bpf: fix u64_stats_init() usage in bpf_prog_alloc()

edumazet · borkmann · commit 4b9113045b17 · 2019-03-02T00:31:36.000+01:00
We need to iterate through all possible cpus. Fixes: 492ecee ("bpf: enable program stats") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Guenter Roeck <linux@roeck-us.net> Tested-by: Guenter Roeck <linux@roeck-us.net> Acked-by: Song Liu <songliubraving@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
@@ -109,6 +109,7 @@ struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags)
 {
 	gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags;
 	struct bpf_prog *prog;
+	int cpu;
 
 	prog = bpf_prog_alloc_no_stats(size, gfp_extra_flags);
 	if (!prog)
@@ -121,7 +122,12 @@ struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags)
 		return NULL;
 	}
 
-	u64_stats_init(&prog->aux->stats->syncp);
+	for_each_possible_cpu(cpu) {
+		struct bpf_prog_stats *pstats;
+
+		pstats = per_cpu_ptr(prog->aux->stats, cpu);
+		u64_stats_init(&pstats->syncp);
+	}
 	return prog;
 }
 EXPORT_SYMBOL_GPL(bpf_prog_alloc);

Original file line number	Diff line number	Diff line change
`@@ -109,6 +109,7 @@ struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags)`
`109`	`109`	`{`
`110`	`110`	`gfp_t gfp_flags = GFP_KERNEL \| __GFP_ZERO \| gfp_extra_flags;`
`111`	`111`	`struct bpf_prog *prog;`
	`112`	`+ int cpu;`
`112`	`113`
`113`	`114`	`prog = bpf_prog_alloc_no_stats(size, gfp_extra_flags);`
`114`	`115`	`if (!prog)`
`@@ -121,7 +122,12 @@ struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags)`
`121`	`122`	`return NULL;`
`122`	`123`	`}`
`123`	`124`
`124`		`- u64_stats_init(&prog->aux->stats->syncp);`
	`125`	`+ for_each_possible_cpu(cpu) {`
	`126`	`+ struct bpf_prog_stats *pstats;`
	`127`	`+`
	`128`	`+ pstats = per_cpu_ptr(prog->aux->stats, cpu);`
	`129`	`+ u64_stats_init(&pstats->syncp);`
	`130`	`+ }`
`125`	`131`	`return prog;`
`126`	`132`	`}`
`127`	`133`	`EXPORT_SYMBOL_GPL(bpf_prog_alloc);`