[PATCH 5.15 068/917] ia64: kprobes: Fix to pass correct trampoline address to the handler

Greg Kroah-Hartman
2021-11-16T01:12:24Z

From: Masami Hiramatsu <mhiramat@kernel.org>

commit a7fe2378454cf46cd5e2776d05e72bbe8f0a468c upstream.

The following commit:

Commit e792ff804f49 ("ia64: kprobes: Use generic kretprobe trampoline handler")

Passed the wrong trampoline address to __kretprobe_trampoline_handler(): it
passes the descriptor address instead of function entry address.

Pass the right parameter.

Also use correct symbol dereference function to get the function address
from 'kretprobe_trampoline' - an IA64 special.

Link: https://lkml.kernel.org/r/163163042696.489837.12551102356265354730.stgit@devnote2

Fixes: e792ff804f49 ("ia64: kprobes: Use generic kretprobe trampoline handler")
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: X86 ML <x86@kernel.org>
Cc: Daniel Xu <dxu@dxuuu.xyz>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Abhishek Sagar <sagar.abhishek@gmail.com>
Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Paul McKenney <paulmck@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/ia64/kernel/kprobes.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)

--- a/arch/ia64/kernel/kprobes.c
+++ b/arch/ia64/kernel/kprobes.c
@@ -398,7 +398,8 @@ static void kretprobe_trampoline(void)

int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
{
- regs->cr_iip = __kretprobe_trampoline_handler(regs, kretprobe_trampoline, NULL);
+ regs->cr_iip = __kretprobe_trampoline_handler(regs,
+ dereference_function_descriptor(kretprobe_trampoline), NULL);
/*
* By returning a non-zero value, we are telling
* kprobe_handler() that we don't want the post_handler
@@ -414,7 +415,7 @@ void __kprobes arch_prepare_kretprobe(st
ri->fp = NULL;

/* Replace the return addr with trampoline addr */
- regs->b0 = ((struct fnptr *)kretprobe_trampoline)->ip;
+ regs->b0 = (unsigned long)dereference_function_descriptor(kretprobe_trampoline);
}

/* Check the instruction in the slot is break */
@@ -902,14 +903,14 @@ static struct kprobe trampoline_p = {
int __init arch_init_kprobes(void)
{
trampoline_p.addr =
- (kprobe_opcode_t *)((struct fnptr *)kretprobe_trampoline)->ip;
+ dereference_function_descriptor(kretprobe_trampoline);
return register_kprobe(&trampoline_p);
}

int __kprobes arch_trampoline_kprobe(struct kprobe *p)
{
if (p->addr ==
- (kprobe_opcode_t *)((struct fnptr *)kretprobe_trampoline)->ip)
+ dereference_function_descriptor(kretprobe_trampoline))
return 1;

return 0;