This is a note to let you know that I've just added the patch titled
samples: ftrace: Save required argument registers in sample trampolines
to the 6.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
samples-ftrace-save-required-argument-registers-in-sample-trampolines.patch
and it can be found in the queue-6.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 8564c315876ab86fcaf8e7f558d6a84cb2ce5590 Mon Sep 17 00:00:00 2001
From: Florent Revest <revest@xxxxxxxxxxxx>
Date: Thu, 27 Apr 2023 16:06:59 +0200
Subject: samples: ftrace: Save required argument registers in sample trampolines
From: Florent Revest <revest@xxxxxxxxxxxx>
commit 8564c315876ab86fcaf8e7f558d6a84cb2ce5590 upstream.
The ftrace-direct-too sample traces the handle_mm_fault function whose
signature changed since the introduction of the sample. Since:
commit bce617edecad ("mm: do page fault accounting in handle_mm_fault")
handle_mm_fault now has 4 arguments. Therefore, the sample trampoline
should save 4 argument registers.
s390 saves all argument registers already so it does not need a change
but x86_64 needs an extra push and pop.
This also evolves the signature of the tracing function to make it
mirror the signature of the traced function.
Link: https://lkml.kernel.org/r/20230427140700.625241-2-revest@xxxxxxxxxxxx
Cc: stable@xxxxxxxxxxxxxxx
Fixes: bce617edecad ("mm: do page fault accounting in handle_mm_fault")
Reviewed-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
Reviewed-by: Mark Rutland <mark.rutland@xxxxxxx>
Acked-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: Florent Revest <revest@xxxxxxxxxxxx>
Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
samples/ftrace/ftrace-direct-too.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)
--- a/samples/ftrace/ftrace-direct-too.c
+++ b/samples/ftrace/ftrace-direct-too.c
@@ -5,14 +5,14 @@
#include <linux/ftrace.h>
#include <asm/asm-offsets.h>
-extern void my_direct_func(struct vm_area_struct *vma,
- unsigned long address, unsigned int flags);
+extern void my_direct_func(struct vm_area_struct *vma, unsigned long address,
+ unsigned int flags, struct pt_regs *regs);
-void my_direct_func(struct vm_area_struct *vma,
- unsigned long address, unsigned int flags)
+void my_direct_func(struct vm_area_struct *vma, unsigned long address,
+ unsigned int flags, struct pt_regs *regs)
{
- trace_printk("handle mm fault vma=%p address=%lx flags=%x\n",
- vma, address, flags);
+ trace_printk("handle mm fault vma=%p address=%lx flags=%x regs=%p\n",
+ vma, address, flags, regs);
}
extern void my_tramp(void *);
@@ -34,7 +34,9 @@ asm (
" pushq %rdi\n"
" pushq %rsi\n"
" pushq %rdx\n"
+" pushq %rcx\n"
" call my_direct_func\n"
+" popq %rcx\n"
" popq %rdx\n"
" popq %rsi\n"
" popq %rdi\n"
Patches currently in stable-queue which might be from revest@xxxxxxxxxxxx are
queue-6.4/samples-ftrace-save-required-argument-registers-in-sample-trampolines.patch
