dlan17/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

unwind: Finish up unwind when a task exits

Browse Source 
On do_exit() when a task is exiting, if a unwind is requested and the
deferred user stacktrace is deferred via the task_work, the task_work
callback is called after exit_mm() is called in do_exit(). This means that
the user stack trace will not be retrieved and an empty stack is created.

Instead, add a function unwind_deferred_task_exit() and call it just
before exit_mm() so that the unwinder can call the requested callbacks
with the user space stack.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Indu Bhagat <indu.bhagat@oracle.com>
Cc: "Jose E. Marchesi" <jemarch@gnu.org>
Cc: Beau Belgrave <beaub@linux.microsoft.com>
Cc: Jens Remus <jremus@linux.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: Sam James <sam@gentoo.org>
Link: https://lore.kernel.org/20250729182406.504259474@kernel.org
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt
2025-07-31 10:20:11 -04:00
committed by Steven Rostedt (Google)
parent 357eda2d74
commit b3b9cb11aa
3 changed files with 25 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files
kernel/unwind/deferred.c
+20 -3
View File
@@ -114,7 +114,7 @@ int unwind_user_faultable(struct unwind_stacktrace *trace)
/* Should always be called from faultable context */
might_fault();
if (current->flags & PF_EXITING)
if (!current->mm)
return -EINVAL;
if (!info->cache) {
@@ -147,9 +147,9 @@ int unwind_user_faultable(struct unwind_stacktrace *trace)
return 0;
}
static void unwind_deferred_task_work(struct callback_head *head)
static void process_unwind_deferred(struct task_struct *task)
{
struct unwind_task_info *info = container_of(head, struct unwind_task_info, work);
struct unwind_task_info *info = &task->unwind_info;
struct unwind_stacktrace trace;
struct unwind_work *work;
unsigned long bits;
@@ -186,6 +186,23 @@ static void unwind_deferred_task_work(struct callback_head *head)
}
}
static void unwind_deferred_task_work(struct callback_head *head)
{
process_unwind_deferred(current);
}
void unwind_deferred_task_exit(struct task_struct *task)
{
struct unwind_task_info *info = &current->unwind_info;
if (!unwind_pending(info))
return;
process_unwind_deferred(task);
task_work_cancel(task, &info->work);
}
/**
* unwind_deferred_request - Request a user stacktrace on task kernel exit
* @work: Unwind descriptor requesting the trace