From: Daniel Scheller Date: Sun, 26 Nov 2017 13:00:04 +0000 (-0500) Subject: media: dvb-frontends/stv0910: WARN_ON() on consecutive mutex_unlock() X-Git-Tag: v4.16-rc1~57^2~281 X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=aea16005f4081a745c2178e6e4e5825c01a6226e;p=linux.git media: dvb-frontends/stv0910: WARN_ON() on consecutive mutex_unlock() Stack dump when gate_ctrl() is called in a way that consecutive unlocks happen. This is a clear indication that other drivers interfacing with the stv0910 driver don't do things properly or don't check for failures, so dump stack so that those drivers can be identified and fixed. Signed-off-by: Daniel Scheller Tested-by: Richard Scobie Signed-off-by: Mauro Carvalho Chehab --- diff --git a/drivers/media/dvb-frontends/stv0910.c b/drivers/media/dvb-frontends/stv0910.c index 73f6df0abbfe..4b7e901220e4 100644 --- a/drivers/media/dvb-frontends/stv0910.c +++ b/drivers/media/dvb-frontends/stv0910.c @@ -1241,7 +1241,8 @@ static int gate_ctrl(struct dvb_frontend *fe, int enable) if (write_reg(state, state->nr ? RSTV0910_P2_I2CRPT : RSTV0910_P1_I2CRPT, i2crpt) < 0) { /* don't hold the I2C bus lock on failure */ - mutex_unlock(&state->base->i2c_lock); + if (!WARN_ON(!mutex_is_locked(&state->base->i2c_lock))) + mutex_unlock(&state->base->i2c_lock); dev_err(&state->base->i2c->dev, "%s() write_reg failure (enable=%d)\n", __func__, enable); @@ -1251,7 +1252,8 @@ static int gate_ctrl(struct dvb_frontend *fe, int enable) state->i2crpt = i2crpt; if (!enable) - mutex_unlock(&state->base->i2c_lock); + if (!WARN_ON(!mutex_is_locked(&state->base->i2c_lock))) + mutex_unlock(&state->base->i2c_lock); return 0; }