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| author | Martin KaFai Lau <martin.lau@kernel.org> | 2022-10-25 11:45:22 -0700 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2022-10-25 23:11:46 -0700 |
| commit | 8a7dac37f27a3dfbd814bf29a73d6417db2c81d9 (patch) | |
| tree | cec23260f0e710a27b8ac5ad38e9275d3ed43562 | |
| parent | fda64ae0bb3e37b5a4292625c6931cb156224d0f (diff) | |
| download | linux-8a7dac37f27a3dfbd814bf29a73d6417db2c81d9.tar.bz2 | |
bpf: Add new bpf_task_storage_delete proto with no deadlock detection
The bpf_lsm and bpf_iter do not recur that will cause a deadlock.
The situation is similar to the bpf_pid_task_storage_delete_elem()
which is called from the syscall map_delete_elem. It does not need
deadlock detection. Otherwise, it will cause unnecessary failure
when calling the bpf_task_storage_delete() helper.
This patch adds bpf_task_storage_delete proto that does not do deadlock
detection. It will be used by bpf_lsm and bpf_iter program.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20221025184524.3526117-8-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
| -rw-r--r-- | include/linux/bpf.h | 1 | ||||
| -rw-r--r-- | kernel/bpf/bpf_task_storage.c | 28 | ||||
| -rw-r--r-- | kernel/trace/bpf_trace.c | 4 |
3 files changed, 32 insertions, 1 deletions
diff --git a/include/linux/bpf.h b/include/linux/bpf.h index ef3f98afa45d..a5dbac8f5aba 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -2522,6 +2522,7 @@ extern const struct bpf_func_proto bpf_get_socket_ptr_cookie_proto; extern const struct bpf_func_proto bpf_task_storage_get_recur_proto; extern const struct bpf_func_proto bpf_task_storage_get_proto; extern const struct bpf_func_proto bpf_task_storage_delete_recur_proto; +extern const struct bpf_func_proto bpf_task_storage_delete_proto; extern const struct bpf_func_proto bpf_for_each_map_elem_proto; extern const struct bpf_func_proto bpf_btf_find_by_name_kind_proto; extern const struct bpf_func_proto bpf_sk_setsockopt_proto; diff --git a/kernel/bpf/bpf_task_storage.c b/kernel/bpf/bpf_task_storage.c index f3f79b618a68..ba3fe72d1fa5 100644 --- a/kernel/bpf/bpf_task_storage.c +++ b/kernel/bpf/bpf_task_storage.c @@ -311,6 +311,25 @@ BPF_CALL_2(bpf_task_storage_delete_recur, struct bpf_map *, map, struct task_str return ret; } +BPF_CALL_2(bpf_task_storage_delete, struct bpf_map *, map, struct task_struct *, + task) +{ + int ret; + + WARN_ON_ONCE(!bpf_rcu_lock_held()); + if (!task) + return -EINVAL; + + bpf_task_storage_lock(); + /* This helper must only be called from places where the lifetime of the task + * is guaranteed. Either by being refcounted or by being protected + * by an RCU read-side critical section. + */ + ret = task_storage_delete(task, map, true); + bpf_task_storage_unlock(); + return ret; +} + static int notsupp_get_next_key(struct bpf_map *map, void *key, void *next_key) { return -ENOTSUPP; @@ -382,3 +401,12 @@ const struct bpf_func_proto bpf_task_storage_delete_recur_proto = { .arg2_type = ARG_PTR_TO_BTF_ID, .arg2_btf_id = &btf_tracing_ids[BTF_TRACING_TYPE_TASK], }; + +const struct bpf_func_proto bpf_task_storage_delete_proto = { + .func = bpf_task_storage_delete, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_CONST_MAP_PTR, + .arg2_type = ARG_PTR_TO_BTF_ID, + .arg2_btf_id = &btf_tracing_ids[BTF_TRACING_TYPE_TASK], +}; diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index e9759b0f7199..eed1bd952c3a 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -1493,7 +1493,9 @@ bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) return &bpf_task_storage_get_recur_proto; return &bpf_task_storage_get_proto; case BPF_FUNC_task_storage_delete: - return &bpf_task_storage_delete_recur_proto; + if (bpf_prog_check_recur(prog)) + return &bpf_task_storage_delete_recur_proto; + return &bpf_task_storage_delete_proto; case BPF_FUNC_for_each_map_elem: return &bpf_for_each_map_elem_proto; case BPF_FUNC_snprintf: |