Backward compatible issue with pango1.0-1.36.3 about harfbuzz HOT 3 CLOSED

When we tried to use up-to-date harfbuzz-ng with pango 1.36.3, we've got a crash case. The detailed stack traces are reported at crbug.com/503858 and a comment in a patch review.

I saw that, but nothing pops out to my mind why that might be crashing :(.

There are two very different crashes there. It makes me think that objects created using one harfbuzz are being passed to the other.

As far as I looked at the stack traces, this one seems to be offending:

0x00007ffff67c92b0 in hb_shape (font=0x32719220ab0, buffer=0x327191e4620,
features=0x7fffffffcc80, num_features=0)
at ../../third_party/harfbuzz-ng/src/hb-shape.cc:386

So Pango calls hb_shape with invalid features (probably only if num_features == 0) and the current harfbuzz-ng does not like this.

Is it possible not to read features if num_features == 0?

We definitely don't touch features if num_features is zero. And that features array is valid. It points to an array on the stack.

from harfbuzz.

You're right, too new to Linux, sorry for bothering.

from harfbuzz.

No worries. Thanks for taking care of it.

from harfbuzz.