| Message ID | 20191101030700.13080-4-jakub.kicinski@netronome.com |
|---|---|
| State | Accepted |
| Delegated to: | David Miller |
| Headers | show |
| Series | fix BPF offload related bugs | expand |
diff --git a/net/core/dev.c b/net/core/dev.c index 96afd464284a..99ac84ff398f 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -8421,7 +8421,8 @@ int dev_change_xdp_fd(struct net_device *dev, struct netlink_ext_ack *extack, return -EINVAL; } - if (prog->aux->id == prog_id) { + /* prog->aux->id may be 0 for orphaned device-bound progs */ + if (prog->aux->id && prog->aux->id == prog_id) { bpf_prog_put(prog); return 0; }
When netdevice with offloaded BPF programs is destroyed the programs are orphaned and removed from the program IDA - their IDs get released (the programs may remain accessible via existing open file descriptors and pinned files). After IDs are released they are set to 0. This confuses dev_change_xdp_fd() because it compares the __dev_xdp_query() result where 0 means no program with prog->aux->id where 0 means orphaned. dev_change_xdp_fd() would have incorrectly returned success even though it had not installed the program. Since drivers already catch this case via bpf_offload_dev_match() let them handle this case. The error message drivers produce in this case ("program loaded for a different device") is in fact correct as the orphaned program must had to be loaded for a different device. Fixes: c14a9f633d9e ("net: Don't call XDP_SETUP_PROG when nothing is changed") Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> --- CC: Maxim Mikityanskiy <maximmi@mellanox.com> net/core/dev.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)