From: Ross Zwisler zwisler@google.com

The canonical location for the tracefs filesystem is at /sys/kernel/tracing.

But, from Documentation/trace/ftrace.rst:

Before 4.1, all ftrace tracing control files were within the debugfs file system, which is typically located at /sys/kernel/debug/tracing. For backward compatibility, when mounting the debugfs file system, the tracefs file system will be automatically mounted at:

/sys/kernel/debug/tracing

Many comments and samples in the bpf code still refer to this older debugfs path, so let's update them to avoid confusion. There are a few spots where the bpf code explicitly checks both tracefs and debugfs (tools/bpf/bpftool/tracelog.c and tools/lib/api/fs/fs.c) and I've left those alone so that the tools can continue to work with both paths.

Signed-off-by: Ross Zwisler zwisler@google.com Acked-by: Michael S. Tsirkin mst@redhat.com Reviewed-by: Steven Rostedt (Google) rostedt@goodmis.org --- include/uapi/linux/bpf.h | 8 ++++---- samples/bpf/cpustat_kern.c | 4 ++-- samples/bpf/hbm.c | 4 ++-- samples/bpf/ibumad_kern.c | 4 ++-- samples/bpf/lwt_len_hist.sh | 2 +- samples/bpf/offwaketime_kern.c | 2 +- samples/bpf/task_fd_query_user.c | 4 ++-- samples/bpf/test_lwt_bpf.sh | 2 +- samples/bpf/test_overhead_tp.bpf.c | 4 ++-- tools/include/uapi/linux/bpf.h | 8 ++++---- 10 files changed, 21 insertions(+), 21 deletions(-)

diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index d8c534e05b0a..13129df937cd 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -1647,17 +1647,17 @@ union bpf_attr { * Description * This helper is a "printk()-like" facility for debugging. It * prints a message defined by format *fmt* (of size *fmt_size*) - * to file */sys/kernel/debug/tracing/trace* from DebugFS, if + * to file */sys/kernel/tracing/trace* from TraceFS, if * available. It can take up to three additional **u64** * arguments (as an eBPF helpers, the total number of arguments is * limited to five). * * Each time the helper is called, it appends a line to the trace. - * Lines are discarded while */sys/kernel/debug/tracing/trace* is - * open, use */sys/kernel/debug/tracing/trace_pipe* to avoid this. + * Lines are discarded while */sys/kernel/tracing/trace* is + * open, use */sys/kernel/tracing/trace_pipe* to avoid this. * The format of the trace is customizable, and the exact output * one will get depends on the options set in - * */sys/kernel/debug/tracing/trace_options* (see also the + * */sys/kernel/tracing/trace_options* (see also the * *README* file under the same directory). However, it usually * defaults to something like: * diff --git a/samples/bpf/cpustat_kern.c b/samples/bpf/cpustat_kern.c index 5aefd19cdfa1..944f13fe164a 100644 --- a/samples/bpf/cpustat_kern.c +++ b/samples/bpf/cpustat_kern.c @@ -76,8 +76,8 @@ struct {

/* * The trace events for cpu_idle and cpu_frequency are taken from: - * /sys/kernel/debug/tracing/events/power/cpu_idle/format - * /sys/kernel/debug/tracing/events/power/cpu_frequency/format + * /sys/kernel/tracing/events/power/cpu_idle/format + * /sys/kernel/tracing/events/power/cpu_frequency/format * * These two events have same format, so define one common structure. */ diff --git a/samples/bpf/hbm.c b/samples/bpf/hbm.c index 516fbac28b71..ff58ec43f56a 100644 --- a/samples/bpf/hbm.c +++ b/samples/bpf/hbm.c @@ -65,7 +65,7 @@ static void Usage(void); static void read_trace_pipe2(void); static void do_error(char *msg, bool errno_flag);

-#define DEBUGFS "/sys/kernel/debug/tracing/" +#define TRACEFS "/sys/kernel/tracing/"

static struct bpf_program *bpf_prog; static struct bpf_object *obj; @@ -77,7 +77,7 @@ static void read_trace_pipe2(void) FILE *outf; char *outFname = "hbm_out.log";

- trace_fd = open(DEBUGFS "trace_pipe", O_RDONLY, 0); + trace_fd = open(TRACEFS "trace_pipe", O_RDONLY, 0); if (trace_fd < 0) { printf("Error opening trace_pipe\n"); return; diff --git a/samples/bpf/ibumad_kern.c b/samples/bpf/ibumad_kern.c index 9b193231024a..f07474c72525 100644 --- a/samples/bpf/ibumad_kern.c +++ b/samples/bpf/ibumad_kern.c @@ -39,8 +39,8 @@ struct { /* Taken from the current format defined in * include/trace/events/ib_umad.h * and - * /sys/kernel/debug/tracing/events/ib_umad/ib_umad_read/format - * /sys/kernel/debug/tracing/events/ib_umad/ib_umad_write/format + * /sys/kernel/tracing/events/ib_umad/ib_umad_read/format + * /sys/kernel/tracing/events/ib_umad/ib_umad_write/format */ struct ib_umad_rw_args { u64 pad; diff --git a/samples/bpf/lwt_len_hist.sh b/samples/bpf/lwt_len_hist.sh index 7078bfcc4f4d..381b2c634784 100755 --- a/samples/bpf/lwt_len_hist.sh +++ b/samples/bpf/lwt_len_hist.sh @@ -5,7 +5,7 @@ NS1=lwt_ns1 VETH0=tst_lwt1a VETH1=tst_lwt1b BPF_PROG=lwt_len_hist.bpf.o -TRACE_ROOT=/sys/kernel/debug/tracing +TRACE_ROOT=/sys/kernel/tracing

function cleanup { # To reset saved histogram, remove pinned map diff --git a/samples/bpf/offwaketime_kern.c b/samples/bpf/offwaketime_kern.c index eb4d94742e6b..23f12b47e9e5 100644 --- a/samples/bpf/offwaketime_kern.c +++ b/samples/bpf/offwaketime_kern.c @@ -110,7 +110,7 @@ static inline int update_counts(void *ctx, u32 pid, u64 delta) }

#if 1 -/* taken from /sys/kernel/debug/tracing/events/sched/sched_switch/format */ +/* taken from /sys/kernel/tracing/events/sched/sched_switch/format */ struct sched_switch_args { unsigned long long pad; char prev_comm[TASK_COMM_LEN]; diff --git a/samples/bpf/task_fd_query_user.c b/samples/bpf/task_fd_query_user.c index a33d74bd3a4b..1e61f2180470 100644 --- a/samples/bpf/task_fd_query_user.c +++ b/samples/bpf/task_fd_query_user.c @@ -235,7 +235,7 @@ static int test_debug_fs_uprobe(char *binary_path, long offset, bool is_return) struct bpf_link *link; ssize_t bytes;

- snprintf(buf, sizeof(buf), "/sys/kernel/debug/tracing/%s_events", + snprintf(buf, sizeof(buf), "/sys/kernel/tracing/%s_events", event_type); kfd = open(buf, O_WRONLY | O_TRUNC, 0); CHECK_PERROR_RET(kfd < 0); @@ -252,7 +252,7 @@ static int test_debug_fs_uprobe(char *binary_path, long offset, bool is_return) close(kfd); kfd = -1;

- snprintf(buf, sizeof(buf), "/sys/kernel/debug/tracing/events/%ss/%s/id", + snprintf(buf, sizeof(buf), "/sys/kernel/tracing/events/%ss/%s/id", event_type, event_alias); efd = open(buf, O_RDONLY, 0); CHECK_PERROR_RET(efd < 0); diff --git a/samples/bpf/test_lwt_bpf.sh b/samples/bpf/test_lwt_bpf.sh index 2e9f5126963b..0bf2d0f6bf4b 100755 --- a/samples/bpf/test_lwt_bpf.sh +++ b/samples/bpf/test_lwt_bpf.sh @@ -21,7 +21,7 @@ IP_LOCAL="192.168.99.1"

PROG_SRC="test_lwt_bpf.c" BPF_PROG="test_lwt_bpf.o" -TRACE_ROOT=/sys/kernel/debug/tracing +TRACE_ROOT=/sys/kernel/tracing CONTEXT_INFO=$(cat ${TRACE_ROOT}/trace_options | grep context)

function lookup_mac() diff --git a/samples/bpf/test_overhead_tp.bpf.c b/samples/bpf/test_overhead_tp.bpf.c index 67cab3881969..8b498328e961 100644 --- a/samples/bpf/test_overhead_tp.bpf.c +++ b/samples/bpf/test_overhead_tp.bpf.c @@ -7,7 +7,7 @@ #include "vmlinux.h" #include <bpf/bpf_helpers.h>

-/* from /sys/kernel/debug/tracing/events/task/task_rename/format */ +/* from /sys/kernel/tracing/events/task/task_rename/format */ struct task_rename { __u64 pad; __u32 pid; @@ -21,7 +21,7 @@ int prog(struct task_rename *ctx) return 0; }

-/* from /sys/kernel/debug/tracing/events/fib/fib_table_lookup/format */ +/* from /sys/kernel/tracing/events/fib/fib_table_lookup/format */ struct fib_table_lookup { __u64 pad; __u32 tb_id; diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index d8c534e05b0a..13129df937cd 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -1647,17 +1647,17 @@ union bpf_attr { * Description * This helper is a "printk()-like" facility for debugging. It * prints a message defined by format *fmt* (of size *fmt_size*) - * to file */sys/kernel/debug/tracing/trace* from DebugFS, if + * to file */sys/kernel/tracing/trace* from TraceFS, if * available. It can take up to three additional **u64** * arguments (as an eBPF helpers, the total number of arguments is * limited to five). * * Each time the helper is called, it appends a line to the trace. - * Lines are discarded while */sys/kernel/debug/tracing/trace* is - * open, use */sys/kernel/debug/tracing/trace_pipe* to avoid this. + * Lines are discarded while */sys/kernel/tracing/trace* is + * open, use */sys/kernel/tracing/trace_pipe* to avoid this. * The format of the trace is customizable, and the exact output * one will get depends on the options set in - * */sys/kernel/debug/tracing/trace_options* (see also the + * */sys/kernel/tracing/trace_options* (see also the * *README* file under the same directory). However, it usually * defaults to something like: *

From: Ross Zwisler zwisler@google.com

The canonical location for the tracefs filesystem is at /sys/kernel/tracing.

But, from Documentation/trace/ftrace.rst:

Before 4.1, all ftrace tracing control files were within the debugfs file system, which is typically located at /sys/kernel/debug/tracing. For backward compatibility, when mounting the debugfs file system, the tracefs file system will be automatically mounted at:

/sys/kernel/debug/tracing

Many tests in the bpf selftest code still refer to this older debugfs path, so let's update them to avoid confusion.

Signed-off-by: Ross Zwisler zwisler@google.com Acked-by: Michael S. Tsirkin mst@redhat.com --- tools/testing/selftests/bpf/get_cgroup_id_user.c | 9 +++++++-- .../selftests/bpf/prog_tests/kprobe_multi_test.c | 7 ++++++- .../selftests/bpf/prog_tests/task_fd_query_tp.c | 9 +++++++-- .../selftests/bpf/prog_tests/tp_attach_query.c | 9 +++++++-- .../testing/selftests/bpf/prog_tests/trace_printk.c | 10 +++++++--- .../selftests/bpf/prog_tests/trace_vprintk.c | 10 +++++++--- .../selftests/bpf/progs/test_stacktrace_map.c | 2 +- tools/testing/selftests/bpf/progs/test_tracepoint.c | 2 +- tools/testing/selftests/bpf/test_ftrace.sh | 7 ++++++- tools/testing/selftests/bpf/test_tunnel.sh | 13 +++++++++---- tools/testing/selftests/bpf/trace_helpers.c | 8 ++++++-- 11 files changed, 64 insertions(+), 22 deletions(-)

diff --git a/tools/testing/selftests/bpf/get_cgroup_id_user.c b/tools/testing/selftests/bpf/get_cgroup_id_user.c index 156743cf5870..aefd83ebdcd7 100644 --- a/tools/testing/selftests/bpf/get_cgroup_id_user.c +++ b/tools/testing/selftests/bpf/get_cgroup_id_user.c @@ -86,8 +86,13 @@ int main(int argc, char **argv) pid = getpid(); bpf_map_update_elem(pidmap_fd, &key, &pid, 0);

- snprintf(buf, sizeof(buf), - "/sys/kernel/debug/tracing/events/%s/id", probe_name); + if (access("/sys/kernel/tracing/trace", F_OK) == 0) { + snprintf(buf, sizeof(buf), + "/sys/kernel/tracing/events/%s/id", probe_name); + } else { + snprintf(buf, sizeof(buf), + "/sys/kernel/debug/tracing/events/%s/id", probe_name); + } efd = open(buf, O_RDONLY, 0); if (CHECK(efd < 0, "open", "err %d errno %d\n", efd, errno)) goto close_prog; diff --git a/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c b/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c index 113dba349a57..22be0a9a5a0a 100644 --- a/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c +++ b/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c @@ -338,7 +338,12 @@ static int get_syms(char ***symsp, size_t *cntp, bool kernel) * Filtering out duplicates by using hashmap__add, which won't * add existing entry. */ - f = fopen("/sys/kernel/debug/tracing/available_filter_functions", "r"); + + if (access("/sys/kernel/tracing/trace", F_OK) == 0) + f = fopen("/sys/kernel/tracing/available_filter_functions", "r"); + else + f = fopen("/sys/kernel/debug/tracing/available_filter_functions", "r"); + if (!f) return -EINVAL;

diff --git a/tools/testing/selftests/bpf/prog_tests/task_fd_query_tp.c b/tools/testing/selftests/bpf/prog_tests/task_fd_query_tp.c index c717741bf8b6..c91eda624657 100644 --- a/tools/testing/selftests/bpf/prog_tests/task_fd_query_tp.c +++ b/tools/testing/selftests/bpf/prog_tests/task_fd_query_tp.c @@ -17,8 +17,13 @@ static void test_task_fd_query_tp_core(const char *probe_name, if (CHECK(err, "bpf_prog_test_load", "err %d errno %d\n", err, errno)) goto close_prog;

- snprintf(buf, sizeof(buf), - "/sys/kernel/debug/tracing/events/%s/id", probe_name); + if (access("/sys/kernel/tracing/trace", F_OK) == 0) { + snprintf(buf, sizeof(buf), + "/sys/kernel/tracing/events/%s/id", probe_name); + } else { + snprintf(buf, sizeof(buf), + "/sys/kernel/debug/tracing/events/%s/id", probe_name); + } efd = open(buf, O_RDONLY, 0); if (CHECK(efd < 0, "open", "err %d errno %d\n", efd, errno)) goto close_prog; diff --git a/tools/testing/selftests/bpf/prog_tests/tp_attach_query.c b/tools/testing/selftests/bpf/prog_tests/tp_attach_query.c index 770fcc3bb1ba..655d69f0ff0b 100644 --- a/tools/testing/selftests/bpf/prog_tests/tp_attach_query.c +++ b/tools/testing/selftests/bpf/prog_tests/tp_attach_query.c @@ -16,8 +16,13 @@ void serial_test_tp_attach_query(void) for (i = 0; i < num_progs; i++) obj[i] = NULL;

- snprintf(buf, sizeof(buf), - "/sys/kernel/debug/tracing/events/sched/sched_switch/id"); + if (access("/sys/kernel/tracing/trace", F_OK) == 0) { + snprintf(buf, sizeof(buf), + "/sys/kernel/tracing/events/sched/sched_switch/id"); + } else { + snprintf(buf, sizeof(buf), + "/sys/kernel/debug/tracing/events/sched/sched_switch/id"); + } efd = open(buf, O_RDONLY, 0); if (CHECK(efd < 0, "open", "err %d errno %d\n", efd, errno)) return; diff --git a/tools/testing/selftests/bpf/prog_tests/trace_printk.c b/tools/testing/selftests/bpf/prog_tests/trace_printk.c index cade7f12315f..7b9124d506a5 100644 --- a/tools/testing/selftests/bpf/prog_tests/trace_printk.c +++ b/tools/testing/selftests/bpf/prog_tests/trace_printk.c @@ -5,7 +5,8 @@

#include "trace_printk.lskel.h"

-#define TRACEBUF "/sys/kernel/debug/tracing/trace_pipe" +#define TRACEFS_PIPE "/sys/kernel/tracing/trace_pipe" +#define DEBUGFS_PIPE "/sys/kernel/debug/tracing/trace_pipe" #define SEARCHMSG "testing,testing"

void serial_test_trace_printk(void) @@ -34,8 +35,11 @@ void serial_test_trace_printk(void) if (!ASSERT_OK(err, "trace_printk__attach")) goto cleanup;

- fp = fopen(TRACEBUF, "r"); - if (!ASSERT_OK_PTR(fp, "fopen(TRACEBUF)")) + if (access(TRACEFS_PIPE, F_OK) == 0) + fp = fopen(TRACEFS_PIPE, "r"); + else + fp = fopen(DEBUGFS_PIPE, "r"); + if (!ASSERT_OK_PTR(fp, "fopen(TRACE_PIPE)")) goto cleanup;

/* We do not want to wait forever if this test fails... */ diff --git a/tools/testing/selftests/bpf/prog_tests/trace_vprintk.c b/tools/testing/selftests/bpf/prog_tests/trace_vprintk.c index 7a4e313e8558..44ea2fd88f4c 100644 --- a/tools/testing/selftests/bpf/prog_tests/trace_vprintk.c +++ b/tools/testing/selftests/bpf/prog_tests/trace_vprintk.c @@ -5,7 +5,8 @@

#include "trace_vprintk.lskel.h"

-#define TRACEBUF "/sys/kernel/debug/tracing/trace_pipe" +#define TRACEFS_PIPE "/sys/kernel/tracing/trace_pipe" +#define DEBUGFS_PIPE "/sys/kernel/debug/tracing/trace_pipe" #define SEARCHMSG "1,2,3,4,5,6,7,8,9,10"

void serial_test_trace_vprintk(void) @@ -27,8 +28,11 @@ void serial_test_trace_vprintk(void) if (!ASSERT_OK(err, "trace_vprintk__attach")) goto cleanup;

- fp = fopen(TRACEBUF, "r"); - if (!ASSERT_OK_PTR(fp, "fopen(TRACEBUF)")) + if (access(TRACEFS_PIPE, F_OK) == 0) + fp = fopen(TRACEFS_PIPE, "r"); + else + fp = fopen(DEBUGFS_PIPE, "r"); + if (!ASSERT_OK_PTR(fp, "fopen(TRACE_PIPE)")) goto cleanup;

/* We do not want to wait forever if this test fails... */ diff --git a/tools/testing/selftests/bpf/progs/test_stacktrace_map.c b/tools/testing/selftests/bpf/progs/test_stacktrace_map.c index 728dbd39eff0..47568007b668 100644 --- a/tools/testing/selftests/bpf/progs/test_stacktrace_map.c +++ b/tools/testing/selftests/bpf/progs/test_stacktrace_map.c @@ -38,7 +38,7 @@ struct { __type(value, stack_trace_t); } stack_amap SEC(".maps");

-/* taken from /sys/kernel/debug/tracing/events/sched/sched_switch/format */ +/* taken from /sys/kernel/tracing/events/sched/sched_switch/format */ struct sched_switch_args { unsigned long long pad; char prev_comm[TASK_COMM_LEN]; diff --git a/tools/testing/selftests/bpf/progs/test_tracepoint.c b/tools/testing/selftests/bpf/progs/test_tracepoint.c index 43bd7a20cc50..4cb8bbb6a320 100644 --- a/tools/testing/selftests/bpf/progs/test_tracepoint.c +++ b/tools/testing/selftests/bpf/progs/test_tracepoint.c @@ -4,7 +4,7 @@ #include <vmlinux.h> #include <bpf/bpf_helpers.h>

-/* taken from /sys/kernel/debug/tracing/events/sched/sched_switch/format */ +/* taken from /sys/kernel/tracing/events/sched/sched_switch/format */ struct sched_switch_args { unsigned long long pad; char prev_comm[TASK_COMM_LEN]; diff --git a/tools/testing/selftests/bpf/test_ftrace.sh b/tools/testing/selftests/bpf/test_ftrace.sh index 20de7bb873bc..f5109eb0e951 100755 --- a/tools/testing/selftests/bpf/test_ftrace.sh +++ b/tools/testing/selftests/bpf/test_ftrace.sh @@ -1,6 +1,11 @@ #!/bin/bash

-TR=/sys/kernel/debug/tracing/ +if [[ -e /sys/kernel/tracing/trace ]]; then + TR=/sys/kernel/tracing/ +else + TR=/sys/kernel/debug/tracing/ +fi + clear_trace() { # reset trace output echo > $TR/trace } diff --git a/tools/testing/selftests/bpf/test_tunnel.sh b/tools/testing/selftests/bpf/test_tunnel.sh index 06857b689c11..2dec7dbf29a2 100755 --- a/tools/testing/selftests/bpf/test_tunnel.sh +++ b/tools/testing/selftests/bpf/test_tunnel.sh @@ -571,8 +571,13 @@ setup_xfrm_tunnel()

test_xfrm_tunnel() { + if [[ -e /sys/kernel/tracing/trace ]]; then + TRACE=/sys/kernel/tracing/trace + else + TRACE=/sys/kernel/debug/tracing/trace + fi config_device - > /sys/kernel/debug/tracing/trace + > ${TRACE} setup_xfrm_tunnel mkdir -p ${BPF_PIN_TUNNEL_DIR} bpftool prog loadall ${BPF_FILE} ${BPF_PIN_TUNNEL_DIR} @@ -581,11 +586,11 @@ test_xfrm_tunnel() ${BPF_PIN_TUNNEL_DIR}/xfrm_get_state ip netns exec at_ns0 ping $PING_ARG 10.1.1.200 sleep 1 - grep "reqid 1" /sys/kernel/debug/tracing/trace + grep "reqid 1" ${TRACE} check_err $? - grep "spi 0x1" /sys/kernel/debug/tracing/trace + grep "spi 0x1" ${TRACE} check_err $? - grep "remote ip 0xac100164" /sys/kernel/debug/tracing/trace + grep "remote ip 0xac100164" ${TRACE} check_err $? cleanup

diff --git a/tools/testing/selftests/bpf/trace_helpers.c b/tools/testing/selftests/bpf/trace_helpers.c index 09a16a77bae4..934bf28fc888 100644 --- a/tools/testing/selftests/bpf/trace_helpers.c +++ b/tools/testing/selftests/bpf/trace_helpers.c @@ -12,7 +12,8 @@ #include <sys/mman.h> #include "trace_helpers.h"

-#define DEBUGFS "/sys/kernel/debug/tracing/" +#define TRACEFS_PIPE "/sys/kernel/tracing/trace_pipe" +#define DEBUGFS_PIPE "/sys/kernel/debug/tracing/trace_pipe"

#define MAX_SYMS 300000 static struct ksym syms[MAX_SYMS]; @@ -136,7 +137,10 @@ void read_trace_pipe(void) { int trace_fd;

- trace_fd = open(DEBUGFS "trace_pipe", O_RDONLY, 0); + if (access(TRACEFS_PIPE, F_OK) == 0) + trace_fd = open(TRACEFS_PIPE, O_RDONLY, 0); + else + trace_fd = open(DEBUGFS_PIPE, O_RDONLY, 0); if (trace_fd < 0) return;