# Re: \[PATCH 13/18\] exec: make exec path waiting for mmap\_sem killable - From: Michal Hocko \ - Date: 2016-02-29 17:47:45 - List: linux-arch - Page: https://ratatoskr.run/linux-arch/2016/02/4697168 - Thread: https://ratatoskr.run/linux-mm/2016/02/4696944/t.md ```text On Mon 29-02-16 18:23:34, Oleg Nesterov wrote: > On 02/29, Michal Hocko wrote: > > > > @@ -267,7 +267,10 @@ static int __bprm_mm_init(struct linux_binprm *bprm) > > if (!vma) > > return -ENOMEM; > > > > - down_write(&mm->mmap_sem); > > + if (down_write_killable(&mm->mmap_sem)) { > > + err = -EINTR; > > + goto err_free; > > + } > > vma->vm_mm = mm; > > I won't argue, but this looks unnecessary. Nobody else can see this new mm, > down_write() can't block. > > In fact I think we can just remove down_write/up_write here. Except perhaps > there is lockdep_assert_held() somewhere in these paths. This is what I had initially but then I've noticed that mm_alloc() does mm_init(current)->init_new_context(current) so the outside can see this mm AFAICS. Now I guess this shouldn't matter in the real life but the code doesn't seem much harder to follow, the callers are already handling all error paths so I guess it would be better to simply move on this. Or am I misunderstanding the code or missing something? -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org ```