| Message ID | 20240125191840.6740-1-jdamato@fastly.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net-next] net: print error if SO_BUSY_POLL_BUDGET is large | expand |
On Thu, Jan 25, 2024 at 8:18 PM Joe Damato <jdamato@fastly.com> wrote: > > When drivers call netif_napi_add_weight with a weight that is larger > than NAPI_POLL_WEIGHT, the networking code allows the larger weight, but > prints an error. > > Replicate this check for SO_BUSY_POLL_BUDGET; check if the user > specified amount exceeds NAPI_POLL_WEIGHT, allow it anyway, but print an > error. > > Signed-off-by: Joe Damato <jdamato@fastly.com> > --- > net/core/sock.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/net/core/sock.c b/net/core/sock.c > index 158dbdebce6a..ed243bd0dd77 100644 > --- a/net/core/sock.c > +++ b/net/core/sock.c > @@ -1153,6 +1153,9 @@ int sk_setsockopt(struct sock *sk, int level, int optname, > return -EPERM; > if (val < 0 || val > U16_MAX) > return -EINVAL; > + if (val > NAPI_POLL_WEIGHT) > + pr_err("SO_BUSY_POLL_BUDGET %u exceeds suggested maximum %u\n", val, > + NAPI_POLL_WEIGHT); > WRITE_ONCE(sk->sk_busy_poll_budget, val); > return 0; This is code run by privileged (CAP_NET_ADMIN) users, please do not spam the console with such a message. My point was : Do not allow an unpriv user to set an arbitrary value. netif_napi_add_weight() is used from kernel drivers, we network maintainers usually object if a driver attempts to use a big value, at code review time.
Hi Joe, On Thu, Jan 25, 2024 at 07:18:40PM +0000, Joe Damato wrote: > When drivers call netif_napi_add_weight with a weight that is larger > than NAPI_POLL_WEIGHT, the networking code allows the larger weight, but > prints an error. > > Replicate this check for SO_BUSY_POLL_BUDGET; check if the user > specified amount exceeds NAPI_POLL_WEIGHT, allow it anyway, but print an > error. > > Signed-off-by: Joe Damato <jdamato@fastly.com> > --- > net/core/sock.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/net/core/sock.c b/net/core/sock.c > index 158dbdebce6a..ed243bd0dd77 100644 > --- a/net/core/sock.c > +++ b/net/core/sock.c > @@ -1153,6 +1153,9 @@ int sk_setsockopt(struct sock *sk, int level, int optname, > return -EPERM; > if (val < 0 || val > U16_MAX) > return -EINVAL; > + if (val > NAPI_POLL_WEIGHT) > + pr_err("SO_BUSY_POLL_BUDGET %u exceeds suggested maximum %u\n", val, > + NAPI_POLL_WEIGHT); 'val' is a signed value variable. I suspect it will never be negative given the line above (val < 0 || val > U16_MAX), but, I am wondering if you should still print it as signed integer (%d) to keep it consistent.
diff --git a/net/core/sock.c b/net/core/sock.c index 158dbdebce6a..ed243bd0dd77 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -1153,6 +1153,9 @@ int sk_setsockopt(struct sock *sk, int level, int optname, return -EPERM; if (val < 0 || val > U16_MAX) return -EINVAL; + if (val > NAPI_POLL_WEIGHT) + pr_err("SO_BUSY_POLL_BUDGET %u exceeds suggested maximum %u\n", val, + NAPI_POLL_WEIGHT); WRITE_ONCE(sk->sk_busy_poll_budget, val); return 0; #endif
When drivers call netif_napi_add_weight with a weight that is larger than NAPI_POLL_WEIGHT, the networking code allows the larger weight, but prints an error. Replicate this check for SO_BUSY_POLL_BUDGET; check if the user specified amount exceeds NAPI_POLL_WEIGHT, allow it anyway, but print an error. Signed-off-by: Joe Damato <jdamato@fastly.com> --- net/core/sock.c | 3 +++ 1 file changed, 3 insertions(+)