[OpenAFS-devel] oops with 2.6.24.4 and openafs-1.4.7-pre4 reading 0 sized file

[Troy Benjegerdes]

It dies when I try to access a 0-size file in afs_MemRead, or uiomove.
The last working version I had on PPC was 1.4.3rc1, and I
have a working version of 1.4.5 on x86 as well.

Should the call the uiomove/memcpy have a size of zero? Or would there
be some metadata that needs to get moved? Why do we even bother for
a zero sized file?

On Wed, Apr 23, 2008 at 07:49:59PM -0500, Troy Benjegerdes wrote:
> I had to make a few minor tweaks to get things to build, and load, and
> when I boot up one of my nodes using AFS root with (with memcache), and
> I get this:
> 
> Any quick ideas?
> 
> [   25.866784] Unable to handle kernel paging request for data at address 0xd0000000007c9000
> [   25.866800] Faulting instruction address: 0xc0000000000342dc
> [   25.866810] Oops: Kernel access of bad area, sig: 11 [#1]
> [   25.866817] SMP NR_CPUS=8 NUMA pSeries
> [   25.866825] Modules linked in: openafs(P)
> [   25.866834] NIP: c0000000000342dc LR: d0000000007621d4 CTR: 00000000000000b3
> [   25.866843] REGS: c0000003c43032d0 TRAP: 0300   Tainted: P         (2.6.24.4)
> [   25.866851] MSR: 8000000000009032 <EE,ME,IR,DR>  CR: 24224440  XER: 00000005
> [   25.866868] DAR: d0000000007c9000, DSISR: 0000000040000000
> [   25.866876] TASK = c0000003c48992a0[5784] 'cp' THREAD: c0000003c4300000 CPU: 1
> [   25.866885] GPR00: 0000000000000000 c0000003c4303550 c0000000006e4a48 c00000000f06e4c0
> [   25.866899] GPR04: d0000000007c8ff0 0000000000000000 0000000000000000 0000000000000100
> [   25.866912] GPR08: 0000000000000000 0000000000000000 0000000000000001 c000000000034280
> [   25.866926] GPR12: d00000000077aa40 c000000000626400 0000000000000000 0000000000001000
> [   25.866940] GPR16: c0000003c4303b50 c0000003c4303698 c000000000698b88 d0000000007c86a0
> [   25.866954] GPR20: c0000001da552300 c0000003c43037f8 0000000000001000 d0000000007aa4d0
> [   25.866968] GPR24: d0000000007aa4d0 0000000000000000 d0000000007c8b28 0000000000677a48
> [   25.866983] GPR28: 0000000000001000 c0000003c43036b0 d0000000007b69c0 c0000003c32ac000
> [   25.866998] NIP [c0000000000342dc] .memcpy+0x5c/0x280
> [   25.867011] LR [d0000000007621d4] .uiomove+0x134/0x380 [openafs]
> [   25.867082] Call Trace:
> [   25.867087] [c0000003c4303550] [c0000000000e3310] .dput+0x60/0x2a0 (unreliable)
> [   25.867102] [c0000003c4303610] [d00000000072d384] .afs_MemRead+0x224/0x1010 [openafs]
> [   25.867154] [c0000003c4303760] [d0000000007676a4] .afs_linux_readpage+0x174/0x4b0 [openafs]
> [   25.867219] [c0000003c4303880] [c000000000090850] .do_generic_mapping_read+0x110/0x4c0
> [   25.867233] [c0000003c4303970] [c000000000092a80] .generic_file_aio_read+0x110/0x280
> [   25.867246] [c0000003c4303a50] [c0000000000ca074] .do_sync_read+0xd4/0x170
> [   25.867257] [c0000003c4303c00] [d0000000007653d8] .afs_linux_read+0x268/0x2b0 [openafs]
> [   25.867320] [c0000003c4303cf0] [c0000000000ca9b8] .vfs_read+0xe8/0x1b0
> [   25.867331] [c0000003c4303d90] [c0000000000cb1cc] .sys_read+0x4c/0x90
> [   25.867342] [c0000003c4303e30] [c00000000000872c] syscall_exit+0x0/0x40
> [   25.867354] Instruction dump:
> [   25.867359] 78a7e102 e9240000 3884fff8 7ce903a6 70a50007 409c001c 38630008 38840008
> [   25.867375] 7d284b78 41840018 e9240008 f9030008 <e9040011> f9230011 4200fff0 f9030008
> [   25.867391] ---[ end trace 9c7f2a1101886b0b ]---
> 
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-- 
--------------------------------------------------------------------------
Troy Benjegerdes                'da hozer'                hozer@hozed.org  

Somone asked me why I work on this free (http://www.gnu.org/philosophy/)
software stuff and not get a real job. Charles Shultz had the best answer:

"Why do musicians compose symphonies and poets write poems? They do it
because life wouldn't have any meaning for them if they didn't. That's why
I draw cartoons. It's my life." -- Charles Shultz