2 Commits

Author	SHA1	Message	Date
Song Liu	bc235cdb42	bpf: Prevent deadlock from recursive bpf_task_storage_[get|delete] ... BPF helpers bpf_task_storage_[get|delete] could hold two locks: bpf_local_storage_map_bucket->lock and bpf_local_storage->lock. Calling these helpers from fentry/fexit programs on functions in bpf_*_storage.c may cause deadlock on either locks. Prevent such deadlock with a per cpu counter, bpf_task_storage_busy. We need this counter to be global, because the two locks here belong to two different objects: bpf_local_storage_map and bpf_local_storage. If we pick one of them as the owner of the counter, it is still possible to trigger deadlock on the other lock. For example, if bpf_local_storage_map owns the counters, it cannot prevent deadlock on bpf_local_storage->lock when two maps are used. Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20210225234319.336131-3-songliubraving@fb.com	2021-02-26 11:51:48 -08:00
KP Singh	450af8d0f6	bpf: Split bpf_local_storage to bpf_sk_storage ... A purely mechanical change: bpf_sk_storage.c = bpf_sk_storage.c + bpf_local_storage.c bpf_sk_storage.h = bpf_sk_storage.h + bpf_local_storage.h Signed-off-by: KP Singh <kpsingh@google.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20200825182919.1118197-5-kpsingh@chromium.org	2020-08-25 15:00:04 -07:00