Fw: Re: Fw: Re: Why do these mprotect always fail?

[w6b7rk5yu4mt25v3]

See strace:

544091  601347 [main] obr 1831 mprotect: mprotect (addr: 0xA00100000, len 65536, prot 0x7)
   59  601406 [main] obr 1831 mprotect: 0 = mprotect ()
  166  601572 [main] obr 1831 mmap: addr 0x0, len 327680, prot 0x3, flags 0x22, fd -1, off 0x0
  123  601695 [main] obr 1831 mmap: 0x6FFFFFFB0000 = mmap()
   95  601790 [main] obr 1831 mprotect: mprotect (addr: 0x6FFFFFFC0000, len 196608, prot 0x7)
   88  601878 [main] obr 1831 mprotect: 0 = mprotect ()
  255  602133 [main] obr 1831 mmap: addr 0x0, len 393216, prot 0x3, flags 0x22, fd -1, off 0x0
  102  602235 [main] obr 1831 mmap: 0x6FFFFFF50000 = mmap()
  108  602343 [main] obr 1831 mprotect: mprotect (addr: 0x6FFFFFF60000, len 262144, prot 0x7)
   47  602390 [main] obr 1831 mprotect: 0 = mprotect ()
  245  602635 [main] obr 1831 mmap: addr 0x0, len 458752, prot 0x3, flags 0x22, fd -1, off 0x0
   44  602679 [main] obr 1831 mmap: 0x6FFFFFEE0000 = mmap()
   46  602725 [main] obr 1831 mprotect: mprotect (addr: 0x6FFFFFEF0000, len 327680, prot 0x7)
   39  602764 [main] obr 1831 mprotect: 0 = mprotect ()
--- Process 3796 (pid: 1831), exception c0000005 at 0000000a00100061
--- Process 3796 (pid: 1831) thread 2928 exited with status 0xc0000005
--- Process 3796 (pid: 1831) exited with status 0xc0000005
Segmentation fault

I still think it's Cygwin's bug.

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------- Original Message -------
On Wednesday, February 15th, 2023 at 23:33, Corinna Vinschen <corinna-cygwin@cygwin.com> wrote:


> On Feb 15 15:31, w6b7rk5yu4mt25v3 via Cygwin wrote:
> 
> > I asked the developer of the interpreter. He said it's OK to use the PAGE_SIZE value different than 4096. So I used this dirty hack:
> > 
> > #ifndef CYGWIN
> > #define PAGE_SIZE 4096
> > #endif
> > 
> > This means on Cygwin it will use the default PAGE_SIZE defined on limits.h (I'm taking advantage of the naming conflict here so I don't have to rename PAGE_SIZE to JIT_PAGE_SIZE as suggested by the developer of the interpreter).
> > 
> > The result is it's no longer error with "Unable to mprotect" but will
> > silently crashed without any error messages printed on the screen. So
> > after all, it's Cygwin's quirks here.
> 
> 
> I still think it's a bug in the code which requires some debugging effort
> on your side.
> 
> Having said that, if it's actually a Cygwin bug and you want it fixed,
> please provide a simple, self-contained testcase in plain C, with a
> minimum of code to reproduce the issue, and which compiles OOTB.
> 
> 
> Corinna