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bpf: bpf_stackmap_copy depends on CONFIG_PERF_EVENTS

PATCH Applied Alexei Starovoitov 2 participants 2 messages Mar 10, 2016

Subsystems (4)
Networking Network drivers BPF BPF core
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Alexei Starovoitov

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#0 lore raw

PATCH 1/1 bpf: bpf_stackmap_copy depends on CONFIG_PERF_EVENTS

0-day bot reported build error:
kernel/built-in.o: In function `map_lookup_elem':

Quoted 1 line
Quoted 1 line

kernel/bpf/.tmp_syscall.o:(.text+0x329b3c): undefined reference to `bpf_stackmap_copy'

when CONFIG_BPF_SYSCALL is set and CONFIG_PERF_EVENTS is not. Add weak definition to resolve it.
This code path in map_lookup_elem() is never taken when CONFIG_PERF_EVENTS is not set.

Fixes 557c0c6e7df8 ("bpf: convert stackmap to pre-allocation")
Reported-by Fengguang Wu <[email protected]>
Signed-off-by Alexei Starovoitov <[email protected]>
---
 kernel/bpf/syscall.c | 5 +++++
 1 file changed, 5 insertions(+)
kernel/bpf/syscall.c +5 -0
index 2978d0d08869..2a2efe1bc76c 100644
@@ -244,6 +244,11 @@ static void __user *u64_to_ptr(__u64 val)
 	return (void __user *) (unsigned long) val;
 }
 
+int __weak bpf_stackmap_copy(struct bpf_map *map, void *key, void *value)
+{
+	return -ENOTSUPP;
+}
+
 /* last field in 'union bpf_attr' used by this command */
 #define BPF_MAP_LOOKUP_ELEM_LAST_FIELD value
Signature · 1 line
2.8.0.rc1
maintainer Applied
#1 lore raw

From: Alexei Starovoitov <[email protected]>
Date: Wed, 9 Mar 2016 18:56:49 -0800

Quoted 11 lines

0-day bot reported build error:
kernel/built-in.o: In function `map_lookup_elem':

Quoted 1 line
Quoted 1 line

kernel/bpf/.tmp_syscall.o:(.text+0x329b3c): undefined reference to `bpf_stackmap_copy'

when CONFIG_BPF_SYSCALL is set and CONFIG_PERF_EVENTS is not. Add weak definition to resolve it.
This code path in map_lookup_elem() is never taken when CONFIG_PERF_EVENTS is not set.

Fixes 557c0c6e7df8 ("bpf: convert stackmap to pre-allocation")
Reported-by Fengguang Wu <[email protected]>
Signed-off-by Alexei Starovoitov <[email protected]>

Applied.