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?
> ----------------------------------------------------------------
> char *tgt_targetname(int tid)
> {
> struct target *target;
>
> target = target_lookup(tid);
> if (!target)
> return NULL;
>
> return target->name;
> }
> ----------------------------------------------------------------
>
> I propose the following patch to address this:
>
> ---
> diff --git a/usr/iscsi/target.c b/usr/iscsi/target.c
> index 7afd7fd0ba87..b0a36e7de7b4 100644
> --- a/usr/iscsi/target.c
> +++ b/usr/iscsi/target.c
> @@ -369,9 +369,11 @@ void target_list_build(struct iscsi_connection *conn, char *addr, char *name)
> struct iscsi_target *target_find_by_name(const char *name)
> {
> struct iscsi_target *target;
> + char *tname;
>
> list_for_each_entry(target, &iscsi_targets_list, tlist) {
> - if (!strcmp(tgt_targetname(target->tid), name))
> + tname = tgt_targetname(target->tid);
> + if (tname && !strcmp(tname, name))
> return target;
> }
>
>
> --
> Lee Duncan
> --
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