Geert Uytterhoeven wrote:
> 8 locks held by s2ram/1899:
> #0: (sb_writers#7){.+.+.+}, at: [<ffffff80081ca1a4>] vfs_write+0xa8/0x15c
> #1: (&of->mutex){+.+.+.}, at: [<ffffff8008245964>] kernfs_fop_write+0xf0/0x194
> #2: (s_active#48){.+.+.+}, at: [<ffffff800824596c>] kernfs_fop_write+0xf8/0x194
> #3: (pm_mutex){+.+.+.}, at: [<ffffff80081059a4>] pm_suspend+0x16c/0xabc
> #4: (&dev->mutex){......}, at: [<ffffff80083d4920>] device_resume+0x58/0x190
> #5: (cma_mutex){+.+...}, at: [<ffffff80081c516c>] cma_alloc+0x150/0x374
> #6: (lock){+.+...}, at: [<ffffff800818b8ec>] lru_add_drain_all+0x4c/0x1b4
> #7: (cpu_hotplug.dep_map){++++++}, at: [<ffffff80080ab8f4>] get_online_cpus+0x3c/0x9c
I think this situation suggests that
int pm_suspend(suspend_state_t state) {
error = enter_state(state) {
if (!mutex_trylock(&pm_mutex)) /* #3 */
return -EBUSY;
error = suspend_devices_and_enter(state) {
error = suspend_enter(state, &wakeup) {
enable_nonboot_cpus() {
cpu_maps_update_begin() {
mutex_lock(&cpu_add_remove_lock);
}
pr_info("Enabling non-boot CPUs ...\n");
for_each_cpu(cpu, frozen_cpus) {
error = _cpu_up(cpu, 1, CPUHP_ONLINE) {
cpu_hotplug_begin() {
mutex_lock(&cpu_hotplug.lock);
}
cpu_hotplug_done() {
mutex_unlock(&cpu_hotplug.lock);
}
}
if (!error) {
pr_info("CPU%d is up\n", cpu);
continue;
}
}
cpu_maps_update_done() {
mutex_unlock(&cpu_add_remove_lock);
}
}
}
dpm_resume_end(PMSG_RESUME) {
dpm_resume(state) {
mutex_lock(&dpm_list_mtx);
while (!list_empty(&dpm_suspended_list)) {
mutex_unlock(&dpm_list_mtx);
error = device_resume(dev, state, false) {
dpm_wait_for_superior(dev, async);
dpm_watchdog_set(&wd, dev);
device_lock(dev) {
mutex_lock(&dev->mutex); /* #4 */
}
error = dpm_run_callback(callback, dev, state, info) {
cma_alloc() {
mutex_lock(&cma_mutex); /* #5 */
alloc_contig_range() {
lru_add_drain_all() {
mutex_lock(&lock); /* #6 */
get_online_cpus() {
mutex_lock(&cpu_hotplug.lock); /* #7 hang? */
mutex_unlock(&cpu_hotplug.lock);
}
put_online_cpus();
mutex_unlock(&lock); /* #6 */
}
}
mutex_unlock(&cma_mutex); /* #5 */
}
}
device_unlock(dev) {
mutex_unlock(&dev->mutex); /* #4 */
}
}
mutex_lock(&dpm_list_mtx);
}
mutex_unlock(&dpm_list_mtx);
}
dpm_complete(state) {
mutex_lock(&dpm_list_mtx);
while (!list_empty(&dpm_prepared_list)) {
mutex_unlock(&dpm_list_mtx);
device_complete(dev, state) {
}
mutex_lock(&dpm_list_mtx);
}
mutex_unlock(&dpm_list_mtx);
}
}
}
mutex_unlock(&pm_mutex); /* #3 */
}
}
Somebody is waiting forever with cpu_hotplug.lock held?
I think that full dmesg with SysRq-t output is appreciated.
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