_pages, int node)
{
	unsigned long mode_rw;
	unsigned long start = (unsigned long)start_page;
	unsigned long end = (unsigned long)(start_page + nr_pages);
	unsigned long page_size = 1 << mmu_psize_defs[mmu_linear_psize].shift;

	mode_rw = _PAGE_ACCESSED | _PAGE_DIRTY | _PAGE_COHERENT | PP_RWXX;

	/* Align to the page size of the linear mapping. */
	start = _ALIGN_DOWN(start, page_size);

	for (; start < end; start += page_size) {
		int mapped;
		void *p;

		if (vmemmap_populated(start, page_size))
			continue;

		p = vmemmap_alloc_block(page_size, node);
		if (!p)
			return -ENOMEM;

		pr_debug("vmemmap %08lx allocated at %p, physical %08lx.\n",
			start, p, __pa(p));

		mapped = htab_bolt_mapping(start, start + page_size,
					__pa(p), mode_rw, mmu_linear_psize,
					mmu_kernel_ssize);
=====>		BUG_ON(mapped < 0);
	}

	return 0;
}

Beats me.  pseries?  Badari has been diddling with the bolted memory code
in git-powerpc...