[ovs-dev] [PATCH 1/4] tests: Add bundle action test with buffer realloc.

Ben Pfaff blp at ovn.org
Sat Mar 5 19:26:10 UTC 2016


On Thu, Mar 03, 2016 at 09:22:48PM +1300, Joe Stringer wrote:
> Add a test which causes internal reallocation of the ofpacts buffer,
> followed by a large bundle action which should cause a subsequent
> reallocation while decoding slave ports. Running this test under
> valgrind reveals the issue below, which is fixed in the following
> commit.
> 
> Invalid read of size 4
>    at 0x4CED87: decode_bundle (ofp-actions.c:1253)
>    by 0x4CEDFC: decode_NXAST_RAW_BUNDLE (ofp-actions.c:1272)
>    by 0x4DBDE6: ofpact_decode (ofp-actions.inc2:3765)
>    by 0x4D6914: ofpacts_decode (ofp-actions.c:5735)
>    by 0x4D6A3D: ofpacts_pull_openflow_actions__ (ofp-actions.c:5772)
>    by 0x4D74F3: ofpacts_pull_openflow_instructions (ofp-actions.c:6352)
>    by 0x4F59FA: ofputil_decode_flow_mod (ofp-util.c:1704)
>    by 0x4EAD18: ofp_print_flow_mod (ofp-print.c:786)
>    by 0x4F0711: ofp_to_string__ (ofp-print.c:3220)
>    by 0x4F0D98: ofp_to_string (ofp-print.c:3453)
>    by 0x5486B3: do_recv (vconn.c:644)
>    by 0x548498: vconn_recv (vconn.c:598)
>    by 0x524582: rconn_recv (rconn.c:703)
>    by 0x45DA61: ofconn_run (connmgr.c:1370)
>    by 0x45B3B4: connmgr_run (connmgr.c:323)
>    by 0x41D1E8: ofproto_run (ofproto.c:1762)
>    by 0x40CEE0: bridge_run__ (bridge.c:2885)
>    by 0x40D093: bridge_run (bridge.c:2940)
>    by 0x412F7E: main (ovs-vswitchd.c:120)
> Address 0x66aa460 is 1,152 bytes inside a block of size 1,184 free'd
>    at 0x4C2AF2E: realloc (vg_replace_malloc.c:692)
>    by 0x543D27: xrealloc (util.c:123)
>    by 0x5089EF: ofpbuf_resize__ (ofpbuf.c:243)
>    by 0x508B81: ofpbuf_prealloc_tailroom (ofpbuf.c:290)
>    by 0x508D5C: ofpbuf_put_uninit (ofpbuf.c:364)
>    by 0x508DEF: ofpbuf_put (ofpbuf.c:387)
>    by 0x4CED7D: decode_bundle (ofp-actions.c:1255)
>    by 0x4CEDFC: decode_NXAST_RAW_BUNDLE (ofp-actions.c:1272)
>    by 0x4DBDE6: ofpact_decode (ofp-actions.inc2:3765)
>    by 0x4D6914: ofpacts_decode (ofp-actions.c:5735)
>    by 0x4D6A3D: ofpacts_pull_openflow_actions__ (ofp-actions.c:5772)
>    by 0x4D74F3: ofpacts_pull_openflow_instructions (ofp-actions.c:6352)
>    by 0x4F59FA: ofputil_decode_flow_mod (ofp-util.c:1704)
>    by 0x4EAD18: ofp_print_flow_mod (ofp-print.c:786)
>    by 0x4F0711: ofp_to_string__ (ofp-print.c:3220)
>    by 0x4F0D98: ofp_to_string (ofp-print.c:3453)
>    by 0x5486B3: do_recv (vconn.c:644)
>    by 0x548498: vconn_recv (vconn.c:598)
>    by 0x524582: rconn_recv (rconn.c:703)
>    by 0x45DA61: ofconn_run (connmgr.c:1370)
> 
> Signed-off-by: Joe Stringer <joe at ovn.org>

I'd add a comment to the test explaining why it's useful.

It might be a good idea to add a second command to dump the flow back
out, because it's never too convincing when a test just verifies that a
command exits with status 0 and no output.

Usually, when a series fixes a bug and adds a test for it, we put the
new test either in the same commit as the bug fix or just after the bug
fix, because that maintains bisect-ability.  I guess that this is less
important when the bug only shows up under valgrind, but I still think
that it is a sound principle.



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