Commit 4279adb0 authored by Martin KaFai Lau's avatar Martin KaFai Lau Committed by Alexei Starovoitov

bpf: Add new bpf_task_storage_get 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_lookup_elem()
which is called from the syscall map_lookup_elem.  It does not need
deadlock detection.  Otherwise, it will cause unnecessary failure
when calling the bpf_task_storage_get() helper.

This patch adds bpf_task_storage_get proto that does not do deadlock
detection.  It will be used by bpf_lsm and bpf_iter programs.
Signed-off-by: default avatarMartin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20221025184524.3526117-6-martin.lau@linux.devSigned-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent e8b02296
...@@ -2520,6 +2520,7 @@ extern const struct bpf_func_proto bpf_ktime_get_coarse_ns_proto; ...@@ -2520,6 +2520,7 @@ extern const struct bpf_func_proto bpf_ktime_get_coarse_ns_proto;
extern const struct bpf_func_proto bpf_sock_from_file_proto; extern const struct bpf_func_proto bpf_sock_from_file_proto;
extern const struct bpf_func_proto bpf_get_socket_ptr_cookie_proto; 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_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_recur_proto;
extern const struct bpf_func_proto bpf_for_each_map_elem_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_btf_find_by_name_kind_proto;
......
...@@ -269,6 +269,23 @@ BPF_CALL_5(bpf_task_storage_get_recur, struct bpf_map *, map, struct task_struct ...@@ -269,6 +269,23 @@ BPF_CALL_5(bpf_task_storage_get_recur, struct bpf_map *, map, struct task_struct
return (unsigned long)data; return (unsigned long)data;
} }
/* *gfp_flags* is a hidden argument provided by the verifier */
BPF_CALL_5(bpf_task_storage_get, struct bpf_map *, map, struct task_struct *,
task, void *, value, u64, flags, gfp_t, gfp_flags)
{
void *data;
WARN_ON_ONCE(!bpf_rcu_lock_held());
if (flags & ~BPF_LOCAL_STORAGE_GET_F_CREATE || !task)
return (unsigned long)NULL;
bpf_task_storage_lock();
data = __bpf_task_storage_get(map, task, value, flags,
gfp_flags, true);
bpf_task_storage_unlock();
return (unsigned long)data;
}
BPF_CALL_2(bpf_task_storage_delete_recur, struct bpf_map *, map, struct task_struct *, BPF_CALL_2(bpf_task_storage_delete_recur, struct bpf_map *, map, struct task_struct *,
task) task)
{ {
...@@ -342,6 +359,17 @@ const struct bpf_func_proto bpf_task_storage_get_recur_proto = { ...@@ -342,6 +359,17 @@ const struct bpf_func_proto bpf_task_storage_get_recur_proto = {
.arg4_type = ARG_ANYTHING, .arg4_type = ARG_ANYTHING,
}; };
const struct bpf_func_proto bpf_task_storage_get_proto = {
.func = bpf_task_storage_get,
.gpl_only = false,
.ret_type = RET_PTR_TO_MAP_VALUE_OR_NULL,
.arg1_type = ARG_CONST_MAP_PTR,
.arg2_type = ARG_PTR_TO_BTF_ID,
.arg2_btf_id = &btf_tracing_ids[BTF_TRACING_TYPE_TASK],
.arg3_type = ARG_PTR_TO_MAP_VALUE_OR_NULL,
.arg4_type = ARG_ANYTHING,
};
const struct bpf_func_proto bpf_task_storage_delete_recur_proto = { const struct bpf_func_proto bpf_task_storage_delete_recur_proto = {
.func = bpf_task_storage_delete_recur, .func = bpf_task_storage_delete_recur,
.gpl_only = false, .gpl_only = false,
......
...@@ -6,6 +6,7 @@ ...@@ -6,6 +6,7 @@
#include <linux/types.h> #include <linux/types.h>
#include <linux/slab.h> #include <linux/slab.h>
#include <linux/bpf.h> #include <linux/bpf.h>
#include <linux/bpf_verifier.h>
#include <linux/bpf_perf_event.h> #include <linux/bpf_perf_event.h>
#include <linux/btf.h> #include <linux/btf.h>
#include <linux/filter.h> #include <linux/filter.h>
...@@ -1488,7 +1489,9 @@ bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) ...@@ -1488,7 +1489,9 @@ bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
case BPF_FUNC_this_cpu_ptr: case BPF_FUNC_this_cpu_ptr:
return &bpf_this_cpu_ptr_proto; return &bpf_this_cpu_ptr_proto;
case BPF_FUNC_task_storage_get: case BPF_FUNC_task_storage_get:
return &bpf_task_storage_get_recur_proto; if (bpf_prog_check_recur(prog))
return &bpf_task_storage_get_recur_proto;
return &bpf_task_storage_get_proto;
case BPF_FUNC_task_storage_delete: case BPF_FUNC_task_storage_delete:
return &bpf_task_storage_delete_recur_proto; return &bpf_task_storage_delete_recur_proto;
case BPF_FUNC_for_each_map_elem: case BPF_FUNC_for_each_map_elem:
......
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