linux/kernel/trace/trace.c, branch v4.15

tracing: Update stack trace skipping for ORC unwinder

2018-01-23T20:57:00Z

With the addition of ORC unwinder and FRAME POINTER unwinder, the stack trace skipping requirements have changed. I went through the tracing stack trace dumps with ORC and with frame pointers and recalculated the proper values. Signed-off-by: Steven Rostedt (VMware)

tracing: Fix possible double free on failure of allocating trace buffer

2017-12-27T19:21:27Z

Jing Xia and Chunyan Zhang reported that on failing to allocate part of the tracing buffer, memory is freed, but the pointers that point to them are not initialized back to NULL, and later paths may try to free the freed memory again. Jing and Chunyan fixed one of the locations that does this, but missed a spot. Link: http://lkml.kernel.org/r/20171226071253.8968-1-chunyan.zhang@spreadtrum.com Cc: stable@vger.kernel.org Fixes: 737223fbca3b1 ("tracing: Consolidate buffer allocation code") Reported-by: Jing Xia Reported-by: Chunyan Zhang Signed-off-by: Steven Rostedt (VMware)

tracing: Fix crash when it fails to alloc ring buffer

2017-12-27T19:21:16Z

Double free of the ring buffer happens when it fails to alloc new ring buffer instance for max_buffer if TRACER_MAX_TRACE is configured. The root cause is that the pointer is not set to NULL after the buffer is freed in allocate_trace_buffers(), and the freeing of the ring buffer is invoked again later if the pointer is not equal to Null, as: instance_mkdir() |-allocate_trace_buffers() |-allocate_trace_buffer(tr, &tr->trace_buffer...) |-allocate_trace_buffer(tr, &tr->max_buffer...) // allocate fail(-ENOMEM),first free // and the buffer pointer is not set to null |-ring_buffer_free(tr->trace_buffer.buffer) // out_free_tr |-free_trace_buffers() |-free_trace_buffer(&tr->trace_buffer); //if trace_buffer is not null, free again |-ring_buffer_free(buf->buffer) |-rb_free_cpu_buffer(buffer->buffers[cpu]) // ring_buffer_per_cpu is null, and // crash in ring_buffer_per_cpu->pages Link: http://lkml.kernel.org/r/20171226071253.8968-1-chunyan.zhang@spreadtrum.com Cc: stable@vger.kernel.org Fixes: 737223fbca3b1 ("tracing: Consolidate buffer allocation code") Signed-off-by: Jing Xia Signed-off-by: Chunyan Zhang Signed-off-by: Steven Rostedt (VMware)

tracing: Remove extra zeroing out of the ring buffer page

2017-12-27T19:20:59Z

The ring_buffer_read_page() takes care of zeroing out any extra data in the page that it returns. There's no need to zero it out again from the consumer. It was removed from one consumer of this function, but read_buffers_splice_read() did not remove it, and worse, it contained a nasty bug because of it. Cc: stable@vger.kernel.org Fixes: 2711ca237a084 ("ring-buffer: Move zeroing out excess in page to ring buffer code") Signed-off-by: Steven Rostedt (VMware)

tracing: Pass export pointer as argument to ->write()

2017-12-04T12:14:30Z

By passing an export descriptor to the write function, users don't need to keep a global static pointer and can rely on container_of() to fetch their own structure. Link: http://lkml.kernel.org/r/20170602102025.5140-1-felipe.balbi@linux.intel.com Acked-by: Steven Rostedt (VMware) Reviewed-by: Chunyan Zhang Signed-off-by: Felipe Balbi Signed-off-by: Steven Rostedt (VMware)

tracing: Allocate mask_str buffer dynamically

2017-12-04T11:52:08Z

The default NR_CPUS can be very large, but actual possible nr_cpu_ids usually is very small. For my x86 distribution, the NR_CPUS is 8192 and nr_cpu_ids is 4. About 2 pages are wasted. Most machines don't have so many CPUs, so define a array with NR_CPUS just wastes memory. So let's allocate the buffer dynamically when need. With this change, the mutext tracing_cpumask_update_lock also can be removed now, which was used to protect mask_str. Link: http://lkml.kernel.org/r/1512013183-19107-1-git-send-email-changbin.du@intel.com Fixes: 36dfe9252bd4c ("ftrace: make use of tracing_cpumask") Cc: stable@vger.kernel.org Signed-off-by: Changbin Du Signed-off-by: Steven Rostedt (VMware)

tracing: Fix code comments in trace.c

2017-12-04T11:52:07Z

Naming in code comments for tracing_snapshot, tracing_snapshot_alloc and trace_pid_filter_add_remove_task don't match the real function names. And latency_trace has been removed from tracing directory. Fix them. Link: http://lkml.kernel.org/r/1508394753-20887-1-git-send-email-chuhu@redhat.com Fixes: cab5037 ("tracing/ftrace: Enable snapshot function trigger") Fixes: 886b5b7 ("tracing: remove /debug/tracing/latency_trace") Signed-off-by: Chunyu Hu [ Replaced /sys/kernel/debug/tracing with /sys/kerne/tracing ] Signed-off-by: Steven Rostedt (VMware)

tracing: Make traceprobe parsing code reusable

2017-10-04T17:06:44Z

traceprobe_probes_write() and traceprobe_command() actually contain nothing that ties them to kprobes - the code is generically useful for similar types of parsing elsewhere, so separate it out and move it to trace.c/trace.h. Other than moving it, the only change is in naming: traceprobe_probes_write() becomes trace_parse_run_command() and traceprobe_command() becomes trace_run_command(). Link: http://lkml.kernel.org/r/ae5c26ea40c196a8986854d921eb6e713ede7e3f.1506105045.git.tom.zanussi@linux.intel.com Signed-off-by: Tom Zanussi Signed-off-by: Steven Rostedt (VMware)

tracing: Reverse the order of trace_types_lock and event_mutex

2017-10-04T15:36:56Z

In order to make future changes where we need to call tracing_set_clock() from within an event command, the order of trace_types_lock and event_mutex must be reversed, as the event command will hold event_mutex and the trace_types_lock is taken from within tracing_set_clock(). Link: http://lkml.kernel.org/r/20170921162249.0dde3dca@gandalf.local.home Requested-by: Tom Zanussi Signed-off-by: Steven Rostedt (VMware)

tracing: Fix trace_pipe behavior for instance traces

2017-09-19T22:33:42Z

When reading data from trace_pipe, tracing_wait_pipe() performs a check to see if tracing has been turned off after some data was read. Currently, this check always looks at global trace state, but it should be checking the trace instance where trace_pipe is located at. Because of this bug, cat instances/i1/trace_pipe in the following script will immediately exit instead of waiting for data: cd /sys/kernel/debug/tracing echo 0 > tracing_on mkdir -p instances/i1 echo 1 > instances/i1/tracing_on echo 1 > instances/i1/events/sched/sched_process_exec/enable cat instances/i1/trace_pipe Link: http://lkml.kernel.org/r/20170917102348.1615-1-tahsin@google.com Cc: stable@vger.kernel.org Fixes: 10246fa35d4f ("tracing: give easy way to clear trace buffer") Signed-off-by: Tahsin Erdogan Signed-off-by: Steven Rostedt (VMware)