Steven Rostedt d0949cd44a tracing: Return from tracing_buffers_read() if the file has been closed ... When running the following: # cd /sys/kernel/tracing/ # echo 1 > events/sched/sched_waking/enable # echo 1 > events/sched/sched_switch/enable # echo 0 > tracing_on # dd if=per_cpu/cpu0/trace_pipe_raw of=/tmp/raw0.dat The dd task would get stuck in an infinite loop in the kernel. What would happen is the following: When ring_buffer_read_page() returns -1 (no data) then a check is made to see if the buffer is empty (as happens when the page is not full), it will call wait_on_pipe() to wait until the ring buffer has data. When it is it will try again to read data (unless O_NONBLOCK is set). The issue happens when there's a reader and the file descriptor is closed. The wait_on_pipe() will return when that is the case. But this loop will continue to try again and wait_on_pipe() will again return immediately and the loop will continue and never stop. Simply check if the file was closed before looping and exit out if it is. Cc: stable@vger.kernel.org Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Link: https://lore.kernel.org/20240808235730.78bf63e5@rorschach.local.home Fixes: 2aa043a55b ("tracing/ring-buffer: Fix wait_on_pipe() race") Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>		2024-08-09 12:59:35 -04:00
..
rv	rv: Update rv_en(dis)able_monitor doc to match kernel-doc	2024-05-21 19:03:35 -04:00
blktrace.c	blktrace: convert strncpy() to strscpy_pad()	2024-04-25 21:07:08 -07:00
bpf_trace.c	bpf: Change bpf_session_cookie return value to __u64 *	2024-06-21 19:32:36 +02:00
bpf_trace.h	tracing/treewide: Remove second parameter of __assign_str()	2024-05-22 20:14:47 -04:00
error_report-traces.c
fgraph.c	function_graph: Fix the ret_stack used by ftrace_graph_ret_addr()	2024-08-07 20:20:30 -04:00
fprobe.c	fprobe: Fix to allocate entry_data_size buffer with rethook instances	2024-03-01 09:18:24 +09:00
ftrace_internal.h	function_graph: Make fgraph_update_pid_func() a stub for !DYNAMIC_FTRACE	2024-06-10 18:08:23 -04:00
ftrace.c	sysctl: treewide: constify the ctl_table argument of proc_handlers	2024-07-24 20:59:29 +02:00
Kconfig	tracing: Build event generation tests only as modules	2024-06-12 08:43:12 +09:00
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	trace/pid_list: Change gfp flags in pid_list_fill_irq()	2024-07-15 15:07:14 -04:00
pid_list.h
power-traces.c
preemptirq_delay_test.c	minmax: make generic MIN() and MAX() macros available everywhere	2024-07-28 15:49:18 -07:00
rethook.c	rethook: honor CONFIG_FTRACE_VALIDATE_RCU_IS_WATCHING in rethook_try_get()	2024-05-01 23:18:48 +09:00
ring_buffer_benchmark.c	ring-buffer: Read and write to ring buffers with custom sub buffer size	2023-12-20 07:54:56 -05:00
ring_buffer.c	ring-buffer: Remove unused function ring_buffer_nr_pages()	2024-08-07 20:26:44 -04:00
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_benchmark.c	tracing: Improve benchmark test performance by using do_div()	2024-05-13 20:00:57 -04:00
trace_benchmark.h
trace_boot.c	tracing: Allow creating instances with specified system events	2023-12-18 23:14:16 -05:00
trace_branch.c
trace_btf.c	tracing/probes: Fix to search structure fields correctly	2024-02-17 21:25:42 +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
trace_dynevent.c	tracing: Free buffers when a used dynamic event is removed	2022-11-23 19:07:12 -05:00
trace_dynevent.h
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/probes: Support $argN in return probe (kprobe and fprobe)	2024-03-07 00:27:34 +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_filter_test.h
trace_events_filter.c	tracing: Have trace_event_file have ref counters	2023-11-01 23:44:44 -04:00
trace_events_hist.c	tracing: Have format file honor EVENT_FILE_FL_FREED	2024-08-07 18:12:46 -04:00
trace_events_inject.c	tracing: Have format file honor EVENT_FILE_FL_FREED	2024-08-07 18:12:46 -04:00
trace_events_synth.c	tracing/synthetic: Fix trace_string() return value	2024-02-15 11:40:01 -05:00
trace_events_trigger.c	tracing: Have format file honor EVENT_FILE_FL_FREED	2024-08-07 18:12:46 -04:00
trace_events_user.c	sysctl: treewide: constify the ctl_table argument of proc_handlers	2024-07-24 20:59:29 +02:00
trace_events.c	tracing: Use refcount for trace_event_file reference counter	2024-08-07 18:12:46 -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/probes: support '%pd' type for print struct dentry's name	2024-05-01 23:18:47 +09:00
trace_functions_graph.c	function_graph: Move graph notrace bit to shadow stack global var	2024-06-04 10:37:44 -04:00
trace_functions.c	ftrace: Hide one more entry in stack trace when ftrace_pid is enabled	2024-06-06 15:22:18 -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	function_graph: Move set_graph_function tests to shadow stack global var	2024-06-04 10:37:35 -04:00
trace_kdb.c
trace_kprobe_selftest.c	tracing: arm64: Avoid missing-prototype warnings	2023-07-12 12:06:04 -04:00
trace_kprobe_selftest.h
trace_kprobe.c	tracing/kprobes: Fix build error when find_module() is not available	2024-07-10 09:47:00 +09:00
trace_mmiotrace.c
trace_nop.c
trace_osnoise.c	rtla/osnoise: set the default threshold to 1us	2024-07-01 18:54:31 -04:00
trace_output.c	tracing: Remove precision vsnprintf() check from print event	2024-03-06 13:26:26 -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
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: Support $argN in return probe (kprobe and fprobe)	2024-03-07 00:27:34 +09:00
trace_probe.c	tracing/probes: fix error check in parse_btf_field()	2024-05-27 21:32:35 +09:00
trace_probe.h	tracing/probes: support '%pd' type for print struct dentry's name	2024-05-01 23:18:47 +09:00
trace_recursion_record.c
trace_sched_switch.c	tracing: Move saved_cmdline code into trace_sched_switch.c	2024-03-17 07:58:53 -04:00
trace_sched_wakeup.c	function_graph: Move set_graph_function tests to shadow stack global var	2024-06-04 10:37:35 -04:00
trace_selftest_dynamic.c
trace_selftest.c	fgraph: Use str_plural() in test_graph_storage_single()	2024-07-01 19:57:51 -04:00
trace_seq.c	trace_seq: Increase the buffer size to almost two pages	2023-12-18 23:14:16 -05:00
trace_stack.c	sysctl: treewide: constify the ctl_table argument of proc_handlers	2024-07-24 20:59:29 +02:00
trace_stat.c
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	uprobes: prevent mutex_lock() under rcu_read_lock()	2024-05-24 07:44:44 +09:00
trace.c	tracing: Return from tracing_buffers_read() if the file has been closed	2024-08-09 12:59:35 -04:00
trace.h	tracing: Have format file honor EVENT_FILE_FL_FREED	2024-08-07 18:12:46 -04:00
tracing_map.c	tracing: Fix overflow in get_free_elt()	2024-08-07 20:23:12 -04:00
tracing_map.h	tracing: Remove unused extern declaration tracing_map_set_field_descr()	2023-07-23 11:08:14 -04:00