diff -urN 2.4.11pre3aa1/arch/alpha/mm/fault.c recurse/arch/alpha/mm/fault.c
--- 2.4.11pre3aa1/arch/alpha/mm/fault.c	Sun Sep 23 21:11:28 2001
+++ recurse/arch/alpha/mm/fault.c	Thu Oct  4 18:50:12 2001
@@ -113,7 +113,7 @@
 		goto vmalloc_fault;
 #endif
 
-	down_read(&mm->mmap_sem);
+	down_read_recursive(&mm->mmap_sem, &current->mm_recursor);
 	vma = find_vma(mm, address);
 	if (!vma)
 		goto bad_area;
@@ -147,7 +147,7 @@
 	 * the fault.
 	 */
 	fault = handle_mm_fault(mm, vma, address, cause > 0);
-	up_read(&mm->mmap_sem);
+	up_read_recursive(&mm->mmap_sem, &current->mm_recursor);
 
 	if (fault < 0)
 		goto out_of_memory;
@@ -161,7 +161,7 @@
  * Fix it, but check if it's kernel or user first..
  */
 bad_area:
-	up_read(&mm->mmap_sem);
+	up_read_recursive(&mm->mmap_sem, &current->mm_recursor);
 
 	if (user_mode(regs)) {
 		force_sig(SIGSEGV, current);
@@ -198,7 +198,7 @@
 	if (current->pid == 1) {
 		current->policy |= SCHED_YIELD;
 		schedule();
-		down_read(&mm->mmap_sem);
+		down_read_recursive(&mm->mmap_sem, &current->mm_recursor);
 		goto survive;
 	}
 	printk(KERN_ALERT "VM: killing process %s(%d)\n",
diff -urN 2.4.11pre3aa1/arch/i386/mm/fault.c recurse/arch/i386/mm/fault.c
--- 2.4.11pre3aa1/arch/i386/mm/fault.c	Sun Sep 23 21:11:28 2001
+++ recurse/arch/i386/mm/fault.c	Thu Oct  4 18:50:12 2001
@@ -191,7 +191,7 @@
 	if (in_interrupt() || !mm)
 		goto no_context;
 
-	down_read(&mm->mmap_sem);
+	down_read_recursive(&mm->mmap_sem, &current->mm_recursor);
 
 	vma = find_vma(mm, address);
 	if (!vma)
@@ -265,7 +265,7 @@
 		if (bit < 32)
 			tsk->thread.screen_bitmap |= 1 << bit;
 	}
-	up_read(&mm->mmap_sem);
+	up_read_recursive(&mm->mmap_sem, &current->mm_recursor);
 	return;
 
 /*
@@ -273,7 +273,7 @@
  * Fix it, but check if it's kernel or user first..
  */
 bad_area:
-	up_read(&mm->mmap_sem);
+	up_read_recursive(&mm->mmap_sem, &current->mm_recursor);
 
 	/* User mode accesses just cause a SIGSEGV */
 	if (error_code & 4) {
@@ -341,11 +341,11 @@
  * us unable to handle the page fault gracefully.
  */
 out_of_memory:
-	up_read(&mm->mmap_sem);
+	up_read_recursive(&mm->mmap_sem, &current->mm_recursor);
 	if (tsk->pid == 1) {
 		tsk->policy |= SCHED_YIELD;
 		schedule();
-		down_read(&mm->mmap_sem);
+		down_read_recursive(&mm->mmap_sem, &current->mm_recursor);
 		goto survive;
 	}
 	printk("VM: killing process %s\n", tsk->comm);
@@ -354,7 +354,7 @@
 	goto no_context;
 
 do_sigbus:
-	up_read(&mm->mmap_sem);
+	up_read_recursive(&mm->mmap_sem, &current->mm_recursor);
 
 	/*
 	 * Send a sigbus, regardless of whether we were in kernel
diff -urN 2.4.11pre3aa1/arch/ia64/mm/fault.c recurse/arch/ia64/mm/fault.c
--- 2.4.11pre3aa1/arch/ia64/mm/fault.c	Tue May  1 19:35:18 2001
+++ recurse/arch/ia64/mm/fault.c	Thu Oct  4 18:50:12 2001
@@ -60,7 +60,7 @@
 	if (in_interrupt() || !mm)
 		goto no_context;
 
-	down_read(&mm->mmap_sem);
+	down_read_recursive(&mm->mmap_sem, &current->mm_recursor);
 
 	vma = find_vma_prev(mm, address, &prev_vma);
 	if (!vma)
@@ -112,7 +112,7 @@
 	      default:
 		goto out_of_memory;
 	}
-	up_read(&mm->mmap_sem);
+	up_read_recursive(&mm->mmap_sem, &current->mm_recursor);
 	return;
 
   check_expansion:
@@ -135,7 +135,7 @@
 	goto good_area;
 
   bad_area:
-	up_read(&mm->mmap_sem);
+	up_read_recursive(&mm->mmap_sem, &current->mm_recursor);
 	if (isr & IA64_ISR_SP) {
 		/*
 		 * This fault was due to a speculative load set the "ed" bit in the psr to
@@ -184,7 +184,7 @@
 	return;
 
   out_of_memory:
-	up_read(&mm->mmap_sem);
+	up_read_recursive(&mm->mmap_sem, &current->mm_recursor);
 	printk("VM: killing process %s\n", current->comm);
 	if (user_mode(regs))
 		do_exit(SIGKILL);
diff -urN 2.4.11pre3aa1/arch/ppc/mm/fault.c recurse/arch/ppc/mm/fault.c
--- 2.4.11pre3aa1/arch/ppc/mm/fault.c	Thu Oct  4 10:06:33 2001
+++ recurse/arch/ppc/mm/fault.c	Thu Oct  4 18:50:12 2001
@@ -103,7 +103,7 @@
 		bad_page_fault(regs, address, SIGSEGV);
 		return;
 	}
-	down_read(&mm->mmap_sem);
+	down_read_recursive(&mm->mmap_sem, &current->mm_recursor);
 	vma = find_vma(mm, address);
 	if (!vma)
 		goto bad_area;
@@ -164,7 +164,7 @@
                 goto out_of_memory;
 	}
 
-	up_read(&mm->mmap_sem);
+	up_read_recursive(&mm->mmap_sem, &current->mm_recursor);
 	/*
 	 * keep track of tlb+htab misses that are good addrs but
 	 * just need pte's created via handle_mm_fault()
@@ -174,7 +174,7 @@
 	return;
 
 bad_area:
-	up_read(&mm->mmap_sem);
+	up_read_recursive(&mm->mmap_sem, &current->mm_recursor);
 	pte_errors++;	
 
 	/* User mode accesses cause a SIGSEGV */
@@ -195,7 +195,7 @@
  * us unable to handle the page fault gracefully.
  */
 out_of_memory:
-	up_read(&mm->mmap_sem);
+	up_read_recursive(&mm->mmap_sem, &current->mm_recursor);
 	if (current->pid == 1) {
 		current->policy |= SCHED_YIELD;
 		schedule();
@@ -209,7 +209,7 @@
 	return;
 
 do_sigbus:
-	up_read(&mm->mmap_sem);
+	up_read_recursive(&mm->mmap_sem, &current->mm_recursor);
 	info.si_signo = SIGBUS;
 	info.si_errno = 0;
 	info.si_code = BUS_ADRERR;
diff -urN 2.4.11pre3aa1/fs/exec.c recurse/fs/exec.c
--- 2.4.11pre3aa1/fs/exec.c	Sun Sep 23 21:11:39 2001
+++ recurse/fs/exec.c	Thu Oct  4 18:50:12 2001
@@ -969,9 +969,9 @@
 	if (do_truncate(file->f_dentry, 0) != 0)
 		goto close_fail;
 
-	down_read(&current->mm->mmap_sem);
+	down_read_recursive(&current->mm->mmap_sem, &current->mm_recursor);
 	retval = binfmt->core_dump(signr, regs, file);
-	up_read(&current->mm->mmap_sem);
+	up_read_recursive(&current->mm->mmap_sem, &current->mm_recursor);
 
 close_fail:
 	filp_close(file, NULL);
diff -urN 2.4.11pre3aa1/include/linux/rwsem.h recurse/include/linux/rwsem.h
--- 2.4.11pre3aa1/include/linux/rwsem.h	Thu Oct  4 18:49:53 2001
+++ recurse/include/linux/rwsem.h	Thu Oct  4 18:50:12 2001
@@ -18,6 +18,11 @@
 #endif
 };
 
+struct rw_sem_recursor
+{
+	int counter;
+};
+
 #if RWSEM_DEBUG
 #define __SEM_DEBUG_INIT(name) \
 	, (long)&(name).__magic
@@ -42,6 +47,7 @@
 	__SEM_DEBUG_INIT(name)			\
 }
 #define RWSEM_INITIALIZER(name) __RWSEM_INITIALIZER(name, 0)
+#define RWSEM_RECURSOR_INITIALIZER ((struct rw_sem_recursor) { 0, })
 
 #define __DECLARE_RWSEM(name, count) \
 	struct rw_semaphore name = __RWSEM_INITIALIZER(name, count)
@@ -112,6 +118,34 @@
 	spin_lock(&sem->lock);
 	sem->count -= RWSEM_WRITE_BIAS;
 	if (unlikely(sem->count))
+		rwsem_wake(sem);
+	spin_unlock(&sem->lock);
+}
+
+static inline void down_read_recursive(struct rw_semaphore *sem,
+				       struct rw_sem_recursor * recursor)
+{
+	int count, counter;
+	CHECK_MAGIC(sem->__magic);
+
+	spin_lock(&sem->lock);
+	count = sem->count;
+	sem->count += RWSEM_READ_BIAS;
+	counter = recursor->counter++;
+	if (unlikely(count < 0 && !counter && !(count & RWSEM_READ_MASK)))
+		rwsem_down_failed(sem, RWSEM_READ_BLOCKING_BIAS);
+	spin_unlock(&sem->lock);
+}
+
+static inline void up_read_recursive(struct rw_semaphore *sem,
+				     struct rw_sem_recursor * recursor)
+{
+	CHECK_MAGIC(sem->__magic);
+
+	spin_lock(&sem->lock);
+	sem->count -= RWSEM_READ_BIAS;
+	recursor->counter--;
+	if (unlikely(sem->count < 0 && !(sem->count & RWSEM_READ_MASK)))
 		rwsem_wake(sem);
 	spin_unlock(&sem->lock);
 }
diff -urN 2.4.11pre3aa1/include/linux/sched.h recurse/include/linux/sched.h
--- 2.4.11pre3aa1/include/linux/sched.h	Thu Oct  4 18:49:53 2001
+++ recurse/include/linux/sched.h	Thu Oct  4 18:50:12 2001
@@ -315,6 +315,7 @@
 
 	struct task_struct *next_task, *prev_task;
 	struct mm_struct *active_mm;
+	struct rw_sem_recursor mm_recursor;
 	struct list_head local_pages;
 	unsigned int allocation_order, nr_local_pages;
 
@@ -460,6 +461,7 @@
     policy:		SCHED_OTHER,					\
     mm:			NULL,						\
     active_mm:		&init_mm,					\
+    mm_recursor:	RWSEM_RECURSOR_INITIALIZER,			\
     cpus_allowed:	-1,						\
     run_list:		LIST_HEAD_INIT(tsk.run_list),			\
     next_task:		&tsk,						\