From c8c4a2972f83c8b68ff03b43cecdb898939ff851 Mon Sep 17 00:00:00 2001 From: Daniel Jordan Date: Fri, 13 Mar 2026 11:24:33 -0400 Subject: padata: Put CPU offline callback in ONLINE section to allow failure syzbot reported the following warning: DEAD callback error for CPU1 WARNING: kernel/cpu.c:1463 at _cpu_down+0x759/0x1020 kernel/cpu.c:1463, CPU#0: syz.0.1960/14614 at commit 4ae12d8bd9a8 ("Merge tag 'kbuild-fixes-7.0-2' of git://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux") which tglx traced to padata_cpu_dead() given it's the only sub-CPUHP_TEARDOWN_CPU callback that returns an error. Failure isn't allowed in hotplug states before CPUHP_TEARDOWN_CPU so move the CPU offline callback to the ONLINE section where failure is possible. Fixes: 894c9ef9780c ("padata: validate cpumask without removed CPU during offline") Reported-by: syzbot+123e1b70473ce213f3af@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/69af0a05.050a0220.310d8.002f.GAE@google.com/ Debugged-by: Thomas Gleixner Signed-off-by: Daniel Jordan Signed-off-by: Herbert Xu --- include/linux/cpuhotplug.h | 1 - include/linux/padata.h | 8 ++++---- 2 files changed, 4 insertions(+), 5 deletions(-) (limited to 'include/linux') diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h index 62cd7b35a29c..22ba327ec227 100644 --- a/include/linux/cpuhotplug.h +++ b/include/linux/cpuhotplug.h @@ -92,7 +92,6 @@ enum cpuhp_state { CPUHP_NET_DEV_DEAD, CPUHP_IOMMU_IOVA_DEAD, CPUHP_AP_ARM_CACHE_B15_RAC_DEAD, - CPUHP_PADATA_DEAD, CPUHP_AP_DTPM_CPU_DEAD, CPUHP_RANDOM_PREPARE, CPUHP_WORKQUEUE_PREP, diff --git a/include/linux/padata.h b/include/linux/padata.h index 765f2778e264..b6232bea6edf 100644 --- a/include/linux/padata.h +++ b/include/linux/padata.h @@ -149,23 +149,23 @@ struct padata_mt_job { /** * struct padata_instance - The overall control structure. * - * @cpu_online_node: Linkage for CPU online callback. - * @cpu_dead_node: Linkage for CPU offline callback. + * @cpuhp_node: Linkage for CPU hotplug callbacks. * @parallel_wq: The workqueue used for parallel work. * @serial_wq: The workqueue used for serial work. * @pslist: List of padata_shell objects attached to this instance. * @cpumask: User supplied cpumasks for parallel and serial works. + * @validate_cpumask: Internal cpumask used to validate @cpumask during hotplug. * @kobj: padata instance kernel object. * @lock: padata instance lock. * @flags: padata flags. */ struct padata_instance { - struct hlist_node cpu_online_node; - struct hlist_node cpu_dead_node; + struct hlist_node cpuhp_node; struct workqueue_struct *parallel_wq; struct workqueue_struct *serial_wq; struct list_head pslist; struct padata_cpumask cpumask; + cpumask_var_t validate_cpumask; struct kobject kobj; struct mutex lock; u8 flags; -- cgit v1.2.3