On Thu, 2016-04-07 at 16:44 -0700, Bart Van Assche wrote: > On 04/07/2016 04:37 PM, Nicholas A. Bellinger wrote: > > On Thu, 2016-04-07 at 15:55 -0700, Bart Van Assche wrote: > >> That patch causes the ib_srpt driver to crash as soon as the first > >> SCSI command is received. This means that that patch was untested. > >> Hence revert it. The shortcomings of that patch are as follows: > >> - It makes the ib_srpt driver use I/O contexts allocated by > >> transport_alloc_session_tags() but it does not initialize these > >> I/O contexts properly. All the initializations performed by > >> srpt_alloc_ioctx() are skipped. > >> - It swaps the order of the send ioctx allocation and the transition > >> to RTR mode which is wrong. > >> - The amount of memory that is needed for I/O contexts is doubled. > >> - srpt_rdma_ch.free_list is no longer used but is not removed. > >> > >> Revert commit 0fd10721fe36 and thereby fix the following kernel crash: > >> > >> kernel BUG at drivers/infiniband/ulp/srpt/ib_srpt.c:1439! > >> invalid opcode: 0000 [#1] SMP > >> Workqueue: target_completion target_complete_ok_work [target_core_mod] > >> RIP: 0010:[<ffffffffa052ef37>] [<ffffffffa052ef37>] srpt_queue_response+0x437/0x4a0 [ib_srpt] > >> Call Trace: > >> [<ffffffffa052f009>] srpt_queue_data_in+0x9/0x10 [ib_srpt] > >> [<ffffffffa04f1ee2>] target_complete_ok_work+0x152/0x2b0 [target_core_mod] > >> [<ffffffff81071ea7>] process_one_work+0x197/0x480 > >> [<ffffffff810721d9>] worker_thread+0x49/0x490 > >> [<ffffffff8107878a>] kthread+0xea/0x100 > >> [<ffffffff8159b172>] ret_from_fork+0x22/0x40 > >> > >> Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxxxxxx> > >> Cc: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx> > > > > I've already asked you not to revert the patch [ ... ] > > But why not to revert that patch? Your patch was completely untested and > makes the ib_srpt driver unusable. I think the regular approach for such > patches is to revert them and to rework these in a later kernel version. > Linus, please let me know if you disagree. Because I'm actively working on a bug-fix for the regression, and it's -rc2 in a target driver that hardly anyone cares about. If the regression is not addressed before v4.6-rc6, then by all means revert the original patch. -- To unsubscribe from this list: send the line "unsubscribe target-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
