This Linux kernel change "bpf: decrease usercnt if bpf_map_new_fd() fails in bpf_map_get_fd_by_id()" is included in the Linux 5.0 release. This change is authored by Peng Sun <sironhide0null [at] gmail.com> on Tue Feb 26 22:15:37 2019 +0800. The commit for this change in Linux stable tree is 781e628 (patch).
bpf: decrease usercnt if bpf_map_new_fd() fails in bpf_map_get_fd_by_id() In bpf/syscall.c, bpf_map_get_fd_by_id() use bpf_map_inc_not_zero() to increase the refcount, both map->refcnt and map->usercnt. Then, if bpf_map_new_fd() fails, should handle map->usercnt too. Fixes: bd5f5f4ecb78 ("bpf: Add BPF_MAP_GET_FD_BY_ID") Signed-off-by: Peng Sun <[email protected]> Acked-by: Martin KaFai Lau <[email protected]> Signed-off-by: Daniel Borkmann <[email protected]>
There are 2 lines of Linux source code added/deleted in this change. Code changes to Linux kernel are as follows.
kernel/bpf/syscall.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 8577bb7..f98328a 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -1986,7 +1986,7 @@ static int bpf_map_get_fd_by_id(const union bpf_attr *attr) fd = bpf_map_new_fd(map, f_flags); if (fd < 0) - bpf_map_put(map); + bpf_map_put_with_uref(map); return fd; }