Commit b0c51f15 authored by Jiri Slaby's avatar Jiri Slaby Committed by Thomas Gleixner

stacktrace: Don't skip first entry on noncurrent tasks

When doing cat /proc/<PID>/stack, the output is missing the first entry.
When the current code walks the stack starting in stack_trace_save_tsk,
it skips all scheduler functions (that's OK) plus one more function. But
this one function should be skipped only for the 'current' task as it is
stack_trace_save_tsk proper.

The original code (before the common infrastructure) skipped one
function only for the 'current' task -- see save_stack_trace_tsk before
3599fe12. So do so also in the new infrastructure now.

Fixes: 214d8ca6 ("stacktrace: Provide common infrastructure")
Signed-off-by: default avatarJiri Slaby <jslaby@suse.cz>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Tested-by: default avatarMichal Suchanek <msuchanek@suse.de>
Acked-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
Link: https://lkml.kernel.org/r/20191030072545.19462-1-jslaby@suse.cz
parent a99d8080
......@@ -141,7 +141,8 @@ unsigned int stack_trace_save_tsk(struct task_struct *tsk, unsigned long *store,
struct stacktrace_cookie c = {
.store = store,
.size = size,
.skip = skipnr + 1,
/* skip this function if they are tracing us */
.skip = skipnr + !!(current == tsk),
};
if (!try_get_task_stack(tsk))
......@@ -298,7 +299,8 @@ unsigned int stack_trace_save_tsk(struct task_struct *task,
struct stack_trace trace = {
.entries = store,
.max_entries = size,
.skip = skipnr + 1,
/* skip this function if they are tracing us */
.skip = skipnr + !!(current == task),
};
save_stack_trace_tsk(task, &trace);
......
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