From patchwork Fri Mar 10 23:07:41 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dave Marchevsky X-Patchwork-Id: 13170383 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id AE188C6FA99 for ; Fri, 10 Mar 2023 23:08:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229827AbjCJXIF (ORCPT ); Fri, 10 Mar 2023 18:08:05 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58482 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231269AbjCJXID (ORCPT ); Fri, 10 Mar 2023 18:08:03 -0500 Received: from mx0a-00082601.pphosted.com (mx0a-00082601.pphosted.com [67.231.145.42]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4BF331284B for ; Fri, 10 Mar 2023 15:08:01 -0800 (PST) Received: from pps.filterd (m0044010.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 32AMXIv1000609 for ; Fri, 10 Mar 2023 15:08:01 -0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding : content-type; s=facebook; bh=6ecJVaK+1eQJBBDoPmSlxZHIKPeCG7kiAXjXv6RS+bA=; b=EAZ1ZrsPoyWGEzcgcvJqoe0EEmhGo6uZfRm/tojejU0OkpRpEqAVPmI6Vm7rpNaruQ1B 4ETUakG8KOLoR63R/dWbb/OvFgArdWHgN9S/OjGx0XhiNgsjV+naUDDWCopsa6TLyE5c jER2cuqOlzm7+UDUDBwzM44Dam1o0hQSBX8= Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0a-00082601.pphosted.com (PPS) with ESMTPS id 3p7sp5f4d4-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Fri, 10 Mar 2023 15:08:00 -0800 Received: from ash-exhub204.TheFacebook.com (2620:10d:c0a8:83::4) by ash-exhub103.TheFacebook.com (2620:10d:c0a8:82::c) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.17; Fri, 10 Mar 2023 15:07:58 -0800 Received: from twshared21760.39.frc1.facebook.com (2620:10d:c0a8:1b::d) by mail.thefacebook.com (2620:10d:c0a8:83::4) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.17; Fri, 10 Mar 2023 15:07:58 -0800 Received: by devbig077.ldc1.facebook.com (Postfix, from userid 158236) id D04E81902A1FF; Fri, 10 Mar 2023 15:07:44 -0800 (PST) From: Dave Marchevsky To: CC: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Kernel Team , , Dave Marchevsky Subject: [PATCH v2 bpf-next 1/3] bpf: Support __kptr to local kptrs Date: Fri, 10 Mar 2023 15:07:41 -0800 Message-ID: <20230310230743.2320707-2-davemarchevsky@fb.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230310230743.2320707-1-davemarchevsky@fb.com> References: <20230310230743.2320707-1-davemarchevsky@fb.com> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-ORIG-GUID: zcAZX9K6Qv43ZssCK3n9YZ6TIEeeGRJH X-Proofpoint-GUID: zcAZX9K6Qv43ZssCK3n9YZ6TIEeeGRJH X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.254,Aquarius:18.0.942,Hydra:6.0.573,FMLib:17.11.170.22 definitions=2023-03-10_10,2023-03-10_01,2023-02-09_01 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net If a PTR_TO_BTF_ID type comes from program BTF - not vmlinux or module BTF - it must have been allocated by bpf_obj_new and therefore must be free'd with bpf_obj_drop. Such a PTR_TO_BTF_ID is considered a "local kptr" and is tagged with MEM_ALLOC type tag by bpf_obj_new. This patch adds support for treating __kptr-tagged pointers to "local kptrs" as having an implicit bpf_obj_drop destructor for referenced kptr acquire / release semantics. Consider the following example: struct node_data { long key; long data; struct bpf_rb_node node; }; struct map_value { struct node_data __kptr *node; }; struct { __uint(type, BPF_MAP_TYPE_ARRAY); __type(key, int); __type(value, struct map_value); __uint(max_entries, 1); } some_nodes SEC(".maps"); If struct node_data had a matching definition in kernel BTF, the verifier would expect a destructor for the type to be registered. Since struct node_data does not match any type in kernel BTF, the verifier knows that there is no kfunc that provides a PTR_TO_BTF_ID to this type, and that such a PTR_TO_BTF_ID can only come from bpf_obj_new. So instead of searching for a registered dtor, a bpf_obj_drop dtor can be assumed. This allows the runtime to properly destruct such kptrs in bpf_obj_free_fields, which enables maps to clean up map_vals w/ such kptrs when going away. Implementation notes: * "kernel_btf" variable is renamed to "kptr_btf" in btf_parse_kptr. Before this patch, the variable would only ever point to vmlinux or module BTFs, but now it can point to some program BTF for local kptr type. It's later used to populate the (btf, btf_id) pair in kptr btf field. * It's necessary to btf_get the program BTF when populating btf_field for local kptr. btf_record_free later does a btf_put. * Behavior for non-local referenced kptrs is not modified, as bpf_find_btf_id helper only searches vmlinux and module BTFs for matching BTF type. If such a type is found, btf_field_kptr's btf will pass btf_is_kernel check, and the associated release function is some one-argument dtor. If btf_is_kernel check fails, associated release function is two-arg bpf_obj_drop_impl. Before this patch only btf_field_kptr's w/ kernel or module BTFs were created. Signed-off-by: Dave Marchevsky --- include/linux/bpf.h | 11 ++++++++++- include/linux/btf.h | 2 -- kernel/bpf/btf.c | 37 ++++++++++++++++++++++++++++--------- kernel/bpf/helpers.c | 11 ++++++++--- kernel/bpf/syscall.c | 14 +++++++++++++- 5 files changed, 59 insertions(+), 16 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 3a38db315f7f..756b85f0d0d3 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -189,10 +189,19 @@ enum btf_field_type { BPF_RB_NODE | BPF_RB_ROOT, }; +typedef void (*btf_dtor_kfunc_t)(void *); +typedef void (*btf_dtor_obj_drop)(void *, const struct btf_record *); + struct btf_field_kptr { struct btf *btf; struct module *module; - btf_dtor_kfunc_t dtor; + union { + /* dtor used if btf_is_kernel(btf), otherwise the type + * is program-allocated and obj_drop is used + */ + btf_dtor_kfunc_t dtor; + btf_dtor_obj_drop obj_drop; + }; u32 btf_id; }; diff --git a/include/linux/btf.h b/include/linux/btf.h index 1bba0827e8c4..d53b10cc55f2 100644 --- a/include/linux/btf.h +++ b/include/linux/btf.h @@ -121,8 +121,6 @@ struct btf_struct_metas { struct btf_struct_meta types[]; }; -typedef void (*btf_dtor_kfunc_t)(void *); - extern const struct file_operations btf_fops; void btf_get(struct btf *btf); diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 37779ceefd09..66fad7a16b6c 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -3551,12 +3551,17 @@ static int btf_find_field(const struct btf *btf, const struct btf_type *t, return -EINVAL; } +extern void __bpf_obj_drop_impl(void *p, const struct btf_record *rec); + static int btf_parse_kptr(const struct btf *btf, struct btf_field *field, struct btf_field_info *info) { struct module *mod = NULL; const struct btf_type *t; - struct btf *kernel_btf; + /* If a matching btf type is found in kernel or module BTFs, kptr_ref + * is that BTF, otherwise it's program BTF + */ + struct btf *kptr_btf; int ret; s32 id; @@ -3565,7 +3570,20 @@ static int btf_parse_kptr(const struct btf *btf, struct btf_field *field, */ t = btf_type_by_id(btf, info->kptr.type_id); id = bpf_find_btf_id(__btf_name_by_offset(btf, t->name_off), BTF_INFO_KIND(t->info), - &kernel_btf); + &kptr_btf); + if (id == -ENOENT) { + /* btf_parse_kptr should only be called w/ btf = program BTF */ + WARN_ON_ONCE(btf_is_kernel(btf)); + + /* Type exists only in program BTF. Assume that it's a MEM_ALLOC + * kptr allocated via bpf_obj_new + */ + field->kptr.dtor = (void *)&__bpf_obj_drop_impl; + id = info->kptr.type_id; + kptr_btf = (struct btf *)btf; + btf_get(kptr_btf); + goto found_dtor; + } if (id < 0) return id; @@ -3582,20 +3600,20 @@ static int btf_parse_kptr(const struct btf *btf, struct btf_field *field, * can be used as a referenced pointer and be stored in a map at * the same time. */ - dtor_btf_id = btf_find_dtor_kfunc(kernel_btf, id); + dtor_btf_id = btf_find_dtor_kfunc(kptr_btf, id); if (dtor_btf_id < 0) { ret = dtor_btf_id; goto end_btf; } - dtor_func = btf_type_by_id(kernel_btf, dtor_btf_id); + dtor_func = btf_type_by_id(kptr_btf, dtor_btf_id); if (!dtor_func) { ret = -ENOENT; goto end_btf; } - if (btf_is_module(kernel_btf)) { - mod = btf_try_get_module(kernel_btf); + if (btf_is_module(kptr_btf)) { + mod = btf_try_get_module(kptr_btf); if (!mod) { ret = -ENXIO; goto end_btf; @@ -3605,7 +3623,7 @@ static int btf_parse_kptr(const struct btf *btf, struct btf_field *field, /* We already verified dtor_func to be btf_type_is_func * in register_btf_id_dtor_kfuncs. */ - dtor_func_name = __btf_name_by_offset(kernel_btf, dtor_func->name_off); + dtor_func_name = __btf_name_by_offset(kptr_btf, dtor_func->name_off); addr = kallsyms_lookup_name(dtor_func_name); if (!addr) { ret = -EINVAL; @@ -3614,14 +3632,15 @@ static int btf_parse_kptr(const struct btf *btf, struct btf_field *field, field->kptr.dtor = (void *)addr; } +found_dtor: field->kptr.btf_id = id; - field->kptr.btf = kernel_btf; + field->kptr.btf = kptr_btf; field->kptr.module = mod; return 0; end_mod: module_put(mod); end_btf: - btf_put(kernel_btf); + btf_put(kptr_btf); return ret; } diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index f9b7eeedce08..77d64b6951b9 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -1896,14 +1896,19 @@ __bpf_kfunc void *bpf_obj_new_impl(u64 local_type_id__k, void *meta__ign) return p; } +void __bpf_obj_drop_impl(void *p, const struct btf_record *rec) +{ + if (rec) + bpf_obj_free_fields(rec, p); + bpf_mem_free(&bpf_global_ma, p); +} + __bpf_kfunc void bpf_obj_drop_impl(void *p__alloc, void *meta__ign) { struct btf_struct_meta *meta = meta__ign; void *p = p__alloc; - if (meta) - bpf_obj_free_fields(meta->record, p); - bpf_mem_free(&bpf_global_ma, p); + __bpf_obj_drop_impl(p, meta ? meta->record : NULL); } static void __bpf_list_add(struct bpf_list_node *node, struct bpf_list_head *head, bool tail) diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index cc4b7684910c..0684febc447a 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -659,8 +659,10 @@ void bpf_obj_free_fields(const struct btf_record *rec, void *obj) return; fields = rec->fields; for (i = 0; i < rec->cnt; i++) { + struct btf_struct_meta *pointee_struct_meta; const struct btf_field *field = &fields[i]; void *field_ptr = obj + field->offset; + void *xchgd_field; switch (fields[i].type) { case BPF_SPIN_LOCK: @@ -672,7 +674,17 @@ void bpf_obj_free_fields(const struct btf_record *rec, void *obj) WRITE_ONCE(*(u64 *)field_ptr, 0); break; case BPF_KPTR_REF: - field->kptr.dtor((void *)xchg((unsigned long *)field_ptr, 0)); + xchgd_field = (void *)xchg((unsigned long *)field_ptr, 0); + if (!btf_is_kernel(field->kptr.btf)) { + pointee_struct_meta = btf_find_struct_meta(field->kptr.btf, + field->kptr.btf_id); + WARN_ON_ONCE(!pointee_struct_meta); + field->kptr.obj_drop(xchgd_field, pointee_struct_meta ? + pointee_struct_meta->record : + NULL); + } else { + field->kptr.dtor(xchgd_field); + } break; case BPF_LIST_HEAD: if (WARN_ON_ONCE(rec->spin_lock_off < 0)) From patchwork Fri Mar 10 23:07:42 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dave Marchevsky X-Patchwork-Id: 13170384 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B5510C6FD1E for ; Fri, 10 Mar 2023 23:08:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231589AbjCJXIF (ORCPT ); Fri, 10 Mar 2023 18:08:05 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58458 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230232AbjCJXID (ORCPT ); Fri, 10 Mar 2023 18:08:03 -0500 Received: from mx0a-00082601.pphosted.com (mx0b-00082601.pphosted.com [67.231.153.30]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 544C4CC07 for ; Fri, 10 Mar 2023 15:07:59 -0800 (PST) Received: from pps.filterd (m0089730.ppops.net [127.0.0.1]) by m0089730.ppops.net (8.17.1.19/8.17.1.19) with ESMTP id 32AM60nu023368 for ; Fri, 10 Mar 2023 15:07:58 -0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding : content-type; s=facebook; bh=W74Cdb8SP5/W9C5GE6xabPQ9i9GblOQeXnEmczfbnFM=; b=JLBHWpl3Cr4UufbmCQx5pUroHZPVHE/Aq6y3Pg4NcoXeWtn07z29QKPCiaU+p2UDuKPB fDWuBy5KBIkiA4DCgAmxigeLix37CtRVsz6I6IoEFYXb1fWIJgy0JxqEpZJ7HvacOqic 1H8n8RN0dNFSnhpIBky/3apChLNEo0/jrI0= Received: from maileast.thefacebook.com ([163.114.130.16]) by m0089730.ppops.net (PPS) with ESMTPS id 3p7p0xhcfm-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Fri, 10 Mar 2023 15:07:58 -0800 Received: from twshared4298.02.ash9.facebook.com (2620:10d:c0a8:1b::d) by mail.thefacebook.com (2620:10d:c0a8:82::d) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.17; Fri, 10 Mar 2023 15:07:56 -0800 Received: by devbig077.ldc1.facebook.com (Postfix, from userid 158236) id BAB591902A20B; Fri, 10 Mar 2023 15:07:45 -0800 (PST) From: Dave Marchevsky To: CC: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Kernel Team , , Dave Marchevsky Subject: [PATCH v2 bpf-next 2/3] bpf: Allow local kptrs to be exchanged via bpf_kptr_xchg Date: Fri, 10 Mar 2023 15:07:42 -0800 Message-ID: <20230310230743.2320707-3-davemarchevsky@fb.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230310230743.2320707-1-davemarchevsky@fb.com> References: <20230310230743.2320707-1-davemarchevsky@fb.com> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-ORIG-GUID: vK_ZUwIrh5mM76S0wCgbedNwtMF71lBz X-Proofpoint-GUID: vK_ZUwIrh5mM76S0wCgbedNwtMF71lBz X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.254,Aquarius:18.0.942,Hydra:6.0.573,FMLib:17.11.170.22 definitions=2023-03-10_10,2023-03-10_01,2023-02-09_01 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net The previous patch added necessary plumbing for verifier and runtime to know what to do with non-kernel PTR_TO_BTF_IDs in map values, but didn't provide any way to get such local kptrs into a map value. This patch modifies verifier handling of bpf_kptr_xchg to allow MEM_ALLOC kptr types. check_reg_type is modified accept MEM_ALLOC-flagged input to bpf_kptr_xchg despite such types not being in btf_ptr_types. This could have been done with a MAYBE_MEM_ALLOC equivalent to MAYBE_NULL, but bpf_kptr_xchg is the only helper that I can forsee using MAYBE_MEM_ALLOC, so keep it special-cased for now. The verifier tags bpf_kptr_xchg retval MEM_ALLOC if and only if the BTF associated with the retval is not kernel BTF. Signed-off-by: Dave Marchevsky --- kernel/bpf/verifier.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 073c56dbec63..519d465407ef 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -7123,6 +7123,9 @@ static int check_reg_type(struct bpf_verifier_env *env, u32 regno, if (arg_type & PTR_MAYBE_NULL) type &= ~PTR_MAYBE_NULL; + if (meta->func_id == BPF_FUNC_kptr_xchg && type & MEM_ALLOC) + type &= ~MEM_ALLOC; + for (i = 0; i < ARRAY_SIZE(compatible->types); i++) { expected = compatible->types[i]; if (expected == NOT_INIT) @@ -7185,7 +7188,8 @@ static int check_reg_type(struct bpf_verifier_env *env, u32 regno, break; } case PTR_TO_BTF_ID | MEM_ALLOC: - if (meta->func_id != BPF_FUNC_spin_lock && meta->func_id != BPF_FUNC_spin_unlock) { + if (meta->func_id != BPF_FUNC_spin_lock && meta->func_id != BPF_FUNC_spin_unlock && + meta->func_id != BPF_FUNC_kptr_xchg) { verbose(env, "verifier internal error: unimplemented handling of MEM_ALLOC\n"); return -EFAULT; } @@ -9151,6 +9155,8 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn if (func_id == BPF_FUNC_kptr_xchg) { ret_btf = meta.kptr_field->kptr.btf; ret_btf_id = meta.kptr_field->kptr.btf_id; + if (!btf_is_kernel(ret_btf)) + regs[BPF_REG_0].type |= MEM_ALLOC; } else { if (fn->ret_btf_id == BPF_PTR_POISON) { verbose(env, "verifier internal error:"); From patchwork Fri Mar 10 23:07:43 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dave Marchevsky X-Patchwork-Id: 13170385 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1A895C6FD19 for ; Fri, 10 Mar 2023 23:08:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230460AbjCJXIQ (ORCPT ); Fri, 10 Mar 2023 18:08:16 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59064 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231366AbjCJXIO (ORCPT ); Fri, 10 Mar 2023 18:08:14 -0500 Received: from mx0a-00082601.pphosted.com (mx0a-00082601.pphosted.com [67.231.145.42]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 01DDD2331B for ; Fri, 10 Mar 2023 15:08:10 -0800 (PST) Received: from pps.filterd (m0148461.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 32AMdYpx001910 for ; Fri, 10 Mar 2023 15:08:10 -0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding : content-type; s=facebook; bh=meW9fN007JFLBzHsn52WNHiMcEdWC8KNJ2rDF+qdnzU=; b=Snmmh8kNV3P91NjqTGgGB8C9z5Q0+vhFr+oydH63O6CiNzdKgJEqN0rGqrtdW7ALb1nJ vxCUj8Zw23ALIRbEdUxJztE8iwSuzc3fcC1xV3tcYGkNQ/sBvNRdaLJ3apXCzMFHgIlh QAXqXpzaUeraeuNN8IQimr9+zinfQnBCjc4= Received: from mail.thefacebook.com ([163.114.132.120]) by mx0a-00082601.pphosted.com (PPS) with ESMTPS id 3p86w0k4ue-3 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Fri, 10 Mar 2023 15:08:10 -0800 Received: from twshared21709.17.frc2.facebook.com (2620:10d:c085:208::11) by mail.thefacebook.com (2620:10d:c085:11d::7) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.17; Fri, 10 Mar 2023 15:07:58 -0800 Received: by devbig077.ldc1.facebook.com (Postfix, from userid 158236) id CFCAE1902A211; Fri, 10 Mar 2023 15:07:47 -0800 (PST) From: Dave Marchevsky To: CC: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Kernel Team , , Dave Marchevsky Subject: [PATCH v2 bpf-next 3/3] selftests/bpf: Add local kptr stashing test Date: Fri, 10 Mar 2023 15:07:43 -0800 Message-ID: <20230310230743.2320707-4-davemarchevsky@fb.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230310230743.2320707-1-davemarchevsky@fb.com> References: <20230310230743.2320707-1-davemarchevsky@fb.com> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-ORIG-GUID: oxpEt1vw3pMGhsOZF24q_bJxL-4MKNWW X-Proofpoint-GUID: oxpEt1vw3pMGhsOZF24q_bJxL-4MKNWW X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.254,Aquarius:18.0.942,Hydra:6.0.573,FMLib:17.11.170.22 definitions=2023-03-10_10,2023-03-10_01,2023-02-09_01 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Add a new selftest, local_kptr_stash, which uses bpf_kptr_xchg to stash a bpf_obj_new-allocated object in a map. Test the following scenarios: * Stash two rb_nodes in an arraymap, don't unstash them, rely on map free to destruct them * Stash two rb_nodes in an arraymap, unstash the second one in a separate program, rely on map free to destruct first Signed-off-by: Dave Marchevsky --- .../bpf/prog_tests/local_kptr_stash.c | 60 ++++++++++ .../selftests/bpf/progs/local_kptr_stash.c | 108 ++++++++++++++++++ 2 files changed, 168 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/local_kptr_stash.c create mode 100644 tools/testing/selftests/bpf/progs/local_kptr_stash.c diff --git a/tools/testing/selftests/bpf/prog_tests/local_kptr_stash.c b/tools/testing/selftests/bpf/prog_tests/local_kptr_stash.c new file mode 100644 index 000000000000..76f1da877f81 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/local_kptr_stash.c @@ -0,0 +1,60 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */ + +#include +#include + +#include "local_kptr_stash.skel.h" +static void test_local_kptr_stash_simple(void) +{ + LIBBPF_OPTS(bpf_test_run_opts, opts, + .data_in = &pkt_v4, + .data_size_in = sizeof(pkt_v4), + .repeat = 1, + ); + struct local_kptr_stash *skel; + int ret; + + skel = local_kptr_stash__open_and_load(); + if (!ASSERT_OK_PTR(skel, "local_kptr_stash__open_and_load")) + return; + + ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.stash_rb_nodes), &opts); + ASSERT_OK(ret, "local_kptr_stash_add_nodes run"); + ASSERT_OK(opts.retval, "local_kptr_stash_add_nodes retval"); + + local_kptr_stash__destroy(skel); +} + +static void test_local_kptr_stash_unstash(void) +{ + LIBBPF_OPTS(bpf_test_run_opts, opts, + .data_in = &pkt_v4, + .data_size_in = sizeof(pkt_v4), + .repeat = 1, + ); + struct local_kptr_stash *skel; + int ret; + + skel = local_kptr_stash__open_and_load(); + if (!ASSERT_OK_PTR(skel, "local_kptr_stash__open_and_load")) + return; + + ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.stash_rb_nodes), &opts); + ASSERT_OK(ret, "local_kptr_stash_add_nodes run"); + ASSERT_OK(opts.retval, "local_kptr_stash_add_nodes retval"); + + ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.unstash_rb_node), &opts); + ASSERT_OK(ret, "local_kptr_stash_add_nodes run"); + ASSERT_EQ(opts.retval, 42, "local_kptr_stash_add_nodes retval"); + + local_kptr_stash__destroy(skel); +} + +void test_local_kptr_stash_success(void) +{ + if (test__start_subtest("local_kptr_stash_simple")) + test_local_kptr_stash_simple(); + if (test__start_subtest("local_kptr_stash_unstash")) + test_local_kptr_stash_unstash(); +} diff --git a/tools/testing/selftests/bpf/progs/local_kptr_stash.c b/tools/testing/selftests/bpf/progs/local_kptr_stash.c new file mode 100644 index 000000000000..2e50ac1f64a0 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/local_kptr_stash.c @@ -0,0 +1,108 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */ + +#include +#include +#include +#include +#include "bpf_experimental.h" + +struct node_data { + long key; + long data; + struct bpf_rb_node node; +}; + +struct map_value { + struct prog_test_ref_kfunc *not_kptr; + struct prog_test_ref_kfunc __kptr *val; + struct node_data __kptr *node; +}; + +/* This is necessary so that LLVM generates BTF for node_data struct + * If it's not included, a fwd reference for node_data will be generated but + * no struct. Example BTF of "node" field in map_value when not included: + * + * [10] PTR '(anon)' type_id=35 + * [34] FWD 'node_data' fwd_kind=struct + * [35] TYPE_TAG 'kptr_ref' type_id=34 + * + * (with no node_data struct defined) + * Had to do the same w/ bpf_kfunc_call_test_release below + */ +struct node_data *just_here_because_btf_bug; + +extern void bpf_kfunc_call_test_release(struct prog_test_ref_kfunc *p) __ksym; + +struct { + __uint(type, BPF_MAP_TYPE_ARRAY); + __type(key, int); + __type(value, struct map_value); + __uint(max_entries, 2); +} some_nodes SEC(".maps"); + +static int create_and_stash(int idx, int val) +{ + struct map_value *mapval; + struct node_data *res; + + mapval = bpf_map_lookup_elem(&some_nodes, &idx); + if (!mapval) + return 1; + + res = bpf_obj_new(typeof(*res)); + if (!res) + return 1; + res->key = val; + + res = bpf_kptr_xchg(&mapval->node, res); + if (res) + bpf_obj_drop(res); + return 0; +} + +SEC("tc") +long stash_rb_nodes(void *ctx) +{ + return create_and_stash(0, 41) ?: create_and_stash(1, 42); +} + +SEC("tc") +long unstash_rb_node(void *ctx) +{ + struct map_value *mapval; + struct node_data *res; + long retval; + int key = 1; + + mapval = bpf_map_lookup_elem(&some_nodes, &key); + if (!mapval) + return 1; + + res = bpf_kptr_xchg(&mapval->node, NULL); + if (res) { + retval = res->key; + bpf_obj_drop(res); + return retval; + } + return 1; +} + +SEC("tc") +long stash_test_ref_kfunc(void *ctx) +{ + struct prog_test_ref_kfunc *res; + struct map_value *mapval; + int key = 0; + + mapval = bpf_map_lookup_elem(&some_nodes, &key); + if (!mapval) + return 1; + + res = bpf_kptr_xchg(&mapval->val, NULL); + if (res) + bpf_kfunc_call_test_release(res); + return 0; +} + +char _license[] SEC("license") = "GPL";