On 2020-08-05 10:54, Greg Kroah-Hartman wrote:
On Tue, Aug 04, 2020 at 10:23:06PM +0100, Marc Zyngier wrote:
On 2020-08-04 19:33, Linus Torvalds wrote:
On Tue, Aug 4, 2020 at 1:21 AM Greg Kroah-Hartman gregkh@linuxfoundation.org wrote:
So Linus's tree is also broken here.
No, there's 835d1c3a9879 ("arm64: Drop unnecessary include from asm/smp.h") upstream.
My bet is that Greg ended up with this patch backported to 5.7, but doesn't have 62a679cb2825 ("arm64: simplify ptrauth initialization") as the latter isn't a fix.
I don't think any of these two patches are worth backporting, to be honest.
I didn't have either of those patches, so I can try applying them to see if the build errors go away. But if you don't think they should be applied, what should I do?
Here's what I did have queued up:
f227e3ec3b5c ("random32: update the net random state on interrupt and activity") aa54ea903abb ("ARM: percpu.h: fix build error") 1c9df907da83 ("random: fix circular include dependency on arm64 after addition of percpu.h") 83bdc7275e62 ("random32: remove net_rand_state from the latent entropy gcc plugin") c0842fbc1b18 ("random32: move the pseudo-random 32-bit definitions to prandom.h")
Not what I expected, then. I stand corrected.
And that caused the builds to blow up.
So, what should I do here?
OK, this is getting hairy. I solved it by grabbing:
d0055da5266a ("arm64: remove ptrauth_keys_install_kernel sync arg") 62a679cb2825 ("arm64: simplify ptrauth initialization")
and at which point you might as well take 835d1c3a9879 despite everything I said earlier. And backporting that further down the line is fraught with danger.
I came up with yet another "quality" hack, which gets the job done, see below. It is obviously much simpler, but also terribly ugly.
M.
From 34ee193a4a84718689cffd13f976b7f31e4c5ad4 Mon Sep 17 00:00:00 2001 From: Marc Zyngier maz@kernel.org Date: Wed, 5 Aug 2020 12:10:44 +0100 Subject: [PATCH] arm64: Workaround circular dependency in pointer_auth.h MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit
With the backport of f227e3ec3b5c ("random32: update the net random state on interrupt and activity") and its associated fixes, the arm64 build explodes early:
In file included from ../include/linux/smp.h:67, from ../include/linux/percpu.h:7, from ../include/linux/prandom.h:12, from ../include/linux/random.h:118, from ../arch/arm64/include/asm/pointer_auth.h:6, from ../arch/arm64/include/asm/processor.h:39, from ../include/linux/mutex.h:19, from ../include/linux/kernfs.h:12, from ../include/linux/sysfs.h:16, from ../include/linux/kobject.h:20, from ../include/linux/of.h:17, from ../include/linux/irqdomain.h:35, from ../include/linux/acpi.h:13, from ../include/acpi/apei.h:9, from ../include/acpi/ghes.h:5, from ../include/linux/arm_sdei.h:8, from ../arch/arm64/kernel/asm-offsets.c:10: ../arch/arm64/include/asm/smp.h:100:29: error: field ‘ptrauth_key’ has incomplete type
This is due to struct ptrauth_keys_kernel not being defined before we transitively include asm/smp.h from linux/random.h.
Paper over it by moving the inclusion of linux/random.h *after* the type has been defined.
Signed-off-by: Marc Zyngier maz@kernel.org --- arch/arm64/include/asm/pointer_auth.h | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/include/asm/pointer_auth.h b/arch/arm64/include/asm/pointer_auth.h index c6b4f0603024..be7f853738e6 100644 --- a/arch/arm64/include/asm/pointer_auth.h +++ b/arch/arm64/include/asm/pointer_auth.h @@ -3,7 +3,6 @@ #define __ASM_POINTER_AUTH_H
#include <linux/bitops.h> -#include <linux/random.h>
#include <asm/cpufeature.h> #include <asm/memory.h> @@ -34,6 +33,13 @@ struct ptrauth_keys_kernel { struct ptrauth_key apia; };
+/* + * Only include random.h once ptrauth_keys_* structures are defined + * to avoid yet another circular include hell (random.h * ends up + * including asm/smp.h, which requires ptrauth_keys_kernel). + */ +#include <linux/random.h> + static inline void ptrauth_keys_init_user(struct ptrauth_keys_user *keys) { if (system_supports_address_auth()) {