From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Naveen N. Rao" Date: Mon, 14 Jun 2021 15:58:26 +0000 Subject: Re: [PATCH -tip v7 03/13] kprobes: treewide: Remove trampoline_address from kretprobe_trampoline_han Message-Id: <1623685371.y5qy4nxer2.naveen@linux.ibm.com> List-Id: References: <162209754288.436794.3904335049560916855.stgit@devnote2> <162209757191.436794.12654958417415894884.stgit@devnote2> In-Reply-To: <162209757191.436794.12654958417415894884.stgit@devnote2> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Masami Hiramatsu , Ingo Molnar , Steven Rostedt Cc: Andrii Nakryiko , ast@kernel.org, bpf@vger.kernel.org, Daniel Xu , Josh Poimboeuf , kernel-team@fb.com, kuba@kernel.org, linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org, mingo@redhat.com, Abhishek Sagar , tglx@linutronix.de, X86 ML , yhs@fb.com Hi Masami, Masami Hiramatsu wrote: > Remove trampoline_address from kretprobe_trampoline_handler(). > Instead of passing the address, kretprobe_trampoline_handler() > can use new kretprobe_trampoline_addr(). > > Signed-off-by: Masami Hiramatsu > Tested-by: Andrii Nakryik > --- > Changes in v3: > - Remove wrong kretprobe_trampoline declaration from > arch/x86/include/asm/kprobes.h. > Changes in v2: > - Remove arch_deref_entry_point() from comment. > --- > arch/arc/kernel/kprobes.c | 2 +- > arch/arm/probes/kprobes/core.c | 3 +-- > arch/arm64/kernel/probes/kprobes.c | 3 +-- > arch/csky/kernel/probes/kprobes.c | 2 +- > arch/ia64/kernel/kprobes.c | 5 ++--- > arch/mips/kernel/kprobes.c | 3 +-- > arch/parisc/kernel/kprobes.c | 4 ++-- > arch/powerpc/kernel/kprobes.c | 2 +- > arch/riscv/kernel/probes/kprobes.c | 2 +- > arch/s390/kernel/kprobes.c | 2 +- > arch/sh/kernel/kprobes.c | 2 +- > arch/sparc/kernel/kprobes.c | 2 +- > arch/x86/include/asm/kprobes.h | 1 - > arch/x86/kernel/kprobes/core.c | 2 +- > include/linux/kprobes.h | 18 +++++++++++++----- > kernel/kprobes.c | 3 +-- > 16 files changed, 29 insertions(+), 27 deletions(-) > > diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h > index d65c041b5c22..65dadd4238a2 100644 > --- a/include/linux/kprobes.h > +++ b/include/linux/kprobes.h > @@ -205,15 +205,23 @@ extern void arch_prepare_kretprobe(struct kretprobe_instance *ri, > struct pt_regs *regs); > extern int arch_trampoline_kprobe(struct kprobe *p); > > +void kretprobe_trampoline(void); > +/* > + * Since some architecture uses structured function pointer, > + * use dereference_function_descriptor() to get real function address. > + */ > +static nokprobe_inline void *kretprobe_trampoline_addr(void) > +{ > + return dereference_function_descriptor(kretprobe_trampoline); I'm afraid this won't work correctly. For kernel functions, please use dereference_kernel_function_descriptor() which checks if the function has a descriptor before dereferencing it. Thanks, Naveen