[ofa-general] Re: System crashed while booting Linux (ia64) with three Mellanox HCAs (15b3:6274)

[Roland Dreier]

 > System crashes with three Mellanox mezzanine cards (VID=15b3,
 > DID=0x6274) installed when booting Linux (ia64).  I am using Linux
 > 2.6.24, but this issue also occurs with Linux kernel 2.6.29-rc8.

this is a pretty interesting crash.  Do you have the ib_mthca driver
built into your kernel, or is it being loaded as a module?

 > A partial listing from ib_mad_post_receive_mad.S is posted below the "C" code.
 > The exact instruction that cause the system crash was located at
 > 
 > ib_mad_post_*+0x0080           st4              [r2]=r3                      MII
 >                                nop.i            0x0
 >                                nop.i            0x0
 > 
 > It tries to store r3=0x1600 to [r2] @ 0xE0000007E01C7CCC.

Looking at the assembly, it seems the relevant parts are:

ib_mad_post_*+0x0060           ld4              r3=[r11]                     MMI
                               st8              [r2]=r8
                               adds             r2=28,r12
ib_mad_post_*+0x0070           st4              [r9]=r10                     MMI
                               st8              [r45]=r0
                               nop.i            0x0;;
ib_mad_post_*+0x0080           st4              [r2]=r3                      MII

The main points are "adds r2=28,r12" -- ie r2 now points into the
stack -- and "st4 [r2]=r3" -- ie a store onto the stack is crashing.

In the same function, we have "adds r9=56,r12" and "st4 [r9]=r10"
slightly earlier, so the stack isn't totally messed up (apparently).

Not sure how to debug this since the crash as it stands doesn't seem to
make much sense...