We assume to have only one reference counter for one uprobe.
Don't allow user to register multiple uprobes having same
inode+offset but different reference counter.
Signed-off-by: Ravi Bangoria <ravi.bangoria@xxxxxxxxxxxxx>
Acked-by: Srikar Dronamraju <srikar@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Oleg Nesterov <oleg@xxxxxxxxxx>
---
kernel/events/uprobes.c | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 35065febcb6c..ecee371a59c7 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -679,6 +679,16 @@ static struct uprobe *insert_uprobe(struct uprobe *uprobe)
return u;
}
+static void
+ref_ctr_mismatch_warn(struct uprobe *cur_uprobe, struct uprobe *uprobe)
+{
+ pr_warn("ref_ctr_offset mismatch. inode: 0x%lx offset: 0x%llx "
+ "ref_ctr_offset(old): 0x%llx ref_ctr_offset(new): 0x%llx\n",
+ uprobe->inode->i_ino, (unsigned long long) uprobe->offset,
+ (unsigned long long) cur_uprobe->ref_ctr_offset,
+ (unsigned long long) uprobe->ref_ctr_offset);
+}
+
static struct uprobe *alloc_uprobe(struct inode *inode, loff_t offset,
loff_t ref_ctr_offset)
{
@@ -698,6 +708,12 @@ static struct uprobe *alloc_uprobe(struct inode *inode, loff_t offset,
cur_uprobe = insert_uprobe(uprobe);
/* a uprobe exists for this inode:offset combination */
if (cur_uprobe) {
+ if (cur_uprobe->ref_ctr_offset != uprobe->ref_ctr_offset) {
+ ref_ctr_mismatch_warn(cur_uprobe, uprobe);
+ put_uprobe(cur_uprobe);
+ kfree(uprobe);
+ return ERR_PTR(-EINVAL);
+ }
kfree(uprobe);
uprobe = cur_uprobe;
}
@@ -1112,6 +1128,9 @@ static int __uprobe_register(struct inode *inode, loff_t offset,
uprobe = alloc_uprobe(inode, offset, ref_ctr_offset);
if (!uprobe)
return -ENOMEM;
+ if (IS_ERR(uprobe))
+ return PTR_ERR(uprobe);
+
/*
* We can race with uprobe_unregister()->delete_uprobe().
* Check uprobe_is_active() and retry if it is false.
--
2.14.4
