6.1-stable review patch. If anyone has any objections, please let me know.
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From: Jiri Slaby (SUSE) jirislaby@kernel.org
[ Upstream commit c180188ec02281126045414e90d08422a80f75b4 ]
Commit 7acf8a1e8a28 ("Replace 2 jiffies with sysctl netdev_budget_usecs to enable softirq tuning") added a possibility to set net_hotdata.netdev_budget_usecs, but added no lower bound checking.
Commit a4837980fd9f ("net: revert default NAPI poll timeout to 2 jiffies") made the *initial* value HZ-dependent, so the initial value is at least 2 jiffies even for lower HZ values (2 ms for 1000 Hz, 8ms for 250 Hz, 20 ms for 100 Hz).
But a user still can set improper values by a sysctl. Set .extra1 (the lower bound) for net_hotdata.netdev_budget_usecs to the same value as in the latter commit. That is to 2 jiffies.
Fixes: a4837980fd9f ("net: revert default NAPI poll timeout to 2 jiffies") Fixes: 7acf8a1e8a28 ("Replace 2 jiffies with sysctl netdev_budget_usecs to enable softirq tuning") Signed-off-by: Jiri Slaby (SUSE) jirislaby@kernel.org Cc: Dmitry Yakunin zeil@yandex-team.ru Cc: Konstantin Khlebnikov khlebnikov@yandex-team.ru Link: https://patch.msgid.link/20250220110752.137639-1-jirislaby@kernel.org Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/core/sysctl_net_core.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c index 47ca6d3ddbb56..75efc712bb9bc 100644 --- a/net/core/sysctl_net_core.c +++ b/net/core/sysctl_net_core.c @@ -30,6 +30,7 @@ static int min_sndbuf = SOCK_MIN_SNDBUF; static int min_rcvbuf = SOCK_MIN_RCVBUF; static int max_skb_frags = MAX_SKB_FRAGS; static int min_mem_pcpu_rsv = SK_MEMORY_PCPU_RESERVE; +static int netdev_budget_usecs_min = 2 * USEC_PER_SEC / HZ;
static int net_msg_warn; /* Unused, but still a sysctl */
@@ -554,7 +555,7 @@ static struct ctl_table net_core_table[] = { .maxlen = sizeof(unsigned int), .mode = 0644, .proc_handler = proc_dointvec_minmax, - .extra1 = SYSCTL_ZERO, + .extra1 = &netdev_budget_usecs_min, }, { .procname = "fb_tunnels_only_for_init_net",