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.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-4.19.y git checkout FETCH_HEAD git cherry-pick -x 932d8476399f622aa0767a4a0a9e78e5341dc0e1 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2024070143-petunia-runaround-2e19@gregkh' --subject-prefix 'PATCH 4.19.y' HEAD^..

Possible dependencies:

932d8476399f ("cpu/hotplug: Fix dynstate assignment in __cpuhp_setup_state_cpuslocked()") 11bc021d1fba ("cpu/hotplug: Eliminate all kernel-doc warnings") 33c3736ec888 ("cpu/hotplug: Hide cpu_up/down()") b99a26593b51 ("cpu/hotplug: Move bringup of secondary CPUs out of smp_init()") d720f9860439 ("cpu/hotplug: Provide bringup_hibernate_cpu()") 0441a5597c5d ("cpu/hotplug: Create a new function to shutdown nonboot cpus") 93ef1429e556 ("cpu/hotplug: Add new {add,remove}_cpu() functions")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 932d8476399f622aa0767a4a0a9e78e5341dc0e1 Mon Sep 17 00:00:00 2001 From: Yuntao Wang ytcoode@gmail.com Date: Wed, 15 May 2024 21:45:54 +0800 Subject: [PATCH] cpu/hotplug: Fix dynstate assignment in __cpuhp_setup_state_cpuslocked()

Commit 4205e4786d0b ("cpu/hotplug: Provide dynamic range for prepare stage") added a dynamic range for the prepare states, but did not handle the assignment of the dynstate variable in __cpuhp_setup_state_cpuslocked().

This causes the corresponding startup callback not to be invoked when calling __cpuhp_setup_state_cpuslocked() with the CPUHP_BP_PREPARE_DYN parameter, even though it should be.

Currently, the users of __cpuhp_setup_state_cpuslocked(), for one reason or another, have not triggered this bug.

Fixes: 4205e4786d0b ("cpu/hotplug: Provide dynamic range for prepare stage") Signed-off-by: Yuntao Wang ytcoode@gmail.com Signed-off-by: Thomas Gleixner tglx@linutronix.de Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20240515134554.427071-1-ytcoode@gmail.com

diff --git a/kernel/cpu.c b/kernel/cpu.c index 563877d6c28b..74cfdb66a9bd 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -2446,7 +2446,7 @@ EXPORT_SYMBOL_GPL(__cpuhp_state_add_instance); * The caller needs to hold cpus read locked while calling this function. * Return: * On success: - * Positive state number if @state is CPUHP_AP_ONLINE_DYN; + * Positive state number if @state is CPUHP_AP_ONLINE_DYN or CPUHP_BP_PREPARE_DYN; * 0 for all other states * On failure: proper (negative) error code */ @@ -2469,7 +2469,7 @@ int __cpuhp_setup_state_cpuslocked(enum cpuhp_state state, ret = cpuhp_store_callbacks(state, name, startup, teardown, multi_instance);

- dynstate = state == CPUHP_AP_ONLINE_DYN; + dynstate = state == CPUHP_AP_ONLINE_DYN || state == CPUHP_BP_PREPARE_DYN; if (ret > 0 && dynstate) { state = ret; ret = 0; @@ -2500,8 +2500,8 @@ int __cpuhp_setup_state_cpuslocked(enum cpuhp_state state, out: mutex_unlock(&cpuhp_state_mutex); /* - * If the requested state is CPUHP_AP_ONLINE_DYN, return the - * dynamically allocated state in case of success. + * If the requested state is CPUHP_AP_ONLINE_DYN or CPUHP_BP_PREPARE_DYN, + * return the dynamically allocated state in case of success. */ if (!ret && dynstate) return state;