tracing: Add last boot delta offset for stack traces

The addresses of a stack trace event are relative to the kallsyms. As that
can change between boots, when printing the stack trace from a buffer that
was from the last boot, it needs all the addresses to be added to the
"text_delta" that gives the delta between the addresses of the functions
for the current boot compared to the address of the last boot. Then it can
be passed to kallsyms to find the function name, otherwise it just shows a
useless list of addresses.

Link: https://lkml.kernel.org/r/[email protected]
Cc: Masami Hiramatsu <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Mathieu Desnoyers <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Vincent Donnefort <[email protected]>
Cc: Joel Fernandes <[email protected]>
Cc: Daniel Bristot de Oliveira <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Vineeth Pillai <[email protected]>
Cc: Youssef Esmat <[email protected]>
Cc: Beau Belgrave <[email protected]>
Cc: Alexander Graf <[email protected]>
Cc: Baoquan He <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: "Paul E. McKenney" <[email protected]>
Cc: David Howells <[email protected]>
Cc: Mike Rapoport <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Tony Luck <[email protected]>
Cc: Guenter Roeck <[email protected]>
Cc: Ross Zwisler <[email protected]>
Cc: Kees Cook <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>

diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index b9d2c64c06484f69fc1949e9672bee06ea95604c..48de935988972346b7fecbb61cf812b157a89c28 100644 (file)
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -1233,6 +1233,7 @@ static enum print_line_t trace_stack_print(struct trace_iterator *iter,
        struct trace_seq *s = &iter->seq;
        unsigned long *p;
        unsigned long *end;
+       long delta = iter->tr->text_delta;
 
        trace_assign_type(field, iter->ent);
        end = (unsigned long *)((long)iter->ent + iter->ent_size);
@@ -1245,7 +1246,7 @@ static enum print_line_t trace_stack_print(struct trace_iterator *iter,
                        break;
 
                trace_seq_puts(s, " => ");
-               seq_print_ip_sym(s, *p, flags);
+               seq_print_ip_sym(s, (*p) + delta, flags);
                trace_seq_putc(s, '\n');
        }