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v4l2: delay pipewire init until first openat call

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Initialization of PipeWire could happen too early and deadlock in some
cases. Instead, initialize pipewire right before we're going to actually
use it for the first time.

Fixes #4859
This commit is contained in:
Wim Taymans 2025-09-01 13:31:47 +02:00
parent d46a4686a8
commit 0d42f11b87
1 changed files with 23 additions and 4 deletions
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27
pipewire-v4l2/src/pipewire-v4l2.c
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@ -772,6 +772,19 @@ static int v4l2_dup(int oldfd)
return do_dup(oldfd, FD_MAP_DUP);
}
/* Deferred PipeWire init (called on first device access) */
static void pipewire_init_func(void)
{
pw_init(NULL, NULL);
PW_LOG_TOPIC_INIT(v4l2_log_topic);
}
static void ensure_pipewire_init(void)
{
static pthread_once_t pipewire_once = PTHREAD_ONCE_INIT;
pthread_once(&pipewire_once, pipewire_init_func);
}
static int v4l2_openat(int dirfd, const char *path, int oflag, mode_t mode)
{
int res, flags;
@ -795,6 +808,8 @@ static int v4l2_openat(int dirfd, const char *path, int oflag, mode_t mode)
if (passthrough)
return globals.old_fops.openat(dirfd, path, oflag, mode);
ensure_pipewire_init();
pw_log_info("path:%s oflag:%d mode:%d", path, oflag, mode);
if ((file = find_file_by_dev(dev_id)) != NULL) {
@ -2565,10 +2580,14 @@ static void initialize(void)
globals.old_fops.ioctl = dlsym(RTLD_NEXT, "ioctl");
globals.old_fops.mmap = dlsym(RTLD_NEXT, "mmap64");
globals.old_fops.munmap = dlsym(RTLD_NEXT, "munmap");
pw_init(NULL, NULL);
PW_LOG_TOPIC_INIT(v4l2_log_topic);
/* NOTE:
* We avoid calling pw_init() here (constructor/early init path) because
* that can deadlock in certain host processes (e.g. Zoom >= 5.0) when
* the preload causes PipeWire initialisation to run too early.
*
* PipeWire initialisation (pw_init + PW_LOG_TOPIC_INIT) is deferred
* to ensure it runs on-demand in the first actual V4L2 open call.
*/
pthread_mutex_init(&globals.lock, NULL);
pw_array_init(&globals.file_maps, 1024);
pw_array_init(&globals.fd_maps, 256);