mmap() with PROT_WRITE on RHEL5 incompatible with RHEL4
Issue
- The problem is page fault code file is different on x86_64 and x86_32 code.
- mmap() with PROT_WRITE only is incompatible between RHEL4 and RHEL5.
- When you mmap() a page with specifying PROT_WRITE only as the 'prot' argument,
- (a) if you read the page for the first time, it will cause SIGSEGV,
- (b) but if you read it after write it once, this read will succeed.
- This is an inconsistency ((a) SEGV v.s. (b) success) problem, and fixed on RHEL4.5 or later so that the first read (a) will succeed too.
Environment
- Red Hat Enterprise Linux 5.4 or earlier
- kernel-xen
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