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| author | Martin KaFai Lau <martin.lau@kernel.org> | 2022-10-25 11:45:20 -0700 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2022-10-25 23:11:46 -0700 |
| commit | 4279adb094a17132423f1271c3d11b593fc2327e (patch) | |
| tree | 0601ed0271392f68e41f4672f63565bf27df3989 /kernel/bpf/bpf_task_storage.c | |
| parent | e8b02296a6b8d07de752d6157d863a642117bcd3 (diff) | |
| download | linux-stable-4279adb094a17132423f1271c3d11b593fc2327e.tar.gz linux-stable-4279adb094a17132423f1271c3d11b593fc2327e.tar.bz2 linux-stable-4279adb094a17132423f1271c3d11b593fc2327e.zip | |
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: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20221025184524.3526117-6-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'kernel/bpf/bpf_task_storage.c')
| -rw-r--r-- | kernel/bpf/bpf_task_storage.c | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/kernel/bpf/bpf_task_storage.c b/kernel/bpf/bpf_task_storage.c index bc52bc8b59f7..c3a841be438f 100644 --- a/kernel/bpf/bpf_task_storage.c +++ b/kernel/bpf/bpf_task_storage.c @@ -269,6 +269,23 @@ BPF_CALL_5(bpf_task_storage_get_recur, struct bpf_map *, map, struct task_struct 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 *, task) { @@ -342,6 +359,17 @@ const struct bpf_func_proto bpf_task_storage_get_recur_proto = { .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 = { .func = bpf_task_storage_delete_recur, .gpl_only = false, |