Segmentation fault when printing a float

[z3ntu]

EDIT: This issue seems to be present in a bunch of tests. This issue was written only with test_input in mind! (I was debugging that one and found the issue)

Printing a float, like printf("float: %f\n", 1.0); in the function on_new_event results in a Segmentation fault. Doing the same in the main function, everything works as expected.

Showcase: z3ntu/libhybris@ea24333
Output of that:

root@localhost:~/libhybris/hybris/tests# ./test_input 
This will work:
float: 1.000000
<note: pressed the touchscreen there>
This won't work:
Segmentation fault

gdb backtrace - mirror of the paste is here

This problem causes the test_input test to crash: https://github.com/libhybris/libhybris/blob/master/hybris/tests/test_input.c#L51-L54 .

Casting the two variables into an integer and printing them works around the issue. Sample patch: z3ntu/libhybris@5773400

[Tofee]

This looks like a softfp/hardfp issue. When I look at my N5 binaries, I have:

• test_sensors which is built with hardfp
• sensors.qcom which is built with softfp

This leads to the floats being actually integers in the structure, but the compiler doesn't know that and uses them directly as floats.

[krnlyng]

@Tofee This is not the issue here, libhybris uses the softfp calling convention when issuing calls to softfp libraries.