Xiao Yang 0bbe7f7199 tracing: Fix the race between registering 'snapshot' event trigger and triggering 'snapshot' operation ... 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: 93e31ffbf4 ("tracing: Add 'snapshot' event trigger command") Signed-off-by: Xiao Yang <yangx.jy@cn.fujitsu.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>		2020-04-14 22:02:10 -04:00
..
blktrace.c	blktrace: fix dereference after null check	2020-03-05 13:42:40 -07:00
bpf_trace.c	Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next	2020-03-30 19:52:37 -07:00
fgraph.c	tracing: Define MCOUNT_INSN_SIZE when not defined without direct calls	2020-01-02 21:56:44 -05:00
ftrace_internal.h
ftrace.c	New tracing features:	2020-04-05 10:36:18 -07:00
Kconfig	bootconfig: Fix CONFIG_BOOTTIME_TRACING dependency issue	2020-02-25 19:07:58 -05:00
kprobe_event_gen_test.c	tracing: Add kprobe event command generation test module	2020-01-30 09:46:28 -05:00
Makefile	tracing: Add kprobe event command generation test module	2020-01-30 09:46:28 -05:00
power-traces.c
preemptirq_delay_test.c	preemptirq_delay_test: Add the burst feature and a sysfs trigger	2019-11-13 09:37:28 -05:00
ring_buffer_benchmark.c	tracing: Make struct ring_buffer less ambiguous	2020-01-13 13:19:38 -05:00
ring_buffer.c	ring-buffer/tracing: Have iterator acknowledge dropped events	2020-03-27 16:39:01 -04:00
rpm-traces.c
synth_event_gen_test.c	tracing: Have synthetic event test use raw_smp_processor_id()	2020-02-20 17:43:41 -05:00
trace_benchmark.c	trace: Use pr_warn instead of pr_warning	2019-10-18 15:01:57 +02:00
trace_benchmark.h
trace_boot.c	tracing: Change trace_boot to use synth_event interface	2020-01-31 12:59:26 -05:00
trace_branch.c	tracing: Make struct ring_buffer less ambiguous	2020-01-13 13:19:38 -05:00
trace_clock.c
trace_dynevent.c	tracing: Use seq_buf for building dynevent_cmd string	2020-02-01 13:10:15 -05:00
trace_dynevent.h	tracing: Remove check_arg() callbacks from dynevent args	2020-02-01 13:09:23 -05:00
trace_entries.h	tracing: Have hwlat ts be first instance and record count of instances	2020-03-03 17:33:43 -05:00
trace_event_perf.c	Merge branch 'perf/urgent' into perf/core, to pick up fixes	2019-10-28 12:38:26 +01:00
trace_events_filter_test.h
trace_events_filter.c	tracing: Avoid memory leak in process_system_preds()	2019-12-19 18:24:17 -05:00
trace_events_hist.c	Tracing updates:	2020-02-26 10:34:42 -08:00
trace_events_inject.c	tracing: Initialize val to zero in parse_entry of inject code	2020-01-02 19:04:57 -05:00
trace_events_trigger.c	tracing: Fix the race between registering 'snapshot' event trigger and triggering 'snapshot' operation	2020-04-14 22:02:10 -04:00
trace_events.c	tracing: Create set_event_notrace_pid to not trace tasks	2020-03-27 16:39:02 -04:00
trace_export.c	Linux 5.5-rc1	2019-12-10 10:11:00 +01:00
trace_functions_graph.c	ring-buffer: Rename ring_buffer_read() to read_buffer_iter_advance()	2020-03-19 19:11:19 -04:00
trace_functions.c	tracing: Rename trace_buffer to array_buffer	2020-01-13 13:19:38 -05:00
trace_hwlat.c	tracing: Have hwlat ts be first instance and record count of instances	2020-03-03 17:33:43 -05:00
trace_irqsoff.c	tracing: Rename trace_buffer to array_buffer	2020-01-13 13:19:38 -05:00
trace_kdb.c	tracing: Rename trace_buffer to array_buffer	2020-01-13 13:19:38 -05:00
trace_kprobe_selftest.c
trace_kprobe_selftest.h
trace_kprobe.c	ftrace/kprobe: Show the maxactive number on kprobe_events	2020-03-27 16:39:02 -04:00
trace_mmiotrace.c	tracing: Make struct ring_buffer less ambiguous	2020-01-13 13:19:38 -05:00
trace_nop.c
trace_output.c	tracing: Save off entry when peeking at next entry	2020-03-19 17:48:36 -04:00
trace_output.h
trace_preemptirq.c
trace_printk.c	tracing: Add locked_down checks to the open calls of files created for tracefs	2019-10-12 20:48:06 -04:00
trace_probe_tmpl.h
trace_probe.c	tracing/kprobes: Have uname use __get_str() in print_fmt	2020-01-27 10:56:02 -05:00
trace_probe.h	tracing/uprobe: Fix to make trace_uprobe_filter alignment safe	2020-01-22 07:09:20 -05:00
trace_sched_switch.c	tracing: Fix sched switch start/stop refcount racy updates	2020-01-30 09:46:10 -05:00
trace_sched_wakeup.c	tracing: Make struct ring_buffer less ambiguous	2020-01-13 13:19:38 -05:00
trace_selftest_dynamic.c
trace_selftest.c	tracing: Rename trace_buffer to array_buffer	2020-01-13 13:19:38 -05:00
trace_seq.c	tracing: Remove unused TRACE_SEQ_BUF_USED	2020-01-21 18:39:54 -05:00
trace_stack.c	tracing: Have stack tracer compile when MCOUNT_INSN_SIZE is not defined	2020-01-02 22:04:07 -05:00
trace_stat.c	tracing: Fix tracing_stat return values in error handling paths	2020-01-24 18:06:48 -05:00
trace_stat.h	tracing: Use generic type for comparator function	2019-11-14 13:15:11 -05:00
trace_syscalls.c	Tracing updates:	2020-02-06 07:12:11 +00:00
trace_uprobe.c	bpf: disable preemption for bpf progs attached to uprobe	2020-02-24 16:17:14 -08:00
trace.c	tracing: Do not allocate buffer in trace_find_next_entry() in atomic	2020-04-03 11:30:50 -04:00
trace.h	tracing: Create set_event_notrace_pid to not trace tasks	2020-03-27 16:39:02 -04:00
tracing_map.c	tracing: Have the histogram compare functions convert to u64 first	2019-12-19 18:26:00 -05:00
tracing_map.h