QGis 3.10.2 crashes when displaying two PostGIS raster layers

[Veence]

Guys,
After loading two PostGIS raster layers and tinkering a bit with their symbology, each time I zoom in or out QGIS crashes with that message:

Qgis3(98042,0x700004632000) malloc: double free for ptr 0x7fc495453e00

Of course the actual address changes, but the reason remains the same.

Forensic examination of the stack suggests this is a problem in proj –

Thread 13 Crashed:: Thread (pooled)
0   libsystem_kernel.dylib        	0x00007fff5ea092c2 __pthread_kill + 10
1   libsystem_pthread.dylib       	0x00007fff5eac4bf1 pthread_kill + 284
2   libsystem_c.dylib             	0x00007fff5e9736a6 abort + 127
3   libsystem_malloc.dylib        	0x00007fff5ea82077 malloc_vreport + 545
4   libsystem_malloc.dylib        	0x00007fff5ea9ae0d malloc_zone_error + 183
5   libproj.15.dylib              	0x000000010a7051f8 std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >::operator=(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >&&) + 54
6   libproj.15.dylib              	0x000000010a704f8c proj_as_wkt + 527
7   org.qgis.qgis3_core           	0x000000010820f448 QgsCoordinateReferenceSystem::toWkt(QgsCoordinateReferenceSystem::WktVariant, bool, int) const + 588
8   org.qgis.qgis3_core           	0x0000000108249d4c QgsCoordinateTransform::setFromCache(QgsCoordinateReferenceSystem const&, QgsCoordinateReferenceSystem const&, QString const&) + 236

But I'm still posting this here in case there's something wrong with QgsCoordinateReferenceSystem::toWkt(QgsCoordinateReferenceSystem::WktVariant, bool, int). If you deem this irrelevant, please ignore.

[roya0045]

Please provide information about your qgis (about section).

[Veence]

Sure, here it is!

QGIS version | 3.10.2-A Coruña |
QGIS code branch | Release QGIS code branch.3
Compiled against Qt | 5.14.1 | Running against Qt | 5.14.1
Compiled against GDAL/OGR | 3.0.3 | Running against GDAL/OGR | 3.0.3
Compiled against GEOS | 3.8.0-CAPI-1.13.1 | Running against GEOS | 3.8.0-CAPI-1.13.1
Compiled against SQLite | 3.31.1 | Running against SQLite | 3.31.1
PostgreSQL Client Version | 12.1 | SpatiaLite Version | 5.0.0-beta0
QWT Version | 6.1.4 | QScintilla2 Version | 2.11.2
Compiled against PROJ | 6.3.0 | Running against PROJ | Rel. 6.3.0, January 1st, 2020
OS Version | macOS Mojave (10.14)
Active python plugins | quick_map_services; Climb; processing; db_manager

[gioman]

@Veence please try qgis master, there have been changes about postgis rasters. If possible also add the two postgis rasters as table dumps.

[Veence]

@gioman
Ciao Giovanni,

I have been tinkering with the rasters, and the bug seems to have gone away. The key thing was to change the georeferencing of one raster. The one I changed had a positive scaleY while the other had a negative scaleY, and both had the same SRID (2154). I regenerated the first raster with a negative scaleY parameter in ST_AsRaster, and everything seems to be fine right now. However, I can have a go at it using the current version of QGis if need be. It’s a matter of a few seconds to recreate the original raster that caused the bug. Tell me.

Nel frattempo buon weekend!

[gioman]

However, I can have a go at it using the current version of QGis

@Veence yes please

t’s a matter of a few seconds to recreate the original raster that caused the bug. Tell me.

it would be important to have here attached the original rasters that caused the crash, in a ideal world QGIS should never crash.

[rouault]

I strongly believe this bug was fixed by

commit 8a7109163a9362af2a5e0187cf2b57fc0219fe59
Author: Nyall Dawson <nyall.dawson@gmail.com>
Date:   Tue Jan 21 11:21:14 2020 +1000

    Fix crash in rendering on proj 6 builds
    
    Ensure PJ* objects are never reused across threads.
    
    Fixes #33902

which landed in 3.10.3 in the LTR. Previously proj_as_wkt() could potentially be called on the same CRS object from several threads simultaneously, which would lead to the crash stack of this report