Re: [PATCH v4 bpf-next 1/6] bpf: enable task local storage for tracing programs

On Feb 23, 2021, at 11:23 AM, Martin Lau [off-list ref] wrote:

On Mon, Feb 22, 2021 at 05:20:09PM -0800, Song Liu wrote:
[ ... ]

quoted

diff --git a/kernel/bpf/bpf_task_storage.c b/kernel/bpf/bpf_task_storage.c
index e0da0258b732d..2034019966d44 100644
--- a/kernel/bpf/bpf_task_storage.c
+++ b/kernel/bpf/bpf_task_storage.c

@@ -15,7 +15,6 @@

#include <linux/bpf_local_storage.h>
#include <linux/filter.h>
#include <uapi/linux/btf.h>
-#include <linux/bpf_lsm.h>
#include <linux/btf_ids.h>
#include <linux/fdtable.h>

@@ -24,12 +23,8 @@ DEFINE_BPF_STORAGE_CACHE(task_cache);

static struct bpf_local_storage __rcu **task_storage_ptr(void *owner)
{
	struct task_struct *task = owner;
-	struct bpf_storage_blob *bsb;

-	bsb = bpf_task(task);
-	if (!bsb)
-		return NULL;

task_storage_ptr() no longer returns NULL.  All "!task_storage_ptr(task)"
checks should be removed also.  e.g. In bpf_task_storage_get
and bpf_pid_task_storage_update_elem.

Good catch! Fixed it in v5. 

Thanks,
Song

quoted

-	return &bsb->storage;
+	return &task->bpf_storage;
}