FileStorage SIGSEGV (without doing I/O)

[framp]

First, thanks a lot for this monumental work, it's great to have opencv in rust land!

1. Operating system: MacOS
2. The way you installed OpenCV: nix-darwin opencv4.3, brew opencv 4.5
3. OpenCV version: 4.3, 4.5
4. rustc version: 1.48.0

I have a small program which SIGSEGV sporadically; it calls a few opencv functions - these ones in particular (or real code here):

let src = Mat::from_slice(&buffer).unwrap();
let src = src.reshape(4, h as i32).unwrap();
in_range(&src, &Scalar::new(...),  &Scalar::new(...), &mut mask)?;
bitwise_or(&mask, &mask2, &mut mask3, &Mat::default()?)?;
find_contours(&mask3, &mut contours, ...)?;
for contour in contours {
    contour_area(&contour, false)?;
    moments(&contour, true)?
}

If I call this code several times, after a few times it will spawn a lot of threads:

[New Thread 0xf0f of process 45225]
[New Thread 0x150b of process 45225]
[New Thread 0x1707 of process 45225]
[New Thread 0x1807 of process 45225]
[New Thread 0x1907 of process 45225]
[New Thread 0x1a07 of process 45225]
[New Thread 0x1b07 of process 45225]
[New Thread 0x1c07 of process 45225]
[New Thread 0x1d07 of process 45225]
[New Thread 0x1e07 of process 45225]
[New Thread 0x1f07 of process 45225]
[New Thread 0x2007 of process 45225]
[New Thread 0x2107 of process 45225]
[New Thread 0x2207 of process 45225]
[New Thread 0x2307 of process 45225]
[New Thread 0x2407 of process 45225]
[New Thread 0x2507 of process 45225]
[New Thread 0x280b of process 45225]
[New Thread 0x2b0b of process 45225]

and then SIGSEGV.

At no point I ever read or write to file storage. Funnily enough the backtrace of my SIGSEGV points at:
On opencv 4.3

#0  0x00007fff36e8b159 in ?? ()
#1  0x000070000f270230 in ?? ()
#2  0x000070000f270308 in ?? ()
#3  0x000070000f270308 in ?? ()
#4  0x000070000f270290 in ?? ()
#5  0x000070000f270000 in ?? ()
#6  0x34cc42fed19d000b in ?? ()
#7  0x000070000f2706e0 in ?? ()
#8  0x000070000f2705e0 in ?? ()
#9  0x000070000f270280 in ?? ()
#10 0x00000001000a28f9 in opencv::opencv::hub::core::write_str (fs=0x1000a29c0 <opencv::opencv::hub::core::write_str+800>, name=..., value=...)
    at /Users/framp/.cargo/registry/src/github.com-1ecc6299db9ec823/opencv-0.46.3/src/opencv/hub/core.rs:6239
#11 0x000070000f2702a0 in ?? ()
#12 0x0000000103a04a00 in ?? ()
#13 0x00000001038214f0 in ?? ()
#14 0x00000001038214f0 in ?? ()
#15 0x000070000f2702a0 in ?? ()
#16 0x00000001000a1891 in opencv::opencv::hub::core::vconcat2 (src1=..., src2=..., dst=...) at /Users/framp/.cargo/registry/src/github.com-1ecc6299db9ec823/opencv-0.46.3/src/opencv/hub/core.rs:6158
#17 0x00000001038214e0 in ?? ()
#18 0x00000001038214f0 in ?? ()
#19 0x000070000f2702d0 in ?? ()
#20 0x00000001000a19fa in opencv::opencv::hub::core::vconcat2 (src1=..., src2=..., dst=...) at /Users/framp/.cargo/registry/src/github.com-1ecc6299db9ec823/opencv-0.46.3/src/opencv/hub/core.rs:6159
#21 0x000070000f2702d0 in ?? ()
#22 0x00000001038214f0 in ?? ()
#23 0x00000001038214f0 in ?? ()
#24 0x00000001038214f0 in ?? ()
#25 0x000070000f270380 in ?? ()
#26 0x00000001000a4e7f in opencv::opencv::hub::core::FileStorage::new (filename=..., flags=0, encoding=...)
    at /Users/framp/.cargo/registry/src/github.com-1ecc6299db9ec823/opencv-0.46.3/src/opencv/hub/core.rs:7849
#27 0x000000010b350000 in ?? ()
#28 0x00000001038214f0 in ?? ()
#29 0x00000001038214e0 in ?? ()
#30 0x000070000f2703c0 in ?? ()
#31 0x00000000007a8000 in ?? ()
#32 0x0000000000000000 in ?? ()

On opencv 4.5

0x00000001000a122c in opencv::opencv::hub::core::vconcat2 (src1=..., src2=..., dst=...) at /Users/framp/.cargo/registry/src/github.com-1ecc6299db9ec823/opencv-0.46.3/src/opencv/hub/core.rs:6165
6165            input_array_arg!(src1);
(gdb) bt
#0  0x00000001000a122c in opencv::opencv::hub::core::vconcat2 (src1=..., src2=..., dst=...) at /Users/framp/.cargo/registry/src/github.com-1ecc6299db9ec823/opencv-0.46.3/src/opencv/hub/core.rs:6165
#1  0x000070000ff782b0 in ?? ()
#2  0x0000000000000012 in ?? ()
#3  0x000070000ff782d0 in ?? ()
#4  0x00000001000a2006 in opencv::opencv::hub::core::write_sparsemat (fs=0x0, name=..., value=0x0)
    at /Users/framp/.cargo/registry/src/github.com-1ecc6299db9ec823/opencv-0.46.3/src/opencv/hub/core.rs:6241
#5  0x000070000ff78308 in ?? ()
#6  0x0000000000000012 in ?? ()
#7  0x000070000ff78308 in ?? ()
#8  0x0000000000000012 in ?? ()
#9  0x000070000ff78380 in ?? ()
#10 0x00000001000a48e4 in opencv::opencv::hub::core::FileStorage::new (filename=..., flags=0, encoding=...)
    at /Users/framp/.cargo/registry/src/github.com-1ecc6299db9ec823/opencv-0.46.3/src/opencv/hub/core.rs:7861
#11 0x0000000174cf8000 in ?? ()
#12 0x00000000007a8000 in ?? ()
#13 0x0000000000000012 in ?? ()
#14 0x000070000ff783c0 in ?? ()
#15 0x00000000007a8000 in ?? ()
#16 0x0000000174cf8000 in ?? ()
#17 0x0000000174cf8000 in ?? ()
#18 0x00000000007a8000 in ?? ()
#19 0x000070000ff78380 in ?? ()
#20 0x00000001000a2387 in opencv::opencv::hub::core::write_str (fs=0x0, name=..., value=...)
    at /Users/framp/.cargo/registry/src/github.com-1ecc6299db9ec823/opencv-0.46.3/src/opencv/hub/core.rs:6247
#21 0x00000000007a8000 in ?? ()
#22 0x0000000174cf8000 in ?? ()
#23 0x00000000007a8000 in ?? ()
#24 0x0000000174cf8000 in ?? ()
#25 0x000070000ff783d8 in ?? ()
#26 0x0000000110b04410 in ?? ()
#27 0x000001000ff783d8 in ?? ()
#28 0x0000000155004ce0 in ?? ()
#29 0x0000000174cf8000 in ?? ()
#30 0x00000000007a8000 in ?? ()
#31 0x000070000ff78410 in ?? ()
#32 0x00000001000a431f in opencv::opencv::hub::core::FileNode::new (fs=0x155004ce0, block_idx=123145570190000, ofs=18)
    at /Users/framp/.cargo/registry/src/github.com-1ecc6299db9ec823/opencv-0.46.3/src/opencv/hub/core.rs:7440
#33 0x0000000000000000 in ?? ()

I'll keep on digging in the code to see how I got to a call to FileStorage::new but I'd appreciate some ideas on what could have gone wrong

[twistedfall]

That’s extremely weird, at no point this code should create threads or call FileStorage API. Will you be able to create a minimum reproducible example that I can run locally? I’ve got a debug build of OpenCV so the backtrace will be more clear.

[framp]

This ended up being caused by another dependency, it just happened to find opencv functions at those memory addresses

Thanks for confirming I wasn't missing something OpenCV related and sorry for the noise!