wireguard-linux/kernel/trace, branch jd/unified-crypt-queue

tracing: Fix the race between registering 'snapshot' event trigger and triggering 'snapshot' operation

2020-04-15T02:02:10Z

Traced event can trigger 'snapshot' operation(i.e. calls snapshot_trigger() or snapshot_count_trigger()) when register_snapshot_trigger() has completed registration but doesn't allocate buffer for 'snapshot' event trigger. In the rare case, 'snapshot' operation always detects the lack of allocated buffer so make register_snapshot_trigger() allocate buffer first. trigger-snapshot.tc in kselftest reproduces the issue on slow vm: ----------------------------------------------------------- cat trace ... ftracetest-3028 [002] .... 236.784290: sched_process_fork: comm=ftracetest pid=3028 child_comm=ftracetest child_pid=3036 <...>-2875 [003] .... 240.460335: tracing_snapshot_instance_cond: *** SNAPSHOT NOT ALLOCATED *** <...>-2875 [003] .... 240.460338: tracing_snapshot_instance_cond: *** stopping trace here! *** ----------------------------------------------------------- Link: http://lkml.kernel.org/r/20200414015145.66236-1-yangx.jy@cn.fujitsu.com Cc: stable@vger.kernel.org Fixes: 93e31ffbf417a ("tracing: Add 'snapshot' event trigger command") Signed-off-by: Xiao Yang Signed-off-by: Steven Rostedt (VMware)

Merge tag 'trace-v5.7' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

2020-04-05T17:36:18Z

Pull tracing updates from Steven Rostedt: "New tracing features: - The ring buffer is no longer disabled when reading the trace file. The trace_pipe file was made to be used for live tracing and reading as it acted like the normal producer/consumer. As the trace file would not consume the data, the easy way of handling it was to just disable writes to the ring buffer. This came to a surprise to the BPF folks who complained about lost events due to reading. This is no longer an issue. If someone wants to keep the old disabling there's a new option "pause-on-trace" that can be set. - New set_ftrace_notrace_pid file. PIDs in this file will not be traced by the function tracer. Similar to set_ftrace_pid, which makes the function tracer only trace those tasks with PIDs in the file, the set_ftrace_notrace_pid does the reverse. - New set_event_notrace_pid file. PIDs in this file will cause events not to be traced if triggered by a task with a matching PID. Similar to the set_event_pid file but will not be traced. Note, sched_waking and sched_switch events may still be traced if one of the tasks referenced by those events contains a PID that is allowed to be traced. Tracing related features: - New bootconfig option, that is attached to the initrd file. If bootconfig is on the command line, then the initrd file is searched looking for a bootconfig appended at the end. - New GPU tracepoint infrastructure to help the gfx drivers to get off debugfs (acked by Greg Kroah-Hartman) And other minor updates and fixes" * tag 'trace-v5.7' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (27 commits) tracing: Do not allocate buffer in trace_find_next_entry() in atomic tracing: Add documentation on set_ftrace_notrace_pid and set_event_notrace_pid selftests/ftrace: Add test to test new set_event_notrace_pid file selftests/ftrace: Add test to test new set_ftrace_notrace_pid file tracing: Create set_event_notrace_pid to not trace tasks ftrace: Create set_ftrace_notrace_pid to not trace tasks ftrace: Make function trace pid filtering a bit more exact ftrace/kprobe: Show the maxactive number on kprobe_events tracing: Have the document reflect that the trace file keeps tracing enabled ring-buffer/tracing: Have iterator acknowledge dropped events tracing: Do not disable tracing when reading the trace file ring-buffer: Do not disable recording when there is an iterator ring-buffer: Make resize disable per cpu buffer instead of total buffer ring-buffer: Optimize rb_iter_head_event() ring-buffer: Do not die if rb_iter_peek() fails more than thrice ring-buffer: Have rb_iter_head_event() handle concurrent writer ring-buffer: Add page_stamp to iterator for synchronization ring-buffer: Rename ring_buffer_read() to read_buffer_iter_advance() ring-buffer: Have ring_buffer_empty() not depend on tracing stopped tracing: Save off entry when peeking at next entry ...

tracing: Do not allocate buffer in trace_find_next_entry() in atomic

2020-04-03T15:30:50Z

When dumping out the trace data in latency format, a check is made to peek at the next event to compare its timestamp to the current one, and if the delta is of a greater size, it will add a marker showing so. But to do this, it needs to save the current event otherwise peeking at the next event will remove the current event. To save the event, a temp buffer is used, and if the event is bigger than the temp buffer, the temp buffer is freed and a bigger buffer is allocated. This allocation is a problem when called in atomic context. The only way this gets called via atomic context is via ftrace_dump(). Thus, use a static buffer of 128 bytes (which covers most events), and if the event is bigger than that, simply return NULL. The callers of trace_find_next_entry() need to handle a NULL case, as that's what would happen if the allocation failed. Link: https://lore.kernel.org/r/20200326091256.GR11705@shao2-debian Fixes: ff895103a84ab ("tracing: Save off entry when peeking at next entry") Reported-by: kernel test robot Signed-off-by: Steven Rostedt (VMware)

Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

2020-03-31T02:52:37Z

Signed-off-by: David S. Miller

bpf: Introduce BPF_PROG_TYPE_LSM

2020-03-29T23:34:00Z

Introduce types and configs for bpf programs that can be attached to LSM hooks. The programs can be enabled by the config option CONFIG_BPF_LSM. Signed-off-by: KP Singh Signed-off-by: Daniel Borkmann Reviewed-by: Brendan Jackman Reviewed-by: Florent Revest Reviewed-by: Thomas Garnier Acked-by: Yonghong Song Acked-by: Andrii Nakryiko Acked-by: James Morris Link: https://lore.kernel.org/bpf/20200329004356.27286-2-kpsingh@chromium.org

tracing: Create set_event_notrace_pid to not trace tasks

2020-03-27T20:39:02Z

There's currently a way to select a task that should only have its events traced, but there's no way to select a task not to have itsevents traced. Add a set_event_notrace_pid file that acts the same as set_event_pid (and is also affected by event-fork), but the task pids in this file will not be traced even if they are listed in the set_event_pid file. This makes it easy for tools like trace-cmd to "hide" itself from beint traced by events when it is recording other tasks. Signed-off-by: Steven Rostedt (VMware)

ftrace: Create set_ftrace_notrace_pid to not trace tasks

2020-03-27T20:39:02Z

There's currently a way to select a task that should only be traced by functions, but there's no way to select a task not to be traced by the function tracer. Add a set_ftrace_notrace_pid file that acts the same as set_ftrace_pid (and is also affected by function-fork), but the task pids in this file will not be traced even if they are listed in the set_ftrace_pid file. This makes it easy for tools like trace-cmd to "hide" itself from the function tracer when it is recording other tasks. Signed-off-by: Steven Rostedt (VMware)

ftrace: Make function trace pid filtering a bit more exact

2020-03-27T20:39:02Z

The set_ftrace_pid file is used to filter function tracing to only trace tasks that are listed in that file. Instead of testing the pids listed in that file (it's a bitmask) at each function trace event, the logic is done via a sched_switch hook. A flag is set when the next task to run is in the list of pids in the set_ftrace_pid file. But the sched_switch hook is not at the exact location of when the task switches, and the flag gets set before the task to be traced actually runs. This leaves a residue of traced functions that do not belong to the pid that should be filtered on. By changing the logic slightly, where instead of having a boolean flag to test, record the pid that should be traced, with special values for not to trace and always trace. Then at each function call, a check will be made to see if the function should be ignored, or if the current pid matches the function that should be traced, and only trace if it matches (or if it has the special value to always trace). Signed-off-by: Steven Rostedt (VMware)

ftrace/kprobe: Show the maxactive number on kprobe_events

2020-03-27T20:39:02Z

Show maxactive parameter on kprobe_events. This allows user to save the current configuration and restore it without losing maxactive parameter. Link: http://lkml.kernel.org/r/4762764a-6df7-bc93-ed60-e336146dce1f@gmail.com Link: http://lkml.kernel.org/r/158503528846.22706.5549974121212526020.stgit@devnote2 Cc: stable@vger.kernel.org Fixes: 696ced4fb1d76 ("tracing/kprobes: expose maxactive for kretprobe in kprobe_events") Reported-by: Taeung Song Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (VMware)

ring-buffer/tracing: Have iterator acknowledge dropped events

2020-03-27T20:39:01Z

Have the ring_buffer_iterator set a flag if events were dropped as it were to go and peek at the next event. Have the trace file display this fact if it happened with a "LOST EVENTS" message. Link: http://lkml.kernel.org/r/20200317213417.045858900@goodmis.org Signed-off-by: Steven Rostedt (VMware)