Segfault on ppc64 w/ JIT & SEAlloc

[OPNA2608]

With JIT and the SELinux allocator enabled, trying to use a basic regex pattern in grep results gives a segfault in PCRE2 (tested 1.44 & 1.45) on big-endian 64-bit POWER:

puna on HC ~/Development/nixpkgs $ echo '.' | grep -P '^.$'
grep: program error
Aborted

Under GDB:

Program received signal SIGSEGV, Segmentation fault.
sljit_exec_offset (code=0x3ffff7bf0020) at src/../deps/sljit/sljit_src/allocator_src/sljitExecAllocatorCore.c:325
warning: 325    src/../deps/sljit/sljit_src/allocator_src/sljitExecAllocatorCore.c: No such file or directory
(gdb) bt -full
#0  sljit_exec_offset (code=0x3ffff7bf0020) at src/../deps/sljit/sljit_src/allocator_src/sljitExecAllocatorCore.c:325
No locals.
#1  0x00003ffff7f0100c in pcre2_jit_compile_8 (code=0x100621b0, options=1) at src/pcre2_jit_compile.c:13983
        re = 0x100621b0
        exec_memory = 0x3ffff7bf0020
        functions = 0xf8f5f071a41d97
        executable_allocator_is_working = -1
#2  0x0000000010013a1c in Pcompile (pattern=0x10061c60 "^.$\n\367\347\r\200", size=3, ignored=0, exact=false) at pcresearch.c:251
        e = 0
        ec = 100
        flags = 16
        patlim = 0x10061c63 "\n\367\347\r\200"
        pc = 0x10061d00
        gcontext = 0x10061d40
        ccontext = 0x10061980
        extra_options = 256
        re_storage = 0x0
        ERRBUFSIZ = ERRBUFSIZ
#3  0x000000001000e198 in main (argc=4, argv=0x3ffffffff5c8) at grep.c:2980
        keys = 0x10061c60 "^.$\n\367\347\r\200"
        keycc = 3
        keyalloc = 0
        matcher = 6
        opt = -1
        prev_optind = 2
        last_recursive = 0
        default_context = -1
        fp = 0x3ffffffff540
        filename_option = 0
        possibly_tty = true
        tmp_stat = {st_dev = 19, st_ino = 4, st_nlink = 1, st_mode = 8594, st_uid = 1000, st_gid = 1000, __pad2 = 0, st_rdev = 34817, 
          st_size = 0, st_blksize = 1024, st_blocks = 0, st_atim = {tv_sec = 1752222536, tv_nsec = 468974401}, st_mtim = {
            tv_sec = 1752222536, tv_nsec = 468974401}, st_ctim = {tv_sec = 1752033965, tv_nsec = 468974401}, __glibc_reserved4 = 0, 
          __glibc_reserved5 = 0, __glibc_reserved6 = 0}
        eolbytes = "\000\000"
        match_size = 5
        num_operands = 0
        psize = 0
        files = 0x0
        status = false

Disabling the SELinux allocator fixes the segfault. As does disabling JIT, obviously.

[zherczeg]

Probably setting the memory permissions with mprotect was unsuccessful. It is hard to tell. Maybe the os rejected it because some permissions were missing.