On 25.07.2025 20:55, Steven Rostedt wrote:

From: Steven Rostedt <rostedt@goodmis.org>

Add a new API to retrieve a user space callstack called
unwind_user_faultable(). The difference between this user space stack
tracer from the current user space stack tracer is that this must be
called from faultable context as it may use routines to access user space
data that needs to be faulted in.

It can be safely called from entering or exiting a system call as the code
can still be faulted in there.

This code is based on work by Josh Poimboeuf's deferred unwinding code:

Link: https://lore.kernel.org/all/6052e8487746603bdb29b65f4033e739092d9925.1737511963.git.jpoimboe@kernel.org/ (local)

Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

Reviewed-by: Jens Remus <redacted>

---
 include/linux/sched.h                 |  5 +++
 include/linux/unwind_deferred.h       | 24 +++++++++++
 include/linux/unwind_deferred_types.h |  9 ++++
 kernel/fork.c                         |  4 ++
 kernel/unwind/Makefile                |  2 +-
 kernel/unwind/deferred.c              | 60 +++++++++++++++++++++++++++
 6 files changed, 103 insertions(+), 1 deletion(-)
 create mode 100644 include/linux/unwind_deferred.h
 create mode 100644 include/linux/unwind_deferred_types.h
 create mode 100644 kernel/unwind/deferred.c

Regards,
Jens
-- 
Jens Remus
Linux on Z Development (D3303)
+49-7031-16-1128 Office
jremus@de.ibm.com

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