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authorRavi Bangoria <ravi.bangoria@linux.ibm.com>2018-08-20 10:12:48 +0530
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2018-09-24 04:44:54 -0400
commit22bad38286d9a652d7061a02f9743bb2ebb84e59 (patch)
treea43f88655fda4bdaf5470133c9b0fd367f22d3f6 /kernel/events/uprobes.c
parent1cc33161a83d20b5462b1e93f95d3ce6388079ee (diff)
downloadlinux-22bad38286d9a652d7061a02f9743bb2ebb84e59.tar.bz2
uprobes/sdt: Prevent multiple reference counter for same uprobe
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. Link: http://lkml.kernel.org/r/20180820044250.11659-3-ravi.bangoria@linux.ibm.com Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Song Liu <songliubraving@fb.com> Tested-by: Song Liu <songliubraving@fb.com> Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/events/uprobes.c')
-rw-r--r--kernel/events/uprobes.c19
1 files changed, 19 insertions, 0 deletions
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 934feb39f6be..96fb51f3994f 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.