On 02/19/2016 12:10 PM, Peter Rosin wrote:
Hi! I'm looking at this code in drivers/media/dvb-frontends/m88ds3103.c in the m88ds3103_set_frontend() function, line 600 (give or take): s32tmp = 0x10000 * (tuner_frequency - c->frequency); s32tmp = DIV_ROUND_CLOSEST(s32tmp, priv->mclk_khz); if (s32tmp < 0) s32tmp += 0x10000; There is code that tries to handle negative s32tmp, so I assume that negative s32tmp is a possibility. Further, priv->mclk_khz is an unsigned type as far as I can tell. But then we have this comment for the DIV_ROUND_CLOSEST macro: /* * Divide positive or negative dividend by positive divisor and round * to closest integer. Result is undefined for negative divisors and * for negative dividends if the divisor variable type is unsigned. */ #define DIV_ROUND_CLOSEST(x, divisor)( \ I don't know how bad this is, and what the consequences of garbage are, but from here it looks like a problem waiting to happen...
Divisor type (mclk) needs to be changed signed then somehow... regards Antti -- http://palosaari.fi/ -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
