Commit 5aa7eea9 authored by Arnd Bergmann's avatar Arnd Bergmann Committed by Petr Mladek
Browse files

printk: avoid -Wsometimes-uninitialized warning 



clang notices that the pi_get_entry() function would use
uninitialized data if it was called with a non-NULL module
pointer on a kernel that does not support modules:

kernel/printk/index.c:32:6: error: variable 'nr_entries' is used uninitialized whenever 'if' condition is false [-Werror,-Wsometimes-uninitialized]
        if (!mod) {
            ^~~~
kernel/printk/index.c:38:13: note: uninitialized use occurs here
        if (pos >= nr_entries)
                   ^~~~~~~~~~
kernel/printk/index.c:32:2: note: remove the 'if' if its condition is always true
        if (!mod) {

Rework the condition to make it clear to the compiler that we are always
in the second case. Unfortunately the #ifdef is still required as the
definition of 'struct module' is hidden when modules are disabled.

Fixes: 33701557 ("printk: Userspace format indexing support")
Suggested-by: default avatarSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
Signed-off-by: default avatarPetr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20210928093456.2438109-1-arnd@kernel.org
parent 9980c425

kernel/printk/index.c

+2 −3
Original line number Diff line number Diff line
@@ -26,10 +26,9 @@ static struct pi_entry *pi_get_entry(const struct module *mod, loff_t pos) 
	if (mod) {

		entries = mod->printk_index_start;

		nr_entries = mod->printk_index_size;

	}

	} else

#endif



	if (!mod) {

	{

		/* vmlinux, comes from linker symbols */

		entries = __start_printk_index;

		nr_entries = __stop_printk_index - __start_printk_index;