Commit de9b7586 authored May 12, 2025 by Sebastian Andrzej Siewior Committed by Greg Kroah-Hartman Jun 27, 2025

ipv4/route: Use this_cpu_inc() for stats on PREEMPT_RT



[ Upstream commit 1c0829788a6e6e165846b9bedd0b908ef16260b6 ]

The statistics are incremented with raw_cpu_inc() assuming it always
happens with bottom half disabled. Without per-CPU locking in
local_bh_disable() on PREEMPT_RT this is no longer true.

Use this_cpu_inc() on PREEMPT_RT for the increment to not worry about
preemption.

Cc: David Ahern <dsahern@kernel.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://patch.msgid.link/20250512092736.229935-4-bigeasy@linutronix.de


Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

parent bcaf3c2f

net/ipv4/route.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -197,7 +197,11 @@ const __u8 ip_tos2prio[16] = {
		EXPORT_SYMBOL(ip_tos2prio);

		static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat);
		#ifndef CONFIG_PREEMPT_RT
		#define RT_CACHE_STAT_INC(field) raw_cpu_inc(rt_cache_stat.field)
		#else
		#define RT_CACHE_STAT_INC(field) this_cpu_inc(rt_cache_stat.field)
		#endif

		#ifdef CONFIG_PROC_FS
		static void rt_cache_seq_start(struct seq_file seq, loff_t *pos)