Re: [PATCH net 04/10] netfilter: xt_cpu: prefer raw_smp_processor_id
From: Eric Dumazet <edumazet@google.com>
Date: 2026-05-22 11:06:27
Also in:
netfilter-devel
On Fri, May 22, 2026 at 3:43 AM Florian Westphal [off-list ref] wrote:
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:
<TASK>
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 <fw@strlen.de>Reviewed-by: Eric Dumazet <edumazet@google.com> Thanks!