From mboxrd@z Thu Jan 1 00:00:00 1970 From: ravi.bangoria@linux.ibm.com (Ravi Bangoria) Date: Tue, 31 Jul 2018 09:21:41 +0530 Subject: [PATCH v7 4/6] Uprobes/sdt: Prevent multiple reference counter for same uprobe In-Reply-To: <20180731035143.11942-1-ravi.bangoria@linux.ibm.com> References: <20180731035143.11942-1-ravi.bangoria@linux.ibm.com> Message-ID: <20180731035143.11942-5-ravi.bangoria@linux.ibm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 --- kernel/events/uprobes.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index ad92fed11526..c27546929ae7 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -679,6 +679,12 @@ 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) { + pr_warn("Reference counter offset mismatch.\n"); + put_uprobe(cur_uprobe); + kfree(uprobe); + return ERR_PTR(-EINVAL); + } kfree(uprobe); uprobe = cur_uprobe; } @@ -1093,6 +1099,9 @@ 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