| Message ID | 57274AF9.1040205@ti.com |
|---|---|
| State | New |
| Headers | show |
Hi Nikolaus, On 08/05/16 09:46, H. Nikolaus Schaller wrote: > Hi Roger, > >> Am 02.05.2016 um 15:03 schrieb H. Nikolaus Schaller <hns@goldelico.com>: >> >> Hi Roger, >> >>> Am 02.05.2016 um 14:41 schrieb Roger Quadros <rogerq@ti.com>: >>> >>> Hi Nikolaus, >>> >>> On 30/04/16 20:24, H. Nikolaus Schaller wrote: >>>> Hi, >>>> I have observed this kernel oops on an omap5 board from time to time (approx. 1% of boot processes): >>>> >>>> [ 5.830970] ehci-omap: OMAP-EHCI Host Controller driver >>>> [ 5.830974] driver_register 'ehci-omap' >>>> [ 5.895849] driver_register 'wl1271_sdio' >>>> [ 5.896870] BUG: scheduling while atomic: udevd/994/0x00000002 >>>> [ 5.896876] 4 locks held by udevd/994: >>>> [ 5.896904] #0: (&dev->mutex){......}, at: [<c049597c>] __driver_attach+0x60/0xac >>>> [ 5.896923] #1: (&dev->mutex){......}, at: [<c049598c>] __driver_attach+0x70/0xac >>>> [ 5.896946] #2: (tll_lock){+.+...}, at: [<c04c2630>] omap_tll_enable+0x2c/0xd0 >>>> [ 5.896966] #3: (prepare_lock){+.+...}, at: [<c05ce9c8>] clk_prepare_lock+0x48/0xe0 >>>> [ 5.897042] Modules linked in: wlcore_sdio(+) ehci_omap(+) dwc3_omap snd_soc_ts3a225e leds_is31fl319x bq27xxx_battery_i2c tsc2007 bq27xxx_battery bq2429x_charger ina2xx tca8418_keypad as5013 leds_tca6507 twl6040_vibra gpio_twl6040 bmp085_i2c(+) palmas_gpadc usb3503 palmas_pwrbutton bmg160_i2c(+) bmp085 bma150(+) bmg160_core bmp280 input_polldev snd_soc_omap_mcbsp snd_soc_omap_mcpdm snd_soc_omap snd_pcm_dmaengine >>>> [ 5.897048] Preemption disabled at:[< (null)>] (null) >>>> [ 5.897051] >>>> [ 5.897059] CPU: 0 PID: 994 Comm: udevd Not tainted 4.6.0-rc5-letux+ #233 >>>> [ 5.897062] Hardware name: Generic OMAP5 (Flattened Device Tree) >>>> [ 5.897076] [<c010e714>] (unwind_backtrace) from [<c010af34>] (show_stack+0x10/0x14) >>>> [ 5.897087] [<c010af34>] (show_stack) from [<c040aa7c>] (dump_stack+0x88/0xc0) >>>> [ 5.897099] [<c040aa7c>] (dump_stack) from [<c020c558>] (__schedule_bug+0xac/0xd0) >>>> [ 5.897111] [<c020c558>] (__schedule_bug) from [<c06f3d44>] (__schedule+0x88/0x7e4) >>>> [ 5.897120] [<c06f3d44>] (__schedule) from [<c06f46d8>] (schedule+0x9c/0xc0) >>>> [ 5.897129] [<c06f46d8>] (schedule) from [<c06f4904>] (schedule_preempt_disabled+0x14/0x20) >>>> [ 5.897140] [<c06f4904>] (schedule_preempt_disabled) from [<c06f64e4>] (mutex_lock_nested+0x258/0x43c) >>>> [ 5.897150] [<c06f64e4>] (mutex_lock_nested) from [<c05ce9c8>] (clk_prepare_lock+0x48/0xe0) >>>> [ 5.897160] [<c05ce9c8>] (clk_prepare_lock) from [<c05d0e7c>] (clk_prepare+0x10/0x28) >>>> [ 5.897169] [<c05d0e7c>] (clk_prepare) from [<c04c2668>] (omap_tll_enable+0x64/0xd0) >>>> [ 5.897180] [<c04c2668>] (omap_tll_enable) from [<c04c1728>] (usbhs_runtime_resume+0x18/0x17c) >>>> [ 5.897192] [<c04c1728>] (usbhs_runtime_resume) from [<c049d404>] (pm_generic_runtime_resume+0x2c/0x40) >>>> [ 5.897202] [<c049d404>] (pm_generic_runtime_resume) from [<c049f180>] (__rpm_callback+0x38/0x68) >>>> [ 5.897210] [<c049f180>] (__rpm_callback) from [<c049f220>] (rpm_callback+0x70/0x88) >>>> [ 5.897218] [<c049f220>] (rpm_callback) from [<c04a0a00>] (rpm_resume+0x4ec/0x7ec) >>>> [ 5.897227] [<c04a0a00>] (rpm_resume) from [<c04a0f48>] (__pm_runtime_resume+0x4c/0x64) >>>> [ 5.897236] [<c04a0f48>] (__pm_runtime_resume) from [<c04958dc>] (driver_probe_device+0x30/0x70) >>>> [ 5.897246] [<c04958dc>] (driver_probe_device) from [<c04959a4>] (__driver_attach+0x88/0xac) >>>> [ 5.897256] [<c04959a4>] (__driver_attach) from [<c04940f8>] (bus_for_each_dev+0x50/0x84) >>>> [ 5.897267] [<c04940f8>] (bus_for_each_dev) from [<c0494e40>] (bus_add_driver+0xcc/0x1e4) >>>> [ 5.897276] [<c0494e40>] (bus_add_driver) from [<c0496914>] (driver_register+0xac/0xf4) >>>> [ 5.897286] [<c0496914>] (driver_register) from [<c01018e0>] (do_one_initcall+0x100/0x1b8) >>>> [ 5.897296] [<c01018e0>] (do_one_initcall) from [<c01c7a54>] (do_init_module+0x58/0x1c0) >>>> [ 5.897304] [<c01c7a54>] (do_init_module) from [<c01c8a3c>] (SyS_finit_module+0x88/0x90) >>>> [ 5.897313] [<c01c8a3c>] (SyS_finit_module) from [<c0107120>] (ret_fast_syscall+0x0/0x1c) >>>> [ 5.912697] ------------[ cut here ]------------ >>>> [ 5.912711] WARNING: CPU: 0 PID: 994 at kernel/sched/core.c:2996 _raw_spin_unlock+0x28/0x58 >>>> [ 5.912717] DEBUG_LOCKS_WARN_ON(val > preempt_count()) >>>> >>>> A liitle analysis of the code shows me: >>>> >>>> * udevd tries to initialize some (usb driver?) module >>>> * this calls usbhs_runtime_resume: http://lxr.free-electrons.com/source/drivers/mfd/omap-usb-host.c#L310 >>>> * which calls omap_tll_enable: http://lxr.free-electrons.com/source/drivers/mfd/omap-usb-tll.c#L403 >>>> * this does a spinlock: http://lxr.free-electrons.com/source/drivers/mfd/omap-usb-tll.c#L413 >>>> * but calls clk_prepare_enable: http://lxr.free-electrons.com/source/include/linux/clk.h#L467 >>>> * which calls: http://lxr.free-electrons.com/source/drivers/clk/clk.c#L658 >>>> * and there is a another lock being tried in clk_prepare_lock: http://lxr.free-electrons.com/source/drivers/clk/clk.c#L91 >>>> * and that is a mutex_try_lock >>>> >>>> So the lock dependency report is very valid. Inside a spinlock, there is a mutex_try_lock. >>>> >>>> It appears as if the spinlock was introduced in 2008 by 76a0775d46da052f123b8598a3dfc3b330b8de4f >>>> And the mutex in 2013 by 533ddeb1e86f506129ee388a6cc13796dcf31311 >>>> >>>> Please fix. >>>> >>>> Thank you, >>>> Nikolaus >>> >>> Does this patch fix it for you? >>> >>> -- >>> cheers, >>> -roger >>> >>> diff --git a/drivers/mfd/omap-usb-tll.c b/drivers/mfd/omap-usb-tll.c >>> index b7b3e8e..c30290f 100644 >>> --- a/drivers/mfd/omap-usb-tll.c >>> +++ b/drivers/mfd/omap-usb-tll.c >>> @@ -269,6 +269,8 @@ static int usbtll_omap_probe(struct platform_device *pdev) >>> >>> if (IS_ERR(tll->ch_clk[i])) >>> dev_dbg(dev, "can't get clock : %s\n", clkname); >>> + else >>> + clk_prepare(tll->ch_clk[i]); >>> } >>> >>> pm_runtime_put_sync(dev); >>> @@ -301,9 +303,12 @@ static int usbtll_omap_remove(struct platform_device *pdev) >>> tll_dev = NULL; >>> spin_unlock(&tll_lock); >>> >>> - for (i = 0; i < tll->nch; i++) >>> - if (!IS_ERR(tll->ch_clk[i])) >>> + for (i = 0; i < tll->nch; i++) { >>> + if (!IS_ERR(tll->ch_clk[i])) { >>> + clk_unprepare(tll->ch_clk[i]); >>> clk_put(tll->ch_clk[i]); >>> + } >>> + } >>> >>> pm_runtime_disable(&pdev->dev); >>> return 0; >>> @@ -420,7 +425,7 @@ int omap_tll_enable(struct usbhs_omap_platform_data *pdata) >>> if (IS_ERR(tll->ch_clk[i])) >>> continue; >>> >>> - r = clk_prepare_enable(tll->ch_clk[i]); >>> + r = clk_enable(tll->ch_clk[i]); >>> if (r) { >>> dev_err(tll_dev, >>> "Error enabling ch %d clock: %d\n", i, r); >>> @@ -448,7 +453,7 @@ int omap_tll_disable(struct usbhs_omap_platform_data *pdata) >>> for (i = 0; i < tll->nch; i++) { >>> if (omap_usb_mode_needs_tll(pdata->port_mode[i])) { >>> if (!IS_ERR(tll->ch_clk[i])) >>> - clk_disable_unprepare(tll->ch_clk[i]); >>> + clk_disable(tll->ch_clk[i]); >>> } >>> } >> >> I will give it a try. Since it is sporadic I can tell only after some days of use if it did not happen any more. > > I have it in my tree for a while and did no longer observe the BUG. > And I did not experience side effects (e.g. usb not working...). > > So I think it works and solves the issue. > Thanks for the bug report and the test. Official patch is on its way. cheers, -roger -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/mfd/omap-usb-tll.c b/drivers/mfd/omap-usb-tll.c index b7b3e8e..c30290f 100644 --- a/drivers/mfd/omap-usb-tll.c +++ b/drivers/mfd/omap-usb-tll.c @@ -269,6 +269,8 @@ static int usbtll_omap_probe(struct platform_device *pdev) if (IS_ERR(tll->ch_clk[i])) dev_dbg(dev, "can't get clock : %s\n", clkname); + else + clk_prepare(tll->ch_clk[i]); } pm_runtime_put_sync(dev); @@ -301,9 +303,12 @@ static int usbtll_omap_remove(struct platform_device *pdev) tll_dev = NULL; spin_unlock(&tll_lock); - for (i = 0; i < tll->nch; i++) - if (!IS_ERR(tll->ch_clk[i])) + for (i = 0; i < tll->nch; i++) { + if (!IS_ERR(tll->ch_clk[i])) { + clk_unprepare(tll->ch_clk[i]); clk_put(tll->ch_clk[i]); + } + } pm_runtime_disable(&pdev->dev); return 0; @@ -420,7 +425,7 @@ int omap_tll_enable(struct usbhs_omap_platform_data *pdata) if (IS_ERR(tll->ch_clk[i])) continue; - r = clk_prepare_enable(tll->ch_clk[i]); + r = clk_enable(tll->ch_clk[i]); if (r) { dev_err(tll_dev, "Error enabling ch %d clock: %d\n", i, r); @@ -448,7 +453,7 @@ int omap_tll_disable(struct usbhs_omap_platform_data *pdata) for (i = 0; i < tll->nch; i++) { if (omap_usb_mode_needs_tll(pdata->port_mode[i])) { if (!IS_ERR(tll->ch_clk[i])) - clk_disable_unprepare(tll->ch_clk[i]); + clk_disable(tll->ch_clk[i]); } } -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in