[fprint] Memory management Libfprint
Benjamin Berg
benjamin at sipsolutions.net
Wed Apr 21 08:30:20 UTC 2021
Hi Carlos,
the image returned by fp_device_capture_finish is owned by your code
(marked as "transfer full"). It is a GObject, and you are responsible
to eventually call g_object_unref on it.
There are various ways of achieving that. If you can use the modern
GLib autoptr features, then I would suggest:
* Change the declaration in etr_fp_dev_capture_cb to:
g_autoptr(FpImage) image = NULL;
* Change the fp_image_detect_minutiae call to steal the reference:
fp_image_detect_minutiae(g_steal_pointer (&image),
aut->ctx.clops,
(GAsyncReadyCallback)etr_fp_extract_minutiae,aut);
* Add a variable auto unref in etr_fp_extract_minutiae:
g_autoptr(FpImage) img_free = img;
After that the memory leak should be gone.
You can of course also call g_object_unref manually, but then you need
to make sure to handle all the error paths correctly.
Benjamin
On Tue, 2021-04-20 at 23:09 +0000, Carlos Garcia wrote:
>
> Hi everyone. I have some questions with the memory management with
> libfprint.
> I’m creating a program for capture image and retrieve the minutiae
> from the captured image. I’m using:
>
> * fp_device_capture
> * fp_device_capture_finish
> * fp_image_detect_minutiae
> * fp_image_detect_minutiae_finish
>
> I have relied on the img-capture.c example from the version 1.90.7
> examples.
> Here is my code:
>
> ///< This function is executed in another thread using pthreads
> static void * etr_fp_gmain_loop(void *data)
> {
> FpContext *context = NULL;
> tAUTOMATON_DATA *aut = (tAUTOMATON_DATA *) data;
> aut->ctx.clops = g_cancellable_new();
>
> // Create libfprint context
>
> if ((context = etr_fp_find_device(aut)) != NULL) // Inside this f
> unction open device with fp_device_open_sync
> {
> KernelInsertEvent(aut->fsm->aut_id,AUT_EVT_OPENED,NULL,0);
> aut->ctx.gmloop = g_main_loop_new(NULL,FALSE);
> g_main_loop_run(aut-
> >ctx.gmloop); // Run until g_main_loop_quit is called.
>
> // Free resources.
> g_main_loop_unref(aut->ctx.gmloop);
> g_clear_object(&context);
> aut->ctx.device = NULL;
> aut->ctx.gmloop = NULL;
> }
>
> g_clear_object(&aut->ctx.clops); // Free GCancellable.
>
> return NULL;
> }
> //-------------------------------------------------------------------
> --------
>
> static void etr_fp_extract_minutiae(FpImage *img, GAsyncResult *res,
> void *user_data)
> {
> GPtrArray *minutiaes = NULL;
> g_autoptr(GError) error = NULL;
> tAUTOMATON_DATA *aut = (tAUTOMATON_DATA *) user_data;
>
> if (fp_image_detect_minutiae_finish(img,res,&error))
> {
> minutiaes = fp_image_get_minutiae(img);
> if (minutiaes != NULL)
> {
> gint img_w = fp_image_get_width(img);
> gint img_h = fp_image_get_height(img);
> // Do something
>
> }
> else
> LogError("Error retrieving minutiae");
> }
> else
> {
> LogError("Error retrieving minutiae from FingerPrint. %s",(er
> ror) ? error->message : "Unknown Error");
> if (error != NULL && error->code == G_IO_ERROR_CANCELLED)
> g_cancellable_reset(aut->ctx.clops);
> }
>
> KernelInsertEvent(aut->fsm->aut_id,AUT_EVT_DATA,NULL,0);
> }
>
> //-------------------------------------------------------------------
> --------
>
> static void etr_fp_dev_capture_cb(FpDevice *dev, GAsyncResult *res, v
> oid *user_data)
> {
> int result;
> FpImage *image = NULL;
> g_autoptr(GError) error = NULL;
> tAUTOMATON_DATA *aut = (tAUTOMATON_DATA *) user_data;
>
> image = fp_device_capture_finish(dev, res, &error);
>
> if (!image)
> {
> LogError("Error capturing fingerprint: %s",error->message);
>
> if (aut->ctx.cap_cb)
> aut->ctx.cap_cb(error->code,NULL,aut->ctx.u_data);
>
> if (error->code == G_IO_ERROR_CANCELLED) {
> g_cancellable_reset(aut->ctx.clops);
> KernelInsertEvent(aut->fsm->aut_id,AUT_EVT_DATA,NULL,0);
> }
>
> else {
>
> etr_fp_dev_close(aut);
> KernelInsertEvent(aut->fsm-
> >aut_id,AUT_EVT_REMOVED,NULL,0);
> }
>
> return;
> }
>
> if (aut->ctx.imgpath != NULL)
> if ((result = etr_fp_save_image_to_pgm(image, aut-
> >ctx.imgpath)) < 0)
> LogError("Unable to save the image in specified path: %s.
> Error code: %d",aut->ctx.imgpath,result);
>
> fp_image_detect_minutiae(image,aut-
> >ctx.clops,(GAsyncReadyCallback)etr_fp_extract_minutiae,aut);
> }
> //-------------------------------------------------------------------
> --------
>
> gboolean etr_fp_start_capture(gpointer data)
> {
> tAUTOMATON_DATA *aut = (tAUTOMATON_DATA *) data;
>
> fp_device_capture(aut->ctx.device, TRUE, aut-
> >ctx.clops, (GAsyncReadyCallback) etr_fp_dev_capture_cb, aut);
>
> return FALSE;
> }
> //-------------------------------------------------------------------
> --------
>
> void capturing__entry(void* aut_data)
> {
> g_idle_add(etr_fp_start_capture,aut_data);
> }
> //-------------------------------------------------------------------
> --------
>
> static gboolean etr_fp_dev_close(gpointer data)
> {
> g_autoptr(GError) gerror = NULL;
> tAUTOMATON_DATA *aut = (tAUTOMATON_DATA *)data;
>
> if (!fp_device_close_sync(aut->ctx.device,NULL,&gerror))
> LogError("Error closing device: %s",gerror->message);
>
> g_main_loop_quit(aut->ctx.gmloop);
>
> return FALSE;
> }
> //-------------------------------------------------------------------
> --------
>
> int etr_fp_init(void *aut)
> {
> /*
> do other things.
> */
>
> if (pthread_create(&aut-
> >ctx.event_t,NULL,&etr_fp_gmain_loop,aut))
> {
> LogError("%s:Id%d Unable to create glib event loop thread",K_
> ETR_FP_API_PREFIX,id);
> return K_ETR_FP_FAILURE;
> }
>
> return K_ETR_FP_OK;
> }
> //-------------------------------------------------------------------
> --------
>
> int etr_fp_end(void *aut)
> {
> // Free libfrpint, glib resources when gmainloop ends free automa
> ton.;
> g_idle_add_full(G_PRIORITY_HIGH_IDLE,etr_fp_dev_close,aut,NULL);
> pthread_join(aut->ctx.event_t,NULL);
>
> return 0;
> }
> //-------------------------------------------------------------------
> --------
>
>
>
> I have read some things about valgrind with Glib and possible
> problems. So,my first question is:
>
> Can I use Valgrind with libfprint?
>
> When I run valgrind with the following configuration:
>
> valgrind --leak-check=full --show-leak-kinds=definite,indirect --
> track-origins=yes --verbose --log-file=valgrind-out.txt ./myapp
>
> The following catches my attention:
>
> ==35461== 1,113,600 bytes in 10 blocks are indirectly lost in loss
> record 910 of 912
> ==35461== at 0x483B7F3: malloc (in /usr/lib/x86_64-linux-
> gnu/valgrind/vgpreload_memcheck-amd64-linux.so)
> ==35461== by 0x4AECCB8: g_malloc (in /usr/lib/x86_64-linux-
> gnu/libglib-2.0.so.0.6400.6)
> ==35461== by 0x5450990: binarize_image_V2 (in /usr/lib/x86_64-
> linux-gnu/libfprint.so.2.0.0)
> ==35461== by 0x5450B3C: binarize_V2 (in /usr/lib/x86_64-linux-
> gnu/libfprint.so.2.0.0)
> ==35461== by 0x544605A: lfs_detect_minutiae_V2 (in
> /usr/lib/x86_64-linux-gnu/libfprint.so.2.0.0)
> ==35461== by 0x543EE8D: get_minutiae (in /usr/lib/x86_64-linux-
> gnu/libfprint.so.2.0.0)
> ==35461== by 0x540E7C1: fp_image_detect_minutiae_thread_func (in
> /usr/lib/x86_64-linux-gnu/libfprint.so.2.0.0)
> ==35461== by 0x8457C81: ??? (in /usr/lib/x86_64-linux-gnu/libgio-
> 2.0.so.0.6400.6)
> ==35461== by 0x4B111B3: ??? (in /usr/lib/x86_64-linux-gnu/libglib-
> 2.0.so.0.6400.6)
> ==35461== by 0x4B10910: ??? (in /usr/lib/x86_64-linux-gnu/libglib-
> 2.0.so.0.6400.6)
> ==35461== by 0x858C608: start_thread (pthread_create.c:477)
> ==35461== by 0x4CE2292: clone (clone.S:95)
> ==35461==
> ==35461== 1,113,600 bytes in 10 blocks are indirectly lost in loss
> record 911 of 912
> ==35461== at 0x483B7F3: malloc (in /usr/lib/x86_64-linux-
> gnu/valgrind/vgpreload_memcheck-amd64-linux.so)
> ==35461== by 0x4AECCB8: g_malloc (in /usr/lib/x86_64-linux-
> gnu/libglib-2.0.so.0.6400.6)
> ==35461== by 0x540EF98: fp_image_detect_minutiae (in
> /usr/lib/x86_64-linux-gnu/libfprint.so.2.0.0)
> ==35461== by 0x484E10B: etr_fp_dev_capture_cb (fingerprint.c:528)
> ==35461== by 0x8456F68: ??? (in /usr/lib/x86_64-linux-gnu/libgio-
> 2.0.so.0.6400.6)
> ==35461== by 0x8457B5C: ??? (in /usr/lib/x86_64-linux-gnu/libgio-
> 2.0.so.0.6400.6)
> ==35461== by 0x54375AA: fp_device_task_return_in_idle_cb (in
> /usr/lib/x86_64-linux-gnu/libfprint.so.2.0.0)
> ==35461== by 0x4AE6E6D: g_main_context_dispatch (in
> /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0.6400.6)
> ==35461== by 0x4AE721F: ??? (in /usr/lib/x86_64-linux-gnu/libglib-
> 2.0.so.0.6400.6)
> ==35461== by 0x4AE7512: g_main_loop_run (in /usr/lib/x86_64-linux-
> gnu/libglib-2.0.so.0.6400.6)
> ==35461== by 0x484DAA7: etr_fp_gmain_loop (fingerprint.c:401)
> ==35461== by 0x858C608: start_thread (pthread_create.c:477)
> ==35461==
> ==35461== 2,333,120 (800 direct, 2,332,320 indirect) bytes in 10
> blocks are definitely lost in loss record 912 of 912
> ==35461== at 0x483B7F3: malloc (in /usr/lib/x86_64-linux-
> gnu/valgrind/vgpreload_memcheck-amd64-linux.so)
> ==35461== by 0x4AECCB8: g_malloc (in /usr/lib/x86_64-linux-
> gnu/libglib-2.0.so.0.6400.6)
> ==35461== by 0x4B052A5: g_slice_alloc (in /usr/lib/x86_64-linux-
> gnu/libglib-2.0.so.0.6400.6)
> ==35461== by 0x4B058CD: g_slice_alloc0 (in /usr/lib/x86_64-linux-
> gnu/libglib-2.0.so.0.6400.6)
> ==35461== by 0x837B0CF: g_type_create_instance (in
> /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.6400.6)
> ==35461== by 0x835A34C: ??? (in /usr/lib/x86_64-linux-
> gnu/libgobject-2.0.so.0.6400.6)
> ==35461== by 0x835C377: g_object_new_valist (in /usr/lib/x86_64-
> linux-gnu/libgobject-2.0.so.0.6400.6)
> ==35461== by 0x835C6CC: g_object_new (in /usr/lib/x86_64-linux-
> gnu/libgobject-2.0.so.0.6400.6)
> ==35461== by 0x5428644: imaging_run_state (in /usr/lib/x86_64-
> linux-gnu/libfprint.so.2.0.0)
> ==35461== by 0x543E345: transfer_finish_cb (in /usr/lib/x86_64-
> linux-gnu/libfprint.so.2.0.0)
> ==35461== by 0x8456F68: ??? (in /usr/lib/x86_64-linux-gnu/libgio-
> 2.0.so.0.6400.6)
> ==35461== by 0x8456FAC: ??? (in /usr/lib/x86_64-linux-gnu/libgio-
> 2.0.so.0.6400.6)
> ==35461==
> ==35461== LEAK SUMMARY:
> ==35461== definitely lost: 1,128 bytes in 22 blocks
> ==35461== indirectly lost: 2,334,793 bytes in 2,604 blocks
> ==35461== possibly lost: 34,119 bytes in 142 blocks
> ==35461== still reachable: 190,826 bytes in 1,292 blocks
> ==35461== of which reachable via heuristic:
> ==35461== length64 : 1,160 bytes in
> 29 blocks
> ==35461== newarray : 1,584 bytes in
> 19 blocks
> ==35461== suppressed: 0 bytes in 0 blocks
> ==35461== Reachable blocks (those to which a pointer was found) are
> not shown.
> ==35461== To see them, rerun with: --leak-check=full --show-leak-
> kinds=all
> ==35461==
> ==35461== ERROR SUMMARY: 135 errors from 135 contexts (suppressed: 0
> from 0)
>
> So fp_image_detect_minutiae have a memory leak?
>
> Or maybe is a Valgrind problem. Every time I run a capture the memory
> usage grows and it doesn't seem to return the resources used.
> I am executing the g_main_loop_run in another thread and the calls to
> the capture function are made usingg_idle_add
>
> Another problem detected is when unplug device, next call capture
> process. The removed device error is detected correctly but when I
> reinitialize the library creating a new object of type:
>
> * FPContext
> * GmainLoop
>
> Have the next error:
>
> (process:35): libfprint-context-DEBUG: 17:47:21.078: No driver found
> for USB device 1D6B:0001 ---> Device was removed and not plugged in
> yet .
> (process:35): libfprint-image_device-DEBUG: 17:47:21.225: Image
> device open completed --> Device plugged in again, free up memory and
> create new objects.
> (process:35): libfprint-device-DEBUG: 17:47:21.225: Device reported
> open completion
> (process:35): libfprint-device-DEBUG: 17:47:21.225: Completing action
> FPI_DEVICE_ACTION_OPEN in idle!
> (process:35): GLib-CRITICAL **: 17:47:21.226:
> g_ptr_array_find_with_equal_func: assertion 'haystack != NULL' failed
> (process:35): libfprint-context-CRITICAL **: 17:47:21.226:
> remove_device_idle_cb: assertion 'g_ptr_array_find (priv->devices,
> data->device, &idx)' failed
>
>
> The library works fine when the device is reconnected, but I want to
> know about these 2 errors.
> Thanks for all the support provided.
>
>
> _______________________________________________
> fprint mailing list
> fprint at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/fprint
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