xserver: Branch 'server-1.20-branch'
GitLab Mirror
gitlab-mirror at kemper.freedesktop.org
Wed Nov 20 20:41:47 UTC 2019
Xext/sleepuntil.c | 3 +--
dix/dixutils.c | 9 +--------
os/connection.c | 8 ++++++++
record/record.c | 4 ++--
4 files changed, 12 insertions(+), 12 deletions(-)
New commits:
commit 2edadf26f1f8deddbe171115fa502337ac62df02
Author: Aaron Plattner <aplattner at nvidia.com>
Date: Tue Nov 19 10:08:51 2019 -0800
os: Don't crash in AttendClient if the client is gone
If a client is in the process of being closed down, then its client->osPrivate
pointer will be set to NULL by CloseDownConnection. This can cause a crash if
freeing the client's resources results in a call to AttendClient. For example,
if the client has a pending sync fence:
Thread 1 "X" received signal SIGSEGV, Segmentation fault.
AttendClient (client=0x5571c4aed9a0) at ../os/connection.c:942
(gdb) bt
#0 AttendClient (client=0x5571c4aed9a0) at ../os/connection.c:942
#1 0x00005571c3dbb865 in SyncAwaitTriggerFired (pTrigger=<optimized out>) at ../Xext/sync.c:694
#2 0x00005571c3dd5749 in miSyncDestroyFence (pFence=0x5571c5063980) at ../miext/sync/misync.c:120
#3 0x00005571c3dbbc69 in FreeFence (obj=<optimized out>, id=<optimized out>) at ../Xext/sync.c:1909
#4 0x00005571c3d7a01d in doFreeResource (res=0x5571c506e3d0, skip=skip at entry=0) at ../dix/resource.c:880
#5 0x00005571c3d7b1dc in FreeClientResources (client=0x5571c4aed9a0) at ../dix/resource.c:1146
#6 FreeClientResources (client=0x5571c4aed9a0) at ../dix/resource.c:1109
#7 0x00005571c3d5525f in CloseDownClient (client=0x5571c4aed9a0) at ../dix/dispatch.c:3473
#8 0x00005571c3d55eeb in Dispatch () at ../dix/dispatch.c:492
#9 0x00005571c3d59e96 in dix_main (argc=3, argv=0x7ffe7854bc28, envp=<optimized out>) at ../dix/main.c:276
#10 0x00007fea4837cb6b in __libc_start_main (main=0x5571c3d1d060 <main>, argc=3, argv=0x7ffe7854bc28, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7ffe7854bc18) at ../csu/libc-start.c:308
#11 0x00005571c3d1d09a in _start () at ../Xext/sync.c:2378
(gdb) print client->osPrivate
$1 = (void *) 0x0
Since the client is about to be freed, its ignore count doesn't matter and
AttendClient can simply be a no-op. Check for client->clientGone in AttendClient
and remove similar checks from two callers that had them.
Signed-off-by: Aaron Plattner <aplattner at nvidia.com>
(cherry picked from commit 4308f5d3d1fbd0f5dce81e22c0c3f08c65a7c9d8)
diff --git a/Xext/sleepuntil.c b/Xext/sleepuntil.c
index 68a7a9bee..334c2784a 100644
--- a/Xext/sleepuntil.c
+++ b/Xext/sleepuntil.c
@@ -125,8 +125,7 @@ ClientSleepUntil(ClientPtr client,
static void
ClientAwaken(ClientPtr client, void *closure)
{
- if (!client->clientGone)
- AttendClient(client);
+ AttendClient(client);
}
static int
diff --git a/dix/dixutils.c b/dix/dixutils.c
index 2983174a1..331ccfb96 100644
--- a/dix/dixutils.c
+++ b/dix/dixutils.c
@@ -662,14 +662,7 @@ ClientWakeup(ClientPtr client)
if (q->client == client) {
*prev = q->next;
free(q);
- if (client->clientGone)
- /* Oops -- new zombie cleanup code ensures this only
- * happens from inside CloseDownClient; don't want to
- * recurse here...
- */
- /* CloseDownClient(client) */ ;
- else
- AttendClient(client);
+ AttendClient(client);
break;
}
prev = &q->next;
diff --git a/os/connection.c b/os/connection.c
index 229bbe745..32d2cda2a 100644
--- a/os/connection.c
+++ b/os/connection.c
@@ -935,6 +935,14 @@ AttendClient(ClientPtr client)
{
OsCommPtr oc = (OsCommPtr) client->osPrivate;
+ if (client->clientGone) {
+ /*
+ * client is gone, so any pending requests will be dropped and its
+ * ignore count doesn't matter.
+ */
+ return;
+ }
+
client->ignoreCount--;
if (client->ignoreCount)
return;
diff --git a/record/record.c b/record/record.c
index fdcee7e00..f0b739b0c 100644
--- a/record/record.c
+++ b/record/record.c
@@ -2362,9 +2362,9 @@ RecordDisableContext(RecordContextPtr pContext)
if (!pContext->pRecordingClient->clientGone) {
RecordAProtocolElement(pContext, NULL, XRecordEndOfData, NULL, 0, 0, 0);
RecordFlushReplyBuffer(pContext, NULL, 0, NULL, 0);
- /* Re-enable request processing on this connection. */
- AttendClient(pContext->pRecordingClient);
}
+ /* Re-enable request processing on this connection. */
+ AttendClient(pContext->pRecordingClient);
for (pRCAP = pContext->pListOfRCAP; pRCAP; pRCAP = pRCAP->pNextRCAP) {
RecordUninstallHooks(pRCAP, 0);
More information about the xorg-commit
mailing list