Date: Tue, 16 Apr 2013 14:12:54 -0700 From: Carl Shapiro <carl.shapiro@gmail.com> To: FreeBSD Hackers <freebsd-hackers@freebsd.org> Subject: MADV_FREE and wait4 EFAULT Message-ID: <CANVK_QgKRkpzWjA=H2u2HTp_vpxFhNLBGTVuFZmMEpBLTbzeaA@mail.gmail.com>
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I am seeing wait4 system calls failing with an EFAULT and I am trying to understand what might be going wrong. An inspection of the wait4 implementation suggests the opportunity for EFAULT is within its invocations of copyout. In my situation, the status and rusage pointer arguments contain addresses to mmaped pages which have been madvised as MADV_FREE. Is it permissible to pass pages which have been madvised MADV_FREE to wait4 or any other system call for that matter? Might there be another opportunity for a wait4 to EFAULT?
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