linux/kernel/trace
Steven Rostedt (VMware) 726b3d3f14 ftrace: Handle tracing when switching between context
When an interrupt or NMI comes in and switches the context, there's a delay
from when the preempt_count() shows the update. As the preempt_count() is
used to detect recursion having each context have its own bit get set when
tracing starts, and if that bit is already set, it is considered a recursion
and the function exits. But if this happens in that section where context
has changed but preempt_count() has not been updated, this will be
incorrectly flagged as a recursion.

To handle this case, create another bit call TRANSITION and test it if the
current context bit is already set. Flag the call as a recursion if the
TRANSITION bit is already set, and if not, set it and continue. The
TRANSITION bit will be cleared normally on the return of the function that
set it, or if the current context bit is clear, set it and clear the
TRANSITION bit to allow for another transition between the current context
and an even higher one.

Cc: stable@vger.kernel.org
Fixes: edc15cafcb ("tracing: Avoid unnecessary multiple recursion checks")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-11-02 08:52:18 -05:00
..
blktrace.c block: add a bdget_part helper 2020-10-05 10:38:33 -06:00
bpf_trace.c networking changes for the 5.10 merge window 2020-10-15 18:42:13 -07:00
bpf_trace.h bpf: Use dedicated bpf_trace_printk event instead of trace_printk() 2020-07-13 16:55:49 -07:00
fgraph.c fgraph: Convert ret_stack tasklist scanning to rcu 2020-09-21 21:06:02 -04:00
ftrace.c Updates for tracing and bootconfig: 2020-10-15 15:51:28 -07:00
ftrace_internal.h x86/ftrace: Have ftrace trampolines turn read-only at the end of system boot up 2020-05-12 18:24:34 -04:00
Kconfig Tracing updates for 5.8: 2020-06-09 10:06:18 -07:00
kprobe_event_gen_test.c tracing: Add kprobe event command generation test module 2020-01-30 09:46:28 -05:00
Makefile Kbuild updates for v5.9 2020-08-09 14:10:26 -07:00
power-traces.c
preemptirq_delay_test.c tracing: Wait for preempt irq delay thread to execute 2020-05-11 17:00:34 -04:00
ring_buffer.c ring-buffer: Update the description for ring_buffer_wait 2020-10-22 11:26:26 -04:00
ring_buffer_benchmark.c sched,tracing: Convert to sched_set_fifo() 2020-07-29 11:43:53 +02:00
rpm-traces.c
synth_event_gen_test.c tracing: Add support for dynamic strings to synthetic events 2020-10-05 19:32:18 -04:00
trace.c tracing: Fix out of bounds write in get_trace_buf 2020-11-02 08:52:18 -05:00
trace.h ftrace: Handle tracing when switching between context 2020-11-02 08:52:18 -05:00
trace_benchmark.c trace: Use pr_warn instead of pr_warning 2019-10-18 15:01:57 +02:00
trace_benchmark.h tracing: Fix SPDX format headers to use C++ style comments 2018-08-16 19:08:06 -04:00
trace_boot.c tracing/boot: Add ftrace.instance.*.alloc_snapshot option 2020-10-15 12:01:13 -04:00
trace_branch.c tracing: Make struct ring_buffer less ambiguous 2020-01-13 13:19:38 -05:00
trace_clock.c tracing: Add SPDX License format tags to tracing files 2018-08-16 19:08:06 -04:00
trace_dynevent.c tracing: Delete repeated words in comments 2020-09-21 21:06:02 -04:00
trace_dynevent.h tracing: Remove check_arg() callbacks from dynevent args 2020-02-01 13:09:23 -05:00
trace_entries.h tracing: Make ftrace packed events have align of 1 2020-06-16 21:21:02 -04:00
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.c Tracing: Fix mismatch section of adding early trace events 2020-10-16 14:56:52 -07:00
trace_events_filter.c treewide: Use fallthrough pseudo-keyword 2020-08-23 17:36:59 -05:00
trace_events_filter_test.h tracing: Fix SPDX format headers to use C++ style comments 2018-08-16 19:08:06 -04:00
trace_events_hist.c tracing: Check return value of __create_val_fields() before using its result 2020-10-15 12:00:59 -04:00
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_synth.c tracing, synthetic events: Replace buggy strcat() with seq_buf operations 2020-10-27 09:25:36 -04:00
trace_events_trigger.c tracing: Fix event trigger to accept redundant spaces 2020-06-23 21:51:40 -04:00
trace_export.c treewide: Convert macro and uses of __section(foo) to __section("foo") 2020-10-25 14:51:49 -07:00
trace_functions.c tracing: Enable creating new instance early boot 2020-09-21 21:06:04 -04:00
trace_functions_graph.c tracing: make tracing_init_dentry() returns an integer instead of a d_entry pointer 2020-09-18 22:17:14 -04:00
trace_hwlat.c tracing: make tracing_init_dentry() returns an integer instead of a d_entry pointer 2020-09-18 22:17:14 -04:00
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.c kprobes: Use module_name() macro 2020-09-24 15:55:49 +02:00
trace_kprobe_selftest.c selftest/ftrace: Move kprobe selftest function to separate compile unit 2018-07-30 18:41:04 -04:00
trace_kprobe_selftest.h tracing: Fix SPDX format headers to use C++ style comments 2018-08-16 19:08:06 -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: Make the space reserved for the pid wider 2020-09-18 12:42:11 -04:00
trace_output.h tracing: Fix SPDX format headers to use C++ style comments 2018-08-16 19:08:06 -04:00
trace_preemptirq.c lockdep: fix order in trace_hardirqs_off_caller() 2020-09-14 10:08:07 +02:00
trace_printk.c Updates for tracing and bootconfig: 2020-10-15 15:51:28 -07:00
trace_probe.c tracing/probe: Fix memleak in fetch_op_data operations 2020-06-16 21:21:02 -04:00
trace_probe.h tracing: Move is_good_name() from trace_probe.h to trace.h 2020-10-15 12:01:13 -04:00
trace_probe_tmpl.h tracing/probe: Support user-space dereference 2019-05-25 23:04:42 -04:00
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.c ftrace: Handle tracing when switching between context 2020-11-02 08:52:18 -05:00
trace_selftest_dynamic.c
trace_seq.c tracing: Remove unused TRACE_SEQ_BUF_USED 2020-01-21 18:39:54 -05:00
trace_stack.c tracing: make tracing_init_dentry() returns an integer instead of a d_entry pointer 2020-09-18 22:17:14 -04:00
trace_stat.c tracing: make tracing_init_dentry() returns an integer instead of a d_entry pointer 2020-09-18 22:17:14 -04:00
trace_stat.h tracing: Use generic type for comparator function 2019-11-14 13:15:11 -05:00
trace_synth.h tracing: Add support for dynamic strings to synthetic events 2020-10-05 19:32:18 -04:00
trace_syscalls.c Tracing updates: 2020-02-06 07:12:11 +00:00
trace_uprobe.c tracing/uprobes: Support perf-style return probe 2020-09-21 21:06:03 -04:00
tracing_map.c tracing: Delete repeated words in comments 2020-09-21 21:06:02 -04:00
tracing_map.h tracing: Fix SPDX format headers to use C++ style comments 2018-08-16 19:08:06 -04:00