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authorAndrii Nakryiko <andrii@kernel.org>2024-03-27 22:24:25 -0700
committerAlexei Starovoitov <ast@kernel.org>2024-03-28 18:47:45 -0700
commite9c856cabefb71d47b2eeb197f72c9c88e9b45b0 (patch)
tree29cf5df350ae5d3441fc6dcd010bc06e21509659
parent037965402a010898d34f4e35327d22c0a95cd51f (diff)
bpf: put uprobe link's path and task in release callback
There is no need to delay putting either path or task to deallocation step. It can be done right after bpf_uprobe_unregister. Between release and dealloc, there could be still some running BPF programs, but they don't access either task or path, only data in link->uprobes, so it is safe to do. On the other hand, doing path_put() in dealloc callback makes this dealloc sleepable because path_put() itself might sleep. Which is problematic due to the need to call uprobe's dealloc through call_rcu(), which is what is done in the next bug fix patch. So solve the problem by releasing these resources early. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20240328052426.3042617-1-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
-rw-r--r--kernel/trace/bpf_trace.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 0a5c4efc73c3..0b73fe5f7206 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -3157,6 +3157,9 @@ static void bpf_uprobe_multi_link_release(struct bpf_link *link)
umulti_link = container_of(link, struct bpf_uprobe_multi_link, link);
bpf_uprobe_unregister(&umulti_link->path, umulti_link->uprobes, umulti_link->cnt);
+ if (umulti_link->task)
+ put_task_struct(umulti_link->task);
+ path_put(&umulti_link->path);
}
static void bpf_uprobe_multi_link_dealloc(struct bpf_link *link)
@@ -3164,9 +3167,6 @@ static void bpf_uprobe_multi_link_dealloc(struct bpf_link *link)
struct bpf_uprobe_multi_link *umulti_link;
umulti_link = container_of(link, struct bpf_uprobe_multi_link, link);
- if (umulti_link->task)
- put_task_struct(umulti_link->task);
- path_put(&umulti_link->path);
kvfree(umulti_link->uprobes);
kfree(umulti_link);
}