id,summary,reporter,owner,description,type,status,priority,component,version,resolution,keywords,cc,blockedby,blocking,reproduced,analyzed 474,SIG SEV in clear_blocks_sse in ff_h263_decode_mb,sgarcia,,"Hi, I am using libavcodec in my mcu project and I am latelly getting some random seg faults. I have traced it down to be in clear_blocks_sse called by ff_h263_decode_mb. Here is the gdb info: (gdb) bt #0 0x00e7fb63 in clear_blocks_sse (blocks=0xb36202e0) at libavcodec/x86/dsputil_mmx.c:539 #1 0x00c7d5e9 in ff_h263_decode_mb (s=0xb3600a60, block=0xb36202e0) at libavcodec/ituh263dec.c:634 #2 0x00bcd9af in decode_slice (s=0xb3600a60) at libavcodec/h263dec.c:215 #3 0x00bceb11 in ff_h263_decode_frame (avctx=0xb3600520, data=0xb3600940, data_size=0xb15fbc40, avpkt=0xb15fbbfc) at libavcodec/h263dec.c:671 #4 0x00dea531 in avcodec_decode_video2 (avctx=0xb3600520, picture=0xb3600940, got_picture_ptr=0xb15fbc40, avpkt=0xb15fbbfc) at libavcodec/utils.c:769 #5 0x080c493d in H263Decoder::DecodePacket (this=0xb36004c8, in=0xb15fbcc4 """", inLen=1393, lost=0, last=1) at /usr/local/src/mcu/media/src/h263/h263codec.cpp:476 #6 0x08077852 in VideoStream::RecVideo (this=0xb6a2ad70) at /usr/local/src/mcu/media/src/videostream.cpp:668 #7 0x08076b17 in VideoStream::startReceivingVideo (par=0xb6a2ad70) at /usr/local/src/mcu/media/src/videostream.cpp:190 #8 0x001239e9 in start_thread () from /lib/libpthread.so.0 #9 0x00662f3e in clone () from /lib/libc.so.6 (gdb) list 534 ); 535 } 536 537 static void clear_blocks_sse(DCTELEM *blocks) 538 {\ 539 __asm__ volatile( 540 ""xorps %%xmm0, %%xmm0 \n"" 541 ""mov %1, %%""REG_a"" \n"" 542 ""1: \n"" 543 ""movaps %%xmm0, (%0, %%""REG_a"") \n"" (gdb) print blocks $5 = (DCTELEM *) 0xb36202e0 (gdb) print *blocks $6 = 0 (gdb) up #1 0x00c7d5e9 in ff_h263_decode_mb (s=0xb3600a60, block=0xb36202e0) at libavcodec/ituh263dec.c:634 634 s->dsp.clear_blocks(s->block[0]); (gdb) print *(s->blocks) $7 = {{0 }, {0 }, {0 , 41, 41, 41, 40, 40, 40, 39, 39, 41, 41, 41, 41, 40, 40, 40, 40, 42, 41, 41, 41, 41, 40, 40, 40, 42, 42, 41, 41, 41, 40, 40, 40}, {39, 40, 40, 41, 41, 40, 40, 39, 39, 40, 40, 41, 41, 40, 40, 39, 39, 40, 40, 41, 41, 40, 40, 39, 40 , 41, 40, 40, 39, 39, 40, 40, 41, 41, 40, 40, 39, 39, 40, 40, 41, 41, 40, 40, 39, 39, 40, 40, 41}, {130, 133, 132, 127, 127, 132, 134, 132, 130, 132, 131, 128, 128, 131, 132, 130, 131, 130, 129, 127, 128, 129, 131, 131, 133, 129, 126, 125, 126, 128, 131, 135, 132, 127, 124, 126, 128, 129, 132, 135, 129, 126, 126, 129, 132, 132, 131, 131, 129, 128, 129, 132, 134, 133, 130, 127, 132, 130, 130, 132, 134, 133, 129, 125}, {132, 131, 131, 134, 134, 131, 131, 132, 132, 131, 132, 134, 134, 132, 131, 132, 132, 131, 132, 133, 133, 132, 131, 132, 131, 131, 132, 133, 133, 132, 131, 131, 131, 132, 132, 133, 133, 132, 132, 131, 131, 132, 133, 132, 132, 133, 132, 131, 130, 132, 133, 132, 132, 133, 132, 130, 130, 133, 133, 132, 132, 133, 133, 130}, {0 }, {0 }} (gdb) down #0 0x00e7fb63 in clear_blocks_sse (blocks=0xb36202e0) at libavcodec/x86/dsputil_mmx.c:539 539 __asm__ volatile( Best regards Sergio",defect,closed,important,avcodec,git,needs_more_info,crash SIGSEGV,,,,0,0