workqueue: Don't call cpumask_test_cpu() with -1 CPU in wq_update_node_max_active()

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.

Tejun Heo committed 2 years ago

Commit 15930da1 parent aae17eb1 file · +1 −1Browse files

Showing the changes to kernel/workqueue.c (1 of 1 file). Show all

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kernel/workqueue.c+1−1

@@ -1510,7 +1510,7 @@ static void wq_update_node_max_active(struct workqueue_struct *wq, int off_cpu) · 1509 unmodified lines
1510		1510
1511	lockdep_assert_held(&wq->mutex);	1511	lockdep_assert_held(&wq->mutex);
1512		1512
1513	if (!cpumask_test_cpu(off_cpu, effective))	1513	if (off_cpu >= 0 && !cpumask_test_cpu(off_cpu, effective))
1514	off_cpu = -1;	1514	off_cpu = -1;
1515		1515
1516	total_cpus = cpumask_weight_and(effective, cpu_online_mask);	1516	total_cpus = cpumask_weight_and(effective, cpu_online_mask);