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Disabling preemption in sock_map_sk_acquire conflicts with GFP_ATOMIC allocation later in sk_psock_init_link on PREEMPT_RT kernels, since GFP_ATOMIC might sleep on RT (see bpf: Make BPF and PREEMPT_RT co-exist patchset notes for details). This causes calling bpf_map_update_elem on BPF_MAP_TYPE_SOCKMAP maps to BUG (sleeping function called from invalid context) on RT kernels. preempt_disable was introduced together with lock_sk and rcu_read_lock in commit99ba2b5aba("bpf: sockhash, disallow bpf_tcp_close and update in parallel"), probably to match disabled migration of BPF programs, and is no longer necessary. Remove preempt_disable to fix BUG in sock_map_update_common on RT. Signed-off-by: Tomas Glozar <tglozar@redhat.com> Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com> Link: https://lore.kernel.org/all/20200224140131.461979697@linutronix.de/ Fixes:99ba2b5aba("bpf: sockhash, disallow bpf_tcp_close and update in parallel") Reviewed-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/r/20230728064411.305576-1-tglozar@redhat.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>