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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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