Re: [patch] SLQB slab allocator

Nick Piggin
2009-01-23T03:57:07Z

On Thu, Jan 22, 2009 at 04:45:33PM +0800, Zhang, Yanmin wrote:
> On Wed, 2009-01-21 at 15:30 +0100, Nick Piggin wrote:
> > Hi,
> >
> > Since last posted, I've cleaned up a few bits and pieces, (hopefully)
> > fixed a known bug where it wouldn't boot on memoryless nodes (I don't
> > have a system to test with),
> Panic again on my Montvale Itanium NUMA machine if I start kernel with parameter
> mem=2G.
>
> The call chain is mnt_init => sysfs_init. ???kmem_cache_create fails, so later on
> when ???mnt_init uses kmem_cache sysfs_dir_cache, kernel panic
> at __slab_alloc => get_cpu_slab because parameter s is equal to NULL.
>
> Function __remote_slab_alloc return NULL when s->node[node]==NULL. That causes
> ???sysfs_init => kmem_cache_create fails.

Hmm, I'll probably have to add a bit more fallback logic. I'll have to
work out what semantics the callers require here. Thanks for the report.

>
>
> ------------------log----------------
>
> Dentry cache hash table entries: 262144 (order: 7, 2097152 bytes)
> Inode-cache hash table entries: 131072 (order: 6, 1048576 bytes)
> Mount-cache hash table entries: 1024
> mnt_init: sysfs_init error: -12
> Unable to handle kernel NULL pointer dereference (address 0000000000002058)
> swapper[0]: Oops 8813272891392 [1]
> Modules linked in:
>
> Pid: 0, CPU 0, comm: swapper
> psr : 00001010084a2018 ifs : 8000000000000690 ip : [<a000000100180350>] Not tainted (2.6.29-rc2slqb0121)
> ip is at kmem_cache_alloc+0x150/0x4e0
> unat: 0000000000000000 pfs : 0000000000000690 rsc : 0000000000000003
> rnat: 0009804c8a70433f bsps: a000000100f484b0 pr : 656960155aa65959
> ldrs: 0000000000000000 ccv : 000000000000001a fpsr: 0009804c8a70433f
> csd : 893fffff000f0000 ssd : 893fffff00090000
> b0 : a000000100180270 b6 : a000000100507360 b7 : a000000100507360
> f6 : 000000000000000000000 f7 : 1003e0000000000000800
> f8 : 1003e0000000000000008 f9 : 1003e0000000000000001
> f10 : 1003e0000000000000031 f11 : 1003e7d6343eb1a1f58d1
> r1 : a0000001011bc810 r2 : 0000000000000008 r3 : ffffffffffffffff
> r8 : 0000000000000000 r9 : a000000100ded800 r10 : 0000000000000000
> r11 : a000000100ded800 r12 : a000000100db3d80 r13 : a000000100dac000
> r14 : 0000000000000000 r15 : fffffffffffffffe r16 : a000000100fbcd30
> r17 : a000000100dacc44 r18 : 0000000000002058 r19 : 0000000000000000
> r20 : 0000000000000000 r21 : a000000100dacc44 r22 : 0000000000000002
> r23 : 0000000000000066 r24 : 0000000000000073 r25 : 0000000000000000
> r26 : e000000102014030 r27 : a0007fffffc9f120 r28 : 0000000000000000
> r29 : 0000000000000000 r30 : 0000000000000008 r31 : 0000000000000001
>
> Call Trace:
> [<a000000100016240>] show_stack+0x40/0xa0
> sp=a000000100db3950 bsp=a000000100dad140
> [<a000000100016b50>] show_regs+0x850/0x8a0
> sp=a000000100db3b20 bsp=a000000100dad0e8
> [<a00000010003a5f0>] die+0x230/0x360
> sp=a000000100db3b20 bsp=a000000100dad0a0
> [<a00000010005e0e0>] ia64_do_page_fault+0x8e0/0xa40
> sp=a000000100db3b20 bsp=a000000100dad050
> [<a00000010000c700>] ia64_native_leave_kernel+0x0/0x280
> sp=a000000100db3bb0 bsp=a000000100dad050
> [<a000000100180350>] kmem_cache_alloc+0x150/0x4e0
> sp=a000000100db3d80 bsp=a000000100dacfc8
> [<a000000100238610>] sysfs_new_dirent+0x90/0x240
> sp=a000000100db3d80 bsp=a000000100dacf80
> [<a000000100239140>] create_dir+0x40/0x100
> sp=a000000100db3d90 bsp=a000000100dacf48
> [<a0000001002392b0>] sysfs_create_dir+0xb0/0x100
> sp=a000000100db3db0 bsp=a000000100dacf28
> [<a0000001004eca60>] kobject_add_internal+0x1e0/0x420
> sp=a000000100db3dc0 bsp=a000000100dacee8
> [<a0000001004eceb0>] kobject_add_varg+0x90/0xc0
> sp=a000000100db3dc0 bsp=a000000100daceb0
> [<a0000001004ed620>] kobject_add+0x100/0x140
> sp=a000000100db3dc0 bsp=a000000100dace50
> [<a0000001004ed6b0>] kobject_create_and_add+0x50/0xc0
> sp=a000000100db3e00 bsp=a000000100dace20
> [<a000000100c28ff0>] mnt_init+0x1b0/0x480
> sp=a000000100db3e00 bsp=a000000100dacde0
> [<a000000100c28610>] vfs_caches_init+0x230/0x280
> sp=a000000100db3e20 bsp=a000000100dacdb8
> [<a000000100c01410>] start_kernel+0x830/0x8c0
> sp=a000000100db3e20 bsp=a000000100dacd40
> [<a0000001009d7b60>] __kprobes_text_end+0x760/0x780
> sp=a000000100db3e30 bsp=a000000100dacca0
> Kernel panic - not syncing: Attempted to kill the idle task!