[SCM] Samba Shared Repository - branch v3-5-test updated

Karolin Seeger kseeger at samba.org
Fri Jun 22 11:45:31 MDT 2012

The branch, v3-5-test has been updated
       via  41c2411 s3: Fix a winbind race leading to 100% CPU
      from  dfa5366 Fix for bug #8998 - Notify code can miss a ChDir.


- Log -----------------------------------------------------------------
commit 41c2411286f76919546b677f98f1166f1e40c706
Author: Volker Lendecke <vl at samba.org>
Date:   Fri Aug 26 16:54:18 2011 +0200

    s3: Fix a winbind race leading to 100% CPU
    This fixes a race condition that leads to the winbindd_children list becoming
    corrupted. It happens when on a busy winbind SIGCHLD is a bit late.
    Imagine a winbind with multiple requests in the queue for a single child. Child
    dies, and before the SIGCHLD handler is called we find the socket to be dead.
    wb_child_request_done is called, receiving an error from wb_simple_trans_recv.
    It closes the socket. Then immediately the wb_child_request_trigger will do
    another fork_domain_child before the signal handler is called. This means that
    we do another fork_domain_child, we have child->sock==-1 at this point.
    fork_domain_child will do a DLIST_ADD(winbindd_children, child) a second time
    where the child is already part of that list. This corrupts the list. Then the
    signal handler kicks in, spinning in
    for (child = winbindd_children; child != NULL; child = child->next) {
    forever. Not good. This patch makes sure that both conditions (sock==-1 and not
    part of the list) for a winbindd_child struct match up.
    Autobuild-User: Volker Lendecke <vlendec at samba.org>
    Autobuild-Date: Fri Aug 26 18:51:24 CEST 2011 on sn-devel-104
    Fix bug #9000 - winbindd hangs when disconnect domain connection.


Summary of changes:
 source3/winbindd/winbindd_dual.c |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)

Changeset truncated at 500 lines:

diff --git a/source3/winbindd/winbindd_dual.c b/source3/winbindd/winbindd_dual.c
index 360f1b2..2c0633c 100644
--- a/source3/winbindd/winbindd_dual.c
+++ b/source3/winbindd/winbindd_dual.c
@@ -37,6 +37,8 @@
 extern bool override_logfile;
 extern struct winbindd_methods cache_methods;
+static struct winbindd_child *children = NULL;
 /* Read some data from a client connection */
 static NTSTATUS child_read_request(struct winbindd_cli_state *state)
@@ -170,6 +172,7 @@ static void wb_child_request_done(struct tevent_req *subreq)
 		state->child->sock = -1;
+		DLIST_REMOVE(children, state->child);
 		tevent_req_error(req, err);
@@ -517,8 +520,6 @@ void setup_child(struct winbindd_domain *domain, struct winbindd_child *child,
 	SMB_ASSERT(child->rpccli != NULL);
-struct winbindd_child *children = NULL;
 void winbind_child_died(pid_t pid)
 	struct winbindd_child *child;

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