Re: [PATCH] video: fbdev: mmp: Fix deferred clk handling in mmphw_probe()

[Dan Carpenter]

On Thu, Apr 13, 2023 at 09:33:17PM +0200, Christophe JAILLET wrote:
> When dev_err_probe() is called, 'ret' holds the value of the previous
> successful devm_request_irq() call.
> 'ret' should be assigned with a meaningful value before being used in
> dev_err_probe().
> 
> While at it, use and return "PTR_ERR(ctrl->clk)" instead of a hard-coded
> "-ENOENT" so that -EPROBE_DEFER is handled and propagated correctly.
> 
> Fixes: 81b63420564d ("video: fbdev: mmp: Make use of the helper function 
> dev_err_probe()")
> Signed-off-by: Christophe JAILLET <christophe.jail...@wanadoo.fr>
> ---

Presumably you already wrote a Coccinelle script for this but I've added
it to Smatch as well.

regards,
dan carpenter

diff --git a/check_zero_to_err_ptr.c b/check_zero_to_err_ptr.c
index 88ca0285948a..fa2a1f1603b2 100644
--- a/check_zero_to_err_ptr.c
+++ b/check_zero_to_err_ptr.c
@@ -157,11 +157,12 @@ static void match_err_ptr(const char *fn, struct 
expression *expr, void *data)
 {
        struct expression *arg_expr;
        struct sm_state *sm, *tmp;
+       int arg = PTR_INT(data);
 
        if (is_impossible_path())
                return;
 
-       arg_expr = get_argument_from_call_expr(expr->args, 0);
+       arg_expr = get_argument_from_call_expr(expr->args, arg);
        sm = get_sm_state_expr(SMATCH_EXTRA, arg_expr);
        if (!sm)
                return;
@@ -194,13 +195,36 @@ static void match_err_ptr(const char *fn, struct 
expression *expr, void *data)
        } END_FOR_EACH_PTR(tmp);
 }
 
+static void match_err_ptr_or_zero(const char *fn, struct expression *expr, 
void *data)
+{
+       struct expression *arg;
+       struct range_list *rl;
+       char *name;
+
+       if (is_impossible_path())
+               return;
+
+       arg = get_argument_from_call_expr(expr->args, 0);
+       get_absolute_rl(arg, &rl);
+
+       if (rl_intersection(rl, valid_ptr_rl))
+               return;
+
+       name = expr_to_str(arg);
+       sm_warning("'%s' is never a valid pointer", name);
+       free_string(name);
+}
+
 void check_zero_to_err_ptr(int id)
 {
        if (option_project != PROJ_KERNEL)
                return;
 
        my_id = id;
-       add_function_hook("ERR_PTR", &match_err_ptr, NULL);
-       add_function_hook("ERR_CAST", &match_err_ptr, NULL);
-       add_function_hook("PTR_ERR", &match_err_ptr, NULL);
+       add_function_hook("ERR_PTR", &match_err_ptr, INT_PTR(0));
+       add_function_hook("ERR_CAST", &match_err_ptr, INT_PTR(0));
+       add_function_hook("PTR_ERR", &match_err_ptr, INT_PTR(0));
+       add_function_hook("dev_err_probe", &match_err_ptr, INT_PTR(1));
+
+       add_function_hook("ERR_PTR_OR_ZERO", &match_err_ptr_or_zero, NULL);
 }