Tom,
There were two changes in this patch:
- check for a NULL comm_id pointer - add error returns
My understanding of the subsequent discussion is that:
- we should not have been using the comm_id->state value. We should have been using the event->event value instead
- if we return a non 0 error code, our CM ID will be destroyed
Given those pieces of information:
Do we still want to check for a NULL comm_id pointer? Should we always return 0 from this function?
I think the answer is yes to both of the above, but I want to make sure there is consensus.
james
On Wed, 4 May 2005, Tom Duffy wrote:
This occurred when I did a connect without first setting up a listen using kdapltest.
Unable to handle kernel NULL pointer dereference at 0000000000000020 RIP: <ffffffff882b2c61>{:ib_dat_provider:dapl_cm_passive_cb_handler+27} PGD 371ab067 PUD 36822067 PMD 0 Oops: 0000 [1] SMP CPU 2 Modules linked in: kdapltest ib_dat_provider dat ib_at ib_cm ib_ipoib ib_sa ib_umad md5 ipv6 parport_pc lp parport autofs4 nfs lockd sunrpc pcmcia yenta_socket rsrc_nonstatic pcmcia_core ext3 jbd video container button battery ac uhci_hcd ehci_hcd hw_random i2c_i801 i2c_core ib_mthca ib_mad ib_core e1000 floppy dm_snapshot dm_zero dm_mirror xfs exportfs dm_mod mptscsih mptbase sd_mod scsi_mod Pid: 11326, comm: ib_cm/2 Not tainted 2.6.12-rc3openib RIP: 0010:[<ffffffff882b2c61>] <ffffffff882b2c61>{:ib_dat_provider:dapl_cm_passive_cb_handler+27} RSP: 0018:ffff810038f65d90 EFLAGS: 00010202 RAX: 0000000000000000 RBX: ffff81000b3764b0 RCX: ffff81000b376550 RDX: 0000000000000056 RSI: ffff81000b376548 RDI: ffff81003f0cd8a0 RBP: ffff81003f0cd8a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000020 R11: ffff81003925ae10 R12: ffff81003f0cd8a0 R13: ffff81003dcb8a88 R14: 0000000000000000 R15: ffff81000b3765a0 FS: 0000000000000000(0000) GS:ffffffff80487a00(0000) knlGS:0000000000000000 CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b CR2: 0000000000000020 CR3: 0000000038bbd000 CR4: 00000000000006e0 Process ib_cm/2 (pid: 11326, threadinfo ffff810038f64000, task ffff81003e75af30)Stack: ffffffff882aae32 0100000000000293 0000000000000000 ffff81000b3764b0 000000003f0cd8a0 ffff81003dcb8a88 0000000000000000 ffff81000b3765a0 ffffffff882abd1e ffff810001e1b680 Call Trace:<ffffffff882aae32>{:ib_cm:cm_process_work+50} <ffffffff882abd1e>{:ib_cm:cm_work_handler+1438} <ffffffff801435f8>{do_sigaction+520} <ffffffff882ab780>{:ib_cm:cm_work_handler+0} <ffffffff801489ac>{worker_thread+476} <ffffffff801321c0>{default_wake_function+0} <ffffffff80130283>{__wake_up_common+67} <ffffffff801487d0>{worker_thread+0} <ffffffff8014cfe0>{keventd_create_kthread+0} <ffffffff8014d259>{kthread+217} <ffffffff801336d0>{schedule_tail+64} <ffffffff8010f57b>{child_rip+8} <ffffffff8014cfe0>{keventd_create_kthread+0} <ffffffff8014d180>{kthread+0} <ffffffff8010f573>{child_rip+0}
Code: 8b 40 20 89 44 24 04 83 7c 24 04 03 74 30 83 7c 24 04 03 77 RIP <ffffffff882b2c61>{:ib_dat_provider:dapl_cm_passive_cb_handler+27} RSP <ffff810038f65d90> CR2: 0000000000000020
This cuteness happened in the kdapltest userland program:
Warning: conn_event_wait DAT_CONNECTION_EVENT_DISCONNECTED DT_cs_Client: bad connection event DT_cs_Client: Cleaning Up ... DT_cs_Client: IA mthca0a closed DT_cs_Client: ========== End of Work -- Client Exiting TEST INSTANCE 1 *** glibc detected *** free(): invalid next size (fast): 0x000000000050ca50 *** Aborted (core dumped)
This patches fixes two things. It makes it so that dapl_cm_passive_cb_handler won't dereference a potentially NULL ib_cm_id and also that it returns ret instead of 0 all the time.
Signed-off-by: Tom Duffy <[EMAIL PROTECTED]>
Index: dapl_openib_cm.c =================================================================== --- linux-kernel/dat-provider/dapl_openib_cm.c (revision 2257) +++ linux-kernel/dat-provider/dapl_openib_cm.c (working copy) @@ -227,6 +227,9 @@ int dapl_cm_passive_cb_handler(struct ib { int ret = 0;
+ if (!comm_id) + return -1; + switch (comm_id->state) { case IB_CM_IDLE: ret = do_passive_idle(comm_id); @@ -247,7 +250,7 @@ int dapl_cm_passive_cb_handler(struct ib break; }
- return 0; + return ret; }
static void dapl_ib_destroy_cm_id_work(void *data)
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