diff options
| author | Toke Høiland-Jørgensen <toke@redhat.com> | 2020-09-29 14:45:50 +0200 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2020-09-29 13:09:23 -0700 |
| commit | 3aac1ead5eb6b76f3d2b8d111e6de1c2de23fb34 (patch) | |
| tree | fb66fb0f2de431275e8c5a09d896a97f9641dacb /kernel/bpf/core.c | |
| parent | 85e3f318506ece12714535821d0b3186f7121b5b (diff) | |
| download | linux-3aac1ead5eb6b76f3d2b8d111e6de1c2de23fb34.tar.gz linux-3aac1ead5eb6b76f3d2b8d111e6de1c2de23fb34.tar.xz | |
bpf: Move prog->aux->linked_prog and trampoline into bpf_link on attach
In preparation for allowing multiple attachments of freplace programs, move
the references to the target program and trampoline into the
bpf_tracing_link structure when that is created. To do this atomically,
introduce a new mutex in prog->aux to protect writing to the two pointers
to target prog and trampoline, and rename the members to make it clear that
they are related.
With this change, it is no longer possible to attach the same tracing
program multiple times (detaching in-between), since the reference from the
tracing program to the target disappears on the first attach. However,
since the next patch will let the caller supply an attach target, that will
also make it possible to attach to the same place multiple times.
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/160138355059.48470.2503076992210324984.stgit@toke.dk
Diffstat (limited to 'kernel/bpf/core.c')
| -rw-r--r-- | kernel/bpf/core.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index c4ba45fa4fe1..cda674f1392f 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -99,6 +99,7 @@ struct bpf_prog *bpf_prog_alloc_no_stats(unsigned int size, gfp_t gfp_extra_flag INIT_LIST_HEAD_RCU(&fp->aux->ksym.lnode); mutex_init(&fp->aux->used_maps_mutex); + mutex_init(&fp->aux->dst_mutex); return fp; } @@ -255,6 +256,7 @@ void __bpf_prog_free(struct bpf_prog *fp) { if (fp->aux) { mutex_destroy(&fp->aux->used_maps_mutex); + mutex_destroy(&fp->aux->dst_mutex); free_percpu(fp->aux->stats); kfree(fp->aux->poke_tab); kfree(fp->aux); @@ -2138,7 +2140,8 @@ static void bpf_prog_free_deferred(struct work_struct *work) if (aux->prog->has_callchain_buf) put_callchain_buffers(); #endif - bpf_trampoline_put(aux->trampoline); + if (aux->dst_trampoline) + bpf_trampoline_put(aux->dst_trampoline); for (i = 0; i < aux->func_cnt; i++) bpf_jit_free(aux->func[i]); if (aux->func_cnt) { @@ -2154,8 +2157,8 @@ void bpf_prog_free(struct bpf_prog *fp) { struct bpf_prog_aux *aux = fp->aux; - if (aux->linked_prog) - bpf_prog_put(aux->linked_prog); + if (aux->dst_prog) + bpf_prog_put(aux->dst_prog); INIT_WORK(&aux->work, bpf_prog_free_deferred); schedule_work(&aux->work); } |