Hello Jia-Ju Bai,
The patch b9302fa7ed97: "media: tuners: fix error return code of
hybrid_tuner_request_state()" from Mar 6, 2021, leads to the
following static checker warnings:
drivers/media/tuners/tuner-simple.c:1112 simple_tuner_attach() error: potential null dereference 'priv'. (<unknown> returns null)
drivers/media/tuners/mxl5007t.c:885 mxl5007t_attach() error: potential null dereference 'state'. (<unknown> returns null)
drivers/media/tuners/tda18271-fe.c:1311 tda18271_attach() error: potential null dereference 'priv'. (<unknown> returns null)
drivers/media/tuners/xc4000.c:1685 xc4000_attach() error: potential null dereference 'priv'. (<unknown> returns null)
drivers/media/tuners/xc4000.c:1699 xc4000_attach() error: potential null dereference 'priv'. (<unknown> returns null)
drivers/media/tuners/xc5000.c:1397 xc5000_attach() error: potential null dereference 'priv'. (<unknown> returns null)
drivers/media/tuners/r820t.c:2350 r820t_attach() error: potential null dereference 'priv'. (<unknown> returns null)
drivers/media/tuners/tuner-xc2028.c:1500 xc2028_attach() error: potential null dereference 'priv'. (<unknown> returns null)
drivers/media/tuners/tuner-i2c.h
109 /* The return value of hybrid_tuner_request_state indicates the number of
110 * instances using this tuner object.
111 *
112 * 0 - no instances, indicates an error - kzalloc must have failed
The comment says that hybrid_tuner_request_state() returns an error.
113 *
114 * 1 - one instance, indicates that the tuner object was created successfully
115 *
116 * 2 (or more) instances, indicates that an existing tuner object was found
117 */
118
119 #define hybrid_tuner_request_state(type, state, list, i2cadap, i2caddr, devname)\
120 ({ \
121 int __ret = 0; \
122 list_for_each_entry(state, &list, hybrid_tuner_instance_list) { \
123 if (((i2cadap) && (state->i2c_props.adap)) && \
124 ((i2c_adapter_id(state->i2c_props.adap) == \
125 i2c_adapter_id(i2cadap)) && \
126 (i2caddr == state->i2c_props.addr))) { \
127 __tuner_info(state->i2c_props, \
128 "attaching existing instance\n"); \
129 state->i2c_props.count++; \
130 __ret = state->i2c_props.count; \
131 break; \
132 } \
133 } \
134 if (0 == __ret) { \
135 state = kzalloc(sizeof(type), GFP_KERNEL); \
136 if (!state) { \
137 __ret = -ENOMEM; \
138 goto __fail; \
But the patch changes the code to return -ENOMEM on error. The callers
need to be updated or it intruces a bunch of potential NULL
dereferences.
139 } \
140 state->i2c_props.addr = i2caddr; \
141 state->i2c_props.adap = i2cadap; \
142 state->i2c_props.name = devname; \
143 __tuner_info(state->i2c_props, \
144 "creating new instance\n"); \
145 list_add_tail(&state->hybrid_tuner_instance_list, &list);\
146 state->i2c_props.count++; \
147 __ret = state->i2c_props.count; \
148 } \
149 __fail: \
150 __ret; \
151 })
regards,
dan carpenter
