[Big Sur] open() vs SA_RESTART #48663
Description
It appears that on MacOS Big Sur, open can sometimes return EINTR if it is interrupted by a signal even if the signal has a handler installed with SA_RESTART.
- MonoVM thread suspend/resume sometimes (when using posix instead of Mach) will use suspend/resume signals with the
SA_RESTARTflags. (although this is not the default - we prefer to use Mach suspend/resume operations) - The System.Native PAL installs some signal handlers with
SA_RESTART
We should make sure that all our calls to open handle EINTR.
To be clear, I haven't seen this cause a problem for .NET that can be clearly attributed to this issue. Until we catch it in a repro, this is just a placeholder issue - unless we want to be proactive about mitigating.
(This is affecting other software too. git, for example. It has affected some runtime engineers - git clone --progress https://github.com/dotnet/runtime will sometimes fail with interrupted system call errors and leave the working tree in an unusable state. The workaround is to call git clone --quiet (note that --progress is the default))
The issue seems to be exacerbated by some antivirus software, even if "real time protection" is turned off.