Date: Mon, 22 Jul 2013 21:47:15 +0000 (UTC) From: Jeremie Le Hen <jlh@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r253554 - head/sys/vm Message-ID: <201307222147.r6MLlFaX031684@svn.freebsd.org>
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Author: jlh Date: Mon Jul 22 21:47:14 2013 New Revision: 253554 URL: http://svnweb.freebsd.org/changeset/base/253554 Log: Fix a panic in the racct code when munlock(2) is called with incorrect values. The racct code in sys_munlock() assumed that the boundaries provided by the userland were correct as long as vm_map_unwire() returned successfully. However the latter contains its own logic and sometimes manages to do something out of those boundaries, even if they are buggy. This change makes the racct code to use the accounting done by the vm layer, as it is done in other places such as vm_mlock(). Despite fixing the panic, Alan Cox pointed that this code is still race-y though: two simultaneous callers will produce incorrect values. Reviewed by: alc MFC after: 7 days Modified: head/sys/vm/vm_mmap.c Modified: head/sys/vm/vm_mmap.c ============================================================================== --- head/sys/vm/vm_mmap.c Mon Jul 22 19:38:21 2013 (r253553) +++ head/sys/vm/vm_mmap.c Mon Jul 22 21:47:14 2013 (r253554) @@ -1224,6 +1224,7 @@ sys_munlock(td, uap) { vm_offset_t addr, end, last, start; vm_size_t size; + vm_map_t map; int error; error = priv_check(td, PRIV_VM_MUNLOCK); @@ -1241,7 +1242,9 @@ sys_munlock(td, uap) #ifdef RACCT if (error == KERN_SUCCESS) { PROC_LOCK(td->td_proc); - racct_sub(td->td_proc, RACCT_MEMLOCK, ptoa(end - start)); + map = &td->td_proc->p_vmspace->vm_map; + racct_set(td->td_proc, RACCT_MEMLOCK, + ptoa(pmap_wired_count(map->pmap))); PROC_UNLOCK(td->td_proc); } #endif
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