[PowerPC] 2.6.30-git14 boot failure with SLAB
Sachin Sant
sachinp at in.ibm.com
Sat Jun 20 17:26:39 EST 2009
Benjamin Herrenschmidt wrote:
> That is strange. If I revert that commit, I get breakages on machines
> here. It would be interesting to understand what the problem is here,
> as we -do- use that kmem cache for allocating page tables, so we do
> need it initialized that early. (IE, we can't allow vmalloc for example
> to be called before the page table caches are initialized).
>
> This will need more debugging and understanding as to why it hangs.
>
Hi Ben,
Looks like the control enters pgtable_cache_init but rever returns. The
machine just hangs. I triggered a system reset via HMC to see what's
happening on the cpu. Here is the xmon o/p after a system reset.
The code that was executed was __mutex_lock_slowpath..
cpu 0x0: Vector: 100 (System Reset) at [c000000000b138e0]
pc: c00000000060a4b8: .__mutex_lock_slowpath+0x9c/0x1f4
lr: c00000000060abc8: .mutex_lock+0x50/0x70
sp: c000000000b13b60
msr: 8000000000081032
current = 0xc000000000a3ab70
paca = 0xc000000000be2400
pid = 0, comm = swapper
enter ? for help
[c000000000b13c30] c00000000060abc8 .mutex_lock+0x50/0x70
[c000000000b13cb0] c00000000008c7f0 .get_online_cpus+0x4c/0x84
[c000000000b13d40] c00000000014a120 .kmem_cache_create+0xcc/0x5f4
[c000000000b13e50] c000000000033f38 .pgtable_cache_init+0x28/0x78
[c000000000b13ee0] c0000000008809a4 .start_kernel+0x1f8/0x568
[c000000000b13f90] c0000000000083d8 .start_here_common+0x1c/0x44
0:mon>
0:mon> di $.__mutex_lock_slowpath
c00000000060a41c fba1ffe8 std r29,-24(r1)
c00000000060a420 7c0802a6 mflr r0
.... SNIP .....
c00000000060a46c 7fe4fb78 mr r4,r31
c00000000060a470 419e0014 beq cr7,c00000000060a484 # .__mutex_lock_slowpath+0x68/0x1f4
c00000000060a474 4ba6859d bl c000000000072a10 # .mutex_spin_on_owner+0x0/0xbc
c00000000060a478 60000000 nop
c00000000060a47c 2fa30000 cmpdi cr7,r3,0
c00000000060a480 419e0078 beq cr7,c00000000060a4f8 # .__mutex_lock_slowpath+0xdc/0x1f4
c00000000060a484 93010070 stw r24,112(r1)
c00000000060a488 93210074 stw r25,116(r1)
c00000000060a48c 81210070 lwz r9,112(r1)
c00000000060a490 80010074 lwz r0,116(r1)
c00000000060a494 7d2907b4 extsw r9,r9
c00000000060a498 7c0007b4 extsw r0,r0
0:mon>
c00000000060a49c 7c2004ac lwsync
c00000000060a4a0 7d60e828 lwarx r11,0,r29
c00000000060a4a4 7c0b4800 cmpw r11,r9
c00000000060a4a8 40c20010 bne- c00000000060a4b8 # .__mutex_lock_slowpath+0x9c/0x1f4
c00000000060a4ac 7c00e92d stwcx. r0,0,r29
c00000000060a4b0 40c2fff0 bne- c00000000060a4a0 # .__mutex_lock_slowpath+0x84/0x1f4
c00000000060a4b4 4c00012c isync
c00000000060a4b8 2f8b0001 cmpwi cr7,r11,1
^^^^^ PC points to this instruction ^^^^^^^^
c00000000060a4bc 2f3f0000 cmpdi cr6,r31,0
c00000000060a4c0 409e0010 bne cr7,c00000000060a4d0 # .__mutex_lock_slowpath+0xb4/0x1f4
c00000000060a4c4 78200464 rldicr r0,r1,0,49
c00000000060a4c8 f81d0030 std r0,48(r29)
c00000000060a4cc 48000118 b c00000000060a5e4 # .__mutex_lock_slowpath+0x1c8/0x1f4
c00000000060a4d0 409a001c bne cr6,c00000000060a4ec # .__mutex_lock_slowpath+0xd0/0x1f4
c00000000060a4d4 e81b0000 ld r0,0(r27)
c00000000060a4d8 7809f7e3 rldicl. r9,r0,62,63
0:mon> r
R00 = 0000000000000000 R16 = 0000000002bc4b68
R01 = c000000000b13b60 R17 = 0000000000000000
R02 = c000000000b0bca0 R18 = c0000000008c4b68
R03 = c000000000d07fd0 R19 = 0000000001b1fc90
R04 = 0000000000000000 R20 = 00000000000000b8
R05 = 000000000000005e R21 = c0000000007ec008
R06 = 0000000000040000 R22 = 00000000007c28bb
R07 = c000000000a95288 R23 = c0000000007cbdd5
R08 = 0000000000000000 R24 = 0000000000000001
R09 = 0000000000000001 R25 = 0000000000000000
R10 = 0000000000000000 R26 = c000000000d08000
R11 = 00000000ffffffff R27 = c000000000b10080
R12 = 0000000024000082 R28 = c000000000a3ab70
R13 = c000000000be2400 R29 = c000000000d07fd0
R14 = c0000000008c4c30 R30 = c000000000a75be8
R15 = c000000000a95288 R31 = 0000000000000000
pc = c00000000060a4b8 .__mutex_lock_slowpath+0x9c/0x1f4
lr = c00000000060abc8 .mutex_lock+0x50/0x70
msr = 8000000000081032 cr = 84000022
ctr = 0000000000136f8c xer = 0000000000000001 trap = 100
0:mon>
Let me know if i can provide more information.
Thanks
-Sachin
--
---------------------------------
Sachin Sant
IBM Linux Technology Center
India Systems and Technology Labs
Bangalore, India
---------------------------------
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