res_pjsip_pubsub: Address SEGV when attempting to terminate a subscription

Occasionally under load we'll attempt to send a final NOTIFY on a
subscription that's already been terminated and a SEGV will occur
down in pjproject's evsub_destroy function.  This is a result of a
race condition between all the paths that can generate a notify
and/or destroy the underlying pjproject evsub object:

 * The client can send a SUBSCRIBE with Expires: 0.
 * The client can send a SUBSCRIBE/refresh.
 * The subscription timer can expire.
 * An extension state can change.
 * An MWI event can be generated.
 * The pjproject transaction timer (timer_b) can expire.

Normally when our pubsub_on_evsub_state is called with a terminate,
we push a task to the serializer and return at which point the dialog
is unlocked.  This is usually not a problem because the task runs
immediately and locks the dialog again.  When the system is heavily
loaded though, there may be a delay between the unlock and relock
during which another event may occur such as the subscription timer
or timer_b expiring, an extension state change, etc.  These may also
cause a terminate to be processed and if so, we could cause pjproject
to try to destroy the evsub structure twice.  There's no way for us to
tell that the evsub was already destroyed and the evsub's group lock
can't tolerate this and SEGVs.

The remedy is twofold.

 * A patch has been submitted to Teluu and added to the bundled
   pjproject which adds add/decrement operations on evsub's group lock.

 * In res_pjsip_pubsub:
   * configure.ac and pjproject-bundled's configure.m4 were updated
     to check for the new evsub group lock APIs.
   * We now add a reference to the evsub group lock when we create
     the subscription and remove the reference when we clean up the
     subscription.  This prevents evsub from being destroyed before
     we're done with it.
   * A state has been added to the subscription tree structure so
     termination progress can be tracked through the asyncronous tasks.
   * The pubsub_on_evsub_state callback has been split so it's not doing
     double duty.  It now only handles the final cleanup of the
     subscription tree.  pubsub_on_rx_refresh now handles both client
     refreshes and client terminates.  It was always being called for
     both anyway.
   * The serialized_on_server_timeout task was removed since
     serialized_pubsub_on_rx_refresh was almost identical.
   * Missing state checks and ao2_cleanups were added.
   * Some debug levels were adjusted to make seeing only off-nominal
     things at level 1 and nominal or progress things at level 2+.

ASTERISK-26099 #close
Reported-by: Ross Beer.

Change-Id: I779d11802cf672a51392e62a74a1216596075ba1

1 files changed, 129 insertions, 5 deletions

diff --git a/configure b/configure
index ff34770a1..cb2862e32 100755
--- a/configure
+++ b/configure
@@ -915,6 +915,10 @@ PBX_POPT
 POPT_DIR
 POPT_INCLUDE
 POPT_LIB
+PBX_PJSIP_EVSUB_GRP_LOCK
+PJSIP_EVSUB_GRP_LOCK_DIR
+PJSIP_EVSUB_GRP_LOCK_INCLUDE
+PJSIP_EVSUB_GRP_LOCK_LIB
 PBX_PJSIP_TLS_TRANSPORT_PROTO
 PJSIP_TLS_TRANSPORT_PROTO_DIR
 PJSIP_TLS_TRANSPORT_PROTO_INCLUDE
@@ -10563,6 +10567,18 @@ PBX_PJSIP_TLS_TRANSPORT_PROTO=0
 
 
 
+PJSIP_EVSUB_GRP_LOCK_DESCRIP="PJSIP EVSUB Group Lock support"
+PJSIP_EVSUB_GRP_LOCK_OPTION=pjsip
+PJSIP_EVSUB_GRP_LOCK_DIR=${PJPROJECT_DIR}
+
+PBX_PJSIP_EVSUB_GRP_LOCK=0
+
+
+
+
+
+
+
 
     POPT_DESCRIP="popt"
     POPT_OPTION="popt"
@@ -13612,7 +13628,7 @@ else
     We can't simply define LARGE_OFF_T to be 9223372036854775807,
     since some C++ compilers masquerading as C compilers
     incorrectly reject 9223372036854775807.  */
-#define LARGE_OFF_T ((((off_t) 1 << 31) << 31) - 1 + (((off_t) 1 << 31) << 31))
+#define LARGE_OFF_T (((off_t) 1 << 62) - 1 + ((off_t) 1 << 62))
   int off_t_is_large[(LARGE_OFF_T % 2147483629 == 721
 		       && LARGE_OFF_T % 2147483647 == 1)
 		      ? 1 : -1];
@@ -13658,7 +13674,7 @@ else
     We can't simply define LARGE_OFF_T to be 9223372036854775807,
     since some C++ compilers masquerading as C compilers
     incorrectly reject 9223372036854775807.  */
-#define LARGE_OFF_T ((((off_t) 1 << 31) << 31) - 1 + (((off_t) 1 << 31) << 31))
+#define LARGE_OFF_T (((off_t) 1 << 62) - 1 + ((off_t) 1 << 62))
   int off_t_is_large[(LARGE_OFF_T % 2147483629 == 721
 		       && LARGE_OFF_T % 2147483647 == 1)
 		      ? 1 : -1];
@@ -13682,7 +13698,7 @@ rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
     We can't simply define LARGE_OFF_T to be 9223372036854775807,
     since some C++ compilers masquerading as C compilers
     incorrectly reject 9223372036854775807.  */
-#define LARGE_OFF_T ((((off_t) 1 << 31) << 31) - 1 + (((off_t) 1 << 31) << 31))
+#define LARGE_OFF_T (((off_t) 1 << 62) - 1 + ((off_t) 1 << 62))
   int off_t_is_large[(LARGE_OFF_T % 2147483629 == 721
 		       && LARGE_OFF_T % 2147483647 == 1)
 		      ? 1 : -1];
@@ -13727,7 +13743,7 @@ else
     We can't simply define LARGE_OFF_T to be 9223372036854775807,
     since some C++ compilers masquerading as C compilers
     incorrectly reject 9223372036854775807.  */
-#define LARGE_OFF_T ((((off_t) 1 << 31) << 31) - 1 + (((off_t) 1 << 31) << 31))
+#define LARGE_OFF_T (((off_t) 1 << 62) - 1 + ((off_t) 1 << 62))
   int off_t_is_large[(LARGE_OFF_T % 2147483629 == 721
 		       && LARGE_OFF_T % 2147483647 == 1)
 		      ? 1 : -1];
@@ -13751,7 +13767,7 @@ rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
     We can't simply define LARGE_OFF_T to be 9223372036854775807,
     since some C++ compilers masquerading as C compilers
     incorrectly reject 9223372036854775807.  */
-#define LARGE_OFF_T ((((off_t) 1 << 31) << 31) - 1 + (((off_t) 1 << 31) << 31))
+#define LARGE_OFF_T (((off_t) 1 << 62) - 1 + ((off_t) 1 << 62))
   int off_t_is_large[(LARGE_OFF_T % 2147483629 == 721
 		       && LARGE_OFF_T % 2147483647 == 1)
 		      ? 1 : -1];
@@ -24463,6 +24479,9 @@ rm -f conftest*
 $as_echo "#define HAVE_PJSIP_TLS_TRANSPORT_PROTO 1" >>confdefs.h
 
 
+$as_echo "#define HAVE_PJSIP_EVSUB_GRP_LOCK 1" >>confdefs.h
+
+
    else
 
    if test "x${PBX_PJPROJECT}" != "x1" -a "${USE_PJPROJECT}" != "no"; then
@@ -25178,6 +25197,111 @@ rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 
       LIBS="${saved_libs}"
       CPPFLAGS="${saved_cppflags}"
+
+
+if test "x${PBX_PJSIP_EVSUB_GRP_LOCK}" != "x1" -a "${USE_PJSIP_EVSUB_GRP_LOCK}" != "no"; then
+   pbxlibdir=""
+   # if --with-PJSIP_EVSUB_GRP_LOCK=DIR has been specified, use it.
+   if test "x${PJSIP_EVSUB_GRP_LOCK_DIR}" != "x"; then
+      if test -d ${PJSIP_EVSUB_GRP_LOCK_DIR}/lib; then
+         pbxlibdir="-L${PJSIP_EVSUB_GRP_LOCK_DIR}/lib"
+      else
+         pbxlibdir="-L${PJSIP_EVSUB_GRP_LOCK_DIR}"
+      fi
+   fi
+   pbxfuncname="pjsip_evsub_add_lock"
+   if test "x${pbxfuncname}" = "x" ; then   # empty lib, assume only headers
+      AST_PJSIP_EVSUB_GRP_LOCK_FOUND=yes
+   else
+      ast_ext_lib_check_save_CFLAGS="${CFLAGS}"
+      CFLAGS="${CFLAGS} $PJPROJECT_CFLAGS"
+      as_ac_Lib=`$as_echo "ac_cv_lib_pjsip_${pbxfuncname}" | $as_tr_sh`
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for ${pbxfuncname} in -lpjsip" >&5
+$as_echo_n "checking for ${pbxfuncname} in -lpjsip... " >&6; }
+if eval \${$as_ac_Lib+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_check_lib_save_LIBS=$LIBS
+LIBS="-lpjsip ${pbxlibdir} $PJPROJECT_LIB $LIBS"
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char ${pbxfuncname} ();
+int
+main ()
+{
+return ${pbxfuncname} ();
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+  eval "$as_ac_Lib=yes"
+else
+  eval "$as_ac_Lib=no"
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS
+fi
+eval ac_res=\$$as_ac_Lib
+	       { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5
+$as_echo "$ac_res" >&6; }
+if eval test \"x\$"$as_ac_Lib"\" = x"yes"; then :
+  AST_PJSIP_EVSUB_GRP_LOCK_FOUND=yes
+else
+  AST_PJSIP_EVSUB_GRP_LOCK_FOUND=no
+fi
+
+      CFLAGS="${ast_ext_lib_check_save_CFLAGS}"
+   fi
+
+   # now check for the header.
+   if test "${AST_PJSIP_EVSUB_GRP_LOCK_FOUND}" = "yes"; then
+      PJSIP_EVSUB_GRP_LOCK_LIB="${pbxlibdir} -lpjsip $PJPROJECT_LIB"
+      # if --with-PJSIP_EVSUB_GRP_LOCK=DIR has been specified, use it.
+      if test "x${PJSIP_EVSUB_GRP_LOCK_DIR}" != "x"; then
+         PJSIP_EVSUB_GRP_LOCK_INCLUDE="-I${PJSIP_EVSUB_GRP_LOCK_DIR}/include"
+      fi
+      PJSIP_EVSUB_GRP_LOCK_INCLUDE="${PJSIP_EVSUB_GRP_LOCK_INCLUDE} $PJPROJECT_CFLAGS"
+      if test "xpjsip.h" = "x" ; then	# no header, assume found
+         PJSIP_EVSUB_GRP_LOCK_HEADER_FOUND="1"
+      else				# check for the header
+         ast_ext_lib_check_saved_CPPFLAGS="${CPPFLAGS}"
+         CPPFLAGS="${CPPFLAGS} ${PJSIP_EVSUB_GRP_LOCK_INCLUDE}"
+         ac_fn_c_check_header_mongrel "$LINENO" "pjsip.h" "ac_cv_header_pjsip_h" "$ac_includes_default"
+if test "x$ac_cv_header_pjsip_h" = xyes; then :
+  PJSIP_EVSUB_GRP_LOCK_HEADER_FOUND=1
+else
+  PJSIP_EVSUB_GRP_LOCK_HEADER_FOUND=0
+fi
+
+
+         CPPFLAGS="${ast_ext_lib_check_saved_CPPFLAGS}"
+      fi
+      if test "x${PJSIP_EVSUB_GRP_LOCK_HEADER_FOUND}" = "x0" ; then
+         PJSIP_EVSUB_GRP_LOCK_LIB=""
+         PJSIP_EVSUB_GRP_LOCK_INCLUDE=""
+      else
+         if test "x${pbxfuncname}" = "x" ; then		# only checking headers -> no library
+            PJSIP_EVSUB_GRP_LOCK_LIB=""
+         fi
+         PBX_PJSIP_EVSUB_GRP_LOCK=1
+         cat >>confdefs.h <<_ACEOF
+#define HAVE_PJSIP_EVSUB_GRP_LOCK 1
+_ACEOF
+
+      fi
+   fi
+fi
+
+
    fi
 fi