2015-01-23 18:42 GMT+09:00 Johannes Berg <johannes@xxxxxxxxxxxxxxxx>: > Ok - but that doesn't really disable the timer? Perhaps we should have a > new userspace API to explicitly disable it? OTOH, worst case I guess > that means it's like >100 years in the future, so I guess it doesn't > matter. However, though, you can hardly rely on this fix being present > in the kernel, so you can't really set such a large value > unconditionally anyway, no? Otherwise a newer wpa_supplicant running on > an older kernel would suddenly behave incorrectly. That doesn't seem > right. > > Having an explicit feature to disable plink timeout would perhaps be > better? Thank you for your review. On my environment, HZ macro is 250. So jiffies counts up 250 per seconds. So jiffies overflows in 199 days. It is a large value still. But on my arm64 environment, jiffies could over the u32 max value. Because it looks starts with about 0xffff0000. So I need this patch. On the i386 environment, it does not occur. > I'm not convinced this is right. For one, I believe on 32-bit machines > you'll need to write "0x100000000ULL" instead of the plain constant. > Perhaps preferably, you'd use use ">= MAX_UINT". I have written such a code "0x100000000ULL" few years ago. But now, "0x100000000" works. I re-tested on 64bit. Anyway I think using "MAX_UINT" is better. > However, the argument to ieee80211_sta_expire() is an unsigned long (as > is jiffies), so on 64-bit machines you could even still use the value > and the conditional isn't needed. Yes, this is a code for 32bit machine. > Given these complications, I would prefer having a feature attribute to > treat e.g. 0 as disabling the timer entirely, and if this feature isn't > present then have wpa_supplicant instead use a safe value that doesn't > trigger the kernel bug - e.g. 0xffffffff/1000 [which is the max possible > HZ]. Looks fine. I will modify this patch. -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
