libguestfs/0001-ocaml-Fix-locking-in-event-callbacks.patch
2011-07-26 19:05:40 +01:00

80 lines
2.6 KiB
Diff

From 2b8b3f9794ceb43eabd3083e225c669896d8b186 Mon Sep 17 00:00:00 2001
From: "Richard W.M. Jones" <rjones@redhat.com>
Date: Tue, 26 Jul 2011 18:57:19 +0100
Subject: [PATCH] ocaml: Fix locking in event callbacks.
We weren't acquiring the GC lock around some allocations, resulting in
segfaults when an event callback ran at the same time as a main thread
allocation or garbage collection.
In particular this fixes a noticable crash in guestfs-browser.
---
ocaml/guestfs_c.c | 36 +++++++++++++++++++++++++++---------
1 files changed, 27 insertions(+), 9 deletions(-)
diff --git a/ocaml/guestfs_c.c b/ocaml/guestfs_c.c
index 3f862ea..96e8a35 100644
--- a/ocaml/guestfs_c.c
+++ b/ocaml/guestfs_c.c
@@ -327,13 +327,13 @@ event_bitmask_to_event (uint64_t event)
}
static void
-event_callback_wrapper (guestfs_h *g,
- void *data,
- uint64_t event,
- int event_handle,
- int flags,
- const char *buf, size_t buf_len,
- const uint64_t *array, size_t array_len)
+event_callback_wrapper_locked (guestfs_h *g,
+ void *data,
+ uint64_t event,
+ int event_handle,
+ int flags,
+ const char *buf, size_t buf_len,
+ const uint64_t *array, size_t array_len)
{
CAMLparam0 ();
CAMLlocal5 (gv, evv, ehv, bufv, arrayv);
@@ -360,9 +360,7 @@ event_callback_wrapper (guestfs_h *g,
value args[5] = { gv, evv, ehv, bufv, arrayv };
- caml_leave_blocking_section ();
rv = caml_callbackN_exn (*(value*)data, 5, args);
- caml_enter_blocking_section ();
/* Callbacks shouldn't throw exceptions. There's not much we can do
* except to print it.
@@ -375,6 +373,26 @@ event_callback_wrapper (guestfs_h *g,
CAMLreturn0;
}
+static void
+event_callback_wrapper (guestfs_h *g,
+ void *data,
+ uint64_t event,
+ int event_handle,
+ int flags,
+ const char *buf, size_t buf_len,
+ const uint64_t *array, size_t array_len)
+{
+ /* Ensure we are holding the GC lock before any GC operations are
+ * possible. (RHBZ#725824)
+ */
+ caml_leave_blocking_section ();
+
+ event_callback_wrapper_locked (g, data, event, event_handle, flags,
+ buf, buf_len, array, array_len);
+
+ caml_enter_blocking_section ();
+}
+
value
ocaml_guestfs_last_errno (value gv)
{
--
1.7.5.2