On 09/01/2009 12:48 PM, Grant Grundler wrote:
+linux-scsi
On Tue, Sep 1, 2009 at 9:17 AM, Jonathan Nell<crtrn13@xxxxxxxxx> wrote:
2009/9/1 Grant Grundler<grundler@xxxxxxxxxx>:
The ideal tool is a protocol analyzer for whatever transport the SCSI
device is attached to.
Here's the slide deck from a talk I once gave at OLS outlining the HW
debug tools:
http://iou.parisc-linux.org/ols_2001/slides/generated/
(and "SCSI" in that slide deck often means Parallel SCSI transport.)
Using the scsi_logging hooks described by Stefan Richter are often enough
to understand where in the process something is failing.
hth,
grant
Unfortunately I need a data dump as well so the scsi_logging hooks
aren't going to do the job I believe.
IMHO, if a data dump is needed, a logic analyzer is probably the right tool.
Which transport is being used here?
Folks might have suggestions on tools that are available. Often those can
be rented for a few days/week at a time.
You can get specific analyzers for storage protocols (Fibre channel,
s-ata, SAS, etc). They can be pricey (especially if you need to monitor
multiple devices with a multi-port analyzer)
ric
My next though was to wrap the
SG_IO ioctl call (i.e. trap it in the kernel) and have that dump the
data from (struct sg_io_hdr).dxferp. (The ioctl sniffer would be
useful anyway for other things).
The drawback here is it only tells you what data is being handed to
the interface card, not what data is sent to the device or how it is
sent exactly (framing, timing, etc).
Having issues with doing the kernel trap in the newer kernel versions
though (trying on 2.6.30). The syscall table is now read-only but for
some reason my set_memory_rw() call is failing... Any ideas how to do
this properly?
Nope, sorry. At least not offhand.
cheers,
grant
Here are the relevant bits of code:
unsigned long **find_sys_call_table(void)
{
unsigned long **sctable;
unsigned long ptr;
sctable = NULL;
for (ptr = (unsigned long)&unlock_kernel;
ptr< (unsigned long)&loops_per_jiffy;
ptr += sizeof(void *))
{
unsigned long *p;
p = (unsigned long *)ptr;
if (p[__NR_close] == (unsigned long) sys_close)
{
sctable = (unsigned long **)p;
return&sctable[0];
}
}
return NULL;
}
static int __init scsisniff_init_module(void)
{
if ( (sys_call_table = find_sys_call_table()) ) {
real_ioctl = (int(*)(unsigned int fd, unsigned int cmd,
unsigned long arg))sys_call_table[__NR_ioctl];
if ( set_memory_rw( (unsigned
long)sys_call_table[__NR_ioctl], 1 ) )
printk( "set_memory_rw: succeeded\n" );
else {
printk( "set_memory_rw: failed!\n" );
return -1;
}
sys_call_table[__NR_ioctl] = (unsigned long)my_ioctl;
}
else {
return -1;
}
return 0;
}
This gives me a lovely OOPS:
[ 71.143742] WARNING: at arch/x86/mm/pageattr.c:833
change_page_attr_set_clr+0x1a0/0x400()
[ 71.143745] Modules linked in: scsi_sniff(+) i915 binfmt_misc drm
i2c_algo_bit bridge stp bnep lp snd_hda_codec_analog snd_hda_intel
snd_hda_codec snd_hwdep snd_pcm_oss snd_mixer_oss snd_pcm
snd_seq_dummy snd_seq_oss snd_seq_midi snd_rawmidi snd_seq_midi_event
snd_seq snd_timer snd_seq_device video snd psmouse tpm_infineon tpm
ppdev soundcore serio_raw pcspkr intel_agp tpm_bios output heci(C)
iTCO_wdt iTCO_vendor_support parport_pc parport snd_page_alloc floppy
usbhid usb_storage e1000e
[ 71.143768] Pid: 3378, comm: insmod Tainted: G C
2.6.30.4custom-1.0 #6
[ 71.143769] Call Trace:
[ 71.143773] [<ffffffff802da6d5>] ? __vunmap+0xc5/0x110
[ 71.143775] [<ffffffff80235200>] ? change_page_attr_set_clr+0x1a0/0x400
[ 71.143778] [<ffffffff8024edf8>] warn_slowpath_common+0x78/0xd0
[ 71.143780] [<ffffffff8024ee5f>] warn_slowpath_null+0xf/0x20
[ 71.143783] [<ffffffff80235200>] change_page_attr_set_clr+0x1a0/0x400
[ 71.143785] [<ffffffffa0274050>] ? my_ioctl+0x0/0x120 [scsi_sniff]
[ 71.143789] [<ffffffff802a6dcd>] ? marker_update_probe_range+0x1dd/0x2d0
[ 71.143791] [<ffffffffa0277000>] ? scsisniff_init_module+0x0/0xf4
[scsi_sniff]
[ 71.143793] [<ffffffff80235b9a>] set_memory_rw+0x2a/0x30
[ 71.143796] [<ffffffff802ff000>] ? sys_fcntl+0x180/0x420
[ 71.143798] [<ffffffffa02770bb>] scsisniff_init_module+0xbb/0xf4
[scsi_sniff]
[ 71.143801] [<ffffffff8020a04c>] do_one_initcall+0x3c/0x180
[ 71.143804] [<ffffffff8026b7f3>] ? __blocking_notifier_call_chain+0x63/0x80
[ 71.143807] [<ffffffff8027dc0d>] sys_init_module+0xad/0x200
[ 71.143810] [<ffffffff80210fc2>] system_call_fastpath+0x16/0x1b
[ 71.143812] ---[ end trace 5b3efe312296b587 ]---
[ 71.143958] set_memory_rw: failed!
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