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bpf: Fix usage of trace RCU in local storage.

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bpf_{sk,task,inode}_storage_free() do not need to use
call_rcu_tasks_trace as no BPF program should be accessing the owner
as it's being destroyed. The only other reader at this point is
bpf_local_storage_map_free() which uses normal RCU.

The only path that needs trace RCU are:

* bpf_local_storage_{delete,update} helpers
* map_{delete,update}_elem() syscalls

Fixes: 0fe4b381a5 ("bpf: Allow bpf_local_storage to be used by sleepable programs")
Signed-off-by: KP Singh <kpsingh@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20220418155158.2865678-1-kpsingh@kernel.org
This commit is contained in:
KP Singh
2022-04-18 15:51:58 +00:00
committed by Alexei Starovoitov
parent 0e5aefa334
commit dcf456c9a0
5 changed files with 28 additions and 19 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
kernel/bpf/bpf_task_storage.c
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@@ -102,7 +102,7 @@ void bpf_task_storage_free(struct task_struct *task)
*/
bpf_selem_unlink_map(selem);
free_task_storage = bpf_selem_unlink_storage_nolock(
local_storage, selem, false);
local_storage, selem, false, false);
}
raw_spin_unlock_irqrestore(&local_storage->lock, flags);
bpf_task_storage_unlock();
@@ -192,7 +192,7 @@ static int task_storage_delete(struct task_struct *task, struct bpf_map *map)
if (!sdata)
return -ENOENT;
bpf_selem_unlink(SELEM(sdata));
bpf_selem_unlink(SELEM(sdata), true);
return 0;
}