From 147b12162da60da1ebfe38f626e9f82b2102f26b Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Tue, 13 Oct 2015 18:29:04 +0200 Subject: avutil/fifo: Fix thread saftey of av_fifo_generic_peek() changing the context state and restoring it is not safe if another thread writes data into the fifo Signed-off-by: Michael Niedermayer --- libavutil/fifo.c | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-) (limited to 'libavutil') diff --git a/libavutil/fifo.c b/libavutil/fifo.c index 07fb4ec811..1a227087be 100644 --- a/libavutil/fifo.c +++ b/libavutil/fifo.c @@ -153,24 +153,22 @@ int av_fifo_generic_peek(AVFifoBuffer *f, void *dest, int buf_size, { // Read memory barrier needed for SMP here in theory uint8_t *rptr = f->rptr; - uint32_t rndx = f->rndx; do { - int len = FFMIN(f->end - f->rptr, buf_size); + int len = FFMIN(f->end - rptr, buf_size); if (func) - func(dest, f->rptr, len); + func(dest, rptr, len); else { - memcpy(dest, f->rptr, len); + memcpy(dest, rptr, len); dest = (uint8_t *)dest + len; } // memory barrier needed for SMP here in theory - av_fifo_drain(f, len); + rptr += len; + if (rptr >= f->end) + rptr -= f->end - f->buffer; buf_size -= len; } while (buf_size > 0); - f->rptr = rptr; - f->rndx = rndx; - return 0; } -- cgit v1.2.3