Messages in this thread | | | Date | Wed, 2 Mar 2022 14:47:16 -0500 | From | Steven Rostedt <> | Subject | Re: [PATCH v2 12/39] x86/ibt,ftrace: Search for __fentry__ location |
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On Wed, 2 Mar 2022 11:01:38 -0500 Steven Rostedt <rostedt@goodmis.org> wrote:
> On Wed, 2 Mar 2022 14:20:23 +0100 > Peter Zijlstra <peterz@infradead.org> wrote: > > > Like so, or is something else needed? > > > > diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c > > index 68ecd3e35342..d1b30b5c5c23 100644 > > --- a/kernel/trace/ftrace.c > > +++ b/kernel/trace/ftrace.c > > @@ -4980,7 +4980,8 @@ ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove) > > { > > struct ftrace_func_entry *entry; > > > > - if (!ftrace_location(ip)) > > + ip = ftrace_location(ip); > > + if (!ip) > > return -EINVAL; > > This could possibly work. I'd have to test all this though. > > I probably could just take this patch and try it out. You can remove the > "x86/ibt" from the subject, as this patch may be a requirement for that > (include that in the commit log), but it is has no changes to x86/ibt > specifically. >
Note, I just pulled this patch, and I hit this warning:
WARNING: CPU: 0 PID: 6965 at arch/x86/kernel/kprobes/core.c:205 recover_probed_instruction+0x8f/0xa0
static unsigned long __recover_probed_insn(kprobe_opcode_t *buf, unsigned long addr) { struct kprobe *kp; unsigned long 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)) <<---- HERE return 0UL; /* * Use the current code if it is not modified by Kprobe * and it cannot be modified by ftrace. */ if (!kp && !faddr) return addr;
I guess this patch needs kprobe updates.
I'll pull down the latest tip and test that code.
-- Steve
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