Description of problem:
I notice this issue trying to build 'seed' on rawhide. Here is the error message during seed build:

Making all in readline
make[4]: Entering directory `/builddir/fedora/seed/master/seed-3.8.1/doc/modules/readline'
../../../src/seed ../../../doc/modules/make-functions.js ../../../doc/modules/readline/readline.js > ../../../doc/modules/readline/readline-funcs.xml
1   0x3fff92ed6f5c /lib64/libjavascriptcoregtk-3.0.so.0(WTFCrash-0x14038c) [0x3fff92ed6f5c]
2   0x3fff92ef99c8 /lib64/libjavascriptcoregtk-3.0.so.0(_ZN3WTF11OSAllocator6commitEPvmbb-0x11e6a0) [0x3fff92ef99c8]
3   0x3fff92c40120 /lib64/libjavascriptcoregtk-3.0.so.0(_ZN3JSC7JSStack12growSlowCaseEPNS_8RegisterE-0x3c8b78) [0x3fff92c40120]
4   0x3fff92c3de68 /lib64/libjavascriptcoregtk-3.0.so.0(_ZN3JSC7JSStack10entryCheckEPNS_9CodeBlockEi-0x3cab20) [0x3fff92c3de68]
5   0x3fff92c3c5d0 /lib64/libjavascriptcoregtk-3.0.so.0(_ZN3JSC11Interpreter7executeEPNS_17ProgramExecutableEPNS_9ExecStateEPNS_8JSObjectE-0x3cc638) [0x3fff92c3c5d0]
6   0x3fff92d40a28 /lib64/libjavascriptcoregtk-3.0.so.0(_ZN3JSC8evaluateEPNS_9ExecStateERKNS_10SourceCodeENS_7JSValueEPS5_-0x2cda90) [0x3fff92d40a28]
7   0x3fff92b2ec30 /lib64/libjavascriptcoregtk-3.0.so.0(JSEvaluateScript-0x4d1aa8) [0x3fff92b2ec30]
8   0x3fff9333128c /builddir/fedora/seed/master/seed-3.8.1/libseed/.libs/libseed-gtk3.so.0(seed_simple_evaluate-0x2f90c) [0x3fff9333128c]
9   0x3fff93336c6c /builddir/fedora/seed/master/seed-3.8.1/libseed/.libs/libseed-gtk3.so.0(seed_init_constrained_with_context_and_group-0x2a3ec) [0x3fff93336c6c]
10  0x3fff93336f04 /builddir/fedora/seed/master/seed-3.8.1/libseed/.libs/libseed-gtk3.so.0(seed_init_with_context_and_group-0x2a164) [0x3fff93336f04]
11  0x3fff93337028 /builddir/fedora/seed/master/seed-3.8.1/libseed/.libs/libseed-gtk3.so.0(seed_init_with_context_group-0x2a050) [0x3fff93337028]
12  0x3fff933370a0 /builddir/fedora/seed/master/seed-3.8.1/libseed/.libs/libseed-gtk3.so.0(seed_init-0x29fe8) [0x3fff933370a0]
13  0x100010dc /builddir/fedora/seed/master/seed-3.8.1/src/.libs/lt-seed() [0x100010dc]
14  0x3fff931166ec /lib64/libc.so.6(+0x466ec) [0x3fff931166ec]
15  0x3fff931168f4 /lib64/libc.so.6(__libc_start_main-0x1aaf0c) [0x3fff931168f4]
/bin/sh: line 1:  4677 Segmentation fault      ../../../src/seed ../../../doc/modules/make-functions.js ../../../doc/modules/readline/readline.js > ../../../doc/modules/readline/readline-funcs.xml


And here is a backtrace from gdb:

(gdb) bt  
#0  0x00003fffb7916f70 in WTFCrash () at Source/WTF/wtf/Assertions.cpp:333
#1  0x00003fffb79399c8 in WTF::OSAllocator::commit (address=0x3fffb39cc000, bytes=16384, writable=<optimized out>, executable=<optimized out>)
    at Source/WTF/wtf/OSAllocatorPosix.cpp:134
#2  0x00003fffb7680120 in commit (this=0x3fffb44cef38, this=0x3fffb44cef38, this=0x3fffb44cef38, size=<optimized out>, start=<optimized out>)
    at Source/WTF/wtf/PageReservation.h:85
#3  JSC::JSStack::growSlowCase (this=0x3fffb44cef18, newEnd=0x3fffb39cff70) at Source/JavaScriptCore/interpreter/JSStack.cpp:89
#4  0x00003fffb767de68 in grow (newEnd=<optimized out>, this=0x3fffb44cef18) at Source/JavaScriptCore/interpreter/JSStackInlines.h:180
#5  JSC::JSStack::entryCheck (this=0x3fffb44cef18, codeBlock=<optimized out>, argsCount=<optimized out>)
    at Source/JavaScriptCore/interpreter/JSStackInlines.h:77
#6  0x00003fffb767c5d0 in JSC::Interpreter::execute (this=0x3fffb44cef00, program=0x3fffb34eff70, callFrame=0x3fffb359f9b0, thisObj=0x3fffb357fbb0)
    at Source/JavaScriptCore/interpreter/Interpreter.cpp:891
#7  0x00003fffb7780a28 in JSC::evaluate (exec=0x3fffb359f9b0, source=..., thisValue=..., returnedException=0x3fffffffed90)
    at Source/JavaScriptCore/runtime/Completion.cpp:82
#8  0x00003fffb756ec30 in JSEvaluateScript (ctx=<optimized out>, script=0x3fffb44b3258, thisObject=0x0, sourceURL=<optimized out>, 
    startingLineNumber=<optimized out>, exception=0x0) at Source/JavaScriptCore/API/JSBase.cpp:63
#9  0x00003fffb7d7128c in seed_simple_evaluate (ctx=0x3fffb359f9b0, source=<optimized out>, exception=0x0) at seed-api.c:305
#10 0x00003fffb7d76c6c in seed_init_constrained_with_context_and_group (argc=<optimized out>, argv=<optimized out>, context=0x3fffb359f9b0, 
    group=0x3fffb44b4000) at seed-engine.c:1734
#11 0x00003fffb7d76f04 in seed_init_with_context_and_group (argc=<optimized out>, argv=<optimized out>, context=<optimized out>, group=<optimized out>)
    at seed-engine.c:1792
#12 0x00003fffb7d77028 in seed_init_with_context_group (argc=0x3ffffffff200, argv=0x3ffffffff198, group=0x3fffb44b4000) at seed-engine.c:1830
#13 0x00003fffb7d770a0 in seed_init (argc=0x3ffffffff200, argv=<optimized out>) at seed-engine.c:1852
#14 0x00000000100010dc in main (argc=1, argv=<error reading variable: value has been optimized out>) at main.c:152


As you can see, the 'address' parameter on frame #1, which is passed to mprotect(), is not aligned to 64k (the page size for Fedora kernel on PPC64). The mprotect() syscall requires the address to be aligned to the kernel page size. A quick look at the code points to:

./Source/JavaScriptCore/interpreter/JSStack.h:76: static const size_t commitSize = 16 * 1024;


Would it be feasible to use 64k commitSize? Or maybe decouple the commitSize logic from the kernel page size?

Either way, please don't try to predict the kernel page size on build time. PPC64 (and other architectures) support multiple page sizes, so you can only rely on the the page size reported by the kernel on runtime. You can get it by calling 'sysconf(_SC_PAGESIZE)'.


Version-Release number of selected component (if applicable):
webkitgtk3-2.3.90-3.fc21.ppc64

How reproducible:
Always.

Steps to Reproduce:
1. yum install seed
2. seed
3.

Actual results:
See crash above.

Expected results:
Seed's prompt.

Additional info: