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-rw-r--r--arch/arm64/include/asm/kprobes.h2
-rw-r--r--arch/arm64/kernel/probes/kprobes.c28
2 files changed, 5 insertions, 25 deletions
diff --git a/arch/arm64/include/asm/kprobes.h b/arch/arm64/include/asm/kprobes.h
index 61b49150dfa3..1737aecfcc5e 100644
--- a/arch/arm64/include/asm/kprobes.h
+++ b/arch/arm64/include/asm/kprobes.h
@@ -22,7 +22,6 @@
#define __ARCH_WANT_KPROBES_INSN_SLOT
#define MAX_INSN_SIZE 1
-#define MAX_STACK_SIZE 128
#define flush_insn_slot(p) do { } while (0)
#define kretprobe_blacklist_size 0
@@ -47,7 +46,6 @@ struct kprobe_ctlblk {
struct prev_kprobe prev_kprobe;
struct kprobe_step_ctx ss_ctx;
struct pt_regs jprobe_saved_regs;
- char jprobes_stack[MAX_STACK_SIZE];
};
void arch_remove_kprobe(struct kprobe *);
diff --git a/arch/arm64/kernel/probes/kprobes.c b/arch/arm64/kernel/probes/kprobes.c
index 6487b62fe002..1ee93c7c5a75 100644
--- a/arch/arm64/kernel/probes/kprobes.c
+++ b/arch/arm64/kernel/probes/kprobes.c
@@ -41,15 +41,6 @@ DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
static void __kprobes
post_kprobe_handler(struct kprobe_ctlblk *, struct pt_regs *);
-static inline unsigned long min_stack_size(unsigned long addr)
-{
- unsigned long size;
-
- size = (unsigned long)current_thread_info() + THREAD_START_SP - addr;
-
- return min(size, FIELD_SIZEOF(struct kprobe_ctlblk, jprobes_stack));
-}
-
static void __kprobes arch_prepare_ss_slot(struct kprobe *p)
{
/* prepare insn slot */
@@ -486,20 +477,15 @@ int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
{
struct jprobe *jp = container_of(p, struct jprobe, kp);
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
- long stack_ptr = kernel_stack_pointer(regs);
kcb->jprobe_saved_regs = *regs;
/*
- * As Linus pointed out, gcc assumes that the callee
- * owns the argument space and could overwrite it, e.g.
- * tailcall optimization. So, to be absolutely safe
- * we also save and restore enough stack bytes to cover
- * the argument area.
+ * Since we can't be sure where in the stack frame "stacked"
+ * pass-by-value arguments are stored we just don't try to
+ * duplicate any of the stack. Do not use jprobes on functions that
+ * use more than 64 bytes (after padding each to an 8 byte boundary)
+ * of arguments, or pass individual arguments larger than 16 bytes.
*/
- kasan_disable_current();
- memcpy(kcb->jprobes_stack, (void *)stack_ptr,
- min_stack_size(stack_ptr));
- kasan_enable_current();
instruction_pointer_set(regs, (unsigned long) jp->entry);
preempt_disable();
@@ -551,10 +537,6 @@ int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
}
unpause_graph_tracing();
*regs = kcb->jprobe_saved_regs;
- kasan_disable_current();
- memcpy((void *)stack_addr, kcb->jprobes_stack,
- min_stack_size(stack_addr));
- kasan_enable_current();
preempt_enable_no_resched();
return 1;
}