Date: Sat, 22 Jul 2017 04:20:09 +0000 (UTC) From: Alan Cox <alc@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-11@freebsd.org Subject: svn commit: r321358 - in stable/11/sys: kern vm Message-ID: <201707220420.v6M4K9wm000905@repo.freebsd.org>
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Author: alc Date: Sat Jul 22 04:20:08 2017 New Revision: 321358 URL: https://svnweb.freebsd.org/changeset/base/321358 Log: MFC r320498 Clear the MAP_WIREFUTURE flag on the vm map in exec_new_vmspace() when it recycles the current vm space. Otherwise, an mlockall(MCL_FUTURE) could still be in effect on the process after an execve(2), which violates the specification for mlockall(2). It's pointless for vm_map_stack() to check the MEMLOCK limit. It will never be asked to wire the stack. Moreover, it doesn't even implement wiring of the stack. Modified: stable/11/sys/kern/kern_exec.c stable/11/sys/vm/vm_map.c Directory Properties: stable/11/ (props changed) Modified: stable/11/sys/kern/kern_exec.c ============================================================================== --- stable/11/sys/kern/kern_exec.c Sat Jul 22 03:54:04 2017 (r321357) +++ stable/11/sys/kern/kern_exec.c Sat Jul 22 04:20:08 2017 (r321358) @@ -1096,6 +1096,10 @@ exec_new_vmspace(imgp, sv) shmexit(vmspace); pmap_remove_pages(vmspace_pmap(vmspace)); vm_map_remove(map, vm_map_min(map), vm_map_max(map)); + /* An exec terminates mlockall(MCL_FUTURE). */ + vm_map_lock(map); + vm_map_modflags(map, 0, MAP_WIREFUTURE); + vm_map_unlock(map); } else { error = vmspace_exec(p, sv_minuser, sv->sv_maxuser); if (error) Modified: stable/11/sys/vm/vm_map.c ============================================================================== --- stable/11/sys/vm/vm_map.c Sat Jul 22 03:54:04 2017 (r321357) +++ stable/11/sys/vm/vm_map.c Sat Jul 22 04:20:08 2017 (r321358) @@ -3557,25 +3557,23 @@ vmspace_fork(struct vmspace *vm1, vm_ooffset_t *fork_c return (vm2); } +/* + * Create a process's stack for exec_new_vmspace(). This function is never + * asked to wire the newly created stack. + */ int vm_map_stack(vm_map_t map, vm_offset_t addrbos, vm_size_t max_ssize, vm_prot_t prot, vm_prot_t max, int cow) { vm_size_t growsize, init_ssize; - rlim_t lmemlim, vmemlim; + rlim_t vmemlim; int rv; + MPASS((map->flags & MAP_WIREFUTURE) == 0); growsize = sgrowsiz; init_ssize = (max_ssize < growsize) ? max_ssize : growsize; vm_map_lock(map); - lmemlim = lim_cur(curthread, RLIMIT_MEMLOCK); vmemlim = lim_cur(curthread, RLIMIT_VMEM); - if (!old_mlock && map->flags & MAP_WIREFUTURE) { - if (ptoa(pmap_wired_count(map->pmap)) + init_ssize > lmemlim) { - rv = KERN_NO_SPACE; - goto out; - } - } /* If we would blow our VMEM resource limit, no go */ if (map->size + init_ssize > vmemlim) { rv = KERN_NO_SPACE;
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