From c376f07e16c02239ed44cabb97145d03f65b4d15 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Tue, 19 May 2026 20:10:08 +0200 Subject: [PATCH] netfilter: xt_cpu: prefer raw_smp_processor_id With PREEMPT_RCU we get splat: BUG: using smp_processor_id() in preemptible [..] caller is cpu_mt+0x53/0xd0 net/netfilter/xt_cpu.c:37 CPU: 1 .. Comm: syz.3.1377 #0 PREEMPT(full) Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 check_preemption_disabled+0xd3/0xe0 lib/smp_processor_id.c:47 cpu_mt+0x53/0xd0 net/netfilter/xt_cpu.c:37 [..] Just use raw version instead. This is similar to 14d14a5d2957 ("netfilter: nft_meta: use raw_smp_processor_id()"). Fixes: 0ca743a55991 ("netfilter: nf_tables: add compatibility layer for x_tables") Reported-by: syzbot+690d3e3ffa7335ac10eb@syzkaller.appspotmail.com Signed-off-by: Florian Westphal --- net/netfilter/xt_cpu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/netfilter/xt_cpu.c b/net/netfilter/xt_cpu.c index 3bdc302a0f91..9cb259902a58 100644 --- a/net/netfilter/xt_cpu.c +++ b/net/netfilter/xt_cpu.c @@ -34,7 +34,7 @@ static bool cpu_mt(const struct sk_buff *skb, struct xt_action_param *par) { const struct xt_cpu_info *info = par->matchinfo; - return (info->cpu == smp_processor_id()) ^ info->invert; + return (info->cpu == raw_smp_processor_id()) ^ info->invert; } static struct xt_match cpu_mt_reg __read_mostly = {