Adding support to use session attachment with tracing_multi link. Adding new BPF_TRACE_FSESSION_MULTI program attach type, that follows the BPF_TRACE_FSESSION behaviour but on the tracing_multi link.
Such program is called on entry and exit of the attached function and allows to pass cookie value from entry to exit execution. Signed-off-by: Jiri Olsa <[email protected]> --- include/linux/bpf.h | 6 ++++- include/uapi/linux/bpf.h | 1 + kernel/bpf/btf.c | 2 ++ kernel/bpf/syscall.c | 1 + kernel/bpf/trampoline.c | 43 +++++++++++++++++++++++++++------- kernel/bpf/verifier.c | 17 ++++++++++---- kernel/trace/bpf_trace.c | 15 +++++++++++- net/bpf/test_run.c | 1 + tools/include/uapi/linux/bpf.h | 1 + tools/lib/bpf/libbpf.c | 1 + 10 files changed, 73 insertions(+), 15 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index a919143a8b35..55f373464da3 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -1902,6 +1902,7 @@ struct bpf_tracing_multi_node { struct bpf_tracing_multi_link { struct bpf_link link; u64 *cookies; + struct bpf_tramp_node *fexits; int nodes_cnt; struct bpf_tracing_multi_node nodes[] __counted_by(nodes_cnt); }; @@ -2136,7 +2137,8 @@ u32 bpf_struct_ops_id(const void *kdata); static inline bool is_tracing_multi(enum bpf_attach_type type) { - return type == BPF_TRACE_FENTRY_MULTI || type == BPF_TRACE_FEXIT_MULTI; + return type == BPF_TRACE_FENTRY_MULTI || type == BPF_TRACE_FEXIT_MULTI || + type == BPF_TRACE_FSESSION_MULTI; } #ifdef CONFIG_NET @@ -2213,6 +2215,8 @@ static inline int bpf_fsession_cnt(struct bpf_tramp_nodes *nodes) for (int i = 0; i < nodes[BPF_TRAMP_FENTRY].nr_nodes; i++) { if (fentries.nodes[i]->link->prog->expected_attach_type == BPF_TRACE_FSESSION) cnt++; + if (fentries.nodes[i]->link->prog->expected_attach_type == BPF_TRACE_FSESSION_MULTI) + cnt++; } return cnt; diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index e28722ddeb5b..4520830fda06 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -1156,6 +1156,7 @@ enum bpf_attach_type { BPF_TRACE_FSESSION, BPF_TRACE_FENTRY_MULTI, BPF_TRACE_FEXIT_MULTI, + BPF_TRACE_FSESSION_MULTI, __MAX_BPF_ATTACH_TYPE }; diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index c8738834bbc9..668a31952510 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -6221,6 +6221,7 @@ static int btf_validate_prog_ctx_type(struct bpf_verifier_log *log, const struct case BPF_TRACE_FEXIT: case BPF_MODIFY_RETURN: case BPF_TRACE_FSESSION: + case BPF_TRACE_FSESSION_MULTI: case BPF_TRACE_FENTRY_MULTI: case BPF_TRACE_FEXIT_MULTI: /* allow u64* as ctx */ @@ -6825,6 +6826,7 @@ bool btf_ctx_access(int off, int size, enum bpf_access_type type, case BPF_LSM_CGROUP: case BPF_TRACE_FEXIT: case BPF_TRACE_FSESSION: + case BPF_TRACE_FSESSION_MULTI: /* When LSM programs are attached to void LSM hooks * they use FEXIT trampolines and when attached to * int LSM hooks, they use MODIFY_RETURN trampolines. diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 94c6a9c81ef0..c13cb812a1d3 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -4388,6 +4388,7 @@ attach_type_to_prog_type(enum bpf_attach_type attach_type) case BPF_TRACE_FENTRY: case BPF_TRACE_FEXIT: case BPF_TRACE_FSESSION: + case BPF_TRACE_FSESSION_MULTI: case BPF_TRACE_FENTRY_MULTI: case BPF_TRACE_FEXIT_MULTI: case BPF_MODIFY_RETURN: diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c index 1aa723dac209..13a2eb62a544 100644 --- a/kernel/bpf/trampoline.c +++ b/kernel/bpf/trampoline.c @@ -199,7 +199,8 @@ bool bpf_prog_has_trampoline(const struct bpf_prog *prog) case BPF_PROG_TYPE_TRACING: if (eatype == BPF_TRACE_FENTRY || eatype == BPF_TRACE_FEXIT || eatype == BPF_MODIFY_RETURN || eatype == BPF_TRACE_FSESSION || - eatype == BPF_TRACE_FENTRY_MULTI || eatype == BPF_TRACE_FEXIT_MULTI) + eatype == BPF_TRACE_FENTRY_MULTI || eatype == BPF_TRACE_FEXIT_MULTI || + eatype == BPF_TRACE_FSESSION_MULTI) return true; return false; case BPF_PROG_TYPE_LSM: @@ -796,6 +797,7 @@ static enum bpf_tramp_prog_type bpf_attach_type_to_tramp(struct bpf_prog *prog) case BPF_TRACE_FEXIT_MULTI: return BPF_TRAMP_FEXIT; case BPF_TRACE_FSESSION: + case BPF_TRACE_FSESSION_MULTI: return BPF_TRAMP_FSESSION; case BPF_LSM_MAC: if (!prog->aux->attach_func_proto->type) @@ -828,15 +830,34 @@ static int bpf_freplace_check_tgt_prog(struct bpf_prog *tgt_prog) return 0; } +static struct bpf_tramp_node *fsession_exit(struct bpf_tramp_node *node) +{ + if (node->link->type == BPF_LINK_TYPE_TRACING) { + struct bpf_tracing_link *link; + + link = container_of(node->link, struct bpf_tracing_link, link.link); + return &link->fexit; + } else if (node->link->type == BPF_LINK_TYPE_TRACING_MULTI) { + struct bpf_tracing_multi_link *link; + struct bpf_tracing_multi_node *mnode; + + link = container_of(node->link, struct bpf_tracing_multi_link, link); + mnode = container_of(node, struct bpf_tracing_multi_node, node); + return &link->fexits[mnode - link->nodes]; + } + + WARN_ON_ONCE(1); + return NULL; +} + static int __bpf_trampoline_link_prog(struct bpf_tramp_node *node, struct bpf_trampoline *tr, struct bpf_prog *tgt_prog, struct bpf_trampoline_ops *ops, void *data) { - struct bpf_tracing_link *tr_link = NULL; enum bpf_tramp_prog_type kind; - struct bpf_tramp_node *node_existing; + struct bpf_tramp_node *node_existing, *fexit; struct hlist_head *prog_list; int err = 0; int cnt = 0, i; @@ -884,8 +905,8 @@ static int __bpf_trampoline_link_prog(struct bpf_tramp_node *node, hlist_add_head(&node->tramp_hlist, prog_list); if (kind == BPF_TRAMP_FSESSION) { tr->progs_cnt[BPF_TRAMP_FENTRY]++; - tr_link = container_of(node, struct bpf_tracing_link, link.node); - hlist_add_head(&tr_link->fexit.tramp_hlist, &tr->progs_hlist[BPF_TRAMP_FEXIT]); + fexit = fsession_exit(node); + hlist_add_head(&fexit->tramp_hlist, &tr->progs_hlist[BPF_TRAMP_FEXIT]); tr->progs_cnt[BPF_TRAMP_FEXIT]++; } else { tr->progs_cnt[kind]++; @@ -895,7 +916,7 @@ static int __bpf_trampoline_link_prog(struct bpf_tramp_node *node, hlist_del_init(&node->tramp_hlist); if (kind == BPF_TRAMP_FSESSION) { tr->progs_cnt[BPF_TRAMP_FENTRY]--; - hlist_del_init(&tr_link->fexit.tramp_hlist); + hlist_del_init(&fexit->tramp_hlist); tr->progs_cnt[BPF_TRAMP_FEXIT]--; } else { tr->progs_cnt[kind]--; @@ -936,10 +957,9 @@ static int __bpf_trampoline_unlink_prog(struct bpf_tramp_node *node, tgt_prog->aux->is_extended = false; return err; } else if (kind == BPF_TRAMP_FSESSION) { - struct bpf_tracing_link *tr_link = - container_of(node, struct bpf_tracing_link, link.node); + struct bpf_tramp_node *fexit = fsession_exit(node); - hlist_del_init(&tr_link->fexit.tramp_hlist); + hlist_del_init(&fexit->tramp_hlist); tr->progs_cnt[BPF_TRAMP_FEXIT]--; kind = BPF_TRAMP_FENTRY; } @@ -1583,6 +1603,11 @@ int bpf_trampoline_multi_attach(struct bpf_prog *prog, u32 *ids, mnode->trampoline = tr; mnode->node.link = &link->link; mnode->node.cookie = link->cookies ? link->cookies[i] : 0; + + if (prog->expected_attach_type == BPF_TRACE_FSESSION_MULTI) { + link->fexits[i].link = &link->link; + link->fexits[i].cookie = link->cookies ? link->cookies[i] : 0; + } } trampoline_lock_all(); diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index ff29e27a85d0..aea514b2c12b 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -17921,6 +17921,7 @@ static bool return_retval_range(struct bpf_verifier_env *env, struct bpf_retval_ case BPF_TRACE_FSESSION: case BPF_TRACE_FENTRY_MULTI: case BPF_TRACE_FEXIT_MULTI: + case BPF_TRACE_FSESSION_MULTI: *range = retval_range(0, 0); break; case BPF_TRACE_RAW_TP: @@ -23310,7 +23311,8 @@ static int fixup_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, insn_buf[0] = BPF_MOV64_REG(BPF_REG_0, BPF_REG_1); *cnt = 1; } else if (desc->func_id == special_kfunc_list[KF_bpf_session_is_return] && - env->prog->expected_attach_type == BPF_TRACE_FSESSION) { + (env->prog->expected_attach_type == BPF_TRACE_FSESSION || + env->prog->expected_attach_type == BPF_TRACE_FSESSION_MULTI)) { /* * inline the bpf_session_is_return() for fsession: * bool bpf_session_is_return(void *ctx) @@ -23323,7 +23325,8 @@ static int fixup_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, insn_buf[2] = BPF_ALU64_IMM(BPF_AND, BPF_REG_0, 1); *cnt = 3; } else if (desc->func_id == special_kfunc_list[KF_bpf_session_cookie] && - env->prog->expected_attach_type == BPF_TRACE_FSESSION) { + (env->prog->expected_attach_type == BPF_TRACE_FSESSION || + env->prog->expected_attach_type == BPF_TRACE_FSESSION_MULTI)) { /* * inline bpf_session_cookie() for fsession: * __u64 *bpf_session_cookie(void *ctx) @@ -24111,6 +24114,7 @@ static int do_misc_fixups(struct bpf_verifier_env *env) if (eatype == BPF_TRACE_FEXIT || eatype == BPF_TRACE_FSESSION || eatype == BPF_TRACE_FEXIT_MULTI || + eatype == BPF_TRACE_FSESSION_MULTI || eatype == BPF_MODIFY_RETURN) { /* Load nr_args from ctx - 8 */ insn_buf[0] = BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8); @@ -25122,7 +25126,8 @@ int bpf_check_attach_target(struct bpf_verifier_log *log, prog_extension && (tgt_prog->expected_attach_type == BPF_TRACE_FENTRY || tgt_prog->expected_attach_type == BPF_TRACE_FEXIT || - tgt_prog->expected_attach_type == BPF_TRACE_FSESSION)) { + tgt_prog->expected_attach_type == BPF_TRACE_FSESSION || + tgt_prog->expected_attach_type == BPF_TRACE_FSESSION_MULTI)) { /* Program extensions can extend all program types * except fentry/fexit. The reason is the following. * The fentry/fexit programs are used for performance @@ -25222,9 +25227,11 @@ int bpf_check_attach_target(struct bpf_verifier_log *log, case BPF_TRACE_FENTRY: case BPF_TRACE_FEXIT: case BPF_TRACE_FSESSION: + case BPF_TRACE_FSESSION_MULTI: case BPF_TRACE_FENTRY_MULTI: case BPF_TRACE_FEXIT_MULTI: - if (prog->expected_attach_type == BPF_TRACE_FSESSION && + if ((prog->expected_attach_type == BPF_TRACE_FSESSION || + prog->expected_attach_type == BPF_TRACE_FSESSION_MULTI) && !bpf_jit_supports_fsession()) { bpf_log(log, "JIT does not support fsession\n"); return -EOPNOTSUPP; @@ -25376,6 +25383,7 @@ static bool can_be_sleepable(struct bpf_prog *prog) case BPF_MODIFY_RETURN: case BPF_TRACE_ITER: case BPF_TRACE_FSESSION: + case BPF_TRACE_FSESSION_MULTI: case BPF_TRACE_FENTRY_MULTI: case BPF_TRACE_FEXIT_MULTI: return true; @@ -25462,6 +25470,7 @@ static int check_attach_btf_id(struct bpf_verifier_env *env) return -EINVAL; } else if ((prog->expected_attach_type == BPF_TRACE_FEXIT || prog->expected_attach_type == BPF_TRACE_FSESSION || + prog->expected_attach_type == BPF_TRACE_FSESSION_MULTI || prog->expected_attach_type == BPF_MODIFY_RETURN) && btf_id_set_contains(&noreturn_deny, btf_id)) { verbose(env, "Attaching fexit/fsession/fmod_ret to __noreturn function '%s' is rejected.\n", diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index b8932434e306..3070b9de174d 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -1306,7 +1306,8 @@ static inline bool is_uprobe_session(const struct bpf_prog *prog) static inline bool is_trace_fsession(const struct bpf_prog *prog) { return prog->type == BPF_PROG_TYPE_TRACING && - prog->expected_attach_type == BPF_TRACE_FSESSION; + (prog->expected_attach_type == BPF_TRACE_FSESSION || + prog->expected_attach_type == BPF_TRACE_FSESSION_MULTI); } static const struct bpf_func_proto * @@ -3612,6 +3613,7 @@ static void bpf_tracing_multi_link_dealloc(struct bpf_link *link) struct bpf_tracing_multi_link *tr_link = container_of(link, struct bpf_tracing_multi_link, link); + kvfree(tr_link->fexits); kvfree(tr_link->cookies); kvfree(tr_link); } @@ -3624,6 +3626,7 @@ static const struct bpf_link_ops bpf_tracing_multi_link_lops = { int bpf_tracing_multi_attach(struct bpf_prog *prog, const union bpf_attr *attr) { struct bpf_tracing_multi_link *link = NULL; + struct bpf_tramp_node *fexits = NULL; struct bpf_link_primer link_primer; u32 cnt, *ids = NULL; u64 *cookies = NULL; @@ -3661,6 +3664,14 @@ int bpf_tracing_multi_attach(struct bpf_prog *prog, const union bpf_attr *attr) } } + if (prog->expected_attach_type == BPF_TRACE_FSESSION_MULTI) { + fexits = kvmalloc_array(cnt, sizeof(*fexits), GFP_KERNEL); + if (!fexits) { + err = -ENOMEM; + goto error; + } + } + link = kvzalloc(struct_size(link, nodes, cnt), GFP_KERNEL); if (!link) { err = -ENOMEM; @@ -3676,6 +3687,7 @@ int bpf_tracing_multi_attach(struct bpf_prog *prog, const union bpf_attr *attr) link->nodes_cnt = cnt; link->cookies = cookies; + link->fexits = fexits; err = bpf_trampoline_multi_attach(prog, ids, link); kvfree(ids); @@ -3686,6 +3698,7 @@ int bpf_tracing_multi_attach(struct bpf_prog *prog, const union bpf_attr *attr) return bpf_link_settle(&link_primer); error: + kvfree(fexits); kvfree(cookies); kvfree(ids); kvfree(link); diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c index 3373450132f0..1aa07d40c80c 100644 --- a/net/bpf/test_run.c +++ b/net/bpf/test_run.c @@ -688,6 +688,7 @@ int bpf_prog_test_run_tracing(struct bpf_prog *prog, case BPF_TRACE_FSESSION: case BPF_TRACE_FENTRY_MULTI: case BPF_TRACE_FEXIT_MULTI: + case BPF_TRACE_FSESSION_MULTI: if (bpf_fentry_test1(1) != 2 || bpf_fentry_test2(2, 3) != 5 || bpf_fentry_test3(4, 5, 6) != 15 || diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index e28722ddeb5b..4520830fda06 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -1156,6 +1156,7 @@ enum bpf_attach_type { BPF_TRACE_FSESSION, BPF_TRACE_FENTRY_MULTI, BPF_TRACE_FEXIT_MULTI, + BPF_TRACE_FSESSION_MULTI, __MAX_BPF_ATTACH_TYPE }; diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 74e579d7f310..1eb3869e3444 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -138,6 +138,7 @@ static const char * const attach_type_name[] = { [BPF_TRACE_UPROBE_SESSION] = "trace_uprobe_session", [BPF_TRACE_FENTRY_MULTI] = "trace_fentry_multi", [BPF_TRACE_FEXIT_MULTI] = "trace_fexit_multi", + [BPF_TRACE_FSESSION_MULTI] = "trace_fsession_multi", }; static const char * const link_type_name[] = { -- 2.53.0
