Re: System freeze when accessing st.ko and /dev/st0

[Brian King <brking@us.ibm.com>]

I have been debugging this same problem in sg today. It appears as if
kobj_unmap is never getting called when a device is deleted. When I
added a call to kobj_unmap, the problem went away. I'm currently working
on a patch for this.

-Brian


Phil Carinhas wrote:
>  System Freeze
> 
> When I tried to access the tape drive via 'tar tvfz /dev/st0'
> the system froze: Here is the call trace:
> 
>  -------- CALL TRACE from /var/log/messages
> Feb  6 12:25:48 taren kernel: st: Version 20031228, fixed bufsize 32768, s/g segs 256
> Feb  6 12:25:48 taren kernel: Attached scsi tape st0 at scsi1, channel 0, id 6, lun 0
> Feb  6 12:25:48 taren kernel: st0: try direct i/o: yes, max page reachable by HBA268435455
> Feb  6 12:32:22 taren kernel: st: Unloaded.
> Feb  6 12:32:46 taren kernel: Badness in kobject_get at lib/kobject.c:431
> Feb  6 12:32:46 taren kernel: Call Trace:
> Feb  6 12:32:46 taren kernel:  [<c0274e50>] kobject_get+0x50/0x60
> Feb  6 12:32:46 taren kernel:  [<c015c0c9>] cdev_get+0x39/0x80
> Feb  6 12:32:46 taren kernel:  [<c015bf9f>] exact_lock+0xf/0x20
> Feb  6 12:32:46 taren kernel:  [<c029a135>] kobj_lookup+0xf5/0x1a0
> Feb  6 12:32:46 taren kernel:  [<c015bf80>] exact_match+0x0/0x10
> Feb  6 12:32:46 taren kernel:  [<c015be73>] chrdev_open+0x143/0x1c0
> Feb  6 12:32:46 taren kernel:  [<c0151c70>] dentry_open+0x130/0x1e0
> Feb  6 12:32:46 taren kernel:  [<c0151b38>] filp_open+0x68/0x70
> Feb  6 12:32:46 taren kernel:  [<c0151f8b>] sys_open+0x5b/0x90
> Feb  6 12:32:46 taren kernel:  [<c01090af>] syscall_call+0x7/0xb
> Feb  6 12:32:46 taren kernel: 
> Feb  6 12:32:46 taren kernel:  printing eip:
> Feb  6 12:32:46 taren kernel: c015beda
> Feb  6 12:32:46 taren kernel: Oops: 0002 [#1]
> Feb  6 12:32:46 taren kernel: CPU:    1
> Feb  6 12:32:46 taren kernel: EIP:    0060:[<c015beda>]    Not tainted
> Feb  6 12:32:46 taren kernel: EFLAGS: 00010246
> Feb  6 12:32:46 taren kernel: EIP is at chrdev_open+0x1aa/0x1c0
> Feb  6 12:32:46 taren kernel: eax: 00000000   ebx: e7b57120   ecx: e7b5715c   edx: f713bd2c
> Feb  6 12:32:46 taren kernel: esi: 00000000   edi: 00000000   ebp: f713bc10   esp: d29bbf20
> Feb  6 12:32:46 taren kernel: ds: 007b   es: 007b   ss: 0068
> Feb  6 12:32:46 taren kernel: Process mt (pid: 5807, threadinfo=d29ba000 task=d6fb6670)
> Feb  6 12:32:46 taren kernel: Stack: f7fe2c00 00900000 d29bbf2c 00000000 dccb73a0f713bc10 ffffffe9 f7fe6760 
> Feb  6 12:32:46 taren kernel:        c0151c70 f713bc10 dccb73a0 00000000 bffffdc4ef414000 d29ba000 c0151b38 
> Feb  6 12:32:46 taren kernel:        f714eb60 f7fe6760 00000000 d29bbf70 f714eb60f7fe6760 fffffff4 ef414000 
> Feb  6 12:32:46 taren kernel: Call Trace:
> Feb  6 12:32:46 taren kernel:  [<c0151c70>] dentry_open+0x130/0x1e0
> Feb  6 12:32:46 taren kernel:  [<c0151b38>] filp_open+0x68/0x70
> Feb  6 12:32:46 taren kernel:  [<c0151f8b>] sys_open+0x5b/0x90
> Feb  6 12:32:46 taren kernel:  [<c01090af>] syscall_call+0x7/0xb
> Feb  6 12:32:46 taren kernel: 
> Feb  6 12:32:46 taren kernel: Code: 89 50 04 89 4a 04 e9 87 fe ff ff 8d 74 26 00 8d bc 27 00 00 
> 
> Here are system specs:
> PIII Copermine dual cpu
> Both Megaraid and sym53c compiled monolithic.
> st is the only module on the system.
> 
>  ====
> cat /proc/scsi/scsi 
> Attached devices:
> Host: scsi1 Channel: 00 Id: 06 Lun: 00
>   Vendor: HP       Model: C1537A           Rev: L907
>   Type:   Sequential-Access                ANSI SCSI revision: 02
> Host: scsi2 Channel: 00 Id: 00 Lun: 00
>   Vendor: MegaRAID Model: LD0 RAID1 17500R Rev:   F 
>   Type:   Direct-Access                    ANSI SCSI revision: 02
> Host: scsi2 Channel: 00 Id: 01 Lun: 00
>   Vendor: MegaRAID Model: LD1 RAID1  8677R Rev:   F 
>   Type:   Direct-Access                    ANSI SCSI revision: 02
> Host: scsi2 Channel: 04 Id: 05 Lun: 00
>   Vendor: HP       Model: SAFTE; U160/M BP Rev: 1020
>   Type:   Processor                        ANSI SCSI revision: 02
>  ====
> cat /proc/scsi/sym53c8xx/*
> Chip sym53c896, device id 0xb, revision id 0x6
> At PCI address 0000:02:06.0, IRQ 24
> Min. period factor 10, Wide SCSI BUS
> Max. started commands 510, max. commands per LUN 64
> Chip sym53c896, device id 0xb, revision id 0x6
> At PCI address 0000:02:06.1, IRQ 25
> Min. period factor 10, Wide SCSI BUS
> Max. started commands 510, max. commands per LUN 64
> 
>  ========
>   Question: will compiling st into the kernel monolithically
>   change this result?
>   
>   If possible, please reply to my email address below. If not,
>   thanks for looking at this.
> 
> -Phil Carinhas
> --
>  .--------------------------------------------------------.
>  | Dr. Philip A. Carinhas       | pac(at)fortuitous.com   |
>  | Fortuitous Technologies Inc. | http://fortuitous.com   |
>  | Linux Consulting & Training  | Tel : 1-512-218-9561    |
>  `--------------------------------------------------------'
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> 


-- 
Brian King
eServer Storage I/O
IBM Linux Technology Center