param: make sure charp isn't used as a core_param
RFC 3/8 param: make sure charp isn't used as a core_param
"charp" sets a variable to point to a char string in a command line. This doesn't work if the command line isn't going to stick around. Add a compile-breaking check for this case, and make a note of it.
Signed-off-by Rusty Russell <[email protected]>
--- include/linux/moduleparam.h | 3 +++ kernel/params.c | 7 +++++++ 2 files changed, 10 insertions(+)
include/linux/moduleparam.h +15 -1
@@ -118,11 +118,15 @@ struct kparam_array* early in boot. This is for compatibility with __setup(), and it * makes sense as truly core parameters aren't tied to the particular * file they're in. +* +* Note: You can't use 'charp' here (which keeps a pointer into our +* tmp cmdline). */ #define core_param (name, var, type, perm) \ param_check_##type(name, &(var)); \ __module_param_call("", "__core_param", name, param_set_##type, \ - param_get_##type, &var, perm) + param_get_##type, &var, perm \ + + BUILD_BUG_ON_ZERO(param_##type##_keeps_reference))#endif /* !MODULE */ /* Actually copy string: maxlen param is usually sizeof(string). */
@@ -150,42 +154,52 @@ extern int param_set_byte(const char *vaextern int param_set_byte (const char *val,struct kernel_param *kp);extern int param_get_byte (char *buffer,struct kernel_param *kp);#define param_check_byte (name, p) __param_check(name, p, unsigned char) +#define param_byte_keeps_reference 0extern int param_set_short (const char *val,struct kernel_param *kp);extern int param_get_short (char *buffer,struct kernel_param *kp);#define param_check_short (name, p) __param_check(name, p, short) +#define param_short_keeps_reference 0extern int param_set_ushort (const char *val,struct kernel_param *kp);extern int param_get_ushort (char *buffer,struct kernel_param *kp);#define param_check_ushort (name, p) __param_check(name, p, unsigned short) +#define param_ushort_keeps_reference 0extern int param_set_int (const char *val,struct kernel_param *kp);extern int param_get_int (char *buffer,struct kernel_param *kp);#define param_check_int (name, p) __param_check(name, p, int) +#define param_int_keeps_reference 0extern int param_set_uint (const char *val,struct kernel_param *kp);extern int param_get_uint (char *buffer,struct kernel_param *kp);#define param_check_uint (name, p) __param_check(name, p, unsigned int) +#define param_uint_keeps_reference 0extern int param_set_long (const char *val,struct kernel_param *kp);extern int param_get_long (char *buffer,struct kernel_param *kp);#define param_check_long (name, p) __param_check(name, p, long) +#define param_long_keeps_reference 0extern int param_set_ulong (const char *val,struct kernel_param *kp);extern int param_get_ulong (char *buffer,struct kernel_param *kp);#define param_check_ulong (name, p) __param_check(name, p, unsigned long) +#define param_ulong_keeps_reference 0extern int param_set_charp (const char *val,struct kernel_param *kp);extern int param_get_charp (char *buffer,struct kernel_param *kp);#define param_check_charp (name, p) __param_check(name, p, char *) +#define param_charp_keeps_reference 1extern int param_set_bool (const char *val,struct kernel_param *kp);extern int param_get_bool (char *buffer,struct kernel_param *kp);#define param_check_bool (name, p) __param_check(name, p, int) +#define param_bool_keeps_reference 0extern int param_set_invbool (const char *val,struct kernel_param *kp);extern int param_get_invbool (char *buffer,struct kernel_param *kp);#define param_check_invbool (name, p) __param_check(name, p, int) +#define param_invbool_keeps_reference 0/* Comma-separated array: *nump is set to number they actually specified. */ #define module_param_array_named (name, array, type, nump, perm) \