[openib-general] Kernel oops: NULL ptr dereference in ib_umem_get

[ardavis]

Hello Roland,

I have openib uDAPL up and running with most of our internal MPI test 
suites (Intel-MPI). Pretty impressive with such an early code drop of 
user verbs. Nice job!

With a little stress, I see the following oops (running latest from the 
trunk). Let me know if you need any more information.

Apr 15 13:03:27 iclust-19 kernel:  <1>Unable to handle kernel NULL 
pointer dereference at 0000000000000010 RIP:
Apr 15 13:03:27 iclust-19 kernel: <ffffffff803815f0>{ib_umem_get+272}
Apr 15 13:03:27 iclust-19 kernel: PGD 33933067 PUD 32a58067 PMD 0
Apr 15 13:03:27 iclust-19 kernel: Oops: 0000 [2] SMP
Apr 15 13:03:27 iclust-19 kernel: CPU 0
Apr 15 13:03:27 iclust-19 kernel: Modules linked in:
Apr 15 13:03:27 iclust-19 kernel: Pid: 13502, comm: transpose2 Not 
tainted 2.6.11
Apr 15 13:03:27 iclust-19 kernel: RIP: 0010:[<ffffffff803815f0>] 
<ffffffff803815f0>{ib_umem_get+272}
Apr 15 13:03:27 iclust-19 kernel: RSP: 0018:ffff81002ed4ddd8  EFLAGS: 
00010206
Apr 15 13:03:27 iclust-19 kernel: RAX: 0000800000000000 RBX: 
000000000000b000 RCX: 00007fffffff5000
Apr 15 13:03:27 iclust-19 kernel: RDX: 0000000000000000 RSI: 
00007fffffff5000 RDI: ffff810027f9e940
Apr 15 13:03:27 iclust-19 kernel: RBP: 00007fffffff5000 R08: 
0000000000000000 R09: 0000000000000000
Apr 15 13:03:27 iclust-19 kernel: R10: 0000000000030b24 R11: 
0000000000000000 R12: ffff810031815c80
Apr 15 13:03:27 iclust-19 kernel: R13: 0000000000000000 R14: 
00007fffffff5000 R15: ffff81002ed15000
Apr 15 13:03:27 iclust-19 kernel: FS:  00002aaaaae55f40(0000) 
GS:ffffffff805fe400(0000) knlGS:0000000000000000
Apr 15 13:03:27 iclust-19 kernel: CS:  0010 DS: 0000 ES: 0000 CR0: 
0000000080050033
Apr 15 13:03:27 iclust-19 kernel: CR2: 0000000000000010 CR3: 
0000000034b16000 CR4: 00000000000006e0
Apr 15 13:03:27 iclust-19 kernel: Process transpose2 (pid: 13502, 
threadinfo ffff81002ed4c000, task ffff81003e3f62f0)
Apr 15 13:03:27 iclust-19 kernel: Stack: ffff810033391ab8 
ffffffff80168e62 000000000000000d ffff810031815cc8
Apr 15 13:03:27 iclust-19 kernel:        000000000000000b 
0000000000000000 ffff810031815ca8 ffff81000235a000
Apr 15 13:03:27 iclust-19 kernel:        ffffffff804ca110 0000000000000030
Apr 15 13:03:27 iclust-19 kernel: Call 
Trace:<ffffffff80168e62>{handle_mm_fault+418} 
<ffffffff80380424>{ib_uverbs_reg_mr+212}
Apr 15 13:03:27 iclust-19 kernel:        
<ffffffff8037f486>{ib_uverbs_write+150} <ffffffff8017ad14>{vfs_write+196}
Apr 15 13:03:27 iclust-19 kernel:        
<ffffffff8017ae73>{sys_write+83} <ffffffff8010e30a>{system_call+126}
Apr 15 13:03:27 iclust-19 kernel:
Apr 15 13:03:27 iclust-19 kernel:
Apr 15 13:03:27 iclust-19 kernel: Code: 4c 8b 72 10 eb ba 49 89 ee 49 81 
e6 00 f0 ff ff 8b 4c 24 20
Apr 15 13:03:27 iclust-19 kernel: RIP 
<ffffffff803815f0>{ib_umem_get+272} RSP <ffff81002ed4ddd8>
Apr 15 13:03:27 iclust-19 kernel: CR2: 0000000000000010

Thanks,

-arlin