[Bug 1616213] [NEW] Core dump on multipathd shutdown - trusty 14.04.4

[Dragan S.]

Public bug reported:

On ubuntu trusty 14.04.4 in multipath-tools version 0.4.9-3ubuntu7.14
there is bug in multipathd on shutdown.

The code will access pathvec pointer which is a valid address:

Reading symbols from /sbin/multipathd...Reading symbols from /usr/lib/debug//sbin/multipathd...done.
done.
[New LWP 41631]
[New LWP 41584]
[New LWP 41633]
[New LWP 41632]
[New LWP 41582]
[New LWP 41583]
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
Core was generated by `/sbin/multipathd'.
Program terminated with signal SIGSEGV, Segmentation fault.
#0  0x00000000004075db in checkerloop (ap=0x1b81040) at main.c:1150

1150				vector_foreach_slot (vecs->pathvec, pp, i) {
(gdb) list
1145			pthread_cleanup_push(cleanup_lock, &vecs->lock);
1146			lock(vecs->lock);
1147			condlog(4, "tick");
1148	
1149			if (vecs->pathvec) {
1150				vector_foreach_slot (vecs->pathvec, pp, i) {
1151					check_path(vecs, pp);
1152				}
1153			}
1154			if (vecs->mpvec) {

Pathvec is a valid pointer:
(gdb) p vecs->pathvec
$1 = (vector) 0x1b81280

But the contents of the structure are just garbage:

(gdb) p *vecs->pathvec
$2 = {allocated = 1651076143, slot = 0x756e696c2d34365f}
(gdb)

** Affects: multipath-tools (Ubuntu)
     Importance: Undecided
     Assignee: Dragan S. (dragan-s)
         Status: In Progress


** Tags: sts trusty

** Changed in: multipath-tools (Ubuntu)
     Assignee: (unassigned) => Dragan S. (dragan-s)

** Changed in: multipath-tools (Ubuntu)
       Status: New => In Progress

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https://bugs.launchpad.net/bugs/1616213

Title:
  Core dump on multipathd shutdown - trusty 14.04.4

Status in multipath-tools package in Ubuntu:
  In Progress

Bug description:
  On ubuntu trusty 14.04.4 in multipath-tools version 0.4.9-3ubuntu7.14
  there is bug in multipathd on shutdown.

  The code will access pathvec pointer which is a valid address:

  Reading symbols from /sbin/multipathd...Reading symbols from /usr/lib/debug//sbin/multipathd...done.
  done.
  [New LWP 41631]
  [New LWP 41584]
  [New LWP 41633]
  [New LWP 41632]
  [New LWP 41582]
  [New LWP 41583]
  [Thread debugging using libthread_db enabled]
  Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
  Core was generated by `/sbin/multipathd'.
  Program terminated with signal SIGSEGV, Segmentation fault.
  #0  0x00000000004075db in checkerloop (ap=0x1b81040) at main.c:1150

  1150				vector_foreach_slot (vecs->pathvec, pp, i) {
  (gdb) list
  1145			pthread_cleanup_push(cleanup_lock, &vecs->lock);
  1146			lock(vecs->lock);
  1147			condlog(4, "tick");
  1148	
  1149			if (vecs->pathvec) {
  1150				vector_foreach_slot (vecs->pathvec, pp, i) {
  1151					check_path(vecs, pp);
  1152				}
  1153			}
  1154			if (vecs->mpvec) {

  Pathvec is a valid pointer:
  (gdb) p vecs->pathvec
  $1 = (vector) 0x1b81280

  But the contents of the structure are just garbage:

  (gdb) p *vecs->pathvec
  $2 = {allocated = 1651076143, slot = 0x756e696c2d34365f}
  (gdb)

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