[PATCH] os: make timers signal-safe
Peter Hutterer
peter.hutterer at who-t.net
Thu Apr 26 19:47:05 PDT 2012
Block signals for all list manipulations in the timers.
If TimerSet() is called from a signal handler (synaptics tap handling code)
may result in list corruption if we're currently inside TimerSet().
See backtrace in
https://bugzilla.redhat.com/show_bug.cgi?id=814869
Signed-off-by: Peter Hutterer <peter.hutterer at who-t.net>
---
os/WaitFor.c | 18 ++++++++++++++++--
1 file changed, 16 insertions(+), 2 deletions(-)
diff --git a/os/WaitFor.c b/os/WaitFor.c
index 95e64ba..393890f 100644
--- a/os/WaitFor.c
+++ b/os/WaitFor.c
@@ -382,6 +382,7 @@ CheckAllTimers(void)
OsTimerPtr timer;
CARD32 now;
+ OsBlockSignals();
start:
now = GetTimeInMillis();
@@ -391,6 +392,7 @@ CheckAllTimers(void)
goto start;
}
}
+ OsReleaseSignals();
}
static void
@@ -398,11 +400,13 @@ DoTimer(OsTimerPtr timer, CARD32 now, OsTimerPtr *prev)
{
CARD32 newTime;
+ OsBlockSignals();
*prev = timer->next;
timer->next = NULL;
newTime = (*timer->callback) (timer, now, timer->arg);
if (newTime)
TimerSet(timer, 0, newTime, timer->callback, timer->arg);
+ OsReleaseSignals();
}
OsTimerPtr
@@ -418,6 +422,7 @@ TimerSet(OsTimerPtr timer, int flags, CARD32 millis,
return NULL;
}
else {
+ OsBlockSignals();
for (prev = &timers; *prev; prev = &(*prev)->next) {
if (*prev == timer) {
*prev = timer->next;
@@ -426,6 +431,7 @@ TimerSet(OsTimerPtr timer, int flags, CARD32 millis,
break;
}
}
+ OsReleaseSignals();
}
if (!millis)
return timer;
@@ -445,26 +451,32 @@ TimerSet(OsTimerPtr timer, int flags, CARD32 millis,
if (!millis)
return timer;
}
+ OsBlockSignals();
for (prev = &timers;
*prev && (int) ((*prev)->expires - millis) <= 0;
prev = &(*prev)->next);
timer->next = *prev;
*prev = timer;
+ OsReleaseSignals();
return timer;
}
Bool
TimerForce(OsTimerPtr timer)
{
+ int rc = FALSE;
OsTimerPtr *prev;
+ OsBlockSignals();
for (prev = &timers; *prev; prev = &(*prev)->next) {
if (*prev == timer) {
DoTimer(timer, GetTimeInMillis(), prev);
- return TRUE;
+ rc = TRUE;
+ break;
}
}
- return FALSE;
+ OsReleaseSignals();
+ return rc;
}
void
@@ -474,12 +486,14 @@ TimerCancel(OsTimerPtr timer)
if (!timer)
return;
+ OsBlockSignals();
for (prev = &timers; *prev; prev = &(*prev)->next) {
if (*prev == timer) {
*prev = timer->next;
break;
}
}
+ OsReleaseSignals();
}
void
--
1.7.10
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