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[192.26.29.3]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-47fd41d0064sm26018984f8f.5.2026.08.02.15.52.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 02 Aug 2026 15:52:10 -0700 (PDT) From: Kumar Kartikeya Dwivedi To: bpf@vger.kernel.org Cc: Andrii Nakryiko , Alexei Starovoitov , Daniel Borkmann , Eduard Zingerman , Emil Tsalapatis , kkd@meta.com, kernel-team@meta.com Subject: [PATCH bpf-next v2 1/3] bpf: Show more useful info in stack depth stats Date: Mon, 3 Aug 2026 00:52:05 +0200 Message-ID: <20260802225209.2511758-2-memxor@gmail.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260802225209.2511758-1-memxor@gmail.com> References: <20260802225209.2511758-1-memxor@gmail.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=8865; i=memxor@gmail.com; h=from:subject; bh=fiX4SO33sQrCOuY30ddzwRHh18TmsoTB/t8uaw2rJBM=; b=owGbwMvMwCXmrmtenRyi38x4Wi2JISv/5P8pv3nfvjQOdrhsWnpWRcbqtaCU9f1t+7lE7HUvy vcfeqPcUcrCIMbFICumyFLyfx+T8YnK34G2y7hh5rAygQxh4OIUgIlsiWBkOHi8xVqx3XVjQ2Tw f5eSDrlHyr9PZui+qXU3Eea50DRtPsNvlq3nU7pmBZ9m+NWnIJH3wX2mzoP/O42WXFk1pUBaqyy QEQA= X-Developer-Key: i=memxor@gmail.com; a=openpgp; fpr=B34BD741DE8494B76E2F717880EF20021D46C59B Content-Transfer-Encoding: 8bit Currently, stack depth statistics are too crude, listing captured depths in subprogram-number order. Since libbpf determines those numbers, it is hard to associate each depth with its subprogram name. Print the maximum stack depth and each subprogram on separate lines: stack depth max stack depth subprog When no subprogram name is available, print . Suggested-by: Andrii Nakryiko Signed-off-by: Kumar Kartikeya Dwivedi --- kernel/bpf/verifier.c | 13 +++++++---- .../bpf/progs/verifier_basic_stack.c | 4 ++-- .../bpf/progs/verifier_bpf_fastcall.c | 23 ++++++++++++------- .../bpf/progs/verifier_private_stack.c | 15 +++++++++--- .../selftests/bpf/progs/verifier_var_off.c | 4 ++-- 5 files changed, 40 insertions(+), 19 deletions(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index b274004fccfd..3b61897ed0d2 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -18777,10 +18777,15 @@ static void print_verification_stats(struct bpf_verifier_env *env) if (env->log.level & BPF_LOG_STATS) { verbose(env, "verification time %lld usec\n", div_u64(env->verification_time, 1000)); - verbose(env, "stack depth %d", env->subprog_info[0].stack_depth); - for (i = 1; i < subprog_cnt; i++) - verbose(env, "+%d", env->subprog_info[i].stack_depth); - verbose(env, " max %d\n", env->max_stack_depth); + verbose(env, "stack depth max %d\n", env->max_stack_depth); + for (i = 0; i < subprog_cnt; i++) { + const char *name = env->subprog_info[i].name; + + if (!name || !name[0]) + name = ""; + verbose(env, "stack depth subprog %d %s %d\n", i, name, + env->subprog_info[i].stack_depth); + } verbose(env, "insns processed %d", env->subprog_info[0].insn_processed); for (i = 1; i < subprog_cnt; i++) if (bpf_subprog_is_global(env, i)) diff --git a/tools/testing/selftests/bpf/progs/verifier_basic_stack.c b/tools/testing/selftests/bpf/progs/verifier_basic_stack.c index fb62e09f2114..61ec8790fd21 100644 --- a/tools/testing/selftests/bpf/progs/verifier_basic_stack.c +++ b/tools/testing/selftests/bpf/progs/verifier_basic_stack.c @@ -27,7 +27,7 @@ __naked void stack_out_of_bounds(void) SEC("socket") __description("uninitialized stack1") -__success __log_level(4) __msg("stack depth 8") +__success __log_level(4) __msg("stack depth subprog 0 uninitialized_stack1 8") __failure_unpriv __msg_unpriv("invalid read from stack") __naked void uninitialized_stack1(void) { @@ -45,7 +45,7 @@ __naked void uninitialized_stack1(void) SEC("socket") __description("uninitialized stack2") -__success __log_level(4) __msg("stack depth 8") +__success __log_level(4) __msg("stack depth subprog 0 uninitialized_stack2 8") __failure_unpriv __msg_unpriv("invalid read from stack") __naked void uninitialized_stack2(void) { diff --git a/tools/testing/selftests/bpf/progs/verifier_bpf_fastcall.c b/tools/testing/selftests/bpf/progs/verifier_bpf_fastcall.c index 83707faea049..cb36866bfed3 100644 --- a/tools/testing/selftests/bpf/progs/verifier_bpf_fastcall.c +++ b/tools/testing/selftests/bpf/progs/verifier_bpf_fastcall.c @@ -10,7 +10,7 @@ SEC("raw_tp") __arch_x86_64 -__log_level(4) __msg("stack depth 8") +__log_level(4) __msg("stack depth subprog 0 simple 8") __xlated("4: r5 = 5") __xlated("5: r0 = ") __xlated("6: r0 = &(void __percpu *)(r0)") @@ -96,7 +96,7 @@ __naked void canary_zero_spills(void) SEC("raw_tp") __arch_x86_64 -__log_level(4) __msg("stack depth 16") +__log_level(4) __msg("stack depth subprog 0 wrong_reg_in_pattern1 16") __xlated("1: *(u64 *)(r10 -16) = r1") __xlated("...") __xlated("3: r0 = &(void __percpu *)(r0)") @@ -598,7 +598,7 @@ __naked static void subprogs_use_independent_offsets_aux(void) SEC("raw_tp") __arch_x86_64 -__log_level(4) __msg("stack depth 8") +__log_level(4) __msg("stack depth subprog 0 helper_call_does_not_prevent_bpf_fastcall 8") __xlated("2: r0 = &(void __percpu *)(r0)") __success __naked void helper_call_does_not_prevent_bpf_fastcall(void) @@ -620,7 +620,7 @@ __naked void helper_call_does_not_prevent_bpf_fastcall(void) SEC("raw_tp") __arch_x86_64 -__log_level(4) __msg("stack depth 24") +__log_level(4) __msg("stack depth subprog 0 may_goto_interaction_x86_64 24") /* may_goto counter at -24 */ __xlated("0: *(u64 *)(r10 -24) =") /* may_goto timestamp at -16 */ @@ -661,7 +661,7 @@ __naked void may_goto_interaction_x86_64(void) SEC("raw_tp") __arch_arm64 __arch_riscv64 -__log_level(4) __msg("stack depth 24") +__log_level(4) __msg("stack depth subprog 0 may_goto_interaction 24") /* may_goto counter at -24 */ __xlated("0: *(u64 *)(r10 -24) =") /* may_goto timestamp at -16 */ @@ -708,7 +708,9 @@ __naked static void dummy_loop_callback(void) SEC("raw_tp") __arch_x86_64 -__log_level(4) __msg("stack depth 32+0") +__log_level(4) +__msg("stack depth subprog 0 bpf_loop_interaction1 32") +__msg("stack depth subprog 1 dummy_loop_callback 0") __xlated("2: r1 = 1") __xlated("3: r0 =") __xlated("4: r0 = &(void __percpu *)(r0)") @@ -756,7 +758,9 @@ __naked int bpf_loop_interaction1(void) SEC("raw_tp") __arch_x86_64 -__log_level(4) __msg("stack depth 40+0") +__log_level(4) +__msg("stack depth subprog 0 bpf_loop_interaction2 40") +__msg("stack depth subprog 1 dummy_loop_callback 0") /* call bpf_get_smp_processor_id */ __xlated("2: r1 = 42") __xlated("3: r0 =") @@ -800,7 +804,10 @@ __naked int bpf_loop_interaction2(void) SEC("raw_tp") __arch_x86_64 -__log_level(4) __msg("stack depth 512+0 max 512") +__log_level(4) +__msg("stack depth max 512") +__msg("stack depth subprog 0 cumulative_stack_depth 512") +__msg("stack depth subprog 1 cumulative_stack_depth_subprog 0") /* just to print xlated version when debugging */ __xlated("r0 = &(void __percpu *)(r0)") __success diff --git a/tools/testing/selftests/bpf/progs/verifier_private_stack.c b/tools/testing/selftests/bpf/progs/verifier_private_stack.c index bb8206e10880..c818898836c1 100644 --- a/tools/testing/selftests/bpf/progs/verifier_private_stack.c +++ b/tools/testing/selftests/bpf/progs/verifier_private_stack.c @@ -86,7 +86,9 @@ __naked static void cumulative_stack_depth_subprog(void) SEC("kprobe") __description("Private stack, subtree > MAX_BPF_STACK") __success -__log_level(4) __msg("stack depth 512+32 max 512") +__log_level(4) __msg("stack depth max 512") +__msg("stack depth subprog 0 private_stack_nested_1 512") +__msg("stack depth subprog 1 cumulative_stack_depth_subprog 32") __arch_x86_64 /* private stack fp for the main prog */ __jited(" movabsq $0x{{.*}}, %r9") @@ -331,7 +333,11 @@ SEC("fentry/bpf_fentry_test9") __description("Private stack, async callback, potential nesting") __success __retval(0) __load_if_JITed() -__log_level(4) __msg("stack depth 8+0+256+0 max 272") +__log_level(4) __msg("stack depth max 272") +__msg("stack depth subprog 0 private_stack_async_callback_2 8") +__msg("stack depth subprog 1 timer_cb1 0") +__msg("stack depth subprog 2 subprog1 256") +__msg("stack depth subprog 3 subprog2 0") __arch_x86_64 __jited(" subq $0x100, %rsp") __arch_arm64 @@ -355,7 +361,10 @@ int private_stack_async_callback_2(void) SEC("fentry/bpf_fentry_test9") __description("private stack, max stack depth is private stack") __success -__log_level(4) __msg("stack depth 8+256+0 max 256") +__log_level(4) __msg("stack depth max 256") +__msg("stack depth subprog 0 private_stack_max_depth 8") +__msg("stack depth subprog 1 subprog1 256") +__msg("stack depth subprog 2 subprog2 0") int private_stack_max_depth(void) { int x = 0; diff --git a/tools/testing/selftests/bpf/progs/verifier_var_off.c b/tools/testing/selftests/bpf/progs/verifier_var_off.c index 24cd0a763673..df436bbc9ecf 100644 --- a/tools/testing/selftests/bpf/progs/verifier_var_off.c +++ b/tools/testing/selftests/bpf/progs/verifier_var_off.c @@ -198,7 +198,7 @@ __success /* Check that the maximum stack depth is correctly maintained according to the * maximum possible variable offset. */ -__log_level(4) __msg("stack depth 16") +__log_level(4) __msg("stack depth subprog 0 stack_write_priv_vs_unpriv 16") __failure_unpriv /* Variable stack access is rejected for unprivileged. */ @@ -238,7 +238,7 @@ __success /* Check that the maximum stack depth is correctly maintained according to the * maximum possible variable offset. */ -__log_level(4) __msg("stack depth 16") +__log_level(4) __msg("stack depth subprog 0 stack_write_followed_by_read 16") __failure_unpriv __msg_unpriv("R2 variable stack access prohibited for !root") __retval(0) -- 2.53.0