From: Steven Rostedt <rostedt@goodmis.org> mainline inclusion from mainline-v6.15-rc1 commit ea8d7647f9ddf1f81e2027ed305299797299aa03 category: bugfix bugzilla: 190584 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- The trace event verifier checks the formats of trace events to make sure that they do not point at memory that is not in the trace event itself or in data that will never be freed. If an event references data that was allocated when the event triggered and that same data is freed before the event is read, then the kernel can crash by reading freed memory. The verifier runs at boot up (or module load) and scans the print formats of the events and checks their arguments to make sure that dereferenced pointers are safe. If the format uses "%*p.." the verifier will ignore it, and that could be dangerous. Cover this case as well. Also add to the sample code a use case of "%*pbl". Link: https://lore.kernel.org/all/bcba4d76-2c3f-4d11-baf0-02905db953dd@oracle.com/ Cc: stable@vger.kernel.org Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Fixes: 5013f454a352c ("tracing: Add check of trace event print fmts for dereferencing pointers") Link: https://lore.kernel.org/20250327195311.2d89ec66@gandalf.local.home Reported-by: Libo Chen <libo.chen@oracle.com> Reviewed-by: Libo Chen <libo.chen@oracle.com> Tested-by: Libo Chen <libo.chen@oracle.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Conflicts: kernel/trace/trace_events.c samples/trace_events/trace-events-sample.h [The conflicts were due to some minor issues] Signed-off-by: Pu Lehui <pulehui@huawei.com> --- kernel/trace/trace_events.c | 7 +++++++ samples/trace_events/trace-events-sample.h | 8 ++++++-- 2 files changed, 13 insertions(+), 2 deletions(-) diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 9d22745cdea5..f2e07d470784 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -470,6 +470,7 @@ static void test_event_printk(struct trace_event_call *call) case '%': continue; case 'p': + do_pointer: /* Find dereferencing fields */ switch (fmt[i + 1]) { case 'B': case 'R': case 'r': @@ -498,6 +499,12 @@ static void test_event_printk(struct trace_event_call *call) continue; if (fmt[i + j] == '*') { star = true; + /* Handle %*pbl case */ + if (!j && fmt[i + 1] == 'p') { + arg++; + i++; + goto do_pointer; + } continue; } if ((fmt[i + j] == 's')) { diff --git a/samples/trace_events/trace-events-sample.h b/samples/trace_events/trace-events-sample.h index 1c6b843b8c4e..6a5d4717f37a 100644 --- a/samples/trace_events/trace-events-sample.h +++ b/samples/trace_events/trace-events-sample.h @@ -315,7 +315,8 @@ TRACE_EVENT(foo_bar, __assign_cpumask(cpum, cpumask_bits(mask)); ), - TP_printk("foo %s %d %s %s %s %s (%s) (%s) %s", __entry->foo, __entry->bar, + TP_printk("foo %s %d %s %s %s %s (%s) (%s) %s [%d] %*pbl", + __entry->foo, __entry->bar, /* * Notice here the use of some helper functions. This includes: @@ -360,7 +361,10 @@ TRACE_EVENT(foo_bar, __get_dynamic_array_len(list) / sizeof(int), sizeof(int)), __get_str(str), __get_bitmask(cpus), __get_cpumask(cpum), - __get_str(vstr)) + __get_str(vstr), + __get_dynamic_array_len(cpus), + __get_dynamic_array_len(cpus), + __get_dynamic_array(cpus)) ); /* -- 2.34.1