Re: [PATCH] [media] stv090x: do not unlock unheld mutex in stv090x_sleep()
On 02/20/2013 10:58 AM, Manu Abraham wrote: > Hi, > > On Wed, Feb 20, 2013 at 12:28 AM, Alexey Khoroshilov > wrote: >> goto err and goto err_gateoff before mutex_lock(>internal->demod_lock) >> lead to unlock of unheld mutex in stv090x_sleep(). > Out of curiosity, what happens when you try to unlock an unlocked mutex ? > > Regards, > Manu > Bad things can happen if someone else holds the mutex and it becomes unexpectedly unlocked. Also it can result that the next lock() operation leaves the mutex in unlocked state. The both cases can lead to data races with unpredictable consequences. -- Alexey Khoroshilov -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] [media] stv090x: do not unlock unheld mutex in stv090x_sleep()
On 02/20/2013 10:58 AM, Manu Abraham wrote: Hi, On Wed, Feb 20, 2013 at 12:28 AM, Alexey Khoroshilov khoroshi...@ispras.ru wrote: goto err and goto err_gateoff before mutex_lock(state-internal-demod_lock) lead to unlock of unheld mutex in stv090x_sleep(). Out of curiosity, what happens when you try to unlock an unlocked mutex ? Regards, Manu Bad things can happen if someone else holds the mutex and it becomes unexpectedly unlocked. Also it can result that the next lock() operation leaves the mutex in unlocked state. The both cases can lead to data races with unpredictable consequences. -- Alexey Khoroshilov -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] [media] stv090x: do not unlock unheld mutex in stv090x_sleep()
Hi, On Wed, Feb 20, 2013 at 12:28 AM, Alexey Khoroshilov wrote: > goto err and goto err_gateoff before mutex_lock(>internal->demod_lock) > lead to unlock of unheld mutex in stv090x_sleep(). Out of curiosity, what happens when you try to unlock an unlocked mutex ? Regards, Manu -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[PATCH] [media] stv090x: do not unlock unheld mutex in stv090x_sleep()
goto err and goto err_gateoff before mutex_lock(>internal->demod_lock) lead to unlock of unheld mutex in stv090x_sleep(). Found by Linux Driver Verification project (linuxtesting.org). Signed-off-by: Alexey Khoroshilov --- drivers/media/dvb-frontends/stv090x.c | 22 -- 1 file changed, 12 insertions(+), 10 deletions(-) diff --git a/drivers/media/dvb-frontends/stv090x.c b/drivers/media/dvb-frontends/stv090x.c index 13caec0..4f600ac 100644 --- a/drivers/media/dvb-frontends/stv090x.c +++ b/drivers/media/dvb-frontends/stv090x.c @@ -3906,12 +3906,12 @@ static int stv090x_sleep(struct dvb_frontend *fe) reg = stv090x_read_reg(state, STV090x_TSTTNR1); STV090x_SETFIELD(reg, ADC1_PON_FIELD, 0); if (stv090x_write_reg(state, STV090x_TSTTNR1, reg) < 0) - goto err; + goto err_unlock; /* power off DiSEqC 1 */ reg = stv090x_read_reg(state, STV090x_TSTTNR2); STV090x_SETFIELD(reg, DISEQC1_PON_FIELD, 0); if (stv090x_write_reg(state, STV090x_TSTTNR2, reg) < 0) - goto err; + goto err_unlock; /* check whether path 2 is already sleeping, that is when ADC2 is off */ @@ -3930,7 +3930,7 @@ static int stv090x_sleep(struct dvb_frontend *fe) if (full_standby) STV090x_SETFIELD(reg, STOP_CLKFEC_FIELD, 1); if (stv090x_write_reg(state, STV090x_STOPCLK1, reg) < 0) - goto err; + goto err_unlock; reg = stv090x_read_reg(state, STV090x_STOPCLK2); /* sampling 1 clock */ STV090x_SETFIELD(reg, STOP_CLKSAMP1_FIELD, 1); @@ -3941,7 +3941,7 @@ static int stv090x_sleep(struct dvb_frontend *fe) if (full_standby) STV090x_SETFIELD(reg, STOP_CLKTS_FIELD, 1); if (stv090x_write_reg(state, STV090x_STOPCLK2, reg) < 0) - goto err; + goto err_unlock; break; case STV090x_DEMODULATOR_1: @@ -3949,12 +3949,12 @@ static int stv090x_sleep(struct dvb_frontend *fe) reg = stv090x_read_reg(state, STV090x_TSTTNR3); STV090x_SETFIELD(reg, ADC2_PON_FIELD, 0); if (stv090x_write_reg(state, STV090x_TSTTNR3, reg) < 0) - goto err; + goto err_unlock; /* power off DiSEqC 2 */ reg = stv090x_read_reg(state, STV090x_TSTTNR4); STV090x_SETFIELD(reg, DISEQC2_PON_FIELD, 0); if (stv090x_write_reg(state, STV090x_TSTTNR4, reg) < 0) - goto err; + goto err_unlock; /* check whether path 1 is already sleeping, that is when ADC1 is off */ @@ -3973,7 +3973,7 @@ static int stv090x_sleep(struct dvb_frontend *fe) if (full_standby) STV090x_SETFIELD(reg, STOP_CLKFEC_FIELD, 1); if (stv090x_write_reg(state, STV090x_STOPCLK1, reg) < 0) - goto err; + goto err_unlock; reg = stv090x_read_reg(state, STV090x_STOPCLK2); /* sampling 2 clock */ STV090x_SETFIELD(reg, STOP_CLKSAMP2_FIELD, 1); @@ -3984,7 +3984,7 @@ static int stv090x_sleep(struct dvb_frontend *fe) if (full_standby) STV090x_SETFIELD(reg, STOP_CLKTS_FIELD, 1); if (stv090x_write_reg(state, STV090x_STOPCLK2, reg) < 0) - goto err; + goto err_unlock; break; default: @@ -3997,7 +3997,7 @@ static int stv090x_sleep(struct dvb_frontend *fe) reg = stv090x_read_reg(state, STV090x_SYNTCTRL); STV090x_SETFIELD(reg, STANDBY_FIELD, 0x01); if (stv090x_write_reg(state, STV090x_SYNTCTRL, reg) < 0) - goto err; + goto err_unlock; } mutex_unlock(>internal->demod_lock); @@ -4005,8 +4005,10 @@ static int stv090x_sleep(struct dvb_frontend *fe) err_gateoff: stv090x_i2c_gate_ctrl(state, 0); -err: + goto err; +err_unlock: mutex_unlock(>internal->demod_lock); +err: dprintk(FE_ERROR, 1, "I/O error"); return -1; } -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[PATCH] [media] stv090x: do not unlock unheld mutex in stv090x_sleep()
goto err and goto err_gateoff before mutex_lock(state-internal-demod_lock) lead to unlock of unheld mutex in stv090x_sleep(). Found by Linux Driver Verification project (linuxtesting.org). Signed-off-by: Alexey Khoroshilov khoroshi...@ispras.ru --- drivers/media/dvb-frontends/stv090x.c | 22 -- 1 file changed, 12 insertions(+), 10 deletions(-) diff --git a/drivers/media/dvb-frontends/stv090x.c b/drivers/media/dvb-frontends/stv090x.c index 13caec0..4f600ac 100644 --- a/drivers/media/dvb-frontends/stv090x.c +++ b/drivers/media/dvb-frontends/stv090x.c @@ -3906,12 +3906,12 @@ static int stv090x_sleep(struct dvb_frontend *fe) reg = stv090x_read_reg(state, STV090x_TSTTNR1); STV090x_SETFIELD(reg, ADC1_PON_FIELD, 0); if (stv090x_write_reg(state, STV090x_TSTTNR1, reg) 0) - goto err; + goto err_unlock; /* power off DiSEqC 1 */ reg = stv090x_read_reg(state, STV090x_TSTTNR2); STV090x_SETFIELD(reg, DISEQC1_PON_FIELD, 0); if (stv090x_write_reg(state, STV090x_TSTTNR2, reg) 0) - goto err; + goto err_unlock; /* check whether path 2 is already sleeping, that is when ADC2 is off */ @@ -3930,7 +3930,7 @@ static int stv090x_sleep(struct dvb_frontend *fe) if (full_standby) STV090x_SETFIELD(reg, STOP_CLKFEC_FIELD, 1); if (stv090x_write_reg(state, STV090x_STOPCLK1, reg) 0) - goto err; + goto err_unlock; reg = stv090x_read_reg(state, STV090x_STOPCLK2); /* sampling 1 clock */ STV090x_SETFIELD(reg, STOP_CLKSAMP1_FIELD, 1); @@ -3941,7 +3941,7 @@ static int stv090x_sleep(struct dvb_frontend *fe) if (full_standby) STV090x_SETFIELD(reg, STOP_CLKTS_FIELD, 1); if (stv090x_write_reg(state, STV090x_STOPCLK2, reg) 0) - goto err; + goto err_unlock; break; case STV090x_DEMODULATOR_1: @@ -3949,12 +3949,12 @@ static int stv090x_sleep(struct dvb_frontend *fe) reg = stv090x_read_reg(state, STV090x_TSTTNR3); STV090x_SETFIELD(reg, ADC2_PON_FIELD, 0); if (stv090x_write_reg(state, STV090x_TSTTNR3, reg) 0) - goto err; + goto err_unlock; /* power off DiSEqC 2 */ reg = stv090x_read_reg(state, STV090x_TSTTNR4); STV090x_SETFIELD(reg, DISEQC2_PON_FIELD, 0); if (stv090x_write_reg(state, STV090x_TSTTNR4, reg) 0) - goto err; + goto err_unlock; /* check whether path 1 is already sleeping, that is when ADC1 is off */ @@ -3973,7 +3973,7 @@ static int stv090x_sleep(struct dvb_frontend *fe) if (full_standby) STV090x_SETFIELD(reg, STOP_CLKFEC_FIELD, 1); if (stv090x_write_reg(state, STV090x_STOPCLK1, reg) 0) - goto err; + goto err_unlock; reg = stv090x_read_reg(state, STV090x_STOPCLK2); /* sampling 2 clock */ STV090x_SETFIELD(reg, STOP_CLKSAMP2_FIELD, 1); @@ -3984,7 +3984,7 @@ static int stv090x_sleep(struct dvb_frontend *fe) if (full_standby) STV090x_SETFIELD(reg, STOP_CLKTS_FIELD, 1); if (stv090x_write_reg(state, STV090x_STOPCLK2, reg) 0) - goto err; + goto err_unlock; break; default: @@ -3997,7 +3997,7 @@ static int stv090x_sleep(struct dvb_frontend *fe) reg = stv090x_read_reg(state, STV090x_SYNTCTRL); STV090x_SETFIELD(reg, STANDBY_FIELD, 0x01); if (stv090x_write_reg(state, STV090x_SYNTCTRL, reg) 0) - goto err; + goto err_unlock; } mutex_unlock(state-internal-demod_lock); @@ -4005,8 +4005,10 @@ static int stv090x_sleep(struct dvb_frontend *fe) err_gateoff: stv090x_i2c_gate_ctrl(state, 0); -err: + goto err; +err_unlock: mutex_unlock(state-internal-demod_lock); +err: dprintk(FE_ERROR, 1, I/O error); return -1; } -- 1.7.9.5 -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] [media] stv090x: do not unlock unheld mutex in stv090x_sleep()
Hi, On Wed, Feb 20, 2013 at 12:28 AM, Alexey Khoroshilov khoroshi...@ispras.ru wrote: goto err and goto err_gateoff before mutex_lock(state-internal-demod_lock) lead to unlock of unheld mutex in stv090x_sleep(). Out of curiosity, what happens when you try to unlock an unlocked mutex ? Regards, Manu -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
