On Fri, Jun 19, 2015 at 07:13:47AM +0000, Seymour, Shane M wrote: > With a size of 48 while it won't overflow since you're using snprintf the > string with a maximum value in %d: > > echo -n "cmd 2147483647 RESET FAILED, new lockup detected" |wc -c > 48
I actually just chose 48 because it was divisible by sizeof(long) on 64 bit. The compiler is going to pad it out a bit anyway because of alignment. > > is 48 characters long without a null terminator on the string (and in the > unlikely event that it's somehow a the largest possible negative value it > would be 49 characters after including the minus sign without a null > terminator). If you always want a complete message no matter what the value > formatted as %d will be I believe it needs to have a length of 50. The worst > that will happen now though because you're using snprintf is you'll drop the > trailing "d" or "ed" in the message with very large positive or negative > numbers. > > My somewhat sketchy memory of the hpsa driver is that the nr_cmds member of > the struct ctlr_info is never more than 1040 (?) anyway. If things are > working correctly I don't think it should ever happen but I thought I should > point out that msg isn't large enough to contain the complete contents of the > longest possible character string. My knowledge is sketchier than yours. When I was reading this I was thinking that instead of 1040 the upper limit was 32. I got that from hpsa_get_max_perf_mode_cmds(). The only negative number was -1, I think. But either way, we both agree that 48 is probably safe. regards, dan carpenter -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
