From 335ff4990cf3bfa42d8846f9b3d8c09456f51801 Mon Sep 17 00:00:00 2001 From: Dave Marchevsky Date: Fri, 17 Sep 2021 11:29:03 -0700 Subject: [PATCH 1/9] bpf: Merge printk and seq_printf VARARG max macros MAX_SNPRINTF_VARARGS and MAX_SEQ_PRINTF_VARARGS are used by bpf helpers bpf_snprintf and bpf_seq_printf to limit their varargs. Both call into bpf_bprintf_prepare for print formatting logic and have convenience macros in libbpf (BPF_SNPRINTF, BPF_SEQ_PRINTF) which use the same helper macros to convert varargs to a byte array. Changing shared functionality to support more varargs for either bpf helper would affect the other as well, so let's combine the _VARARGS macros to make this more obvious. Signed-off-by: Dave Marchevsky Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20210917182911.2426606-2-davemarchevsky@fb.com --- include/linux/bpf.h | 2 ++ kernel/bpf/helpers.c | 4 +--- kernel/trace/bpf_trace.c | 4 +--- 3 files changed, 4 insertions(+), 6 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index f4c16f19f83e..be8d57e6e78a 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -2216,6 +2216,8 @@ int bpf_arch_text_poke(void *ip, enum bpf_text_poke_type t, struct btf_id_set; bool btf_id_set_contains(const struct btf_id_set *set, u32 id); +#define MAX_BPRINTF_VARARGS 12 + int bpf_bprintf_prepare(char *fmt, u32 fmt_size, const u64 *raw_args, u32 **bin_buf, u32 num_args); void bpf_bprintf_cleanup(void); diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 9aabf84afd4b..8f9f392c1322 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -979,15 +979,13 @@ int bpf_bprintf_prepare(char *fmt, u32 fmt_size, const u64 *raw_args, return err; } -#define MAX_SNPRINTF_VARARGS 12 - BPF_CALL_5(bpf_snprintf, char *, str, u32, str_size, char *, fmt, const void *, data, u32, data_len) { int err, num_args; u32 *bin_args; - if (data_len % 8 || data_len > MAX_SNPRINTF_VARARGS * 8 || + if (data_len % 8 || data_len > MAX_BPRINTF_VARARGS * 8 || (data_len && !data)) return -EINVAL; num_args = data_len / 8; diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 067e88c3d2ee..4ec779fa0c1d 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -414,15 +414,13 @@ const struct bpf_func_proto *bpf_get_trace_printk_proto(void) return &bpf_trace_printk_proto; } -#define MAX_SEQ_PRINTF_VARARGS 12 - BPF_CALL_5(bpf_seq_printf, struct seq_file *, m, char *, fmt, u32, fmt_size, const void *, data, u32, data_len) { int err, num_args; u32 *bin_args; - if (data_len & 7 || data_len > MAX_SEQ_PRINTF_VARARGS * 8 || + if (data_len & 7 || data_len > MAX_BPRINTF_VARARGS * 8 || (data_len && !data)) return -EINVAL; num_args = data_len / 8; From 84b4c52960bdccd86d6c3c42a730fd8d0ab75427 Mon Sep 17 00:00:00 2001 From: Dave Marchevsky Date: Fri, 17 Sep 2021 11:29:04 -0700 Subject: [PATCH 2/9] selftests/bpf: Stop using bpf_program__load bpf_program__load is not supposed to be used directly. Replace it with bpf_object__ APIs for the reference_tracking prog_test, which is the last offender in bpf selftests. Some additional complexity is added for this test, namely the use of one bpf_object to iterate through progs, while a second bpf_object is created and opened/closed to test actual loading of progs. This is because the test was doing bpf_program__load then __unload to test loading of individual progs and same semantics with bpf_object__load/__unload result in failure to load an __unload-ed obj. Signed-off-by: Dave Marchevsky Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20210917182911.2426606-3-davemarchevsky@fb.com --- .../bpf/prog_tests/reference_tracking.c | 39 +++++++++++++++---- 1 file changed, 31 insertions(+), 8 deletions(-) diff --git a/tools/testing/selftests/bpf/prog_tests/reference_tracking.c b/tools/testing/selftests/bpf/prog_tests/reference_tracking.c index 4e91f4d6466c..ded2dc8ddd79 100644 --- a/tools/testing/selftests/bpf/prog_tests/reference_tracking.c +++ b/tools/testing/selftests/bpf/prog_tests/reference_tracking.c @@ -1,6 +1,21 @@ // SPDX-License-Identifier: GPL-2.0 #include +static void toggle_object_autoload_progs(const struct bpf_object *obj, + const char *title_load) +{ + struct bpf_program *prog; + + bpf_object__for_each_program(prog, obj) { + const char *title = bpf_program__section_name(prog); + + if (!strcmp(title_load, title)) + bpf_program__set_autoload(prog, true); + else + bpf_program__set_autoload(prog, false); + } +} + void test_reference_tracking(void) { const char *file = "test_sk_lookup_kern.o"; @@ -9,21 +24,21 @@ void test_reference_tracking(void) .object_name = obj_name, .relaxed_maps = true, ); - struct bpf_object *obj; + struct bpf_object *obj_iter, *obj = NULL; struct bpf_program *prog; __u32 duration = 0; int err = 0; - obj = bpf_object__open_file(file, &open_opts); - if (!ASSERT_OK_PTR(obj, "obj_open_file")) + obj_iter = bpf_object__open_file(file, &open_opts); + if (!ASSERT_OK_PTR(obj_iter, "obj_iter_open_file")) return; - if (CHECK(strcmp(bpf_object__name(obj), obj_name), "obj_name", + if (CHECK(strcmp(bpf_object__name(obj_iter), obj_name), "obj_name", "wrong obj name '%s', expected '%s'\n", - bpf_object__name(obj), obj_name)) + bpf_object__name(obj_iter), obj_name)) goto cleanup; - bpf_object__for_each_program(prog, obj) { + bpf_object__for_each_program(prog, obj_iter) { const char *title; /* Ignore .text sections */ @@ -34,19 +49,27 @@ void test_reference_tracking(void) if (!test__start_subtest(title)) continue; + obj = bpf_object__open_file(file, &open_opts); + if (!ASSERT_OK_PTR(obj, "obj_open_file")) + goto cleanup; + + toggle_object_autoload_progs(obj, title); /* Expect verifier failure if test name has 'err' */ if (strstr(title, "err_") != NULL) { libbpf_print_fn_t old_print_fn; old_print_fn = libbpf_set_print(NULL); - err = !bpf_program__load(prog, "GPL", 0); + err = !bpf_object__load(obj); libbpf_set_print(old_print_fn); } else { - err = bpf_program__load(prog, "GPL", 0); + err = bpf_object__load(obj); } CHECK(err, title, "\n"); + bpf_object__close(obj); + obj = NULL; } cleanup: bpf_object__close(obj); + bpf_object__close(obj_iter); } From 10aceb629e198429c849d5e995c3bb1ba7a9aaa3 Mon Sep 17 00:00:00 2001 From: Dave Marchevsky Date: Fri, 17 Sep 2021 11:29:05 -0700 Subject: [PATCH 3/9] bpf: Add bpf_trace_vprintk helper This helper is meant to be "bpf_trace_printk, but with proper vararg support". Follow bpf_snprintf's example and take a u64 pseudo-vararg array. Write to /sys/kernel/debug/tracing/trace_pipe using the same mechanism as bpf_trace_printk. The functionality of this helper was requested in the libbpf issue tracker [0]. [0] Closes: https://github.com/libbpf/libbpf/issues/315 Signed-off-by: Dave Marchevsky Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20210917182911.2426606-4-davemarchevsky@fb.com --- include/linux/bpf.h | 1 + include/uapi/linux/bpf.h | 11 +++++++ kernel/bpf/core.c | 5 ++++ kernel/bpf/helpers.c | 2 ++ kernel/trace/bpf_trace.c | 52 +++++++++++++++++++++++++++++++++- tools/include/uapi/linux/bpf.h | 11 +++++++ 6 files changed, 81 insertions(+), 1 deletion(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index be8d57e6e78a..b6c45a6cbbba 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -1088,6 +1088,7 @@ bool bpf_prog_array_compatible(struct bpf_array *array, const struct bpf_prog *f int bpf_prog_calc_tag(struct bpf_prog *fp); const struct bpf_func_proto *bpf_get_trace_printk_proto(void); +const struct bpf_func_proto *bpf_get_trace_vprintk_proto(void); typedef unsigned long (*bpf_ctx_copy_t)(void *dst, const void *src, unsigned long off, unsigned long len); diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 3e9785f1064a..98ca79a67937 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -4898,6 +4898,16 @@ union bpf_attr { * **-EINVAL** if *flags* is not zero. * * **-ENOENT** if architecture does not support branch records. + * + * long bpf_trace_vprintk(const char *fmt, u32 fmt_size, const void *data, u32 data_len) + * Description + * Behaves like **bpf_trace_printk**\ () helper, but takes an array of u64 + * to format and can handle more format args as a result. + * + * Arguments are to be used as in **bpf_seq_printf**\ () helper. + * Return + * The number of bytes written to the buffer, or a negative error + * in case of failure. */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -5077,6 +5087,7 @@ union bpf_attr { FN(get_attach_cookie), \ FN(task_pt_regs), \ FN(get_branch_snapshot), \ + FN(trace_vprintk), \ /* */ /* integer value in 'imm' field of BPF_CALL instruction selects which helper diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 9f4636d021b1..6fddc13fe67f 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -2357,6 +2357,11 @@ const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void) return NULL; } +const struct bpf_func_proto * __weak bpf_get_trace_vprintk_proto(void) +{ + return NULL; +} + u64 __weak bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size, void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy) diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 8f9f392c1322..2c604ff8c7fb 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -1435,6 +1435,8 @@ bpf_base_func_proto(enum bpf_func_id func_id) return &bpf_snprintf_proto; case BPF_FUNC_task_pt_regs: return &bpf_task_pt_regs_proto; + case BPF_FUNC_trace_vprintk: + return bpf_get_trace_vprintk_proto(); default: return NULL; } diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 4ec779fa0c1d..6b3153841a33 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -398,7 +398,7 @@ static const struct bpf_func_proto bpf_trace_printk_proto = { .arg2_type = ARG_CONST_SIZE, }; -const struct bpf_func_proto *bpf_get_trace_printk_proto(void) +static void __set_printk_clr_event(void) { /* * This program might be calling bpf_trace_printk, @@ -410,10 +410,58 @@ const struct bpf_func_proto *bpf_get_trace_printk_proto(void) */ if (trace_set_clr_event("bpf_trace", "bpf_trace_printk", 1)) pr_warn_ratelimited("could not enable bpf_trace_printk events"); +} +const struct bpf_func_proto *bpf_get_trace_printk_proto(void) +{ + __set_printk_clr_event(); return &bpf_trace_printk_proto; } +BPF_CALL_4(bpf_trace_vprintk, char *, fmt, u32, fmt_size, const void *, data, + u32, data_len) +{ + static char buf[BPF_TRACE_PRINTK_SIZE]; + unsigned long flags; + int ret, num_args; + u32 *bin_args; + + if (data_len & 7 || data_len > MAX_BPRINTF_VARARGS * 8 || + (data_len && !data)) + return -EINVAL; + num_args = data_len / 8; + + ret = bpf_bprintf_prepare(fmt, fmt_size, data, &bin_args, num_args); + if (ret < 0) + return ret; + + raw_spin_lock_irqsave(&trace_printk_lock, flags); + ret = bstr_printf(buf, sizeof(buf), fmt, bin_args); + + trace_bpf_trace_printk(buf); + raw_spin_unlock_irqrestore(&trace_printk_lock, flags); + + bpf_bprintf_cleanup(); + + return ret; +} + +static const struct bpf_func_proto bpf_trace_vprintk_proto = { + .func = bpf_trace_vprintk, + .gpl_only = true, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_MEM, + .arg2_type = ARG_CONST_SIZE, + .arg3_type = ARG_PTR_TO_MEM_OR_NULL, + .arg4_type = ARG_CONST_SIZE_OR_ZERO, +}; + +const struct bpf_func_proto *bpf_get_trace_vprintk_proto(void) +{ + __set_printk_clr_event(); + return &bpf_trace_vprintk_proto; +} + BPF_CALL_5(bpf_seq_printf, struct seq_file *, m, char *, fmt, u32, fmt_size, const void *, data, u32, data_len) { @@ -1160,6 +1208,8 @@ bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) return &bpf_get_func_ip_proto_tracing; case BPF_FUNC_get_branch_snapshot: return &bpf_get_branch_snapshot_proto; + case BPF_FUNC_trace_vprintk: + return bpf_get_trace_vprintk_proto(); default: return bpf_base_func_proto(func_id); } diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 3e9785f1064a..98ca79a67937 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -4898,6 +4898,16 @@ union bpf_attr { * **-EINVAL** if *flags* is not zero. * * **-ENOENT** if architecture does not support branch records. + * + * long bpf_trace_vprintk(const char *fmt, u32 fmt_size, const void *data, u32 data_len) + * Description + * Behaves like **bpf_trace_printk**\ () helper, but takes an array of u64 + * to format and can handle more format args as a result. + * + * Arguments are to be used as in **bpf_seq_printf**\ () helper. + * Return + * The number of bytes written to the buffer, or a negative error + * in case of failure. */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -5077,6 +5087,7 @@ union bpf_attr { FN(get_attach_cookie), \ FN(task_pt_regs), \ FN(get_branch_snapshot), \ + FN(trace_vprintk), \ /* */ /* integer value in 'imm' field of BPF_CALL instruction selects which helper From c2758baa9798bf75d79a9aad8792edb8b694373e Mon Sep 17 00:00:00 2001 From: Dave Marchevsky Date: Fri, 17 Sep 2021 11:29:06 -0700 Subject: [PATCH 4/9] libbpf: Modify bpf_printk to choose helper based on arg count Instead of being a thin wrapper which calls into bpf_trace_printk, libbpf's bpf_printk convenience macro now chooses between bpf_trace_printk and bpf_trace_vprintk. If the arg count (excluding format string) is >3, use bpf_trace_vprintk, otherwise use the older helper. The motivation behind this added complexity - instead of migrating entirely to bpf_trace_vprintk - is to maintain good developer experience for users compiling against new libbpf but running on older kernels. Users who are passing <=3 args to bpf_printk will see no change in their bytecode. __bpf_vprintk functions similarly to BPF_SEQ_PRINTF and BPF_SNPRINTF macros elsewhere in the file - it allows use of bpf_trace_vprintk without manual conversion of varargs to u64 array. Previous implementation of bpf_printk macro is moved to __bpf_printk for use by the new implementation. This does change behavior of bpf_printk calls with >3 args in the "new libbpf, old kernels" scenario. Before this patch, attempting to use 4 args to bpf_printk results in a compile-time error. After this patch, using bpf_printk with 4 args results in a trace_vprintk helper call being emitted and a load-time failure on older kernels. Signed-off-by: Dave Marchevsky Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20210917182911.2426606-5-davemarchevsky@fb.com --- tools/lib/bpf/bpf_helpers.h | 45 ++++++++++++++++++++++++++++++------- 1 file changed, 37 insertions(+), 8 deletions(-) diff --git a/tools/lib/bpf/bpf_helpers.h b/tools/lib/bpf/bpf_helpers.h index b9987c3efa3c..55a308796625 100644 --- a/tools/lib/bpf/bpf_helpers.h +++ b/tools/lib/bpf/bpf_helpers.h @@ -14,14 +14,6 @@ #define __type(name, val) typeof(val) *name #define __array(name, val) typeof(val) *name[] -/* Helper macro to print out debug messages */ -#define bpf_printk(fmt, ...) \ -({ \ - char ____fmt[] = fmt; \ - bpf_trace_printk(____fmt, sizeof(____fmt), \ - ##__VA_ARGS__); \ -}) - /* * Helper macro to place programs, maps, license in * different sections in elf_bpf file. Section names @@ -224,4 +216,41 @@ enum libbpf_tristate { ___param, sizeof(___param)); \ }) +#define __bpf_printk(fmt, ...) \ +({ \ + char ____fmt[] = fmt; \ + bpf_trace_printk(____fmt, sizeof(____fmt), \ + ##__VA_ARGS__); \ +}) + +/* + * __bpf_vprintk wraps the bpf_trace_vprintk helper with variadic arguments + * instead of an array of u64. + */ +#define __bpf_vprintk(fmt, args...) \ +({ \ + static const char ___fmt[] = fmt; \ + unsigned long long ___param[___bpf_narg(args)]; \ + \ + _Pragma("GCC diagnostic push") \ + _Pragma("GCC diagnostic ignored \"-Wint-conversion\"") \ + ___bpf_fill(___param, args); \ + _Pragma("GCC diagnostic pop") \ + \ + bpf_trace_vprintk(___fmt, sizeof(___fmt), \ + ___param, sizeof(___param)); \ +}) + +/* Use __bpf_printk when bpf_printk call has 3 or fewer fmt args + * Otherwise use __bpf_vprintk + */ +#define ___bpf_pick_printk(...) \ + ___bpf_nth(_, ##__VA_ARGS__, __bpf_vprintk, __bpf_vprintk, __bpf_vprintk, \ + __bpf_vprintk, __bpf_vprintk, __bpf_vprintk, __bpf_vprintk, \ + __bpf_vprintk, __bpf_vprintk, __bpf_printk /*3*/, __bpf_printk /*2*/,\ + __bpf_printk /*1*/, __bpf_printk /*0*/) + +/* Helper macro to print out debug messages */ +#define bpf_printk(fmt, args...) ___bpf_pick_printk(args)(fmt, ##args) + #endif From 6c66b0e7c91a1320c1b85ad8150bdd534eb4ddae Mon Sep 17 00:00:00 2001 From: Dave Marchevsky Date: Fri, 17 Sep 2021 11:29:07 -0700 Subject: [PATCH 5/9] libbpf: Use static const fmt string in __bpf_printk The __bpf_printk convenience macro was using a 'char' fmt string holder as it predates support for globals in libbpf. Move to more efficient 'static const char', but provide a fallback to the old way via BPF_NO_GLOBAL_DATA so users on old kernels can still use the macro. Signed-off-by: Dave Marchevsky Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20210917182911.2426606-6-davemarchevsky@fb.com --- tools/lib/bpf/bpf_helpers.h | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/tools/lib/bpf/bpf_helpers.h b/tools/lib/bpf/bpf_helpers.h index 55a308796625..963b1060d944 100644 --- a/tools/lib/bpf/bpf_helpers.h +++ b/tools/lib/bpf/bpf_helpers.h @@ -216,9 +216,15 @@ enum libbpf_tristate { ___param, sizeof(___param)); \ }) +#ifdef BPF_NO_GLOBAL_DATA +#define BPF_PRINTK_FMT_MOD +#else +#define BPF_PRINTK_FMT_MOD static const +#endif + #define __bpf_printk(fmt, ...) \ ({ \ - char ____fmt[] = fmt; \ + BPF_PRINTK_FMT_MOD char ____fmt[] = fmt; \ bpf_trace_printk(____fmt, sizeof(____fmt), \ ##__VA_ARGS__); \ }) From 4190c299a49f323232221e73fe1846c53e3fc3f1 Mon Sep 17 00:00:00 2001 From: Dave Marchevsky Date: Fri, 17 Sep 2021 11:29:08 -0700 Subject: [PATCH 6/9] bpftool: Only probe trace_vprintk feature in 'full' mode Since commit 368cb0e7cdb5e ("bpftool: Make probes which emit dmesg warnings optional"), some helpers aren't probed by bpftool unless `full` arg is added to `bpftool feature probe`. bpf_trace_vprintk can emit dmesg warnings when probed, so include it. Signed-off-by: Dave Marchevsky Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20210917182911.2426606-7-davemarchevsky@fb.com --- tools/bpf/bpftool/feature.c | 1 + tools/testing/selftests/bpf/test_bpftool.py | 22 +++++++++------------ 2 files changed, 10 insertions(+), 13 deletions(-) diff --git a/tools/bpf/bpftool/feature.c b/tools/bpf/bpftool/feature.c index 7f36385aa9e2..ade44577688e 100644 --- a/tools/bpf/bpftool/feature.c +++ b/tools/bpf/bpftool/feature.c @@ -624,6 +624,7 @@ probe_helpers_for_progtype(enum bpf_prog_type prog_type, bool supported_type, */ switch (id) { case BPF_FUNC_trace_printk: + case BPF_FUNC_trace_vprintk: case BPF_FUNC_probe_write_user: if (!full_mode) continue; diff --git a/tools/testing/selftests/bpf/test_bpftool.py b/tools/testing/selftests/bpf/test_bpftool.py index 4fed2dc25c0a..1c2408ee1f5d 100644 --- a/tools/testing/selftests/bpf/test_bpftool.py +++ b/tools/testing/selftests/bpf/test_bpftool.py @@ -57,6 +57,11 @@ def default_iface(f): return f(*args, iface, **kwargs) return wrapper +DMESG_EMITTING_HELPERS = [ + "bpf_probe_write_user", + "bpf_trace_printk", + "bpf_trace_vprintk", + ] class TestBpftool(unittest.TestCase): @classmethod @@ -67,10 +72,7 @@ class TestBpftool(unittest.TestCase): @default_iface def test_feature_dev_json(self, iface): - unexpected_helpers = [ - "bpf_probe_write_user", - "bpf_trace_printk", - ] + unexpected_helpers = DMESG_EMITTING_HELPERS expected_keys = [ "syscall_config", "program_types", @@ -94,10 +96,7 @@ class TestBpftool(unittest.TestCase): bpftool_json(["feature", "probe"]), bpftool_json(["feature"]), ] - unexpected_helpers = [ - "bpf_probe_write_user", - "bpf_trace_printk", - ] + unexpected_helpers = DMESG_EMITTING_HELPERS expected_keys = [ "syscall_config", "system_config", @@ -121,10 +120,7 @@ class TestBpftool(unittest.TestCase): bpftool_json(["feature", "probe", "kernel", "full"]), bpftool_json(["feature", "probe", "full"]), ] - expected_helpers = [ - "bpf_probe_write_user", - "bpf_trace_printk", - ] + expected_helpers = DMESG_EMITTING_HELPERS for tc in test_cases: # Check if expected helpers are included at least once in any @@ -157,7 +153,7 @@ class TestBpftool(unittest.TestCase): not_full_set.add(helper) self.assertCountEqual(full_set - not_full_set, - {"bpf_probe_write_user", "bpf_trace_printk"}) + set(DMESG_EMITTING_HELPERS)) self.assertCountEqual(not_full_set - full_set, set()) def test_feature_macros(self): From d313d45a226fdc59739c3da05bbd065f71bae5a6 Mon Sep 17 00:00:00 2001 From: Dave Marchevsky Date: Fri, 17 Sep 2021 11:29:09 -0700 Subject: [PATCH 7/9] selftests/bpf: Migrate prog_tests/trace_printk CHECKs to ASSERTs Guidance for new tests is to use ASSERT macros instead of CHECK. Since trace_vprintk test will borrow heavily from trace_printk's, migrate its CHECKs so it remains obvious that the two are closely related. Signed-off-by: Dave Marchevsky Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20210917182911.2426606-8-davemarchevsky@fb.com --- .../selftests/bpf/prog_tests/trace_printk.c | 24 +++++++------------ 1 file changed, 9 insertions(+), 15 deletions(-) diff --git a/tools/testing/selftests/bpf/prog_tests/trace_printk.c b/tools/testing/selftests/bpf/prog_tests/trace_printk.c index d39bc00feb45..e47835f0a674 100644 --- a/tools/testing/selftests/bpf/prog_tests/trace_printk.c +++ b/tools/testing/selftests/bpf/prog_tests/trace_printk.c @@ -10,7 +10,7 @@ void test_trace_printk(void) { - int err, iter = 0, duration = 0, found = 0; + int err = 0, iter = 0, found = 0; struct trace_printk__bss *bss; struct trace_printk *skel; char *buf = NULL; @@ -18,25 +18,24 @@ void test_trace_printk(void) size_t buflen; skel = trace_printk__open(); - if (CHECK(!skel, "skel_open", "failed to open skeleton\n")) + if (!ASSERT_OK_PTR(skel, "trace_printk__open")) return; - ASSERT_EQ(skel->rodata->fmt[0], 'T', "invalid printk fmt string"); + ASSERT_EQ(skel->rodata->fmt[0], 'T', "skel->rodata->fmt[0]"); skel->rodata->fmt[0] = 't'; err = trace_printk__load(skel); - if (CHECK(err, "skel_load", "failed to load skeleton: %d\n", err)) + if (!ASSERT_OK(err, "trace_printk__load")) goto cleanup; bss = skel->bss; err = trace_printk__attach(skel); - if (CHECK(err, "skel_attach", "skeleton attach failed: %d\n", err)) + if (!ASSERT_OK(err, "trace_printk__attach")) goto cleanup; fp = fopen(TRACEBUF, "r"); - if (CHECK(fp == NULL, "could not open trace buffer", - "error %d opening %s", errno, TRACEBUF)) + if (!ASSERT_OK_PTR(fp, "fopen(TRACEBUF)")) goto cleanup; /* We do not want to wait forever if this test fails... */ @@ -46,14 +45,10 @@ void test_trace_printk(void) usleep(1); trace_printk__detach(skel); - if (CHECK(bss->trace_printk_ran == 0, - "bpf_trace_printk never ran", - "ran == %d", bss->trace_printk_ran)) + if (!ASSERT_GT(bss->trace_printk_ran, 0, "bss->trace_printk_ran")) goto cleanup; - if (CHECK(bss->trace_printk_ret <= 0, - "bpf_trace_printk returned <= 0 value", - "got %d", bss->trace_printk_ret)) + if (!ASSERT_GT(bss->trace_printk_ret, 0, "bss->trace_printk_ret")) goto cleanup; /* verify our search string is in the trace buffer */ @@ -66,8 +61,7 @@ void test_trace_printk(void) break; } - if (CHECK(!found, "message from bpf_trace_printk not found", - "no instance of %s in %s", SEARCHMSG, TRACEBUF)) + if (!ASSERT_EQ(found, bss->trace_printk_ran, "found")) goto cleanup; cleanup: From 7606729fe24e163923430a5df9d50a246b22d287 Mon Sep 17 00:00:00 2001 From: Dave Marchevsky Date: Fri, 17 Sep 2021 11:29:10 -0700 Subject: [PATCH 8/9] selftests/bpf: Add trace_vprintk test prog This commit adds a test prog for vprintk which confirms that: * bpf_trace_vprintk is writing to /sys/kernel/debug/tracing/trace_pipe * __bpf_vprintk macro works as expected * >3 args are printed * bpf_printk w/ 0 format args compiles * bpf_trace_vprintk call w/ a fmt specifier but NULL fmt data fails Approach and code are borrowed from trace_printk test. Signed-off-by: Dave Marchevsky Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20210917182911.2426606-9-davemarchevsky@fb.com --- tools/testing/selftests/bpf/Makefile | 3 +- .../selftests/bpf/prog_tests/trace_vprintk.c | 68 +++++++++++++++++++ .../selftests/bpf/progs/trace_vprintk.c | 33 +++++++++ 3 files changed, 103 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/bpf/prog_tests/trace_vprintk.c create mode 100644 tools/testing/selftests/bpf/progs/trace_vprintk.c diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile index 1a4d30ff3275..326ea75ce99e 100644 --- a/tools/testing/selftests/bpf/Makefile +++ b/tools/testing/selftests/bpf/Makefile @@ -315,7 +315,8 @@ LINKED_SKELS := test_static_linked.skel.h linked_funcs.skel.h \ linked_vars.skel.h linked_maps.skel.h LSKELS := kfunc_call_test.c fentry_test.c fexit_test.c fexit_sleep.c \ - test_ksyms_module.c test_ringbuf.c atomics.c trace_printk.c + test_ksyms_module.c test_ringbuf.c atomics.c trace_printk.c \ + trace_vprintk.c SKEL_BLACKLIST += $$(LSKELS) test_static_linked.skel.h-deps := test_static_linked1.o test_static_linked2.o diff --git a/tools/testing/selftests/bpf/prog_tests/trace_vprintk.c b/tools/testing/selftests/bpf/prog_tests/trace_vprintk.c new file mode 100644 index 000000000000..61a24e62e1a0 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/trace_vprintk.c @@ -0,0 +1,68 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2021 Facebook */ + +#include + +#include "trace_vprintk.lskel.h" + +#define TRACEBUF "/sys/kernel/debug/tracing/trace_pipe" +#define SEARCHMSG "1,2,3,4,5,6,7,8,9,10" + +void test_trace_vprintk(void) +{ + int err = 0, iter = 0, found = 0; + struct trace_vprintk__bss *bss; + struct trace_vprintk *skel; + char *buf = NULL; + FILE *fp = NULL; + size_t buflen; + + skel = trace_vprintk__open_and_load(); + if (!ASSERT_OK_PTR(skel, "trace_vprintk__open_and_load")) + goto cleanup; + + bss = skel->bss; + + err = trace_vprintk__attach(skel); + if (!ASSERT_OK(err, "trace_vprintk__attach")) + goto cleanup; + + fp = fopen(TRACEBUF, "r"); + if (!ASSERT_OK_PTR(fp, "fopen(TRACEBUF)")) + goto cleanup; + + /* We do not want to wait forever if this test fails... */ + fcntl(fileno(fp), F_SETFL, O_NONBLOCK); + + /* wait for tracepoint to trigger */ + usleep(1); + trace_vprintk__detach(skel); + + if (!ASSERT_GT(bss->trace_vprintk_ran, 0, "bss->trace_vprintk_ran")) + goto cleanup; + + if (!ASSERT_GT(bss->trace_vprintk_ret, 0, "bss->trace_vprintk_ret")) + goto cleanup; + + /* verify our search string is in the trace buffer */ + while (getline(&buf, &buflen, fp) >= 0 || errno == EAGAIN) { + if (strstr(buf, SEARCHMSG) != NULL) + found++; + if (found == bss->trace_vprintk_ran) + break; + if (++iter > 1000) + break; + } + + if (!ASSERT_EQ(found, bss->trace_vprintk_ran, "found")) + goto cleanup; + + if (!ASSERT_LT(bss->null_data_vprintk_ret, 0, "bss->null_data_vprintk_ret")) + goto cleanup; + +cleanup: + trace_vprintk__destroy(skel); + free(buf); + if (fp) + fclose(fp); +} diff --git a/tools/testing/selftests/bpf/progs/trace_vprintk.c b/tools/testing/selftests/bpf/progs/trace_vprintk.c new file mode 100644 index 000000000000..d327241ba047 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/trace_vprintk.c @@ -0,0 +1,33 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2021 Facebook */ + +#include "vmlinux.h" +#include +#include + +char _license[] SEC("license") = "GPL"; + +int null_data_vprintk_ret = 0; +int trace_vprintk_ret = 0; +int trace_vprintk_ran = 0; + +SEC("fentry/__x64_sys_nanosleep") +int sys_enter(void *ctx) +{ + static const char one[] = "1"; + static const char three[] = "3"; + static const char five[] = "5"; + static const char seven[] = "7"; + static const char nine[] = "9"; + static const char f[] = "%pS\n"; + + /* runner doesn't search for \t, just ensure it compiles */ + bpf_printk("\t"); + + trace_vprintk_ret = __bpf_vprintk("%s,%d,%s,%d,%s,%d,%s,%d,%s,%d %d\n", + one, 2, three, 4, five, 6, seven, 8, nine, 10, ++trace_vprintk_ran); + + /* non-NULL fmt w/ NULL data should result in error */ + null_data_vprintk_ret = bpf_trace_vprintk(f, sizeof(f), NULL, 0); + return 0; +} From a42effb0b24fcaf49513c2d7d77ef6daa9e32a6f Mon Sep 17 00:00:00 2001 From: Dave Marchevsky Date: Fri, 17 Sep 2021 11:29:11 -0700 Subject: [PATCH 9/9] bpf: Clarify data_len param in bpf_snprintf and bpf_seq_printf comments Since the data_len in these two functions is a byte len of the preceding u64 *data array, it must always be a multiple of 8. If this isn't the case both helpers error out, so let's make the requirement explicit so users don't need to infer it. Signed-off-by: Dave Marchevsky Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20210917182911.2426606-10-davemarchevsky@fb.com --- include/uapi/linux/bpf.h | 5 +++-- tools/include/uapi/linux/bpf.h | 5 +++-- 2 files changed, 6 insertions(+), 4 deletions(-) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 98ca79a67937..6fc59d61937a 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -4046,7 +4046,7 @@ union bpf_attr { * arguments. The *data* are a **u64** array and corresponding format string * values are stored in the array. For strings and pointers where pointees * are accessed, only the pointer values are stored in the *data* array. - * The *data_len* is the size of *data* in bytes. + * The *data_len* is the size of *data* in bytes - must be a multiple of 8. * * Formats **%s**, **%p{i,I}{4,6}** requires to read kernel memory. * Reading kernel memory may fail due to either invalid address or @@ -4751,7 +4751,8 @@ union bpf_attr { * Each format specifier in **fmt** corresponds to one u64 element * in the **data** array. For strings and pointers where pointees * are accessed, only the pointer values are stored in the *data* - * array. The *data_len* is the size of *data* in bytes. + * array. The *data_len* is the size of *data* in bytes - must be + * a multiple of 8. * * Formats **%s** and **%p{i,I}{4,6}** require to read kernel * memory. Reading kernel memory may fail due to either invalid diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 98ca79a67937..6fc59d61937a 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -4046,7 +4046,7 @@ union bpf_attr { * arguments. The *data* are a **u64** array and corresponding format string * values are stored in the array. For strings and pointers where pointees * are accessed, only the pointer values are stored in the *data* array. - * The *data_len* is the size of *data* in bytes. + * The *data_len* is the size of *data* in bytes - must be a multiple of 8. * * Formats **%s**, **%p{i,I}{4,6}** requires to read kernel memory. * Reading kernel memory may fail due to either invalid address or @@ -4751,7 +4751,8 @@ union bpf_attr { * Each format specifier in **fmt** corresponds to one u64 element * in the **data** array. For strings and pointers where pointees * are accessed, only the pointer values are stored in the *data* - * array. The *data_len* is the size of *data* in bytes. + * array. The *data_len* is the size of *data* in bytes - must be + * a multiple of 8. * * Formats **%s** and **%p{i,I}{4,6}** require to read kernel * memory. Reading kernel memory may fail due to either invalid