| Issue |
89670
|
| Summary |
Sanitizer handler calls emitted without regard to `-mregparm`
|
| Labels |
new issue
|
| Assignees |
|
| Reporter |
kees
|
When sanitizer calls are emitted, the `-mregparm=3` option used by the Linux kernel appears to be ignored. For example, here is a build where the argument are being pushed instead of placed in `%eax` and `%edx` (from `lkdtm_ARRAY_BOUNDS`):
```asm
0xc18e3a5a <+202>: push %ebx
0xc18e3a5b <+203>: push $0xc26001a0
0xc18e3a60 <+208>: call 0xc157d430 <__ubsan_handle_out_of_bounds>
```
The kernel's handler isn't expecting them on the stack. For example, this is setting a bit in the sanitizer's passed-in data structure (from `__ubsan_handle_out_of_bounds`):
```asm
0xc157d491 <+97>: btsl $0x1f,%ds:0x4(%eax)
0xc157d497 <+103>: jae 0xc157d4a1 <__ubsan_handle_out_of_bounds+113>
```
https://github.com/KSPP/linux/issues/350
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