friendly ping ... On 2019/6/4 23:27, Zhiqiang Liu wrote: >> On Wed, May 15, 2019 at 10:53:55PM +0800, Zhiqiang Liu wrote: >> >> (Please include akpm on CC for next versions of this, as he's likely >> the person to take this patch.) > Thanks for your advice. And sorry to reply you so late. > >>>>> In proc_dointvec_jiffies func, the write value is only checked >>>>> whether it is larger than INT_MAX. If the write value is less >>>>> than zero, it can also be successfully writen in the data. >> >> This appears to be "be design", but I see many "unsigned int" users >> that might be tricked into giant values... (for example, see >> net/netfilter/nf_conntrack_standalone.c) >> >> Should proc_dointvec_jiffies() just be fixed to disallow negative values >> entirely? Looking at the implementation, it seems to be very intentional >> about accepting negative values. >> >> However, when I looked through a handful of proc_dointvec_jiffies() >> users, it looks like they're all expecting a positive value. Many in the >> networking subsystem are, in fact, writing to unsigned long variables, >> as I mentioned. >> > I totally agree with you. And I also cannot find an scenario that expects > negative values. Consideing the "negative" scenario may be exist, I add the > proc_dointvec_jiffies_minmax like proc_dointvec_minmax. > >> Are there real-world cases of wanting to set a negative jiffie value >> via proc_dointvec_jiffies()? > Until now, I do not find such cases. > >>>>> >>>>> Here, we add a new func, proc_dointvec_jiffies_minmax, to limit the >>>>> min/max write value, which is similar to the proc_dointvec_minmax func. >>>>> >> >> If proc_dointvec_jiffies() can't just be fixed, where will the new >> function get used? It seems all the "unsigned int" users could benefit. >> > I tend to add the proc_dointvec_jiffies_minmax func to provide more choices and > not change the previous use of proc_dointvec_jiffies func. > > Thanks for your reply again. > > > . >
