About catching the SIGSEGV in multithreaded environment

Question

I\'d like to know if it is possible/the recommended way to catch the SIGSEGV signal in multithreaded environment. I am particularly interested in handling the <

Answer 1

Your code does not call sigaction(2), and I believe it should call it. Read also signal(7) and signal-safety(7). And the signal action (thru sa_sigaction field should do something (machine specific) with its siginfo_t to skip the offending machine instruction, or to mmap the offending address, or call siglongjmp, otherwise when returning from the signal handler you'll get the SIGSEGV again since the offending machine instruction is restarted.

You cannot handle the SIGSEGV in another thread, since synchronous signals (such as SIGSEGV or SIGSYS) are thread specific (see this answer), so what you try to achieve with sigwaitinfo cannot work. In particular SIGSEGV is directed to the offending thread.

Read also all about Linux signals.

PS. An example of clever SIGSEGV handling is offered by the no-more maintained (in May 2019) Ravenbrook MPS garbage collector library. Notice also the Linux specific and recent userfaultfd(2) and signalfd(2) system calls.