From: Punit Agrawal <punitagrawal@gmail.com> stable inclusion from stable-5.10.80 commit 848f1f00c637da8cb5d5b4fb702fade5c03696df bugzilla: 185821 https://gitee.com/openeuler/kernel/issues/I4L7CG Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit 8f7262cd66699a4b02eb7549b35c81b2116aad95 ] debugfs_create_file() takes a pointer argument that can be used during file operation callbacks (accessible via i_private in the inode structure). An obvious requirement is for the pointer to refer to valid memory when used. When creating the debugfs file to dynamically enable / disable kprobes, a pointer to local variable is passed to debugfs_create_file(); which will go out of scope when the init function returns. The reason this hasn't triggered random memory corruption is because the pointer is not accessed during the debugfs file callbacks. Since the enabled state is managed by the kprobes_all_disabled global variable, the local variable is not needed. Fix the incorrect (and unnecessary) usage of local variable during debugfs_file_create() by passing NULL instead. Link: https://lkml.kernel.org/r/163163031686.489837.4476867635937014973.stgit@devn... Fixes: bf8f6e5b3e51 ("Kprobes: The ON/OFF knob thru debugfs") Signed-off-by: Punit Agrawal <punitagrawal@gmail.com> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Chen Jun <chenjun102@huawei.com> Reviewed-by: Weilong Chen <chenweilong@huawei.com> Acked-by: Weilong Chen <chenweilong@huawei.com> Signed-off-by: Chen Jun <chenjun102@huawei.com> Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com> --- kernel/kprobes.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/kernel/kprobes.c b/kernel/kprobes.c index ae9354f2cf2e..036f4c4f177f 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -2946,13 +2946,12 @@ static const struct file_operations fops_kp = { static int __init debugfs_kprobe_init(void) { struct dentry *dir; - unsigned int value = 1; dir = debugfs_create_dir("kprobes", NULL); debugfs_create_file("list", 0400, dir, NULL, &kprobes_fops); - debugfs_create_file("enabled", 0600, dir, &value, &fops_kp); + debugfs_create_file("enabled", 0600, dir, NULL, &fops_kp); debugfs_create_file("blacklist", 0400, dir, NULL, &kprobe_blacklist_fops); -- 2.20.1