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Don't crash when highlighted tabbox client is closed

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Summary:
The compositor tries to switch to the next tabbox client when currently
highlighted client is closed. Though there is a small issue with that.
Because the switch happens too late, a dangling pointer can be inserted
into the unconstrained stacking order, which can lead to a crash later on.

There are two cases:
- compositing is on;
- compositing is off.

Compositing is on: TabBox will try to un-elevate currently highlighted
client, though by that time the client no longer owns EffectWindow, so
this is basically a no-op (that's why we haven't experienced this bug
before).

Compositing is off: TabBox will try to restack currently hightlighted
client under the next tabbox client. Given that the restack method
doesn't do any sanity checks(see Client::manage why), a client that is
about to be destroyed will be re-inserted back into the unconstrained
stacking order.

This change ensures that the switch happens before currently highlighted
client is removed from the stacking order.

BUG: 406784

Test Plan:
- Turn off compositing;
- Follow steps to reproduce in the bug report (see comment 2).

Reviewers: #kwin, davidedmundson

Reviewed By: #kwin, davidedmundson

Subscribers: kwin

Tags: #kwin

Differential Revision: https://phabricator.kde.org/D20916
This commit is contained in:
Vlad Zagorodniy 2019-04-30 11:46:53 +03:00
parent c3c030d8b5
commit d948d247fe
2 changed files with 16 additions and 6 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

15
client.cpp
View file

@ -32,6 +32,9 @@ along with this program. If not, see <http://www.gnu.org/licenses/>.
#include "focuschain.h"
#include "group.h"
#include "shadow.h"
#ifdef KWIN_BUILD_TABBOX
#include "tabbox.h"
#endif
#include "workspace.h"
#include "screenedge.h"
#include "decorations/decorationbridge.h"
@ -205,6 +208,12 @@ void Client::releaseWindow(bool on_shutdown)
{
assert(!deleting);
deleting = true;
#ifdef KWIN_BUILD_TABBOX
TabBox::TabBox *tabBox = TabBox::TabBox::self();
if (tabBox->isDisplayed() && tabBox->currentClient() == this) {
tabBox->nextPrev(true);
}
#endif
destroyWindowManagementInterface();
Deleted* del = NULL;
if (!on_shutdown) {
@ -275,6 +284,12 @@ void Client::destroyClient()
{
assert(!deleting);
deleting = true;
#ifdef KWIN_BUILD_TABBOX
TabBox::TabBox *tabBox = TabBox::TabBox::self();
if (tabBox->isDisplayed() && tabBox->currentClient() == this) {
tabBox->nextPrev(true);
}
#endif
destroyWindowManagementInterface();
Deleted* del = Deleted::create(this);
if (isMoveResize())

7
workspace.cpp
View file

@ -651,12 +651,6 @@ void Workspace::removeClient(Client* c)
clientShortcutUpdated(c); // Needed, since this is otherwise delayed by setShortcut() and wouldn't run
}
#ifdef KWIN_BUILD_TABBOX
TabBox::TabBox *tabBox = TabBox::TabBox::self();
if (tabBox->isDisplayed() && tabBox->currentClient() == c)
tabBox->nextPrev(true);
#endif
Q_ASSERT(clients.contains(c) || desktops.contains(c));
// TODO: if marked client is removed, notify the marked list
clients.removeAll(c);
@ -680,6 +674,7 @@ void Workspace::removeClient(Client* c)
updateStackingOrder(true);
#ifdef KWIN_BUILD_TABBOX
TabBox::TabBox *tabBox = TabBox::TabBox::self();
if (tabBox->isDisplayed())
tabBox->reset(true);
#endif