From fdc4f80ede8da5fd1777df4591c428856b7caa35 Mon Sep 17 00:00:00 2001
From: Oleg Nesterov <oleg@redhat.com>
Date: Sat, 29 Dec 2012 17:49:11 +0100
Subject: [PATCH] --- yaml --- r: 350087 b: refs/heads/master c:
 da1816b1caeccdff04531e763bb35d7caa3ed19f h: refs/heads/master i:   350085:
 baf02fc1de42727ff213441962b05ea6631567f1   350083:
 c7b02cd5d42667519fe21c8cea02031770a21cff   350079:
 d406930bb4190f5ee38efa5f5aa031e74c5c6b9c v: v3

---
 [refs]                        |  2 +-
 trunk/include/linux/uprobes.h |  3 ++
 trunk/kernel/events/uprobes.c | 58 +++++++++++++++++++++++++++++------
 3 files changed, 52 insertions(+), 11 deletions(-)

diff --git a/[refs] b/[refs]
index 6480e9b5bec5..abde634fcc03 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 8a7f2fa0dea3b019500961b86d765e6fdd4bffb2
+refs/heads/master: da1816b1caeccdff04531e763bb35d7caa3ed19f
diff --git a/trunk/include/linux/uprobes.h b/trunk/include/linux/uprobes.h
index c2df6934fdc6..95d0002efda5 100644
--- a/trunk/include/linux/uprobes.h
+++ b/trunk/include/linux/uprobes.h
@@ -35,6 +35,9 @@ struct inode;
 # include <asm/uprobes.h>
 #endif
 
+#define UPROBE_HANDLER_REMOVE		1
+#define UPROBE_HANDLER_MASK		1
+
 enum uprobe_filter_ctx {
 	UPROBE_FILTER_REGISTER,
 	UPROBE_FILTER_UNREGISTER,
diff --git a/trunk/kernel/events/uprobes.c b/trunk/kernel/events/uprobes.c
index c2737be3c4b8..04c104ad9522 100644
--- a/trunk/kernel/events/uprobes.c
+++ b/trunk/kernel/events/uprobes.c
@@ -440,16 +440,6 @@ static struct uprobe *alloc_uprobe(struct inode *inode, loff_t offset)
 	return uprobe;
 }
 
-static void handler_chain(struct uprobe *uprobe, struct pt_regs *regs)
-{
-	struct uprobe_consumer *uc;
-
-	down_read(&uprobe->register_rwsem);
-	for (uc = uprobe->consumers; uc; uc = uc->next)
-		uc->handler(uc, regs);
-	up_read(&uprobe->register_rwsem);
-}
-
 static void consumer_add(struct uprobe *uprobe, struct uprobe_consumer *uc)
 {
 	down_write(&uprobe->consumer_rwsem);
@@ -882,6 +872,33 @@ void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consume
 	put_uprobe(uprobe);
 }
 
+static int unapply_uprobe(struct uprobe *uprobe, struct mm_struct *mm)
+{
+	struct vm_area_struct *vma;
+	int err = 0;
+
+	down_read(&mm->mmap_sem);
+	for (vma = mm->mmap; vma; vma = vma->vm_next) {
+		unsigned long vaddr;
+		loff_t offset;
+
+		if (!valid_vma(vma, false) ||
+		    vma->vm_file->f_mapping->host != uprobe->inode)
+			continue;
+
+		offset = (loff_t)vma->vm_pgoff << PAGE_SHIFT;
+		if (uprobe->offset <  offset ||
+		    uprobe->offset >= offset + vma->vm_end - vma->vm_start)
+			continue;
+
+		vaddr = offset_to_vaddr(vma, uprobe->offset);
+		err |= remove_breakpoint(uprobe, mm, vaddr);
+	}
+	up_read(&mm->mmap_sem);
+
+	return err;
+}
+
 static struct rb_node *
 find_node_in_range(struct inode *inode, loff_t min, loff_t max)
 {
@@ -1435,6 +1452,27 @@ static struct uprobe *find_active_uprobe(unsigned long bp_vaddr, int *is_swbp)
 	return uprobe;
 }
 
+static void handler_chain(struct uprobe *uprobe, struct pt_regs *regs)
+{
+	struct uprobe_consumer *uc;
+	int remove = UPROBE_HANDLER_REMOVE;
+
+	down_read(&uprobe->register_rwsem);
+	for (uc = uprobe->consumers; uc; uc = uc->next) {
+		int rc = uc->handler(uc, regs);
+
+		WARN(rc & ~UPROBE_HANDLER_MASK,
+			"bad rc=0x%x from %pf()\n", rc, uc->handler);
+		remove &= rc;
+	}
+
+	if (remove && uprobe->consumers) {
+		WARN_ON(!uprobe_is_active(uprobe));
+		unapply_uprobe(uprobe, current->mm);
+	}
+	up_read(&uprobe->register_rwsem);
+}
+
 /*
  * Run handler and ask thread to singlestep.
  * Ensure all non-fatal signals cannot interrupt thread while it singlesteps.