On Sun, Jan 19, 2020 at 03:40:08PM +0100, gregkh@linuxfoundation.org wrote:
The patch below does not apply to the 4.19-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From dc8d37ed304eeeea47e65fb9edc1c6c8b0093386 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann arnd@arndb.de Date: Tue, 10 Dec 2019 20:56:04 +0100 Subject: [PATCH] cpu/SMT: Fix x86 link error without CONFIG_SYSFS
When CONFIG_SYSFS is disabled, but CONFIG_HOTPLUG_SMT is enabled, the kernel fails to link:
arch/x86/power/cpu.o: In function `hibernate_resume_nonboot_cpu_disable': (.text+0x38d): undefined reference to `cpuhp_smt_enable' arch/x86/power/hibernate.o: In function `arch_resume_nosmt': hibernate.c:(.text+0x291): undefined reference to `cpuhp_smt_enable' hibernate.c:(.text+0x29c): undefined reference to `cpuhp_smt_disable'
Move the exported functions out of the #ifdef section into its own with the correct conditions.
The patch that caused this is marked for stable backports, so this one may need to be backported as well.
Fixes: ec527c318036 ("x86/power: Fix 'nosmt' vs hibernation triple fault during resume") Signed-off-by: Arnd Bergmann arnd@arndb.de Signed-off-by: Thomas Gleixner tglx@linutronix.de Reviewed-by: Jiri Kosina jkosina@suse.cz Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20191210195614.786555-1-arnd@arndb.de
I'm not actually seeing this failure on 4.19 and older, so I won't try and figure this out.
$ grep 'CONFIG_HOTPLUG_SMT|CONFIG_SYSFS' .config # CONFIG_SYSFS_SYSCALL is not set CONFIG_HOTPLUG_SMT=y # CONFIG_SYSFS is not set $ make -j [...] Kernel: arch/x86/boot/bzImage is ready (#1)