diff options
| author | David S. Miller <davem@davemloft.net> | 2019-08-28 00:23:31 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2019-08-28 00:23:31 +0300 |
| commit | 68aaf4459556b1f9370c259fd486aecad2257552 (patch) | |
| tree | 99d92536a3263634969be6b70a96facea85a0df1 /kernel/bpf/syscall.c | |
| parent | d00ee466a07eb9182ad3caf6140c7ebb527b4c64 (diff) | |
| parent | 9e8312f5e160ade069e131d54ab8652cf0e86e1a (diff) | |
| download | linux-68aaf4459556b1f9370c259fd486aecad2257552.tar.xz | |
Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Minor conflict in r8169, bug fix had two versions in net
and net-next, take the net-next hunks.
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'kernel/bpf/syscall.c')
| -rw-r--r-- | kernel/bpf/syscall.c | 30 |
1 files changed, 18 insertions, 12 deletions
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 5d141f16f6fa..272071e9112f 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -1707,20 +1707,26 @@ static int bpf_prog_load(union bpf_attr *attr, union bpf_attr __user *uattr) if (err) goto free_used_maps; - err = bpf_prog_new_fd(prog); - if (err < 0) { - /* failed to allocate fd. - * bpf_prog_put() is needed because the above - * bpf_prog_alloc_id() has published the prog - * to the userspace and the userspace may - * have refcnt-ed it through BPF_PROG_GET_FD_BY_ID. - */ - bpf_prog_put(prog); - return err; - } - + /* Upon success of bpf_prog_alloc_id(), the BPF prog is + * effectively publicly exposed. However, retrieving via + * bpf_prog_get_fd_by_id() will take another reference, + * therefore it cannot be gone underneath us. + * + * Only for the time /after/ successful bpf_prog_new_fd() + * and before returning to userspace, we might just hold + * one reference and any parallel close on that fd could + * rip everything out. Hence, below notifications must + * happen before bpf_prog_new_fd(). + * + * Also, any failure handling from this point onwards must + * be using bpf_prog_put() given the program is exposed. + */ bpf_prog_kallsyms_add(prog); perf_event_bpf_event(prog, PERF_BPF_EVENT_PROG_LOAD, 0); + + err = bpf_prog_new_fd(prog); + if (err < 0) + bpf_prog_put(prog); return err; free_used_maps: |