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authorLinus Torvalds <torvalds@linux-foundation.org>2021-04-02 08:39:00 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-04-02 08:39:00 -0700
commit05de45383bd134fcb2b7d70d35ebb0bb50b5e4aa (patch)
treee22acb05830c78538a5b98589a6de4c118df4536
parent1678e493d530e7977cce34e59a86bb86f3c5631e (diff)
parent9deb193af69d3fd6dd8e47f292b67c805a787010 (diff)
Merge tag 'trace-v5.12-rc5-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fix from Steven Rostedt: "Fix stack trace entry size to stop showing garbage The macro that creates both the structure and the format displayed to user space for the stack trace event was changed a while ago to fix the parsing by user space tooling. But this change also modified the structure used to store the stack trace event. It changed the caller array field from [0] to [8]. Even though the size in the ring buffer is dynamic and can be something other than 8 (user space knows how to handle this), the 8 extra words was not accounted for when reserving the event on the ring buffer, and added 8 more entries, due to the calculation of "sizeof(*entry) + nr_entries * sizeof(long)", as the sizeof(*entry) now contains 8 entries. The size of the caller field needs to be subtracted from the size of the entry to create the correct allocation size" * tag 'trace-v5.12-rc5-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: tracing: Fix stack trace event size
-rw-r--r--kernel/trace/trace.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index eccb4e1187cc..5c777627212f 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2984,7 +2984,8 @@ static void __ftrace_trace_stack(struct trace_buffer *buffer,
size = nr_entries * sizeof(unsigned long);
event = __trace_buffer_lock_reserve(buffer, TRACE_STACK,
- sizeof(*entry) + size, trace_ctx);
+ (sizeof(*entry) - sizeof(entry->caller)) + size,
+ trace_ctx);
if (!event)
goto out;
entry = ring_buffer_event_data(event);

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