util/qemu-timer: Make timer_free() imply timer_del()

Currently timer_free() is a simple wrapper for g_free().  This means
that the timer being freed must not be currently active, as otherwise
QEMU might crash later when the active list is processed and still
has a pointer to freed memory on it.  As a result almost all calls to
timer_free() are preceded by a timer_del() call, as can be seen in
the output of
  git grep -B1 '\<timer_free\>'

This is unfortunate API design as it makes it easy to accidentally
misuse (by forgetting the timer_del()), and the correct use is
annoyingly verbose.

Make timer_free() imply a timer_del().

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20201215154107.3255-2-peter.maydell@linaro.org
This commit is contained in:
Peter Maydell 2020-12-15 15:41:04 +00:00
parent 416dd95295
commit 5f8e93c3e2

View File

@ -609,17 +609,6 @@ static inline QEMUTimer *timer_new_ms(QEMUClockType type, QEMUTimerCB *cb,
*/
void timer_deinit(QEMUTimer *ts);
/**
* timer_free:
* @ts: the timer
*
* Free a timer (it must not be on the active list)
*/
static inline void timer_free(QEMUTimer *ts)
{
g_free(ts);
}
/**
* timer_del:
* @ts: the timer
@ -631,6 +620,19 @@ static inline void timer_free(QEMUTimer *ts)
*/
void timer_del(QEMUTimer *ts);
/**
* timer_free:
* @ts: the timer
*
* Free a timer. This will call timer_del() for you to remove
* the timer from the active list if it was still active.
*/
static inline void timer_free(QEMUTimer *ts)
{
timer_del(ts);
g_free(ts);
}
/**
* timer_mod_ns:
* @ts: the timer