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tracing/mmiotrace: Add NULL check for mmio_trace_array in logging functions

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mmio_trace_rw() and mmio_trace_mapping() retrieve mmio_trace_array into
tr and pass it to __trace_mmiotrace_rw() and __trace_mmiotrace_map().
If these functions are invoked while mmio_trace_array is NULL (e.g. before
initialization or after disabled), accessing tr->array_buffer.buffer will
result in a NULL pointer dereference crash.

Fix this by adding an explicit NULL check for tr at the beginning of
__trace_mmiotrace_rw() and __trace_mmiotrace_map().

Link: https://patch.msgid.link/178524300062.56416.8362487250709962380.stgit@devnote2
Fixes: f984b51e07 ("ftrace: add mmiotrace plugin")
Assisted-by: Antigravity:gemini-3.6-flash
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Masami Hiramatsu (Google)
2026-07-28 21:50:00 +09:00
committed by Steven Rostedt
parent c786d2bdf1
commit 12b80cdbc5
1 changed files with 10 additions and 2 deletions
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12
kernel/trace/trace_mmiotrace.c
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@@ -294,11 +294,15 @@ device_initcall(init_mmio_trace);
static void __trace_mmiotrace_rw(struct trace_array *tr,
struct mmiotrace_rw *rw)
{
struct trace_buffer *buffer = tr->array_buffer.buffer;
struct trace_buffer *buffer;
struct ring_buffer_event *event;
struct trace_mmiotrace_rw *entry;
unsigned int trace_ctx;
if (!tr)
return;
buffer = tr->array_buffer.buffer;
trace_ctx = tracing_gen_ctx_flags(0);
event = trace_buffer_lock_reserve(buffer, TRACE_MMIO_RW,
sizeof(*entry), trace_ctx);
@@ -321,11 +325,15 @@ void mmio_trace_rw(struct mmiotrace_rw *rw)
static void __trace_mmiotrace_map(struct trace_array *tr,
struct mmiotrace_map *map)
{
struct trace_buffer *buffer = tr->array_buffer.buffer;
struct trace_buffer *buffer;
struct ring_buffer_event *event;
struct trace_mmiotrace_map *entry;
unsigned int trace_ctx;
if (!tr)
return;
buffer = tr->array_buffer.buffer;
trace_ctx = tracing_gen_ctx_flags(0);
event = trace_buffer_lock_reserve(buffer, TRACE_MMIO_MAP,
sizeof(*entry), trace_ctx);