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39eb456dac
linux/kernel/trace
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Steven Rostedt (VMware) 39eb456dac function_graph: Use new curr_ret_depth to manage depth instead of curr_ret_stack 
Currently, the depth of the ret_stack is determined by curr_ret_stack index.
The issue is that there's a race between setting of the curr_ret_stack and
calling of the callback attached to the return of the function.

Commit 03274a3ffb ("tracing/fgraph: Adjust fgraph depth before calling
trace return callback") moved the calling of the callback to after the
setting of the curr_ret_stack, even stating that it was safe to do so, when
in fact, it was the reason there was a barrier() there (yes, I should have
commented that barrier()).

Not only does the curr_ret_stack keep track of the current call graph depth,
it also keeps the ret_stack content from being overwritten by new data.

The function profiler, uses the "subtime" variable of ret_stack structure
and by moving the curr_ret_stack, it allows for interrupts to use the same
structure it was using, corrupting the data, and breaking the profiler.

To fix this, there needs to be two variables to handle the call stack depth
and the pointer to where the ret_stack is being used, as they need to change
at two different locations.

Cc: stable@kernel.org
Fixes: 03274a3ffb ("tracing/fgraph: Adjust fgraph depth before calling trace return callback")
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2018-11-27 20:31:54 -05:00
..
blktrace.c blkcg: revert blkcg cleanups series 2018-11-01 19:59:53 -06:00
bpf_trace.c tracing: Add SPDX License format to bpf_trace.c 2018-08-16 19:07:36 -04:00
ftrace.c function_graph: Use new curr_ret_depth to manage depth instead of curr_ret_stack 2018-11-27 20:31:54 -05:00
Kconfig Masami found an off by one bug in the code that keeps "notrace" functions 2018-08-23 13:07:00 -07:00
Makefile tracing: Allow gcov profiling on only ftrace subsystem 2018-08-21 09:11:49 -04:00
power-traces.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
preemptirq_delay_test.c tracing: Use trace_clock_local() for looping in preemptirq_delay_test.c 2018-10-17 15:35:33 -04:00
ring_buffer_benchmark.c tracing: Add SPDX License format tags to tracing files 2018-08-16 19:08:06 -04:00
ring_buffer.c ring-buffer: Allow for rescheduling when removing pages 2018-09-17 18:15:11 -04:00
rpm-traces.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
trace_benchmark.c rcu: Rename cond_resched_rcu_qs() to cond_resched_tasks_rcu_qs() 2018-05-15 10:27:29 -07:00
trace_benchmark.h tracing: Fix SPDX format headers to use C++ style comments 2018-08-16 19:08:06 -04:00
trace_branch.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
trace_clock.c tracing: Add SPDX License format tags to tracing files 2018-08-16 19:08:06 -04:00
trace_entries.h tracing: Fix SPDX format headers to use C++ style comments 2018-08-16 19:08:06 -04:00
trace_event_perf.c trace_uprobe: support reference counter in fd-based uprobe 2018-10-10 22:14:17 -04:00
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_filter.c tracing: Add SPDX License format tags to tracing files 2018-08-16 19:08:06 -04:00
trace_events_hist.c tracing: Return -ENOENT if there is no target synthetic event 2018-10-28 04:58:15 -04:00
trace_events_trigger.c tracing: Add SPDX License format tags to tracing files 2018-08-16 19:08:06 -04:00
trace_events.c tracing: Add SPDX License format tags to tracing files 2018-08-16 19:08:06 -04:00
trace_export.c tracing: Add trigger file for trace_markers tracefs/ftrace/print 2018-05-29 08:28:53 -04:00
trace_functions_graph.c function_graph: Use new curr_ret_depth to manage depth instead of curr_ret_stack 2018-11-27 20:31:54 -05:00
trace_functions.c tracing: Update stack trace skipping for ORC unwinder 2018-01-23 15:57:00 -05:00
trace_hwlat.c tracing: Add SPDX License format tags to tracing files 2018-08-16 19:08:06 -04:00
trace_irqsoff.c tracing: Add SPDX License format tags to tracing files 2018-08-16 19:08:06 -04:00
trace_kdb.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
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_kprobe.c tracing/kprobes: Allow kprobe-events to record module symbol 2018-10-10 22:19:12 -04:00
trace_mmiotrace.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
trace_nop.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
trace_output.c tracing: Add SPDX License format tags to tracing files 2018-08-16 19:08:06 -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 tracing: More reverting of "tracing: Centralize preemptirq tracepoints and unify their usage" 2018-08-10 15:12:00 -04:00
trace_printk.c tracing: Trivia spelling fix containerof() -> container_of() 2018-09-26 12:21:00 +03:00
trace_probe_tmpl.h tracing: probeevent: Add array type support 2018-10-10 22:19:10 -04:00
trace_probe.c tracing/kprobes: Fix strpbrk() argument order 2018-11-05 09:47:14 -05:00
trace_probe.h tracing/kprobes: Allow kprobe-events to record module symbol 2018-10-10 22:19:12 -04:00
trace_sched_switch.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
trace_sched_wakeup.c Merge branch 'linus' into sched/core, to pick up fixes 2017-11-08 10:17:15 +01:00
trace_selftest_dynamic.c ftrace: Mark function tracer test functions noinline/noclone 2018-01-23 15:57:29 -05:00
trace_selftest.c Tracing updates for 4.15: 2017-11-17 14:58:01 -08:00
trace_seq.c tracing: Add SPDX License format tags to tracing files 2018-08-16 19:08:06 -04:00
trace_stack.c tracing: Have stack tracer trace full stack 2018-10-27 11:15:04 -04:00
trace_stat.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
trace_stat.h tracing: Fix SPDX format headers to use C++ style comments 2018-08-16 19:08:06 -04:00
trace_syscalls.c Tracing updates for 4.15: 2017-11-17 14:58:01 -08:00
trace_uprobe.c tracing/uprobes: Fix to return -EFAULT if copy_from_user failed 2018-10-10 22:19:11 -04:00
trace.c tracing: Export trace_dump_stack to modules 2018-10-27 11:15:03 -04:00
trace.h tracing: Fix SPDX format headers to use C++ style comments 2018-08-16 19:08:06 -04:00
tracing_map.c tracing: Add SPDX License format tags to tracing files 2018-08-16 19:08:06 -04:00
tracing_map.h tracing: Fix SPDX format headers to use C++ style comments 2018-08-16 19:08:06 -04:00