From 4fa1d3e7910c3fbe3aacbe5ae5233d0067569c02 Mon Sep 17 00:00:00 2001 From: Richard Acayan Date: Tue, 25 Jul 2023 17:38:39 -0400 Subject: [PATCH] avcodec/v4l2_context: suppress POLLERR and fix crash when buffers are uninitialized A POLLERR occurs when libavcodec attempts to dequeue output buffers before enqueuing capture buffers. This could happen to an application deciding to send the first coded packet. Suppress these POLLERRs when the buffers are uninitialized and avoid crashing because of enumerating uninitialized buffers. See https://trac.ffmpeg.org/ticket/9957 for the original bug report. Signed-off-by: Richard Acayan Signed-off-by: Marton Balint --- libavcodec/v4l2_context.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/libavcodec/v4l2_context.c b/libavcodec/v4l2_context.c index a40be94690..f20f713e1d 100644 --- a/libavcodec/v4l2_context.c +++ b/libavcodec/v4l2_context.c @@ -325,9 +325,13 @@ start: /* 0. handle errors */ if (pfd.revents & POLLERR) { - /* if we are trying to get free buffers but none have been queued yet - no need to raise a warning */ + /* if we are trying to get free buffers but none have been queued yet, + * or if no buffers have been allocated yet, no need to raise a warning + */ if (timeout == 0) { + if (!ctx->buffers) + return NULL; + for (i = 0; i < ctx->num_buffers; i++) { if (ctx->buffers[i].status != V4L2BUF_AVAILABLE) av_log(logger(ctx), AV_LOG_WARNING, "%s POLLERR\n", ctx->name);