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| author | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2020-11-06 03:32:43 +0100 |
|---|---|---|
| committer | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2020-11-06 14:41:56 +0100 |
| commit | 5d15a624c34b11c8d1c04c8cc004782e7ac2888d (patch) | |
| tree | b5c2fefce0df0f0f8cca81d6de71be5b5c239cda /kernel | |
| parent | livepatch: Trigger WARNING if livepatch function fails due to recursion (diff) | |
| download | linux-5d15a624c34b11c8d1c04c8cc004782e7ac2888d.tar.xz linux-5d15a624c34b11c8d1c04c8cc004782e7ac2888d.zip | |
perf/ftrace: Add recursion protection to the ftrace callback
If a ftrace callback does not supply its own recursion protection and
does not set the RECURSION_SAFE flag in its ftrace_ops, then ftrace will
make a helper trampoline to do so before calling the callback instead of
just calling the callback directly.
The default for ftrace_ops is going to change. It will expect that handlers
provide their own recursion protection, unless its ftrace_ops states
otherwise.
Link: https://lkml.kernel.org/r/20201028115613.444477858@goodmis.org
Link: https://lkml.kernel.org/r/20201106023547.466892083@goodmis.org
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Miroslav Benes <mbenes@suse.cz>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/trace/trace_event_perf.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c index 643e0b19920d..fd58d83861d8 100644 --- a/kernel/trace/trace_event_perf.c +++ b/kernel/trace/trace_event_perf.c @@ -439,10 +439,15 @@ perf_ftrace_function_call(unsigned long ip, unsigned long parent_ip, struct hlist_head head; struct pt_regs regs; int rctx; + int bit; if ((unsigned long)ops->private != smp_processor_id()) return; + bit = ftrace_test_recursion_trylock(); + if (bit < 0) + return; + event = container_of(ops, struct perf_event, ftrace_ops); /* @@ -463,13 +468,15 @@ perf_ftrace_function_call(unsigned long ip, unsigned long parent_ip, entry = perf_trace_buf_alloc(ENTRY_SIZE, NULL, &rctx); if (!entry) - return; + goto out; entry->ip = ip; entry->parent_ip = parent_ip; perf_trace_buf_submit(entry, ENTRY_SIZE, rctx, TRACE_FN, 1, ®s, &head, NULL); +out: + ftrace_test_recursion_unlock(bit); #undef ENTRY_SIZE } |