On 10/28/2015 06:28 AM, FUJITA Tomonori wrote: > On Mon, 19 Oct 2015 08:56:06 -0700 > Lee Duncan <lduncan@xxxxxxxx> wrote: > >> On 10/17/2015 05:57 AM, FUJITA Tomonori wrote: >>> On Tue, 13 Oct 2015 11:10:17 -0700 >>> Lee Duncan <lduncan@xxxxxxxx> wrote: >>> >>>> Hello: >>>> >>>> I recently got a report of a tgtd core dump from our opencloud >>>> group. The stack trace showed that a strcmp against a NULL was causing >>>> the failure: >>>> >>>> ---------------------------------------------------------------- >>>> Program terminated with signal 11, Segmentation fault. >>>> (gdb) bt >>>> #0 0x00007fa701817576 in __strcmp_sse42 () from /lib64/libc.so.6 >>>> #1 0x0000000000408012 in target_find_by_name ( >>>> name=0x6ac16f "iqn.2010-10.org.openstack:volume-e812c705-80bc-4064-a84c-5559cda8b1ca") at iscsi/target.c:216 >>>> #2 0x0000000000406042 in login_start (conn=0x6abea8) at iscsi/iscsid.c:478 >>>> #3 0x0000000000406e77 in cmnd_exec_login (conn=<optimized out>) >>>> at iscsi/iscsid.c:654 >>>> #4 cmnd_execute (conn=<optimized out>) at iscsi/iscsid.c:914 >>>> #5 iscsi_rx_handler (conn=0x6abea8) at iscsi/iscsid.c:2064 >>>> #6 0x0000000000409e98 in iscsi_tcp_event_handler (fd=<optimized out>, >>>> events=1, data=0x63a480 <target_list>) at iscsi/iscsi_tcp.c:158 >>>> #7 0x0000000000418f1e in event_loop () at tgtd.c:272 >>>> #8 0x0000000000419405 in main (argc=1, argv=<optimized out>) at tgtd.c:438 >>>> ---------------------------------------------------------------- >>>> >>>> It looks like target_find_by_name() uses tgt_targetname(), but doesn't >>>> account for the fact that it can return a NULL when the target being >>>> looked up does not (now) exist: >>> >>> Thanks for the patch. But I'm confused why this happens. target with >>> the same tid as iscsi_target must exist? >>> >> >> No, I believe this is happening because the targets are getting >> dynamically removed. But I will verify that. Because if tgt_targetname() >> can return a NULL (as apparently it did this time), there are probably >> other places in the code that need to check for that. > > Ok, I'm still confused but applied the patch. Let's see if it would > help. > > Thanks, I am still trying to look more deeply into how this could happen. This bug was triggered when using cloud storage as the back-end for for their target, and that cloud storage "goes away". (I am still trying to determine what that actually means.) If so, I should be able to simulate by allowing my back-end storage to go away. As you say, let's see if we see any other instances of tgt_targetname() returning null, in other spots in the code. Thank you. -- Lee Duncan -- To unsubscribe from this list: send the line "unsubscribe stgt" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
