lkml.org 
[lkml]   [2022]   [Feb]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH] libbpf: fix BPF_MAP_TYPE_PERF_EVENT_ARRAY auto-pinning
Date
When a BPF map of type BPF_MAP_TYPE_PERF_EVENT_ARRAY doesn't have the
max_entries parameter set, this parameter will be set to the number of
possible CPUs. Due to this, the map_is_reuse_compat function will return
false, causing the following error when trying to reuse the map:

libbpf: couldn't reuse pinned map at '/sys/fs/bpf/m_logging': parameter mismatch

Fix this by checking against the number of possible CPUs if the
max_entries parameter is not set in the map definition.

Fixes: 57a00f41644f ("libbpf: Add auto-pinning of maps when loading BPF objects")
Signed-off-by: Stijn Tintel <stijn@linux-ipv6.be>
---
tools/lib/bpf/libbpf.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 7f10dd501a52..b076ab728f0e 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -4750,7 +4750,7 @@ static bool map_is_reuse_compat(const struct bpf_map *map, int map_fd)
struct bpf_map_info map_info = {};
char msg[STRERR_BUFSIZE];
__u32 map_info_len;
- int err;
+ int def_max_entries, err;

map_info_len = sizeof(map_info);

@@ -4763,10 +4763,15 @@ static bool map_is_reuse_compat(const struct bpf_map *map, int map_fd)
return false;
}

+ if (map->def.type == BPF_MAP_TYPE_PERF_EVENT_ARRAY && !map->def.max_entries)
+ def_max_entries = libbpf_num_possible_cpus();
+ else
+ def_max_entries = map->def.max_entries;
+
return (map_info.type == map->def.type &&
map_info.key_size == map->def.key_size &&
map_info.value_size == map->def.value_size &&
- map_info.max_entries == map->def.max_entries &&
+ map_info.max_entries == def_max_entries &&
map_info.map_flags == map->def.map_flags &&
map_info.map_extra == map->map_extra);
}
--
2.34.1
\
 
 \ /
  Last update: 2022-02-22 21:51    [W:0.042 / U:1.040 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site