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Subject[PATCH 2/2] [media] dib9000: implement error handling for DibAcquireLock
Date
DibAcquireLock() is implemented as mutex_lock_interruptible() 
but the driver does not handle unsuccessful locking.
As a result it may lead to unlock of an unheld mutex.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
---
drivers/media/dvb/frontends/dib9000.c | 115 ++++++++++++++++++++++++++-------
1 files changed, 91 insertions(+), 24 deletions(-)

diff --git a/drivers/media/dvb/frontends/dib9000.c b/drivers/media/dvb/frontends/dib9000.c
index d96b6a1..80848b4 100644
--- a/drivers/media/dvb/frontends/dib9000.c
+++ b/drivers/media/dvb/frontends/dib9000.c
@@ -33,7 +33,7 @@ struct i2c_device {

/* lock */
#define DIB_LOCK struct mutex
-#define DibAcquireLock(lock) do { if (mutex_lock_interruptible(lock) < 0) dprintk("could not get the lock"); } while (0)
+#define DibAcquireLock(lock) mutex_lock_interruptible(lock)
#define DibReleaseLock(lock) mutex_unlock(lock)
#define DibInitLock(lock) mutex_init(lock)
#define DibFreeLock(lock)
@@ -446,7 +446,10 @@ static int dib9000_risc_mem_read(struct dib9000_state *state, u8 cmd, u8 * b, u1
if (!state->platform.risc.fw_is_running)
return -EIO;

- DibAcquireLock(&state->platform.risc.mem_lock);
+ if (DibAcquireLock(&state->platform.risc.mem_lock) < 0) {
+ dprintk("could not get the lock");
+ return -EINTR;
+ }
dib9000_risc_mem_setup(state, cmd | 0x80);
dib9000_risc_mem_read_chunks(state, b, len);
DibReleaseLock(&state->platform.risc.mem_lock);
@@ -459,7 +462,10 @@ static int dib9000_risc_mem_write(struct dib9000_state *state, u8 cmd, const u8
if (!state->platform.risc.fw_is_running)
return -EIO;

- DibAcquireLock(&state->platform.risc.mem_lock);
+ if (DibAcquireLock(&state->platform.risc.mem_lock) < 0) {
+ dprintk("could not get the lock");
+ return -EINTR;
+ }
dib9000_risc_mem_setup(state, cmd);
dib9000_risc_mem_write_chunks(state, b, m->size);
DibReleaseLock(&state->platform.risc.mem_lock);
@@ -531,7 +537,10 @@ static int dib9000_mbx_send_attr(struct dib9000_state *state, u8 id, u16 * data,
if (!state->platform.risc.fw_is_running)
return -EINVAL;

- DibAcquireLock(&state->platform.risc.mbx_if_lock);
+ if (DibAcquireLock(&state->platform.risc.mbx_if_lock) < 0) {
+ dprintk("could not get the lock");
+ return -EINTR;
+ }
tmp = MAX_MAILBOX_TRY;
do {
size = dib9000_read_word_attr(state, 1043, attr) & 0xff;
@@ -593,7 +602,10 @@ static u8 dib9000_mbx_read(struct dib9000_state *state, u16 * data, u8 risc_id,
if (!state->platform.risc.fw_is_running)
return 0;

- DibAcquireLock(&state->platform.risc.mbx_if_lock);
+ if (DibAcquireLock(&state->platform.risc.mbx_if_lock) < 0) {
+ dprintk("could not get the lock");
+ return 0;
+ }
if (risc_id == 1)
mc_base = 16;
else
@@ -701,7 +713,10 @@ static int dib9000_mbx_process(struct dib9000_state *state, u16 attr)
if (!state->platform.risc.fw_is_running)
return -1;

- DibAcquireLock(&state->platform.risc.mbx_lock);
+ if (DibAcquireLock(&state->platform.risc.mbx_lock) < 0) {
+ dprintk("could not get the lock");
+ return -1;
+ }

if (dib9000_mbx_count(state, 1, attr)) /* 1=RiscB */
ret = dib9000_mbx_fetch_to_cache(state, attr);
@@ -1178,7 +1193,10 @@ static int dib9000_fw_get_channel(struct dvb_frontend *fe)
struct dibDVBTChannel *ch;
int ret = 0;

- DibAcquireLock(&state->platform.risc.mem_mbx_lock);
+ if (DibAcquireLock(&state->platform.risc.mem_mbx_lock) < 0) {
+ dprintk("could not get the lock");
+ return -EINTR;
+ }
if (dib9000_fw_memmbx_sync(state, FE_SYNC_CHANNEL) < 0) {
ret = -EIO;
goto error;
@@ -1660,7 +1678,10 @@ static int dib9000_fw_component_bus_xfer(struct i2c_adapter *i2c_adap, struct i2
p[12] = 0;
}

- DibAcquireLock(&state->platform.risc.mem_mbx_lock);
+ if (DibAcquireLock(&state->platform.risc.mem_mbx_lock) < 0) {
+ dprintk("could not get the lock");
+ return 0;
+ }

dib9000_risc_mem_write(state, FE_MM_W_COMPONENT_ACCESS, p);

@@ -1768,7 +1789,10 @@ int dib9000_fw_pid_filter_ctrl(struct dvb_frontend *fe, u8 onoff)
return 0;
}

- DibAcquireLock(&state->demod_lock);
+ if (DibAcquireLock(&state->demod_lock) < 0) {
+ dprintk("could not get the lock");
+ return -EINTR;
+ }

val = dib9000_read_word(state, 294 + 1) & 0xffef;
val |= (onoff & 0x1) << 4;
@@ -1800,7 +1824,10 @@ int dib9000_fw_pid_filter(struct dvb_frontend *fe, u8 id, u16 pid, u8 onoff)
return 0;
}

- DibAcquireLock(&state->demod_lock);
+ if (DibAcquireLock(&state->demod_lock) < 0) {
+ dprintk("could not get the lock");
+ return -EINTR;
+ }
dprintk("Index %x, PID %d, OnOff %d", id, pid, onoff);
ret = dib9000_write_word(state, 300 + 1 + id,
onoff ? (1 << 13) | pid : 0);
@@ -1848,7 +1875,10 @@ static int dib9000_sleep(struct dvb_frontend *fe)
u8 index_frontend;
int ret = 0;

- DibAcquireLock(&state->demod_lock);
+ if (DibAcquireLock(&state->demod_lock) < 0) {
+ dprintk("could not get the lock");
+ return -EINTR;
+ }
for (index_frontend = 1; (index_frontend < MAX_NUMBER_OF_FRONTENDS) && (state->fe[index_frontend] != NULL); index_frontend++) {
ret = state->fe[index_frontend]->ops.sleep(state->fe[index_frontend]);
if (ret < 0)
@@ -1874,8 +1904,12 @@ static int dib9000_get_frontend(struct dvb_frontend *fe)
fe_status_t stat;
int ret = 0;

- if (state->get_frontend_internal == 0)
- DibAcquireLock(&state->demod_lock);
+ if (state->get_frontend_internal == 0) {
+ if (DibAcquireLock(&state->demod_lock) < 0) {
+ dprintk("could not get the lock");
+ return -EINTR;
+ }
+ }

for (index_frontend = 1; (index_frontend < MAX_NUMBER_OF_FRONTENDS) && (state->fe[index_frontend] != NULL); index_frontend++) {
state->fe[index_frontend]->ops.read_status(state->fe[index_frontend], &stat);
@@ -1978,7 +2012,10 @@ static int dib9000_set_frontend(struct dvb_frontend *fe)
}

state->pid_ctrl_index = -1; /* postpone the pid filtering cmd */
- DibAcquireLock(&state->demod_lock);
+ if (DibAcquireLock(&state->demod_lock) < 0) {
+ dprintk("could not get the lock");
+ return 0;
+ }

fe->dtv_property_cache.delivery_system = SYS_DVBT;

@@ -2138,7 +2175,10 @@ static int dib9000_read_status(struct dvb_frontend *fe, fe_status_t * stat)
u8 index_frontend;
u16 lock = 0, lock_slave = 0;

- DibAcquireLock(&state->demod_lock);
+ if (DibAcquireLock(&state->demod_lock) < 0) {
+ dprintk("could not get the lock");
+ return -EINTR;
+ }
for (index_frontend = 1; (index_frontend < MAX_NUMBER_OF_FRONTENDS) && (state->fe[index_frontend] != NULL); index_frontend++)
lock_slave |= dib9000_read_lock(state->fe[index_frontend]);

@@ -2168,8 +2208,15 @@ static int dib9000_read_ber(struct dvb_frontend *fe, u32 * ber)
u16 *c;
int ret = 0;

- DibAcquireLock(&state->demod_lock);
- DibAcquireLock(&state->platform.risc.mem_mbx_lock);
+ if (DibAcquireLock(&state->demod_lock) < 0) {
+ dprintk("could not get the lock");
+ return -EINTR;
+ }
+ if (DibAcquireLock(&state->platform.risc.mem_mbx_lock) < 0) {
+ dprintk("could not get the lock");
+ ret = -EINTR;
+ goto error;
+ }
if (dib9000_fw_memmbx_sync(state, FE_SYNC_CHANNEL) < 0) {
DibReleaseLock(&state->platform.risc.mem_mbx_lock);
ret = -EIO;
@@ -2196,7 +2243,10 @@ static int dib9000_read_signal_strength(struct dvb_frontend *fe, u16 * strength)
u16 val;
int ret = 0;

- DibAcquireLock(&state->demod_lock);
+ if (DibAcquireLock(&state->demod_lock) < 0) {
+ dprintk("could not get the lock");
+ return -EINTR;
+ }
*strength = 0;
for (index_frontend = 1; (index_frontend < MAX_NUMBER_OF_FRONTENDS) && (state->fe[index_frontend] != NULL); index_frontend++) {
state->fe[index_frontend]->ops.read_signal_strength(state->fe[index_frontend], &val);
@@ -2206,7 +2256,11 @@ static int dib9000_read_signal_strength(struct dvb_frontend *fe, u16 * strength)
*strength += val;
}

- DibAcquireLock(&state->platform.risc.mem_mbx_lock);
+ if (DibAcquireLock(&state->platform.risc.mem_mbx_lock) < 0) {
+ dprintk("could not get the lock");
+ ret = -EINTR;
+ goto error;
+ }
if (dib9000_fw_memmbx_sync(state, FE_SYNC_CHANNEL) < 0) {
DibReleaseLock(&state->platform.risc.mem_mbx_lock);
ret = -EIO;
@@ -2233,10 +2287,13 @@ static u32 dib9000_get_snr(struct dvb_frontend *fe)
u32 n, s, exp;
u16 val;

- DibAcquireLock(&state->platform.risc.mem_mbx_lock);
+ if (DibAcquireLock(&state->platform.risc.mem_mbx_lock) < 0) {
+ dprintk("could not get the lock");
+ return 0;
+ }
if (dib9000_fw_memmbx_sync(state, FE_SYNC_CHANNEL) < 0) {
DibReleaseLock(&state->platform.risc.mem_mbx_lock);
- return -EIO;
+ return 0;
}
dib9000_risc_mem_read(state, FE_MM_R_FE_MONITOR, (u8 *) c, 16 * 2);
DibReleaseLock(&state->platform.risc.mem_mbx_lock);
@@ -2269,7 +2326,10 @@ static int dib9000_read_snr(struct dvb_frontend *fe, u16 * snr)
u8 index_frontend;
u32 snr_master;

- DibAcquireLock(&state->demod_lock);
+ if (DibAcquireLock(&state->demod_lock) < 0) {
+ dprintk("could not get the lock");
+ return -EINTR;
+ }
snr_master = dib9000_get_snr(fe);
for (index_frontend = 1; (index_frontend < MAX_NUMBER_OF_FRONTENDS) && (state->fe[index_frontend] != NULL); index_frontend++)
snr_master += dib9000_get_snr(state->fe[index_frontend]);
@@ -2291,8 +2351,15 @@ static int dib9000_read_unc_blocks(struct dvb_frontend *fe, u32 * unc)
u16 *c = (u16 *)state->i2c_read_buffer;
int ret = 0;

- DibAcquireLock(&state->demod_lock);
- DibAcquireLock(&state->platform.risc.mem_mbx_lock);
+ if (DibAcquireLock(&state->demod_lock) < 0) {
+ dprintk("could not get the lock");
+ return -EINTR;
+ }
+ if (DibAcquireLock(&state->platform.risc.mem_mbx_lock) < 0) {
+ dprintk("could not get the lock");
+ ret = -EINTR;
+ goto error;
+ }
if (dib9000_fw_memmbx_sync(state, FE_SYNC_CHANNEL) < 0) {
DibReleaseLock(&state->platform.risc.mem_mbx_lock);
ret = -EIO;
--
1.7.4.1


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