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authorLinus Torvalds <torvalds@linux-foundation.org>2022-10-10 12:20:55 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2022-10-10 12:20:55 -0700
commitcdf072acb5baa18e5b05bdf3f13d6481f62396fc (patch)
tree9e6e6dc4c5adb79b1babab8d4c08cc86f1fe222b /samples
parentdc55342867c9cf2295f4330420461361a9c8117d (diff)
parent4f881a696484a7d31a4d1b12547615b1a3ee5771 (diff)
Merge tag 'trace-v6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull tracing updates from Steven Rostedt: "Major changes: - Changed location of tracing repo from personal git repo to: git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace.git - Added Masami Hiramatsu as co-maintainer - Updated MAINTAINERS file to separate out FTRACE as it is more than just TRACING. Minor changes: - Added Mark Rutland as FTRACE reviewer - Updated user_events to make it on its way to remove the BROKEN tag. The changes should now be acceptable but will run it through a cycle and hopefully we can remove the BROKEN tag next release. - Added filtering to eprobes - Added a delta time to the benchmark trace event - Have the histogram and filter callbacks called via a switch statement instead of indirect functions. This speeds it up to avoid retpolines. - Add a way to wake up ring buffer waiters waiting for the ring buffer to fill up to its watermark. - New ioctl() on the trace_pipe_raw file to wake up ring buffer waiters. - Wake up waiters when the ring buffer is disabled. A reader may block when the ring buffer is disabled, but if it was blocked when the ring buffer is disabled it should then wake up. Fixes: - Allow splice to read partially read ring buffer pages. This fixes splice never moving forward. - Fix inverted compare that made the "shortest" ring buffer wait queue actually the longest. - Fix a race in the ring buffer between resetting a page when a writer goes to another page, and the reader. - Fix ftrace accounting bug when function hooks are added at boot up before the weak functions are set to "disabled". - Fix bug that freed a user allocated snapshot buffer when enabling a tracer. - Fix possible recursive locks in osnoise tracer - Fix recursive locking direct functions - Other minor clean ups and fixes" * tag 'trace-v6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (44 commits) ftrace: Create separate entry in MAINTAINERS for function hooks tracing: Update MAINTAINERS to reflect new tracing git repo tracing: Do not free snapshot if tracer is on cmdline ftrace: Still disable enabled records marked as disabled tracing/user_events: Move pages/locks into groups to prepare for namespaces tracing: Add Masami Hiramatsu as co-maintainer tracing: Remove unused variable 'dups' MAINTAINERS: add myself as a tracing reviewer ring-buffer: Fix race between reset page and reading page tracing/user_events: Update ABI documentation to align to bits vs bytes tracing/user_events: Use bits vs bytes for enabled status page data tracing/user_events: Use refcount instead of atomic for ref tracking tracing/user_events: Ensure user provided strings are safely formatted tracing/user_events: Use WRITE instead of READ for io vector import tracing/user_events: Use NULL for strstr checks tracing: Fix spelling mistake "preapre" -> "prepare" tracing: Wake up waiters when tracing is disabled tracing: Add ioctl() to force ring buffer waiters to wake up tracing: Wake up ring buffer waiters on closing of the file ring-buffer: Add ring_buffer_wake_waiters() ...
Diffstat (limited to 'samples')
-rw-r--r--samples/user_events/example.c25
1 files changed, 18 insertions, 7 deletions
diff --git a/samples/user_events/example.c b/samples/user_events/example.c
index 4f5778e441c0..d06dc24156ec 100644
--- a/samples/user_events/example.c
+++ b/samples/user_events/example.c
@@ -12,13 +12,21 @@
#include <fcntl.h>
#include <stdio.h>
#include <unistd.h>
+#include <asm/bitsperlong.h>
+#include <endian.h>
#include <linux/user_events.h>
+#if __BITS_PER_LONG == 64
+#define endian_swap(x) htole64(x)
+#else
+#define endian_swap(x) htole32(x)
+#endif
+
/* Assumes debugfs is mounted */
const char *data_file = "/sys/kernel/debug/tracing/user_events_data";
const char *status_file = "/sys/kernel/debug/tracing/user_events_status";
-static int event_status(char **status)
+static int event_status(long **status)
{
int fd = open(status_file, O_RDONLY);
@@ -33,7 +41,8 @@ static int event_status(char **status)
return 0;
}
-static int event_reg(int fd, const char *command, int *status, int *write)
+static int event_reg(int fd, const char *command, long *index, long *mask,
+ int *write)
{
struct user_reg reg = {0};
@@ -43,7 +52,8 @@ static int event_reg(int fd, const char *command, int *status, int *write)
if (ioctl(fd, DIAG_IOCSREG, &reg) == -1)
return -1;
- *status = reg.status_index;
+ *index = reg.status_bit / __BITS_PER_LONG;
+ *mask = endian_swap(1L << (reg.status_bit % __BITS_PER_LONG));
*write = reg.write_index;
return 0;
@@ -51,8 +61,9 @@ static int event_reg(int fd, const char *command, int *status, int *write)
int main(int argc, char **argv)
{
- int data_fd, status, write;
- char *status_page;
+ int data_fd, write;
+ long index, mask;
+ long *status_page;
struct iovec io[2];
__u32 count = 0;
@@ -61,7 +72,7 @@ int main(int argc, char **argv)
data_fd = open(data_file, O_RDWR);
- if (event_reg(data_fd, "test u32 count", &status, &write) == -1)
+ if (event_reg(data_fd, "test u32 count", &index, &mask, &write) == -1)
return errno;
/* Setup iovec */
@@ -75,7 +86,7 @@ ask:
getchar();
/* Check if anyone is listening */
- if (status_page[status]) {
+ if (status_page[index] & mask) {
/* Yep, trace out our data */
writev(data_fd, (const struct iovec *)io, 2);