[arch-commits] Commit in libxcb/trunk (2 files)
Laurent Carlier
lcarlier at nymeria.archlinux.org
Sun May 11 08:15:06 UTC 2014
Date: Sunday, May 11, 2014 @ 10:15:06
Author: lcarlier
Revision: 212220
upgpkg: libxcb 1.10-2
fix FS#40289
Added:
libxcb/trunk/Ensure-xcb-owns-socket-and-no-other-threads-are-writ.patch
Modified:
libxcb/trunk/PKGBUILD
------------------------------------------------------------+
Ensure-xcb-owns-socket-and-no-other-threads-are-writ.patch | 121 +++++++++++
PKGBUILD | 11 -
2 files changed, 129 insertions(+), 3 deletions(-)
Added: Ensure-xcb-owns-socket-and-no-other-threads-are-writ.patch
===================================================================
--- Ensure-xcb-owns-socket-and-no-other-threads-are-writ.patch (rev 0)
+++ Ensure-xcb-owns-socket-and-no-other-threads-are-writ.patch 2014-05-11 08:15:06 UTC (rev 212220)
@@ -0,0 +1,121 @@
+From be0fe56c3bcad5124dcc6c47a2fad01acd16f71a Mon Sep 17 00:00:00 2001
+From: Keith Packard <keithp at keithp.com>
+Date: Mon, 23 Dec 2013 21:15:20 -0800
+Subject: [PATCH] Ensure xcb owns socket and no other threads are writing
+ before send_request
+
+send_request may only write to out.queue if no other thread is busy
+writing to the network (as that thread may be writing from out.queue).
+
+send_request may only allocate request sequence numbers if XCB owns
+the socket.
+
+Therefore, send_request must make sure that both conditions are true
+when it holds iolock, which can only be done by looping until both
+conditions are true without having dropped the lock waiting for the
+second condition.
+
+We choose to get the socket back from Xlib first as get_socket_back
+has a complicated test and checking for other threads writing is a
+simple in-lined check.
+
+This also changes the sequence number checks (64k requests with no
+reply, 4M request wrapping) to ensure that both conditions are true
+before queueing the request.
+
+Signed-off-by: Keith Packard <keithp at keithp.com>
+Reviewed-by: Uli Schlachter <psychon at znc.in>
+---
+ src/xcb_out.c | 57 ++++++++++++++++++++++++++++++++++++++++-----------------
+ 1 file changed, 40 insertions(+), 17 deletions(-)
+
+diff --git a/src/xcb_out.c b/src/xcb_out.c
+index 18bb5f9..dc42954 100644
+--- a/src/xcb_out.c
++++ b/src/xcb_out.c
+@@ -103,6 +103,33 @@ static void get_socket_back(xcb_connection_t *c)
+ _xcb_in_replies_done(c);
+ }
+
++static void prepare_socket_request(xcb_connection_t *c)
++{
++ /* We're about to append data to out.queue, so we need to
++ * atomically test for an external socket owner *and* some other
++ * thread currently writing.
++ *
++ * If we have an external socket owner, we have to get the socket back
++ * before we can use it again.
++ *
++ * If some other thread is writing to the socket, we assume it's
++ * writing from out.queue, and so we can't stick data there.
++ *
++ * We satisfy this condition by first calling get_socket_back
++ * (which may drop the lock, but will return when XCB owns the
++ * socket again) and then checking for another writing thread and
++ * escaping the loop if we're ready to go.
++ */
++ for (;;) {
++ if(c->has_error)
++ return;
++ get_socket_back(c);
++ if (!c->out.writing)
++ break;
++ pthread_cond_wait(&c->out.cond, &c->iolock);
++ }
++}
++
+ /* Public interface */
+
+ void xcb_prefetch_maximum_request_length(xcb_connection_t *c)
+@@ -236,24 +263,23 @@ unsigned int xcb_send_request(xcb_connection_t *c, int flags, struct iovec *vect
+
+ /* get a sequence number and arrange for delivery. */
+ pthread_mutex_lock(&c->iolock);
+- /* wait for other writing threads to get out of my way. */
+- while(c->out.writing)
+- pthread_cond_wait(&c->out.cond, &c->iolock);
+- get_socket_back(c);
++
++ prepare_socket_request(c);
+
+ /* send GetInputFocus (sync_req) when 64k-2 requests have been sent without
+- * a reply. */
+- if(req->isvoid && c->out.request == c->in.request_expected + (1 << 16) - 2)
+- send_sync(c);
+- /* Also send sync_req (could use NoOp) at 32-bit wrap to avoid having
++ * a reply.
++ * Also send sync_req (could use NoOp) at 32-bit wrap to avoid having
+ * applications see sequence 0 as that is used to indicate
+- * an error in sending the request */
+- if((unsigned int) (c->out.request + 1) == 0)
++ * an error in sending the request
++ */
++
++ while ((req->isvoid && c->out.request == c->in.request_expected + (1 << 16) - 2) ||
++ (unsigned int) (c->out.request + 1) == 0)
++ {
+ send_sync(c);
++ prepare_socket_request(c);
++ }
+
+- /* The above send_sync calls could drop the I/O lock, but this
+- * thread will still exclude any other thread that tries to write,
+- * so the sequence number postconditions still hold. */
+ send_request(c, req->isvoid, workaround, flags, vector, veclen);
+ request = c->has_error ? 0 : c->out.request;
+ pthread_mutex_unlock(&c->iolock);
+@@ -373,10 +399,7 @@ int _xcb_out_send(xcb_connection_t *c, struct iovec *vector, int count)
+
+ void _xcb_out_send_sync(xcb_connection_t *c)
+ {
+- /* wait for other writing threads to get out of my way. */
+- while(c->out.writing)
+- pthread_cond_wait(&c->out.cond, &c->iolock);
+- get_socket_back(c);
++ prepare_socket_request(c);
+ send_sync(c);
+ }
+
+--
+1.9.2
+
Modified: PKGBUILD
===================================================================
--- PKGBUILD 2014-05-11 00:44:29 UTC (rev 212219)
+++ PKGBUILD 2014-05-11 08:15:06 UTC (rev 212220)
@@ -5,7 +5,7 @@
pkgname=libxcb
pkgver=1.10
-pkgrel=1
+pkgrel=2
pkgdesc="X11 client-side library"
arch=('i686' 'x86_64')
url="http://xcb.freedesktop.org/"
@@ -13,14 +13,19 @@
makedepends=('pkgconfig' 'libxslt' 'python')
license=('custom')
source=($url/dist/$pkgname-$pkgver.tar.bz2
- libxcb-1.1-no-pthread-stubs.patch)
+ libxcb-1.1-no-pthread-stubs.patch
+ Ensure-xcb-owns-socket-and-no-other-threads-are-writ.patch)
sha256sums=('98d9ab05b636dd088603b64229dd1ab2d2cc02ab807892e107d674f9c3f2d5b5'
- '748ed83af60468a0eb6785222e4a5ca589d28f20b9bfc60d5936ec93b8eef356')
+ '748ed83af60468a0eb6785222e4a5ca589d28f20b9bfc60d5936ec93b8eef356'
+ '47de1025bb16446b9e69ff7b6b262a0a1af957d350afe897421b9105c89befeb')
prepare() {
cd "$pkgname-$pkgver"
patch -Np1 -i ../libxcb-1.1-no-pthread-stubs.patch
autoreconf -vfi
+
+ # fix FS#40289 merged upstream
+ patch -Np1 -i ../Ensure-xcb-owns-socket-and-no-other-threads-are-writ.patch
}
build() {
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