From 6a200503521c4187fe9d3c3413283ce3c17f02f4 Mon Sep 17 00:00:00 2001 From: Christophe Fergeau Date: Mon, 19 Sep 2011 16:14:48 +0200 Subject: replace warning with comment in glz_usr_free_image When running some xinerama tests, I got several glz_usr_free_image: error messages. Looking at the code, this error is reported when this function is called from a different DisplayChannelClient than the one which created the glz compressed image. When this happens, the backtrace is at glz_encoder_dictionary.c:362 0x7fff940b6670) at glz_encoder_dictionary.c:449 image_type=LZ_IMAGE_TYPE_RGB32, image_width=512, image_height=256, image_stride=2048, first_lines=0x0, num_first_lines=0, usr_image_context=0x7fff7420da40, image_head_dist=0x7fff9b2a3194) at glz_encoder_dictionary.c:570 top_down=4, lines=0x0, num_lines=0, stride=2048, io_ptr=0x7fff740ea7c0 " ZL", num_io_bytes=65536, usr_context= 0x7fff7420da40, o_enc_dict_context=0x7fff7420da60) at glz_encoder.c:255 drawable=0x7fff9b46bc08, o_comp_data=0x7fff9b2a3350) at red_worker.c:5753 0x7fff9b46bc08, can_lossy=0, o_comp_data=0x7fff9b2a3350) at red_worker.c:6211 0x7fff9b46bc08, can_lossy=0) at red_worker.c:6344 0x7fff74085c50, dpi=0x7fff7445b890, src_allowed_lossy=0) at red_worker.c:7046 0x7fff7445b890) at red_worker.c:7720 at red_worker.c:7964 at red_worker.c:8431 Since the glz dictionary is shared between all the DisplayChannelClient instances that belong to the same client, it can happen that the glz dictionary code decides to free an image from one thread while it was added from another thread (thread == DisplayChannelClient), so the error message that is printed is not an actual error. This commit removes this message and adds a comment explaining what's going on. --- server/red_worker.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/server/red_worker.c b/server/red_worker.c index 3278824b..7af715dc 100644 --- a/server/red_worker.c +++ b/server/red_worker.c @@ -5482,7 +5482,13 @@ static void glz_usr_free_image(GlzEncoderUsrContext *usr, GlzUsrImageContext *im if (this_cc == drawable_cc) { red_display_free_glz_drawable_instance(drawable_cc, glz_drawable_instance); } else { - red_printf("error"); + /* The glz dictionary is shared between all DisplayChannelClient + * instances that belong to the same client, and glz_usr_free_image + * can be called by the dictionary code + * (glz_dictionary_window_remove_head). Thus this function can be + * called from any DisplayChannelClient thread, hence the need for + * this check. + */ pthread_mutex_lock(&drawable_cc->glz_drawables_inst_to_free_lock); ring_add_before(&glz_drawable_instance->free_link, &drawable_cc->glz_drawables_inst_to_free); -- cgit v1.2.3