Steven Rostedt (Google) 39a7dc23a1 tracing: Fix blocked reader of snapshot buffer ... If an application blocks on the snapshot or snapshot_raw files, expecting to be woken up when a snapshot occurs, it will not happen. Or it may happen with an unexpected result. That result is that the application will be reading the main buffer instead of the snapshot buffer. That is because when the snapshot occurs, the main and snapshot buffers are swapped. But the reader has a descriptor still pointing to the buffer that it originally connected to. This is fine for the main buffer readers, as they may be blocked waiting for a watermark to be hit, and when a snapshot occurs, the data that the main readers want is now on the snapshot buffer. But for waiters of the snapshot buffer, they are waiting for an event to occur that will trigger the snapshot and they can then consume it quickly to save the snapshot before the next snapshot occurs. But to do this, they need to read the new snapshot buffer, not the old one that is now receiving new data. Also, it does not make sense to have a watermark "buffer_percent" on the snapshot buffer, as the snapshot buffer is static and does not receive new data except all at once. Link: https://lore.kernel.org/linux-trace-kernel/20231228095149.77f5b45d@gandalf.local.home Cc: stable@vger.kernel.org Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Mark Rutland <mark.rutland@arm.com> Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Fixes: debdd57f51 ("tracing: Make a snapshot feature available from userspace") Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>		2023-12-29 09:18:49 -05:00
..
rv	tracing/tools: Updates for 6.4	2023-04-28 16:11:26 -07:00
blktrace.c	block: remove more NULL checks after bdev_get_queue()	2023-02-21 09:23:22 -07:00
bpf_trace.c	bpf: Add __bpf_kfunc_{start,end}_defs macros	2023-11-01 22:33:53 -07:00
bpf_trace.h
error_report-traces.c
fgraph.c	tracing: arm64: Avoid missing-prototype warnings	2023-07-12 12:06:04 -04:00
fprobe.c	Probes updates for v6.7:	2023-11-01 16:15:42 -10:00
ftrace.c	ftrace: Use LIST_HEAD to initialize clear_hash	2023-09-01 21:18:38 -04:00
ftrace_internal.h	tracing: arm64: Avoid missing-prototype warnings	2023-07-12 12:06:04 -04:00
Kconfig	Probes updates for v6.5:	2023-06-30 10:44:53 -07:00
kprobe_event_gen_test.c	tracing: Fix wrong return in kprobe_event_gen_test.c	2023-03-19 12:20:48 -04:00
Makefile	tracing/probes: Move finding func-proto API and getting func-param API to trace_btf	2023-08-23 09:39:45 +09:00
pid_list.c	tracing: Cleanup double word in comment	2022-04-26 17:58:50 -04:00
pid_list.h	tracing: Create a sparse bitmask for pid filtering	2021-10-05 17:38:45 -04:00
power-traces.c
preemptirq_delay_test.c
rethook.c	kprobes: unused header files removed	2023-10-24 10:04:59 +09:00
ring_buffer.c	tracing: Fix blocked reader of snapshot buffer	2023-12-29 09:18:49 -05:00
ring_buffer_benchmark.c	ring_buffer: Remove unused "event" parameter	2022-11-23 19:08:30 -05:00
rpm-traces.c
synth_event_gen_test.c	tracing / synthetic: Disable events after testing in synth_event_gen_test_init()	2023-12-21 10:04:45 -05:00
trace.c	tracing: Fix blocked reader of snapshot buffer	2023-12-29 09:18:49 -05:00
trace.h	tracing: Fix uaf issue when open the hist or hist_debug file	2023-12-13 23:29:59 -05:00
trace_benchmark.c	tracing: Add numeric delta time to the trace event benchmark	2022-09-26 13:01:09 -04:00
trace_benchmark.h	tracing: Add numeric delta time to the trace event benchmark	2022-09-26 13:01:09 -04:00
trace_boot.c	tracing/boot: Test strscpy() against less than zero for error	2023-07-05 10:30:49 -04:00
trace_branch.c
trace_btf.c	tracing/probes: Add a function to search a member of a struct/union	2023-08-23 09:40:16 +09:00
trace_btf.h	tracing/probes: Add a function to search a member of a struct/union	2023-08-23 09:40:16 +09:00
trace_clock.c	tracing: Do no increment trace_clock_global() by one	2021-06-18 09:10:00 -04:00
trace_dynevent.c	tracing: Free buffers when a used dynamic event is removed	2022-11-23 19:07:12 -05:00
trace_dynevent.h	tracing: Add DYNAMIC flag for dynamic events	2021-08-18 18:10:32 -04:00
trace_entries.h	tracing: Add back FORTIFY_SOURCE logic to kernel_stack event structure	2023-07-30 18:11:44 -04:00
trace_eprobe.c	tracing/eprobe: drop unneeded breaks	2023-10-10 01:03:48 +09:00
trace_event_perf.c	tracing/perf: Use strndup_user instead of kzalloc/strncpy_from_user	2022-11-23 19:08:31 -05:00
trace_events.c	tracing: Have trace_event_file have ref counters	2023-11-01 23:44:44 -04:00
trace_events_filter.c	tracing: Have trace_event_file have ref counters	2023-11-01 23:44:44 -04:00
trace_events_filter_test.h
trace_events_hist.c	tracing: Fix uaf issue when open the hist or hist_debug file	2023-12-13 23:29:59 -05:00
trace_events_inject.c	tracing: Have event inject files inc the trace array ref count	2023-09-07 16:38:54 -04:00
trace_events_synth.c	tracing/synthetic: fix kernel-doc warnings	2023-12-20 12:51:03 -05:00
trace_events_trigger.c	tracing: Fix kernel-doc warnings in trace_events_trigger.c	2023-07-28 19:59:03 -04:00
trace_events_user.c	tracing/user_events: Allow events to persist for perfmon_capable users	2023-10-03 22:29:43 -04:00
trace_export.c	tracing: Add back FORTIFY_SOURCE logic to kernel_stack event structure	2023-07-30 18:11:44 -04:00
trace_fprobe.c	tracing: fprobe-event: Fix to check tracepoint event and return	2023-11-10 20:06:12 +09:00
trace_functions.c	ftrace: disable preemption when recursion locked	2021-10-27 11:21:49 -04:00
trace_functions_graph.c	function_graph: Support recording and printing the return value of function	2023-06-20 18:38:37 -04:00
trace_hwlat.c	tracing: Remove extra space at the end of hwlat_detector/mode	2023-09-01 21:00:00 -04:00
trace_irqsoff.c	tracing: Fix memleak due to race between current_tracer and trace	2023-08-17 13:49:37 -04:00
trace_kdb.c	kdb: Rename members of struct kdbtab_t	2021-07-27 17:05:06 +01:00
trace_kprobe.c	tracing/kprobes: Fix the order of argument descriptions	2023-11-11 08:00:43 +09:00
trace_kprobe_selftest.c	tracing: arm64: Avoid missing-prototype warnings	2023-07-12 12:06:04 -04:00
trace_kprobe_selftest.h
trace_mmiotrace.c
trace_nop.c
trace_osnoise.c	tracing/timerlat: Add user-space interface	2023-06-22 10:39:56 -04:00
trace_output.c	tracing: Add size check when printing trace_marker output	2023-12-12 22:07:22 -05:00
trace_output.h	tracing: Add "fields" option to show raw trace event fields	2023-03-29 06:52:08 -04:00
trace_preemptirq.c	cpuidle: tracing, preempt: Squash _rcuidle tracing	2023-01-31 15:01:46 +01:00
trace_printk.c	tracing: Disable "other" permission bits in the tracefs files	2021-10-08 18:08:43 -04:00
trace_probe.c	tracing/probes: Add string type check with BTF	2023-08-23 09:41:13 +09:00
trace_probe.h	tracing/kprobes: Return EADDRNOTAVAIL when func matches several symbols	2023-10-20 22:10:41 +09:00
trace_probe_kernel.h	tracing/probes: Fix to record 0-length data_loc in fetch_store_string*() if fails	2023-07-14 17:04:58 +09:00
trace_probe_tmpl.h	tracing/probes: Fix to record 0-length data_loc in fetch_store_string*() if fails	2023-07-14 17:04:58 +09:00
trace_recursion_record.c	tracing: Use trace_create_file() to simplify creation of tracefs entries	2022-05-26 21:12:52 -04:00
trace_sched_switch.c	sched/tracing: Append prev_state to tp args instead	2022-05-12 00:37:11 +02:00
trace_sched_wakeup.c	tracing: Fix memleak due to race between current_tracer and trace	2023-08-17 13:49:37 -04:00
trace_selftest.c	tracing: Have function_graph selftest call cond_resched()	2023-05-28 21:15:46 -04:00
trace_selftest_dynamic.c
trace_seq.c	tracing: Move readpos from seq_buf to trace_seq	2023-10-20 12:16:10 -04:00
trace_stack.c	tracing: Disable "other" permission bits in the tracefs files	2021-10-08 18:08:43 -04:00
trace_stat.c	tracing: Disable "other" permission bits in the tracefs files	2021-10-08 18:08:43 -04:00
trace_stat.h
trace_synth.h	tracing: Allow synthetic events to pass around stacktraces	2023-01-25 10:31:24 -05:00
trace_syscalls.c	bpf: Change syscall_nr type to int in struct syscall_tp_t	2023-10-13 12:39:36 -07:00
trace_uprobe.c	Probes updates for v6.6:	2023-09-02 11:10:50 -07:00
tracing_map.c	tracing: Remove unused variable 'dups'	2022-10-03 12:20:31 -04:00
tracing_map.h	tracing: Remove unused extern declaration tracing_map_set_field_descr()	2023-07-23 11:08:14 -04:00