[Xen-changelog] [xen stable-4.5] libxl: Initialise CTX->xce in domain suspend, as needed

[patchbot@xxxxxxx]

commit 6b511af68618a86d5a2258e649042a3f0b8ace52
Author:     Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
AuthorDate: Mon Jan 5 14:31:00 2015 +0000
Commit:     Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>
CommitDate: Mon Jan 5 16:42:11 2015 +0000

    libxl: Initialise CTX->xce in domain suspend, as needed
    
    When excuting xl migrate/Remus, the following error can occur:
      [root@master xen]# xl migrate 5 slaver
      migration target: Ready to receive domain.
      Saving to migration stream new xl format (info 0x1/0x0/1225)
      Loading new save file <incoming migration stream> (new xl fmt info 
0x1/0x0/12\
    )
       Savefile contains xl domain config in JSON format
      Parsing config from <saved>
      Segmentation fault (core dumped)
    
    This is because CTX->xce is used without been initialized.
    The bug was introduced by commit 2ffeb5d7f5d8
        libxl: events: Deregister evtchn fd when not needed
    which removed the initialization of xce from libxl__ctx_alloc.
    
    In this patch we initialise the CTX->xce before using it.  Also, we
    adjust the doc comment for libxl__ev_evtchn_* to mention the need to
    do so.
    
    Signed-off-by: Yang Hongyang <yanghy@xxxxxxxxxxxxxx>
    Signed-off-by: Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>
    Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
    Release-Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
    Cc: Wei Liu <wei.liu2@xxxxxxxxxx>
---
 tools/libxl/libxl_dom.c      |    3 +++
 tools/libxl/libxl_internal.h |    6 ++++--
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/tools/libxl/libxl_dom.c b/tools/libxl/libxl_dom.c
index 74ea84b..94ae818 100644
--- a/tools/libxl/libxl_dom.c
+++ b/tools/libxl/libxl_dom.c
@@ -1824,6 +1824,9 @@ void libxl__domain_suspend(libxl__egc *egc, 
libxl__domain_suspend_state *dss)
     port = xs_suspend_evtchn_port(dss->domid);
 
     if (port >= 0) {
+        rc = libxl__ctx_evtchn_init(gc);
+        if (rc) goto out;
+
         dss->guest_evtchn.port =
             xc_suspend_evtchn_init_exclusive(CTX->xch, CTX->xce,
                                   dss->domid, port, &dss->guest_evtchn_lockfd);
diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
index 9695f18..6dac0f8 100644
--- a/tools/libxl/libxl_internal.h
+++ b/tools/libxl/libxl_internal.h
@@ -800,8 +800,10 @@ static inline int libxl__ev_xswatch_isregistered(const 
libxl__ev_xswatch *xw)
 
 /*
  * The evtchn facility is one-shot per call to libxl__ev_evtchn_wait.
- * You should call some suitable xc bind function on (or to obtain)
- * the port, then libxl__ev_evtchn_wait.
+ * You should:
+ *   Use libxl__ctx_evtchn_init to make sure CTX->xce is valid;
+ *   Call some suitable xc bind function on (or to obtain) the port;
+ *   Then call libxl__ev_evtchn_wait.
  *
  * When the event is signaled then the callback will be made, once.
  * Then you must call libxl__ev_evtchn_wait again, if desired.
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.5

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