tracing/histogram: Don't use strlen to find length of stacktrace variables

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Because stacktraces are saved in dynamic strings,
trace_event_raw_event_synth() uses strlen to determine the length of
the stack.  Stacktraces may contain 0-bytes, though, in the saved
addresses, so the length found and passed to reserve() will be too
small.

Fix this by using the first unsigned long in the stack variables to
store the actual number of elements in the stack and have
trace_event_raw_event_synth() use that to determine the length of the
stack.

Link: https://lkml.kernel.org/r/1ed6906cd9d6477ef2bd8e63c61de20a9ffe64d7.1676063532.git.zanussi@kernel.org

Signed-off-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

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This commit is contained in:

Tom Zanussi 2023-02-10 15:33:03 -06:00 • committed by Steven Rostedt (Google)

parent 9c1c251d67

commit fc1a9dc101

2 changed files with 14 additions and 5 deletions

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12

kernel/trace/trace_events_hist.c

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7

kernel/trace/trace_events_synth.c

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