From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sat, 16 Nov 2002 17:37:41 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sat, 16 Nov 2002 17:37:41 -0500 Received: from verein.lst.de ([212.34.181.86]:15888 "EHLO verein.lst.de") by vger.kernel.org with ESMTP id ; Sat, 16 Nov 2002 17:37:38 -0500 Date: Sat, 16 Nov 2002 23:44:32 +0100 From: Christoph Hellwig To: Ingo Oeser Cc: torvalds@transmeta.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH] fork.c bits for uClinux Message-ID: <20021116234432.A27155@lst.de> Mail-Followup-To: Christoph Hellwig , Ingo Oeser , torvalds@transmeta.com, linux-kernel@vger.kernel.org References: <20021116231718.A26716@lst.de> <20021116233306.J628@nightmaster.csn.tu-chemnitz.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: <20021116233306.J628@nightmaster.csn.tu-chemnitz.de>; from ingo.oeser@informatik.tu-chemnitz.de on Sat, Nov 16, 2002 at 11:33:06PM +0100 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Nov 16, 2002 at 11:33:06PM +0100, Ingo Oeser wrote: > The contents of the old struct mm_struct is copied and the > semaphore of the old structure is taken. Now the content of the > NEW semaphore is taken, which might be wrong, because the > semaphore value is contained in the struct mm_struct and not a > pointer. > > Fix is to do give the oldmm as argument to dup_mm Here's the update patch, thanks for the spot. --- 1.83/kernel/fork.c Tue Nov 5 23:27:16 2002 +++ edited/kernel/fork.c Sat Nov 16 22:40:59 2002 @@ -28,6 +28,7 @@ #include #include #include +#include #include #include @@ -205,12 +206,14 @@ return tsk; } -static inline int dup_mmap(struct mm_struct * mm) +#ifdef CONFIG_MMU +static inline int dup_mmap(struct mm_struct * mm, struct mm_struct * oldmm) { struct vm_area_struct * mpnt, *tmp, **pprev; int retval; unsigned long charge = 0; + down_write(&oldmm->mmap_sem); flush_cache_mm(current->mm); mm->locked_vm = 0; mm->mmap = NULL; @@ -287,11 +290,29 @@ out: flush_tlb_mm(current->mm); + up_write(&oldmm->mmap_sem); return retval; fail_nomem: vm_unacct_memory(charge); goto out; } +static inline int mm_alloc_pgd(struct mm_struct * mm) +{ + mm->pgd = pgd_alloc(mm); + if (unlikely(!mm->pgd)) + return -ENOMEM; + return 0; +} + +static inline void mm_free_pgd(struct mm_struct * mm) +{ + pgd_free(mm->pgd); +} +#else +#define dup_mmap(mm, oldmm) (0) +#define mm_alloc_pgd(mm) (0) +#define mm_free_pgd(mm) +#endif /* CONFIG_MMU */ spinlock_t mmlist_lock __cacheline_aligned_in_smp = SPIN_LOCK_UNLOCKED; int mmlist_nr; @@ -314,8 +335,7 @@ mm->default_kioctx = (struct kioctx)INIT_KIOCTX(mm->default_kioctx, *mm); mm->free_area_cache = TASK_UNMAPPED_BASE; - mm->pgd = pgd_alloc(mm); - if (mm->pgd) + if (likely(!mm_alloc_pgd(mm))) return mm; free_mm(mm); return NULL; @@ -344,8 +364,8 @@ */ inline void __mmdrop(struct mm_struct *mm) { - if (mm == &init_mm) BUG(); - pgd_free(mm->pgd); + BUG_ON(mm == &init_mm); + mm_free_pgd(mm); destroy_context(mm); free_mm(mm); } @@ -444,10 +464,7 @@ if (init_new_context(tsk,mm)) goto free_pt; - down_write(&oldmm->mmap_sem); - retval = dup_mmap(mm); - up_write(&oldmm->mmap_sem); - + retval = dup_mmap(mm, oldmm); if (retval) goto free_pt;