[FFmpeg-devel] [PATCH V2] vf_hwupload: Add missing return value check
Mark Thompson
sw at jkqxz.net
Fri Mar 10 01:49:36 EET 2017
On 09/03/17 00:33, Jun Zhao wrote:
> On 2017/3/8 16:58, Mark Thompson wrote:
>> On 08/03/17 01:25, Jun Zhao wrote:
>>> ping ?
>>>
>>> On 2017/3/3 9:35, Jun Zhao wrote:
>>>> V2: Fix the potential memory leak.2
>>>>
>>>> From eb283d277679b5dac9c43e8d3c98bcc9367b592f Mon Sep 17 00:00:00 2001
>>>> From: Jun Zhao <jun.zhao at intel.com>
>>>> Date: Fri, 3 Mar 2017 09:25:53 +0800
>>>> Subject: [PATCH] vf_hwupload: Add missing return value check
>>>>
>>>> Add missing return value checks and fix the potential memory leak.
>>>>
>>>> Signed-off-by: Jun Zhao <jun.zhao at intel.com>
>>>> ---
>>>> libavfilter/vf_hwupload.c | 18 ++++++++++++------
>>>> 1 file changed, 12 insertions(+), 6 deletions(-)
>>>>
>>>> diff --git a/libavfilter/vf_hwupload.c b/libavfilter/vf_hwupload.c
>>>> index 08af2dd..4b63a2a 100644
>>>> --- a/libavfilter/vf_hwupload.c
>>>> +++ b/libavfilter/vf_hwupload.c
>>>> @@ -74,22 +74,28 @@ static int hwupload_query_formats(AVFilterContext *avctx)
>>>> if (input_pix_fmts) {
>>>> for (i = 0; input_pix_fmts[i] != AV_PIX_FMT_NONE; i++) {
>>>> err = ff_add_format(&input_formats, input_pix_fmts[i]);
>>>> - if (err < 0) {
>>>> - ff_formats_unref(&input_formats);
>>>> + if (err < 0)
>>>> goto fail;
>>>> - }
>>>> }
>>>> }
>>>>
>>>> - ff_formats_ref(input_formats, &avctx->inputs[0]->out_formats);
>>>> + if ((err = ff_formats_ref(input_formats, &avctx->inputs[0]->out_formats)) < 0)
>>>> + goto fail;
>>>>
>>>> - ff_formats_ref(ff_make_format_list(output_pix_fmts),
>>>> - &avctx->outputs[0]->in_formats);
>>>> + if ((err = ff_formats_ref(ff_make_format_list(output_pix_fmts),
>>>> + &avctx->outputs[0]->in_formats)) < 0) {
>>>> + ff_formats_unref(&input_formats);
>>>> + goto fail;
>>>> + }
>>>>
>>>> av_hwframe_constraints_free(&constraints);
>>>> return 0;
>>>>
>>>> fail:
>>>> + if (input_formats) {
>>>> + av_free(input_formats->formats);
>>>> + av_free(input_formats);
>>>> + }
>>>> av_buffer_unref(&ctx->hwdevice_ref);
>>>> av_hwframe_constraints_free(&constraints);
>>>> return err;
>>>> --
>>>> 2.9.3
>>>>
>>
>> Crashes if the second ff_formats_ref() fails:
>>
>> ==32719== Invalid read of size 8
>> ==32719== at 0x23F6E6: ff_formats_unref (formats.c:478)
>> ==32719== by 0x22A028: free_link (avfilter.c:783)
>> ==32719== by 0x22A103: avfilter_free (avfilter.c:805)
>> ==32719== by 0x22C2EF: avfilter_graph_free (avfiltergraph.c:123)
>> ==32719== by 0x1EF08C: cleanup_filtergraph (ffmpeg_filter.c:994)
>> ==32719== by 0x1EFA81: configure_filtergraph (ffmpeg_filter.c:1168)
>> ==32719== by 0x1F7B48: ifilter_send_frame (ffmpeg.c:2193)
>> ==32719== by 0x1F7DC8: send_frame_to_filters (ffmpeg.c:2278)
>> ==32719== by 0x1F8A89: decode_video (ffmpeg.c:2469)
>> ==32719== by 0x1F9375: process_input_packet (ffmpeg.c:2614)
>> ==32719== by 0x1FFC8A: process_input (ffmpeg.c:4350)
>> ==32719== by 0x200104: transcode_step (ffmpeg.c:4461)
>> ==32719== Address 0x12f78798 is 24 bytes inside a block of size 32 free'd
>> ==32719== at 0x4C2CDDB: free (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
>> ==32719== by 0x13BDC21: av_free (mem.c:239)
>> ==32719== by 0x23F7E8: ff_formats_unref (formats.c:478)
>> ==32719== by 0x2F8681: hwupload_query_formats (vf_hwupload.c:87)
>> ==32719== by 0x22CA9C: filter_query_formats (avfiltergraph.c:317)
>> ==32719== by 0x22D040: query_formats (avfiltergraph.c:445)
>> ==32719== by 0x22F368: graph_config_formats (avfiltergraph.c:1159)
>> ==32719== by 0x22F81A: avfilter_graph_config (avfiltergraph.c:1270)
>> ==32719== by 0x1EF688: configure_filtergraph (ffmpeg_filter.c:1096)
>> ==32719== by 0x1F7B48: ifilter_send_frame (ffmpeg.c:2193)
>> ==32719== by 0x1F7DC8: send_frame_to_filters (ffmpeg.c:2278)
>> ==32719== by 0x1F8A89: decode_video (ffmpeg.c:2469)
>> ==32719== Block was alloc'd at
>> ==32719== at 0x4C2DF16: memalign (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
>> ==32719== by 0x4C2E021: posix_memalign (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
>> ==32719== by 0x13BD9DD: av_malloc (mem.c:97)
>> ==32719== by 0x13BDC75: av_mallocz (mem.c:254)
>> ==32719== by 0x23EF33: ff_make_format_list (formats.c:285)
>> ==32719== by 0x2F85A2: hwupload_query_formats (vf_hwupload.c:69)
>> ==32719== by 0x22CA9C: filter_query_formats (avfiltergraph.c:317)
>> ==32719== by 0x22D040: query_formats (avfiltergraph.c:445)
>> ==32719== by 0x22F368: graph_config_formats (avfiltergraph.c:1159)
>> ==32719== by 0x22F81A: avfilter_graph_config (avfiltergraph.c:1270)
>> ==32719== by 0x1EF688: configure_filtergraph (ffmpeg_filter.c:1096)
>> ==32719== by 0x1F7B48: ifilter_send_frame (ffmpeg.c:2193)
>>
>> ... more invalid reads ...
>>
>> ==32719== Process terminating with default action of signal 11 (SIGSEGV)
>> ==32719== Access not within mapped region at address 0x0
>> ==32719== at 0x13BDC35: av_freep (mem.c:247)
>> ==32719== by 0x23FBF6: ff_set_common_channel_layouts (formats.c:552)
>> ==32719== by 0x240100: default_query_formats_common (formats.c:586)
>> ==32719== by 0x24015C: ff_default_query_formats (formats.c:599)
>> ==32719== by 0x22D051: query_formats (avfiltergraph.c:447)
>> ==32719== by 0x22F368: graph_config_formats (avfiltergraph.c:1159)
>> ==32719== by 0x22F81A: avfilter_graph_config (avfiltergraph.c:1270)
>> ==32719== by 0x1EF688: configure_filtergraph (ffmpeg_filter.c:1096)
>> ==32719== by 0x1F68C5: flush_encoders (ffmpeg.c:1876)
>> ==32719== by 0x20032E: transcode (ffmpeg.c:4538)
>> ==32719== by 0x20097D: main (ffmpeg.c:4720)
>
> Mark, can you give the test command for this crash? It's will help me quick reproduce/debug this issue.Tks.
Instrument ff_formats_ref() to work as if the allocation fails the second time:
diff --git a/libavfilter/formats.c b/libavfilter/formats.c
index d4de862237..8244e7432c 100644
--- a/libavfilter/formats.c
+++ b/libavfilter/formats.c
@@ -417,12 +417,12 @@ AVFilterChannelLayouts *ff_all_channel_counts(void)
}
#define FORMATS_REF(f, ref, unref_fn) \
- void *tmp; \
+ void *tmp; static int k; \
\
if (!f || !ref) \
return AVERROR(ENOMEM); \
\
- tmp = av_realloc_array(f->refs, sizeof(*f->refs), f->refcount + 1); \
+ tmp = ++k == 2 ? (av_free(f->refs), NULL) : av_realloc_array(f->refs, sizeof(*f->refs), f->refcount + 1); \
if (!tmp) { \
unref_fn(&f); \
return AVERROR(ENOMEM); \
Then run something using it, like:
./ffmpeg_g -vaapi_device /dev/dri/renderD128 -i in.mp4 -vf hwupload -frames 1 -f null -
(Input file doesn't matter as long as it has video.)
Maybe this is excessive scrutiny, but I know that AVFilterFormats are horrible so a claim to fix memory leaks around them is worth checking to make sure it doesn't introduce crashes. Tbh I would be fine with the original patch with the noop ff_formats_unref() lines removed - see most filters using ff_formats_ref() for examples of ignoring the problem by just leaking the memory of the format list.
Thanks,
- Mark
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