From 7df62b8cca38aa452b508b477b16544cba615084 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Tue, 30 Jan 2024 18:55:55 -1000 Subject: [PATCH] workqueue: Don't call cpumask_test_cpu() with -1 CPU in wq_update_node_max_active() [ Upstream commit 15930da42f8981dc42c19038042947b475b19f47 ] For wq_update_node_max_active(), @off_cpu of -1 indicates that no CPU is going down. The function was incorrectly calling cpumask_test_cpu() with -1 CPU leading to oopses like the following on some archs: Unable to handle kernel paging request at virtual address ffff0002100296e0 .. pc : wq_update_node_max_active+0x50/0x1fc lr : wq_update_node_max_active+0x1f0/0x1fc ... Call trace: wq_update_node_max_active+0x50/0x1fc apply_wqattrs_commit+0xf0/0x114 apply_workqueue_attrs_locked+0x58/0xa0 alloc_workqueue+0x5ac/0x774 workqueue_init_early+0x460/0x540 start_kernel+0x258/0x684 __primary_switched+0xb8/0xc0 Code: 9100a273 35000d01 53067f00 d0016dc1 (f8607a60) ---[ end trace 0000000000000000 ]--- Kernel panic - not syncing: Attempted to kill the idle task! ---[ end Kernel panic - not syncing: Attempted to kill the idle task! ]--- Fix it. Signed-off-by: Tejun Heo Reported-by: Marek Szyprowski Reported-by: Nathan Chancellor Tested-by: Nathan Chancellor Link: http://lkml.kernel.org/r/91eacde0-df99-4d5c-a980-91046f66e612@samsung.com Fixes: 5797b1c18919 ("workqueue: Implement system-wide nr_active enforcement for unbound workqueues") Signed-off-by: Sasha Levin --- kernel/workqueue.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/workqueue.c b/kernel/workqueue.c index b2975e44dffa..7d231bbd1659 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -1500,7 +1500,7 @@ static void wq_update_node_max_active(struct workqueue_struct *wq, int off_cpu) lockdep_assert_held(&wq->mutex); - if (!cpumask_test_cpu(off_cpu, effective)) + if (off_cpu >= 0 && !cpumask_test_cpu(off_cpu, effective)) off_cpu = -1; total_cpus = cpumask_weight_and(effective, cpu_online_mask);