ardour/livetrax
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Work around finish_capture() race

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In rare cases DiskWriter::run() may call finish_capture()
concurrently with the butler thread from transport_stopped_wallclock,
this can lead to memory corruption (CaptureInfo).

Using a Mutex here is not great, but it is not usually contended
and better than crashing at rec-stop.

We should probably change DiskWrWiter::_was_recording into an
atomic bool, and use CAS to prevent concurrent calls.
This commit is contained in:
Robin Gareus 2023-06-04 22:19:53 +02:00
parent 464df06419
commit fbfeff4168
Signed by: rgareus
GPG Key ID: A090BCE02CF57F04
1 changed files with 3 additions and 1 deletions
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4
libs/ardour/disk_writer.cc
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@ -710,6 +710,7 @@ DiskWriter::run (BufferSet& bufs, samplepos_t start_sample, samplepos_t end_samp
/* not recording this time, but perhaps we were before .. */
if (_was_recording) {
Glib::Threads::Mutex::Lock lm (capture_info_lock);
finish_capture (c);
_accumulated_capture_offset = 0;
_capture_start_sample.reset ();
@ -1157,6 +1158,7 @@ DiskWriter::use_new_write_source (DataType dt, uint32_t n)
void
DiskWriter::transport_stopped_wallclock (struct tm& when, time_t twhen, bool abort_capture)
{
Glib::Threads::Mutex::Lock lm (capture_info_lock);
bool more_work = true;
int err = 0;
SourceList audio_srcs;
@ -1186,7 +1188,6 @@ DiskWriter::transport_stopped_wallclock (struct tm& when, time_t twhen, bool abo
}
/* XXX is there anything we can do if err != 0 ? */
Glib::Threads::Mutex::Lock lm (capture_info_lock);
if (capture_info.empty()) {
return;
@ -1326,6 +1327,7 @@ DiskWriter::loop (samplepos_t transport_sample)
{
_transport_looped = false;
if (_was_recording) {
Glib::Threads::Mutex::Lock lm (capture_info_lock);
// all we need to do is finish this capture, with modified capture length
std::shared_ptr<ChannelList const> c = channels.reader();