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 ---
v2 was submitted to bpf-next via a pair of pull requests: https://github.com/kernel-patches/bpf/pull/4672 https://github.com/kernel-patches/bpf/pull/4648
The only change since v2 is that I rebased on the current bpf-next_base.
I've run this through all the BPF selftests on a local machine: sudo ./test_verifier sudo make run_tests
and didn't hit any regressions. I've also tested to make sure each modified selftest runs successfully with each path of tracefs (with and without debugfs).
--- 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: *
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