bpf: Fixes possible race in update_prog_stats() for 32bit arches

mainline inclusion
from mainline-v5.16-rc1
commit d979617a
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I6O293

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=d979617aa84d96acca44c2f5778892b4565e322f

---------------------------

It seems update_prog_stats() suffers from same issue fixed
in the prior patch:

As it can run while interrupts are enabled, it could
be re-entered and the u64_stats syncp could be mangled.

Fixes: fec56f58 ("bpf: Introduce BPF trampoline")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20211026214133.3114279-3-eric.dumazet@gmail.com
Conflicts:
	kernel/bpf/trampoline.c
Signed-off-by: NPu Lehui <pulehui@huawei.com>
Reviewed-by: NXu Kuohai <xukuohai@huawei.com>
Signed-off-by: NJialin Zhang <zhangjialin11@huawei.com>

kernel/bpf/trampoline.c

@@ -526,11 +526,13 @@ void notrace __bpf_prog_exit(struct bpf_prog *prog, u64 start)
 	     * Hence check that 'start' is not zero.
 	     */
 	    start) {
+		unsigned long flags;
+
 		stats = this_cpu_ptr(prog->aux->stats);
-		u64_stats_update_begin(&stats->syncp);
+		flags = u64_stats_update_begin_irqsave(&stats->syncp);
 		stats->cnt++;
 		stats->nsecs += sched_clock() - start;
-		u64_stats_update_end(&stats->syncp);
+		u64_stats_update_end_irqrestore(&stats->syncp, flags);
 	}
 	migrate_enable();
 	rcu_read_unlock();