(Sorry for the possibly double-posting, my last mail got rejected by some mailing lists.) Hi, When I tested this patch series (Based on linux 5.2.0-rc2, and with various other patch series about MT8183) with lockdep enabled, and I'm seeing the following lockdep warning on boot. By bisecting the commits, the first commit that introduce this warning is this patch. The warning also doesn't appear if https://lore.kernel.org/patchwork/patch/1086582/ and https://lore.kernel.org/patchwork/patch/1086583/ are not applied. Do anyone have idea on why this is happening, or any suggestion on which part I should be digging into to figure this out? Thanks. [ 4.664194] ====================================================== [ 4.670368] WARNING: possible circular locking dependency detected [ 4.676545] 5.2.0-rc2-next-20190528-44527-g6c94b6475c04 #20 Tainted: G S [ 4.684539] ------------------------------------------------------ [ 4.690714] kworker/4:1/51 is trying to acquire lock: [ 4.695760] (____ptrval____) (regulator_list_mutex){+.+.}, at:regulator_lock_dependent+0xdc/0x6c4 [ 4.704732] [ 4.704732] but task is already holding lock: [ 4.710556] (____ptrval____) (&genpd->mlock/1){+.+.}, at:genpd_lock_nested_mtx+0x24/0x30 [ 4.718740] [ 4.718740] which lock already depends on the new lock. [ 4.718740] [ 4.726908] [ 4.726908] the existing dependency chain (in reverse order) is: [ 4.734382] [ 4.734382] -> #4 (&genpd->mlock/1){+.+.}: [ 4.739963] __mutex_lock_common+0x1a0/0x1fe8 [ 4.744836] mutex_lock_nested+0x40/0x50 [ 4.749275] genpd_lock_nested_mtx+0x24/0x30 [ 4.754063] genpd_add_subdomain+0x150/0x524 [ 4.758850] pm_genpd_add_subdomain+0x3c/0x5c [ 4.763723] scpsys_probe+0x520/0xe78 [ 4.767902] platform_drv_probe+0xf4/0x134 [ 4.772517] really_probe+0x214/0x4dc [ 4.776696] driver_probe_device+0xcc/0x1d4 [ 4.781396] __device_attach_driver+0x10c/0x180 [ 4.786442] bus_for_each_drv+0x124/0x184 [ 4.790968] __device_attach+0x1c0/0x2d8 [ 4.795407] device_initial_probe+0x20/0x2c [ 4.800106] bus_probe_device+0x80/0x16c [ 4.804546] deferred_probe_work_func+0x120/0x168 [ 4.809767] process_one_work+0x858/0x1208 [ 4.814379] worker_thread+0x9ec/0xcb8 [ 4.818644] kthread+0x2b8/0x2d0 [ 4.822391] ret_from_fork+0x10/0x18 [ 4.826480] [ 4.826480] -> #3 (&genpd->mlock){+.+.}: [ 4.831880] __mutex_lock_common+0x1a0/0x1fe8 [ 4.836752] mutex_lock_nested+0x40/0x50 [ 4.841190] genpd_lock_mtx+0x20/0x2c [ 4.845369] genpd_runtime_resume+0x140/0x434 [ 4.850241] __rpm_callback+0xb0/0x1e4 [ 4.854506] rpm_callback+0x54/0x1a8 [ 4.858597] rpm_resume+0xc6c/0x10c4 [ 4.862689] __pm_runtime_resume+0xb4/0x124 [ 4.867387] device_link_add+0x598/0x8d0 [ 4.871829] mtk_smi_larb_probe+0x2b0/0x340 [ 4.876528] platform_drv_probe+0xf4/0x134 [ 4.881141] really_probe+0x214/0x4dc [ 4.885320] driver_probe_device+0xcc/0x1d4 [ 4.890020] __device_attach_driver+0x10c/0x180 [ 4.895066] bus_for_each_drv+0x124/0x184 [ 4.899591] __device_attach+0x1c0/0x2d8 [ 4.904031] device_initial_probe+0x20/0x2c [ 4.908730] bus_probe_device+0x80/0x16c [ 4.913169] deferred_probe_work_func+0x120/0x168 [ 4.918387] process_one_work+0x858/0x1208 [ 4.923000] worker_thread+0x9ec/0xcb8 [ 4.927264] kthread+0x2b8/0x2d0 [ 4.931009] ret_from_fork+0x10/0x18 [ 4.935098] [ 4.935098] -> #2 (dpm_list_mtx){+.+.}: [ 4.940412] __mutex_lock_common+0x1a0/0x1fe8 [ 4.945284] mutex_lock_nested+0x40/0x50 [ 4.949722] device_pm_lock+0x1c/0x24 [ 4.953900] device_link_add+0x98/0x8d0 [ 4.958252] _regulator_get+0x3f0/0x504 [ 4.962606] _devm_regulator_get+0x58/0xb8 [ 4.967218] devm_regulator_get+0x28/0x34 [ 4.971746] pwm_backlight_probe+0x61c/0x1b90 [ 4.976617] platform_drv_probe+0xf4/0x134 [ 4.981230] really_probe+0x214/0x4dc [ 4.985409] driver_probe_device+0xcc/0x1d4 [ 4.990108] device_driver_attach+0xe4/0x104 [ 4.994894] __driver_attach+0x134/0x14c [ 4.999333] bus_for_each_dev+0x120/0x180 [ 5.003859] driver_attach+0x48/0x54 [ 5.007950] bus_add_driver+0x2ac/0x44c [ 5.012303] driver_register+0x160/0x288 [ 5.016742] __platform_driver_register+0xcc/0xdc [ 5.021964] pwm_backlight_driver_init+0x1c/0x24 [ 5.027097] do_one_initcall+0x38c/0x994 [ 5.031536] do_initcall_level+0x3a4/0x4b8 [ 5.036148] do_basic_setup+0x84/0xa0 [ 5.036153] kernel_init_freeable+0x23c/0x324 [ 5.036158] kernel_init+0x14/0x110 [ 5.036164] ret_from_fork+0x10/0x18 [ 5.036166] [ 5.036166] -> #1 (device_links_lock){+.+.}: [ 5.065905] __mutex_lock_common+0x1a0/0x1fe8 [ 5.070777] mutex_lock_nested+0x40/0x50 [ 5.075215] device_link_remove+0x40/0xe0 [ 5.079740] _regulator_put+0x104/0x2d8 [ 5.084093] regulator_put+0x30/0x44 [ 5.088184] devm_regulator_release+0x38/0x44 [ 5.093056] release_nodes+0x604/0x670 [ 5.097320] devres_release_all+0x70/0x8c [ 5.101846] really_probe+0x270/0x4dc [ 5.106024] driver_probe_device+0xcc/0x1d4 [ 5.110724] device_driver_attach+0xe4/0x104 [ 5.115510] __driver_attach+0x134/0x14c [ 5.119949] bus_for_each_dev+0x120/0x180 [ 5.124474] driver_attach+0x48/0x54 [ 5.128566] bus_add_driver+0x2ac/0x44c [ 5.132919] driver_register+0x160/0x288 [ 5.137357] __platform_driver_register+0xcc/0xdc [ 5.142576] pwm_backlight_driver_init+0x1c/0x24 [ 5.147708] do_one_initcall+0x38c/0x994 [ 5.152146] do_initcall_level+0x3a4/0x4b8 [ 5.156758] do_basic_setup+0x84/0xa0 [ 5.160936] kernel_init_freeable+0x23c/0x324 [ 5.165807] kernel_init+0x14/0x110 [ 5.169813] ret_from_fork+0x10/0x18 [ 5.173901] [ 5.173901] -> #0 (regulator_list_mutex){+.+.}: [ 5.179910] lock_acquire+0x350/0x4d4 [ 5.184088] __mutex_lock_common+0x1a0/0x1fe8 [ 5.184095] mutex_lock_nested+0x40/0x50 [ 5.197475] regulator_lock_dependent+0xdc/0x6c4 [ 5.197482] regulator_disable+0xa0/0x138 [ 5.197487] scpsys_power_off+0x38c/0x4bc [ 5.197495] genpd_power_off+0x3d8/0x6a0 [ 5.209399] genpd_power_off+0x530/0x6a0 [ 5.209406] genpd_power_off_work_fn+0x74/0xc0 [ 5.209411] process_one_work+0x858/0x1208 [ 5.209419] worker_thread+0x9ec/0xcb8 [ 5.219067] kthread+0x2b8/0x2d0 [ 5.219073] ret_from_fork+0x10/0x18 [ 5.219077] [ 5.219077] other info that might help us debug this: [ 5.219077] [ 5.219080] Chain exists of: [ 5.219080] regulator_list_mutex --> &genpd->mlock --> &genpd->mlock/1 [ 5.219080] [ 5.228039] Possible unsafe locking scenario: [ 5.228039] [ 5.228042] CPU0 CPU1 [ 5.228046] ---- ---- [ 5.228048] lock(&genpd->mlock/1); [ 5.228058] lock(&genpd->mlock); [ 5.311647] lock(&genpd->mlock/1); [ 5.317736] lock(regulator_list_mutex); [ 5.321742] [ 5.321742] *** DEADLOCK *** [ 5.321742] [ 5.327655] 4 locks held by kworker/4:1/51: [ 5.331831] #0: (____ptrval____) ((wq_completion)pm){+.+.}, at:process_one_work+0x57c/0x1208 [ 5.340444] #1: (____ptrval____) ((work_completion)(&genpd->power_off_work)){+.+.}, at:process_one_work+0x5b8/0x1208 [ 5.351139] #2: (____ptrval____) (&genpd->mlock){+.+.}, at:genpd_lock_mtx+0x20/0x2c [ 5.358970] #3: (____ptrval____) (&genpd->mlock/1){+.+.}, at:genpd_lock_nested_mtx+0x24/0x30 [ 5.367584] [ 5.367584] stack backtrace: [ 5.371939] CPU: 4 PID: 51 Comm: kworker/4:1 Tainted: G S 5.2.0-rc2-next-20190528-44527-g6c94b6475c04 #20 [ 5.382809] Workqueue: pm genpd_power_off_work_fn [ 5.382816] Call trace: [ 5.382822] dump_backtrace+0x0/0x2c0 [ 5.382830] show_stack+0x20/0x2c [ 5.409174] dump_stack+0x10c/0x17c [ 5.412659] print_circular_bug+0x42c/0x4d0 [ 5.416838] __lock_acquire+0x4c88/0x5484 [ 5.420843] lock_acquire+0x350/0x4d4 [ 5.424500] __mutex_lock_common+0x1a0/0x1fe8 [ 5.428851] mutex_lock_nested+0x40/0x50 [ 5.432770] regulator_lock_dependent+0xdc/0x6c4 [ 5.437383] regulator_disable+0xa0/0x138 [ 5.441389] scpsys_power_off+0x38c/0x4bc [ 5.445393] genpd_power_off+0x3d8/0x6a0 [ 5.449310] genpd_power_off+0x530/0x6a0 [ 5.453229] genpd_power_off_work_fn+0x74/0xc0 [ 5.457667] process_one_work+0x858/0x1208 [ 5.461758] worker_thread+0x9ec/0xcb8 [ 5.465503] kthread+0x2b8/0x2d0 [ 5.468727] ret_from_fork+0x10/0x18 On Mon, Jun 10, 2019 at 8:21 PM Yong Wu <yong.wu@xxxxxxxxxxxx> wrote: > ... > + } else { > + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); > + common->base = devm_ioremap_resource(dev, res); > + if (IS_ERR(common->base)) > + return PTR_ERR(common->base); > } > pm_runtime_enable(dev); > platform_set_drvdata(pdev, common);
