This is a note to let you know that I've just added the patch titled powerpc: Fix HAVE_HARDLOCKUP_DETECTOR_ARCH build configuration to the 5.10-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-fix-have_hardlockup_detector_arch-build-conf.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 024ed8a8f5b5ed4a7dbded2333c8f2c8f3c2aecc Author: Chen Huang <chenhuang5@xxxxxxxxxx> Date: Sat Mar 27 09:49:00 2021 +0000 powerpc: Fix HAVE_HARDLOCKUP_DETECTOR_ARCH build configuration [ Upstream commit 4fe529449d85e78972fa327999961ecc83a0b6db ] When compiling the powerpc with the SMP disabled, it shows the issue: arch/powerpc/kernel/watchdog.c: In function â??watchdog_smp_panicâ??: arch/powerpc/kernel/watchdog.c:177:4: error: implicit declaration of function â??smp_send_nmi_ipiâ??; did you mean â??smp_send_stopâ??? [-Werror=implicit-function-declaration] 177 | smp_send_nmi_ipi(c, wd_lockup_ipi, 1000000); | ^~~~~~~~~~~~~~~~ | smp_send_stop cc1: all warnings being treated as errors make[2]: *** [scripts/Makefile.build:273: arch/powerpc/kernel/watchdog.o] Error 1 make[1]: *** [scripts/Makefile.build:534: arch/powerpc/kernel] Error 2 make: *** [Makefile:1980: arch/powerpc] Error 2 make: *** Waiting for unfinished jobs.... We found that powerpc used ipi to implement hardlockup watchdog, so the HAVE_HARDLOCKUP_DETECTOR_ARCH should depend on the SMP. Fixes: 2104180a5369 ("powerpc/64s: implement arch-specific hardlockup watchdog") Reported-by: Hulk Robot <hulkci@xxxxxxxxxx> Signed-off-by: Chen Huang <chenhuang5@xxxxxxxxxx> Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20210327094900.938555-1-chenhuang5@xxxxxxxxxx Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 31ed8083571f..5afa0ebd78ca 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -222,7 +222,7 @@ config PPC select HAVE_LIVEPATCH if HAVE_DYNAMIC_FTRACE_WITH_REGS select HAVE_MOD_ARCH_SPECIFIC select HAVE_NMI if PERF_EVENTS || (PPC64 && PPC_BOOK3S) - select HAVE_HARDLOCKUP_DETECTOR_ARCH if (PPC64 && PPC_BOOK3S) + select HAVE_HARDLOCKUP_DETECTOR_ARCH if PPC64 && PPC_BOOK3S && SMP select HAVE_OPROFILE select HAVE_OPTPROBES if PPC64 select HAVE_PERF_EVENTS