| Message ID | 20250122062718.3736823-1-avri.altman@wdc.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | scsi: ufs: core: Ensure clk_gating.lock is used only after initialization | expand |
On Wed, Jan 22, 2025 at 08:27:18AM +0200, Avri Altman wrote: > This commit addresses a lockdep warning triggered by the use of the > clk_gating.lock before it is properly initialized. The warning is as > follows: > > [ 4.388838] INFO: trying to register non-static key. > [ 4.395673] The code is fine but needs lockdep annotation, or maybe > [ 4.402118] you didn't initialize this object before use? > [ 4.407673] turning off the locking correctness validator. > [ 4.413334] CPU: 5 UID: 0 PID: 58 Comm: kworker/u32:1 Not tainted 6.12-rc1 #185 > [ 4.413343] Hardware name: Qualcomm Technologies, Inc. Robotics RB5 (DT) > [ 4.413362] Call trace: > [ 4.413364] show_stack+0x18/0x24 (C) > [ 4.413374] dump_stack_lvl+0x90/0xd0 > [ 4.413384] dump_stack+0x18/0x24 > [ 4.413392] register_lock_class+0x498/0x4a8 > [ 4.413400] __lock_acquire+0xb4/0x1b90 > [ 4.413406] lock_acquire+0x114/0x310 > [ 4.413413] _raw_spin_lock_irqsave+0x60/0x88 > [ 4.413423] ufshcd_setup_clocks+0x2c0/0x490 > [ 4.413433] ufshcd_init+0x198/0x10ec > [ 4.413437] ufshcd_pltfrm_init+0x600/0x7c0 > [ 4.413444] ufs_qcom_probe+0x20/0x58 > [ 4.413449] platform_probe+0x68/0xd8 > [ 4.413459] really_probe+0xbc/0x268 > [ 4.413466] __driver_probe_device+0x78/0x12c > [ 4.413473] driver_probe_device+0x40/0x11c > [ 4.413481] __device_attach_driver+0xb8/0xf8 > [ 4.413489] bus_for_each_drv+0x84/0xe4 > [ 4.413495] __device_attach+0xfc/0x18c > [ 4.413502] device_initial_probe+0x14/0x20 > [ 4.413510] bus_probe_device+0xb0/0xb4 > [ 4.413517] deferred_probe_work_func+0x8c/0xc8 > [ 4.413524] process_scheduled_works+0x250/0x658 > [ 4.413534] worker_thread+0x15c/0x2c8 > [ 4.413542] kthread+0x134/0x200 > [ 4.413550] ret_from_fork+0x10/0x20 > > To fix this issue, we use the existing `is_initialized` flag in the > `clk_gating` structure to ensure that the spinlock is only used after it > has been properly initialized. We check this flag before using the > spinlock in the `ufshcd_setup_clocks` function. > > It was incorrect in the first place to call `setup_clocks()` before > `ufshcd_init_clk_gating()`, and the introduction of the new lock > unmasked this bug. If calling setup_clocks() before ufshcd_init_clk_gating() is incorrect, why are you not reordering it? Checking for 'clk_gating.is_initialized' looks like a hack. - Mani > > Fixes: 209f4e43b806 ("scsi: ufs: core: Introduce a new clock_gating lock") > Reported-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org> > Signed-off-by: Avri Altman <avri.altman@wdc.com> > --- > drivers/ufs/core/ufshcd.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c > index f6c38cf10382..a778fc51ca2a 100644 > --- a/drivers/ufs/core/ufshcd.c > +++ b/drivers/ufs/core/ufshcd.c > @@ -9142,7 +9142,7 @@ static int ufshcd_setup_clocks(struct ufs_hba *hba, bool on) > if (!IS_ERR_OR_NULL(clki->clk) && clki->enabled) > clk_disable_unprepare(clki->clk); > } > - } else if (!ret && on) { > + } else if (!ret && on && hba->clk_gating.is_initialized) { > scoped_guard(spinlock_irqsave, &hba->clk_gating.lock) > hba->clk_gating.state = CLKS_ON; > trace_ufshcd_clk_gating(dev_name(hba->dev), > -- > 2.25.1 >
> > To fix this issue, we use the existing `is_initialized` flag in the > > `clk_gating` structure to ensure that the spinlock is only used after > > it has been properly initialized. We check this flag before using the > > spinlock in the `ufshcd_setup_clocks` function. > > > > It was incorrect in the first place to call `setup_clocks()` before > > `ufshcd_init_clk_gating()`, and the introduction of the new lock > > unmasked this bug. > > If calling setup_clocks() before ufshcd_init_clk_gating() is incorrect, why are > you not reordering it? > > Checking for 'clk_gating.is_initialized' looks like a hack. Actually 'clk_gating.is_initialized' seems like the standard way to do this - see e.g. in hold and release. As for moving setup_clocks() around, I have some concerns about moving it out of ufshcd_hba_init. Having considered the alternatives, it seems that using 'clk_gating.is_initialized' , despite its limitations, is the most practical solution we have. I am open though for other suggestions. Thanks, Avri > > - Mani > > > > > Fixes: 209f4e43b806 ("scsi: ufs: core: Introduce a new clock_gating > > lock") > > Reported-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org> > > Signed-off-by: Avri Altman <avri.altman@wdc.com> > > --- > > drivers/ufs/core/ufshcd.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c > > index f6c38cf10382..a778fc51ca2a 100644 > > --- a/drivers/ufs/core/ufshcd.c > > +++ b/drivers/ufs/core/ufshcd.c > > @@ -9142,7 +9142,7 @@ static int ufshcd_setup_clocks(struct ufs_hba > *hba, bool on) > > if (!IS_ERR_OR_NULL(clki->clk) && clki->enabled) > > clk_disable_unprepare(clki->clk); > > } > > - } else if (!ret && on) { > > + } else if (!ret && on && hba->clk_gating.is_initialized) { > > scoped_guard(spinlock_irqsave, &hba->clk_gating.lock) > > hba->clk_gating.state = CLKS_ON; > > trace_ufshcd_clk_gating(dev_name(hba->dev), > > -- > > 2.25.1 > > > > -- > மணிவண்ணன் சதாசிவம்
On Wed, Jan 22, 2025 at 11:04:12AM +0000, Avri Altman wrote: > > > To fix this issue, we use the existing `is_initialized` flag in the > > > `clk_gating` structure to ensure that the spinlock is only used after > > > it has been properly initialized. We check this flag before using the > > > spinlock in the `ufshcd_setup_clocks` function. > > > > > > It was incorrect in the first place to call `setup_clocks()` before > > > `ufshcd_init_clk_gating()`, and the introduction of the new lock > > > unmasked this bug. > > > > If calling setup_clocks() before ufshcd_init_clk_gating() is incorrect, why are > > you not reordering it? > > > > Checking for 'clk_gating.is_initialized' looks like a hack. > Actually 'clk_gating.is_initialized' seems like the standard way to do this - see e.g. in hold and release. > As for moving setup_clocks() around, I have some concerns about moving it out of ufshcd_hba_init. > Having considered the alternatives, it seems that using 'clk_gating.is_initialized' , > despite its limitations, is the most practical solution we have. > > I am open though for other suggestions. > Looking at the code again, I think it is OK to have this fix for now. But someone should spend some time to revisit the locking part in this driver. Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> - Mani
On 1/21/25 10:27 PM, Avri Altman wrote: > This commit addresses a lockdep warning triggered by the use of the > clk_gating.lock before it is properly initialized. The warning is as > follows: > > [ 4.388838] INFO: trying to register non-static key. > [ 4.395673] The code is fine but needs lockdep annotation, or maybe > [ 4.402118] you didn't initialize this object before use? > [ 4.407673] turning off the locking correctness validator. > [ 4.413334] CPU: 5 UID: 0 PID: 58 Comm: kworker/u32:1 Not tainted 6.12-rc1 #185 > [ 4.413343] Hardware name: Qualcomm Technologies, Inc. Robotics RB5 (DT) > [ 4.413362] Call trace: > [ 4.413364] show_stack+0x18/0x24 (C) > [ 4.413374] dump_stack_lvl+0x90/0xd0 > [ 4.413384] dump_stack+0x18/0x24 > [ 4.413392] register_lock_class+0x498/0x4a8 > [ 4.413400] __lock_acquire+0xb4/0x1b90 > [ 4.413406] lock_acquire+0x114/0x310 > [ 4.413413] _raw_spin_lock_irqsave+0x60/0x88 > [ 4.413423] ufshcd_setup_clocks+0x2c0/0x490 > [ 4.413433] ufshcd_init+0x198/0x10ec > [ 4.413437] ufshcd_pltfrm_init+0x600/0x7c0 > [ 4.413444] ufs_qcom_probe+0x20/0x58 > [ 4.413449] platform_probe+0x68/0xd8 > [ 4.413459] really_probe+0xbc/0x268 > [ 4.413466] __driver_probe_device+0x78/0x12c > [ 4.413473] driver_probe_device+0x40/0x11c > [ 4.413481] __device_attach_driver+0xb8/0xf8 > [ 4.413489] bus_for_each_drv+0x84/0xe4 > [ 4.413495] __device_attach+0xfc/0x18c > [ 4.413502] device_initial_probe+0x14/0x20 > [ 4.413510] bus_probe_device+0xb0/0xb4 > [ 4.413517] deferred_probe_work_func+0x8c/0xc8 > [ 4.413524] process_scheduled_works+0x250/0x658 > [ 4.413534] worker_thread+0x15c/0x2c8 > [ 4.413542] kthread+0x134/0x200 > [ 4.413550] ret_from_fork+0x10/0x20 > > To fix this issue, we use the existing `is_initialized` flag in the > `clk_gating` structure to ensure that the spinlock is only used after it > has been properly initialized. We check this flag before using the > spinlock in the `ufshcd_setup_clocks` function. > > It was incorrect in the first place to call `setup_clocks()` before > `ufshcd_init_clk_gating()`, and the introduction of the new lock > unmasked this bug. > > Fixes: 209f4e43b806 ("scsi: ufs: core: Introduce a new clock_gating lock") > Reported-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org> > Signed-off-by: Avri Altman <avri.altman@wdc.com> > --- > drivers/ufs/core/ufshcd.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c > index f6c38cf10382..a778fc51ca2a 100644 > --- a/drivers/ufs/core/ufshcd.c > +++ b/drivers/ufs/core/ufshcd.c > @@ -9142,7 +9142,7 @@ static int ufshcd_setup_clocks(struct ufs_hba *hba, bool on) > if (!IS_ERR_OR_NULL(clki->clk) && clki->enabled) > clk_disable_unprepare(clki->clk); > } > - } else if (!ret && on) { > + } else if (!ret && on && hba->clk_gating.is_initialized) { > scoped_guard(spinlock_irqsave, &hba->clk_gating.lock) > hba->clk_gating.state = CLKS_ON; > trace_ufshcd_clk_gating(dev_name(hba->dev), Has it been considered to move the spin_lock_init(&hba->clk_gating.lock) call from ufshcd_init_clk_gating() such that it occurs before its first use, e.g. just before the ufshcd_hba_init() call in ufshcd_init()? Thanks, Bart.
> On 1/21/25 10:27 PM, Avri Altman wrote: > > This commit addresses a lockdep warning triggered by the use of the > > clk_gating.lock before it is properly initialized. The warning is as > > follows: > > > > [ 4.388838] INFO: trying to register non-static key. > > [ 4.395673] The code is fine but needs lockdep annotation, or maybe > > [ 4.402118] you didn't initialize this object before use? > > [ 4.407673] turning off the locking correctness validator. > > [ 4.413334] CPU: 5 UID: 0 PID: 58 Comm: kworker/u32:1 Not tainted 6.12- > rc1 #185 > > [ 4.413343] Hardware name: Qualcomm Technologies, Inc. Robotics RB5 > (DT) > > [ 4.413362] Call trace: > > [ 4.413364] show_stack+0x18/0x24 (C) > > [ 4.413374] dump_stack_lvl+0x90/0xd0 > > [ 4.413384] dump_stack+0x18/0x24 > > [ 4.413392] register_lock_class+0x498/0x4a8 > > [ 4.413400] __lock_acquire+0xb4/0x1b90 > > [ 4.413406] lock_acquire+0x114/0x310 > > [ 4.413413] _raw_spin_lock_irqsave+0x60/0x88 > > [ 4.413423] ufshcd_setup_clocks+0x2c0/0x490 > > [ 4.413433] ufshcd_init+0x198/0x10ec > > [ 4.413437] ufshcd_pltfrm_init+0x600/0x7c0 > > [ 4.413444] ufs_qcom_probe+0x20/0x58 > > [ 4.413449] platform_probe+0x68/0xd8 > > [ 4.413459] really_probe+0xbc/0x268 > > [ 4.413466] __driver_probe_device+0x78/0x12c > > [ 4.413473] driver_probe_device+0x40/0x11c > > [ 4.413481] __device_attach_driver+0xb8/0xf8 > > [ 4.413489] bus_for_each_drv+0x84/0xe4 > > [ 4.413495] __device_attach+0xfc/0x18c > > [ 4.413502] device_initial_probe+0x14/0x20 > > [ 4.413510] bus_probe_device+0xb0/0xb4 > > [ 4.413517] deferred_probe_work_func+0x8c/0xc8 > > [ 4.413524] process_scheduled_works+0x250/0x658 > > [ 4.413534] worker_thread+0x15c/0x2c8 > > [ 4.413542] kthread+0x134/0x200 > > [ 4.413550] ret_from_fork+0x10/0x20 > > > > To fix this issue, we use the existing `is_initialized` flag in the > > `clk_gating` structure to ensure that the spinlock is only used after > > it has been properly initialized. We check this flag before using the > > spinlock in the `ufshcd_setup_clocks` function. > > > > It was incorrect in the first place to call `setup_clocks()` before > > `ufshcd_init_clk_gating()`, and the introduction of the new lock > > unmasked this bug. > > > > Fixes: 209f4e43b806 ("scsi: ufs: core: Introduce a new clock_gating > > lock") > > Reported-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org> > > Signed-off-by: Avri Altman <avri.altman@wdc.com> > > --- > > drivers/ufs/core/ufshcd.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c > > index f6c38cf10382..a778fc51ca2a 100644 > > --- a/drivers/ufs/core/ufshcd.c > > +++ b/drivers/ufs/core/ufshcd.c > > @@ -9142,7 +9142,7 @@ static int ufshcd_setup_clocks(struct ufs_hba > *hba, bool on) > > if (!IS_ERR_OR_NULL(clki->clk) && clki->enabled) > > clk_disable_unprepare(clki->clk); > > } > > - } else if (!ret && on) { > > + } else if (!ret && on && hba->clk_gating.is_initialized) { > > scoped_guard(spinlock_irqsave, &hba->clk_gating.lock) > > hba->clk_gating.state = CLKS_ON; > > trace_ufshcd_clk_gating(dev_name(hba->dev), > > Has it been considered to move the spin_lock_init(&hba->clk_gating.lock) > call from ufshcd_init_clk_gating() such that it occurs before its first use, e.g. > just before the ufshcd_hba_init() call in ufshcd_init()? While your suggestion has merit, it would unfortunately break the fundamental concept of concentrating the initialization logic in one place, which is essential for maintaining a clean and manageable codebase. Will do that if you think it's better. Thanks, Avri > > Thanks, > > Bart.
Hi Avri, On Wed, Jan 22, 2025 at 7:30 AM Avri Altman <avri.altman@wdc.com> wrote: > This commit addresses a lockdep warning triggered by the use of the > clk_gating.lock before it is properly initialized. The warning is as > follows: > > [ 4.388838] INFO: trying to register non-static key. > [ 4.395673] The code is fine but needs lockdep annotation, or maybe > [ 4.402118] you didn't initialize this object before use? > [ 4.407673] turning off the locking correctness validator. > [ 4.413334] CPU: 5 UID: 0 PID: 58 Comm: kworker/u32:1 Not tainted 6.12-rc1 #185 > [ 4.413343] Hardware name: Qualcomm Technologies, Inc. Robotics RB5 (DT) > [ 4.413362] Call trace: > [ 4.413364] show_stack+0x18/0x24 (C) > [ 4.413374] dump_stack_lvl+0x90/0xd0 > [ 4.413384] dump_stack+0x18/0x24 > [ 4.413392] register_lock_class+0x498/0x4a8 > [ 4.413400] __lock_acquire+0xb4/0x1b90 > [ 4.413406] lock_acquire+0x114/0x310 > [ 4.413413] _raw_spin_lock_irqsave+0x60/0x88 > [ 4.413423] ufshcd_setup_clocks+0x2c0/0x490 > [ 4.413433] ufshcd_init+0x198/0x10ec > [ 4.413437] ufshcd_pltfrm_init+0x600/0x7c0 > [ 4.413444] ufs_qcom_probe+0x20/0x58 > [ 4.413449] platform_probe+0x68/0xd8 > [ 4.413459] really_probe+0xbc/0x268 > [ 4.413466] __driver_probe_device+0x78/0x12c > [ 4.413473] driver_probe_device+0x40/0x11c > [ 4.413481] __device_attach_driver+0xb8/0xf8 > [ 4.413489] bus_for_each_drv+0x84/0xe4 > [ 4.413495] __device_attach+0xfc/0x18c > [ 4.413502] device_initial_probe+0x14/0x20 > [ 4.413510] bus_probe_device+0xb0/0xb4 > [ 4.413517] deferred_probe_work_func+0x8c/0xc8 > [ 4.413524] process_scheduled_works+0x250/0x658 > [ 4.413534] worker_thread+0x15c/0x2c8 > [ 4.413542] kthread+0x134/0x200 > [ 4.413550] ret_from_fork+0x10/0x20 > > To fix this issue, we use the existing `is_initialized` flag in the > `clk_gating` structure to ensure that the spinlock is only used after it > has been properly initialized. We check this flag before using the > spinlock in the `ufshcd_setup_clocks` function. > > It was incorrect in the first place to call `setup_clocks()` before > `ufshcd_init_clk_gating()`, and the introduction of the new lock > unmasked this bug. > > Fixes: 209f4e43b806 ("scsi: ufs: core: Introduce a new clock_gating lock") > Reported-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org> > Signed-off-by: Avri Altman <avri.altman@wdc.com> Thanks for your patch! I just ran into the same issue on R-Car S4 (S4 Starter Kit). > --- a/drivers/ufs/core/ufshcd.c > +++ b/drivers/ufs/core/ufshcd.c > @@ -9142,7 +9142,7 @@ static int ufshcd_setup_clocks(struct ufs_hba *hba, bool on) > if (!IS_ERR_OR_NULL(clki->clk) && clki->enabled) > clk_disable_unprepare(clki->clk); > } > - } else if (!ret && on) { > + } else if (!ret && on && hba->clk_gating.is_initialized) { > scoped_guard(spinlock_irqsave, &hba->clk_gating.lock) > hba->clk_gating.state = CLKS_ON; > trace_ufshcd_clk_gating(dev_name(hba->dev), This looks like a very fragile solution to me... In addition, while this change does fix this particular spinlock warning, it just BUGs in a different place later: do_raw_spin_lock+0x34/0xb4 _raw_spin_lock_irqsave+0x1c/0x30 class_spinlock_irqsave_constructor+0x18/0x30 - ufshcd_setup_clocks+0x98/0x23c - ufshcd_init+0x268/0xd2c + ufshcd_release+0x30/0x74 + ufshcd_send_uic_cmd+0x70/0x90 + ufshcd_link_startup.constprop.0+0x70/0x258 + ufshcd_init+0xa38/0xd2c ufshcd_pltfrm_init+0x618/0x738 ufs_renesas_probe+0x18/0x24 platform_probe+0x68/0xb8 I think you should initialize all your spinlocks (and mutexes) early in ufshcd_init(), instead of sprinkled across various helper functions. Gr{oetje,eeting}s, Geert
> I just ran into the same issue on R-Car S4 (S4 Starter Kit). > > > --- a/drivers/ufs/core/ufshcd.c > > +++ b/drivers/ufs/core/ufshcd.c > > @@ -9142,7 +9142,7 @@ static int ufshcd_setup_clocks(struct ufs_hba *hba, > bool on) > > if (!IS_ERR_OR_NULL(clki->clk) && clki->enabled) > > clk_disable_unprepare(clki->clk); > > } > > - } else if (!ret && on) { > > + } else if (!ret && on && hba->clk_gating.is_initialized) { > > scoped_guard(spinlock_irqsave, &hba->clk_gating.lock) > > hba->clk_gating.state = CLKS_ON; > > trace_ufshcd_clk_gating(dev_name(hba->dev), > > This looks like a very fragile solution to me... > > In addition, while this change does fix this particular spinlock warning, it just > BUGs in a different place later: > > do_raw_spin_lock+0x34/0xb4 > _raw_spin_lock_irqsave+0x1c/0x30 > class_spinlock_irqsave_constructor+0x18/0x30 > - ufshcd_setup_clocks+0x98/0x23c > - ufshcd_init+0x268/0xd2c > + ufshcd_release+0x30/0x74 > + ufshcd_send_uic_cmd+0x70/0x90 > + ufshcd_link_startup.constprop.0+0x70/0x258 > + ufshcd_init+0xa38/0xd2c > ufshcd_pltfrm_init+0x618/0x738 > ufs_renesas_probe+0x18/0x24 > platform_probe+0x68/0xb8 I don't understand how it is possible that `ufshcd_init_clk_gating(hba)` is called after `ufshcd_link_startup(hba)` in 'ufshcd_init'. Nor how concurrency could take place in this init flow. Evidently, this is happening. > > I think you should initialize all your spinlocks (and mutexes) early in > ufshcd_init(), instead of sprinkled across various helper functions. This is the case today. Let me suggest a different fix. Thanks, Avri > > Gr{oetje,eeting}s, > > Geert > > -- > Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux- > m68k.org > > In personal conversations with technical people, I call myself a hacker. But when > I'm talking to journalists I just say "programmer" or something like that. > -- Linus Torvalds
diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c index f6c38cf10382..a778fc51ca2a 100644 --- a/drivers/ufs/core/ufshcd.c +++ b/drivers/ufs/core/ufshcd.c @@ -9142,7 +9142,7 @@ static int ufshcd_setup_clocks(struct ufs_hba *hba, bool on) if (!IS_ERR_OR_NULL(clki->clk) && clki->enabled) clk_disable_unprepare(clki->clk); } - } else if (!ret && on) { + } else if (!ret && on && hba->clk_gating.is_initialized) { scoped_guard(spinlock_irqsave, &hba->clk_gating.lock) hba->clk_gating.state = CLKS_ON; trace_ufshcd_clk_gating(dev_name(hba->dev),
This commit addresses a lockdep warning triggered by the use of the clk_gating.lock before it is properly initialized. The warning is as follows: [ 4.388838] INFO: trying to register non-static key. [ 4.395673] The code is fine but needs lockdep annotation, or maybe [ 4.402118] you didn't initialize this object before use? [ 4.407673] turning off the locking correctness validator. [ 4.413334] CPU: 5 UID: 0 PID: 58 Comm: kworker/u32:1 Not tainted 6.12-rc1 #185 [ 4.413343] Hardware name: Qualcomm Technologies, Inc. Robotics RB5 (DT) [ 4.413362] Call trace: [ 4.413364] show_stack+0x18/0x24 (C) [ 4.413374] dump_stack_lvl+0x90/0xd0 [ 4.413384] dump_stack+0x18/0x24 [ 4.413392] register_lock_class+0x498/0x4a8 [ 4.413400] __lock_acquire+0xb4/0x1b90 [ 4.413406] lock_acquire+0x114/0x310 [ 4.413413] _raw_spin_lock_irqsave+0x60/0x88 [ 4.413423] ufshcd_setup_clocks+0x2c0/0x490 [ 4.413433] ufshcd_init+0x198/0x10ec [ 4.413437] ufshcd_pltfrm_init+0x600/0x7c0 [ 4.413444] ufs_qcom_probe+0x20/0x58 [ 4.413449] platform_probe+0x68/0xd8 [ 4.413459] really_probe+0xbc/0x268 [ 4.413466] __driver_probe_device+0x78/0x12c [ 4.413473] driver_probe_device+0x40/0x11c [ 4.413481] __device_attach_driver+0xb8/0xf8 [ 4.413489] bus_for_each_drv+0x84/0xe4 [ 4.413495] __device_attach+0xfc/0x18c [ 4.413502] device_initial_probe+0x14/0x20 [ 4.413510] bus_probe_device+0xb0/0xb4 [ 4.413517] deferred_probe_work_func+0x8c/0xc8 [ 4.413524] process_scheduled_works+0x250/0x658 [ 4.413534] worker_thread+0x15c/0x2c8 [ 4.413542] kthread+0x134/0x200 [ 4.413550] ret_from_fork+0x10/0x20 To fix this issue, we use the existing `is_initialized` flag in the `clk_gating` structure to ensure that the spinlock is only used after it has been properly initialized. We check this flag before using the spinlock in the `ufshcd_setup_clocks` function. It was incorrect in the first place to call `setup_clocks()` before `ufshcd_init_clk_gating()`, and the introduction of the new lock unmasked this bug. Fixes: 209f4e43b806 ("scsi: ufs: core: Introduce a new clock_gating lock") Reported-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org> Signed-off-by: Avri Altman <avri.altman@wdc.com> --- drivers/ufs/core/ufshcd.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)