This is a note to let you know that I've just added the patch titled powerpc/kprobes: Dereference function pointers only if the address does not belong to kernel text to the 4.13-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: powerpc-kprobes-dereference-function-pointers-only-if-the-address-does-not-belong-to-kernel-text.patch and it can be found in the queue-4.13 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From e6c4dcb308160115287afd87afb63b5684d75a5b Mon Sep 17 00:00:00 2001 From: "Naveen N. Rao" <naveen.n.rao@xxxxxxxxxxxxxxxxxx> Date: Mon, 30 Oct 2017 20:42:09 +0530 Subject: powerpc/kprobes: Dereference function pointers only if the address does not belong to kernel text From: Naveen N. Rao <naveen.n.rao@xxxxxxxxxxxxxxxxxx> commit e6c4dcb308160115287afd87afb63b5684d75a5b upstream. This makes the changes introduced in commit 83e840c770f2c5 ("powerpc64/elfv1: Only dereference function descriptor for non-text symbols") to be specific to the kprobe subsystem. We previously changed ppc_function_entry() to always check the provided address to confirm if it needed to be dereferenced. This is actually only an issue for kprobe blacklisted asm labels (through use of _ASM_NOKPROBE_SYMBOL) and can cause other issues with ftrace. Also, the additional checks are not really necessary for our other uses. As such, move this check to the kprobes subsystem. Fixes: 83e840c770f2 ("powerpc64/elfv1: Only dereference function descriptor for non-text symbols") Signed-off-by: Naveen N. Rao <naveen.n.rao@xxxxxxxxxxxxxxxxxx> Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/powerpc/kernel/kprobes.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) --- a/arch/powerpc/kernel/kprobes.c +++ b/arch/powerpc/kernel/kprobes.c @@ -600,7 +600,12 @@ NOKPROBE_SYMBOL(kprobe_fault_handler); unsigned long arch_deref_entry_point(void *entry) { - return ppc_global_function_entry(entry); +#ifdef PPC64_ELF_ABI_v1 + if (!kernel_text_address((unsigned long)entry)) + return ppc_global_function_entry(entry); + else +#endif + return (unsigned long)entry; } NOKPROBE_SYMBOL(arch_deref_entry_point); Patches currently in stable-queue which might be from naveen.n.rao@xxxxxxxxxxxxxxxxxx are queue-4.13/revert-powerpc64-elfv1-only-dereference-function-descriptor-for-non-text-symbols.patch queue-4.13/powerpc-kprobes-dereference-function-pointers-only-if-the-address-does-not-belong-to-kernel-text.patch