[Xen-changelog] [xen stable-4.4] libxl: Fix carefd lock leak in save callout

[patchbot@xxxxxxx]

commit 4bb3a17449a4472930030a627631f788bb678123
Author:     Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
AuthorDate: Mon Feb 24 14:19:15 2014 +0000
Commit:     Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>
CommitDate: Fri Apr 4 16:01:56 2014 +0100

    libxl: Fix carefd lock leak in save callout
    
    If libxl_pipe fails we leave the carefd locked, which translates to
    the atfork lock remaining held.  This would probably cause the process
    to deadlock shortly afterwards.
    
    Of course libxl_pipe is very unlikely to fail unless things are
    already going very badly.  This bug has not been observed anywhere as
    far as we are aware.
    
    Signed-off-by: Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>
    Acked-by: Ian Campbell <Ian.Campbell@xxxxxxxxxx>
    CC: George Dunlap <george.dunlap@xxxxxxxxxxxxx>
    (cherry picked from commit 7eb73add5de5839f160b902dd894d3aecc10ba0c)
---
 tools/libxl/libxl_save_callout.c |    6 +++++-
 1 files changed, 5 insertions(+), 1 deletions(-)

diff --git a/tools/libxl/libxl_save_callout.c b/tools/libxl/libxl_save_callout.c
index 6e45b2f..e3bda8f 100644
--- a/tools/libxl/libxl_save_callout.c
+++ b/tools/libxl/libxl_save_callout.c
@@ -185,7 +185,11 @@ static void run_helper(libxl__egc *egc, 
libxl__save_helper_state *shs,
     for (childfd=0; childfd<2; childfd++) {
         /* Setting up the pipe for the child's fd childfd */
         int fds[2];
-        if (libxl_pipe(CTX,fds)) { rc = ERROR_FAIL; goto out; }
+        if (libxl_pipe(CTX,fds)) {
+            rc = ERROR_FAIL;
+            libxl__carefd_unlock();
+            goto out;
+        }
         int childs_end = childfd==0 ? 0 /*read*/  : 1 /*write*/;
         int our_end    = childfd==0 ? 1 /*write*/ : 0 /*read*/;
         childs_pipes[childfd] = libxl__carefd_record(CTX, fds[childs_end]);
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.4

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