From aebfd12521d9c7d0b502cf6d06314cfbcdccfe3b Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 8 Mar 2022 16:30:29 +0100 Subject: x86/ibt,ftrace: Search for __fentry__ location Currently a lot of ftrace code assumes __fentry__ is at sym+0. However with Intel IBT enabled the first instruction of a function will most likely be ENDBR. Change ftrace_location() to not only return the __fentry__ location when called for the __fentry__ location, but also when called for the sym+0 location. Then audit/update all callsites of this function to consistently use these new semantics. Suggested-by: Steven Rostedt Signed-off-by: Peter Zijlstra (Intel) Acked-by: Masami Hiramatsu Acked-by: Josh Poimboeuf Link: https://lore.kernel.org/r/20220308154318.227581603@infradead.org --- arch/x86/kernel/kprobes/core.c | 11 ++--------- 1 file changed, 2 insertions(+), 9 deletions(-) (limited to 'arch/x86/kernel/kprobes/core.c') diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c index 6290712cb36d..4d8086a1627e 100644 --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -193,17 +193,10 @@ static unsigned long __recover_probed_insn(kprobe_opcode_t *buf, unsigned long addr) { struct kprobe *kp; - unsigned long faddr; + bool faddr; kp = get_kprobe((void *)addr); - faddr = ftrace_location(addr); - /* - * Addresses inside the ftrace location are refused by - * arch_check_ftrace_location(). Something went terribly wrong - * if such an address is checked here. - */ - if (WARN_ON(faddr && faddr != addr)) - return 0UL; + faddr = ftrace_location(addr) == addr; /* * Use the current code if it is not modified by Kprobe * and it cannot be modified by ftrace. -- cgit v1.2.3