Failed to allocate a guard page

[joerg-krause]

I am cross-compiling a cargo build hello for an unsupported ARMv5 target with a musl toolchain. I am using the instructions from rust-cross-libs to successfully build the rustlibs and hello.

I added an debug output to https://github.com/rust-lang/rust/blob/master/src/libstd/sys/unix/thread.rs#L224 to get the page size used by Rust: psize: 9459

However, using a C test file with long sz = sysconf(_SC_PAGESIZE); prints a page size of 4096, which I assume is correct.

I know ARMv5 and arm---musl are not officially supported, but maybe can give me a hint why os::page_size() returns a wrong and obviously page size.

[alexcrichton]

Was the standard library recompiled for armv5 as well? Right now I don't think we ship any armv5 standard libraries, nor do we have an armv5 target in the compiler.

Maybe the libc definition of _SC_PAGESIZE was wrong as well? Maybe the ABI is wrong? I guess it could be a number of factors.

[joerg-krause]

Yes, the standard library was recompiled for ARMv5. Cross-compiling hello for the ARMv5 target works fine with the glIbc, but somehow fails with musl.

I've seen that _SC_PAGESIZE is defined as an integer value of 30 both in musl and stdlibc. I'll check, if it is really 30 for my build.

[joerg-krause]

Ok, I need some work to do. _SC_PAGESIZE is wrong and I've to fix my custom JSON file to build the standard library correctly for musl and ARMv5.

[joerg-krause]

I fixed my custom JSON target file for armv5te-unkwown-linux-musl.

Now, I can cross-compile cargos hello for my custom target armv5te-unkwown-linux-musl successfully.

[alexcrichton]

Aha, I'm glad it worked out! Should we leave this open? Does a patch need to make its way upstream?

[joerg-krause]

I'll close this. I proposed a PR to libc rust-lang/libc#214 to link with the shared library.