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. Patch 1 makes timer_free() call timer_del() if the timer is active. Patch 2 is a Coccinelle script to remove any timer_del() calls that are immediately before the timer_free(). Patch 3 is the result of running the Coccinelle script on the whole tree. Patch 4 makes a by-hand cleanup of a bit of the Arm CPU code not caught by Coccinelle because it included a pointless timer_deinit() between timer_del() and timer_free(). I could split up patch 3, but for 58 deleted lines over 42 files created entirely automatedly, it seemed to me to be simpler as one patch. Changes v1->v2: * patch 1: unconditionally call timer_del() rather than trying to be clever * patch 4: new patch thanks -- PMM Peter Maydell (4): util/qemu-timer: Make timer_free() imply timer_del() scripts/coccinelle: New script to remove unnecessary timer_del() calls Remove superfluous timer_del() calls target/arm: Remove timer_del()/timer_deinit() before timer_free() scripts/coccinelle/timer-del-timer-free.cocci | 18 +++++++++++++ include/qemu/timer.h | 25 +++++++++++-------- block/iscsi.c | 2 -- block/nbd.c | 1 - block/qcow2.c | 1 - hw/block/nvme.c | 2 -- hw/char/serial.c | 2 -- hw/char/virtio-serial-bus.c | 2 -- hw/ide/core.c | 1 - hw/input/hid.c | 1 - hw/intc/apic.c | 1 - hw/intc/ioapic.c | 1 - hw/ipmi/ipmi_bmc_extern.c | 1 - hw/net/e1000.c | 3 --- hw/net/e1000e_core.c | 8 ------ hw/net/pcnet-pci.c | 1 - hw/net/rtl8139.c | 1 - hw/net/spapr_llan.c | 1 - hw/net/virtio-net.c | 2 -- hw/s390x/s390-pci-inst.c | 1 - hw/sd/sd.c | 1 - hw/sd/sdhci.c | 2 -- hw/usb/dev-hub.c | 1 - hw/usb/hcd-ehci.c | 1 - hw/usb/hcd-ohci-pci.c | 1 - hw/usb/hcd-uhci.c | 1 - hw/usb/hcd-xhci.c | 1 - hw/usb/redirect.c | 1 - hw/vfio/display.c | 1 - hw/virtio/vhost-vsock-common.c | 1 - hw/virtio/virtio-balloon.c | 1 - hw/virtio/virtio-rng.c | 1 - hw/watchdog/wdt_diag288.c | 1 - hw/watchdog/wdt_i6300esb.c | 1 - migration/colo.c | 1 - monitor/hmp-cmds.c | 1 - net/announce.c | 1 - net/colo-compare.c | 1 - net/slirp.c | 1 - replay/replay-debugging.c | 1 - target/arm/cpu.c | 2 -- target/s390x/cpu.c | 2 -- ui/console.c | 1 - ui/spice-core.c | 1 - util/throttle.c | 1 - 45 files changed, 32 insertions(+), 71 deletions(-) create mode 100644 scripts/coccinelle/timer-del-timer-free.cocci -- 2.20.1
