[bug report] fprobe: Add exit_handler support

[Dan Carpenter <dan.carpenter@oracle.com>]

Hello Masami Hiramatsu,

The patch 5b0ab78998e3: "fprobe: Add exit_handler support" from Mar
15, 2022, leads to the following Smatch static checker warning:

	kernel/trace/fprobe.c:155 fprobe_init_rethook()
	warn: struct type mismatch 'rethook_node vs fprobe_rethook_node'

kernel/trace/fprobe.c
    134 static int fprobe_init_rethook(struct fprobe *fp, int num)
    135 {
    136         int i, size;
    137 
    138         if (num < 0)
    139                 return -EINVAL;
    140 
    141         if (!fp->exit_handler) {
    142                 fp->rethook = NULL;
    143                 return 0;
    144         }
    145 
    146         /* Initialize rethook if needed */
    147         size = num * num_possible_cpus() * 2;
    148         if (size < 0)
    149                 return -E2BIG;
    150 
    151         fp->rethook = rethook_alloc((void *)fp, fprobe_exit_handler);
    152         for (i = 0; i < size; i++) {
    153                 struct rethook_node *node;
    154 
--> 155                 node = kzalloc(sizeof(struct fprobe_rethook_node), GFP_KERNEL);

It's hard to tell if we're deliberately allocating a larger struct or
whether it's accidental.

    156                 if (!node) {
    157                         rethook_free(fp->rethook);
    158                         fp->rethook = NULL;
    159                         return -ENOMEM;
    160                 }
    161                 rethook_add_node(fp->rethook, node);
    162         }
    163         return 0;
    164 }

regards,
dan carpenter