RE: [EXT] Re: [PATCH V2 1/4] spi: lpspi: Fix kernel warning dump when probe fail after calling spi_register

2020-07-30 Thread Clark Wang 

> -Original Message-
> From: Mark Brown 
> Sent: Monday, July 27, 2020 19:11
> To: Clark Wang 
> Cc: linux-...@vger.kernel.org; linux-kernel@vger.kernel.org
> Subject: [EXT] Re: [PATCH V2 1/4] spi: lpspi: Fix kernel warning dump when
> probe fail after calling spi_register
> 
> On Mon, Jul 27, 2020 at 11:14:46AM +0800, Clark Wang wrote:
> > Calling devm_spi_register_controller() too early will cause problem.
> > When probe failed occurs after calling devm_spi_register_controller(),
> > the call of spi_controller_put() will trigger the following warning dump.
> >
> > [2.092138] [ cut here ]
> > [2.096876] kernfs: can not remove 'uevent', no directory
> > [2.102440] WARNING: CPU: 0 PID: 181 at fs/kernfs/dir.c:1503
> kernfs_remove_by_name_ns+0xa0/0xb0
> > [2.42] Modules linked in:
> > [2.114207] CPU: 0 PID: 181 Comm: kworker/0:7 Not tainted 5.4.24-05024-
> g775c6e8a738c-dirty #1314
> > [2.122991] Hardware name: Freescale i.MX8DXL EVK (DT)
> > [2.128141] Workqueue: events deferred_probe_work_func
> 
> Please think hard before including complete backtraces in upstream reports,
> they are very large and contain almost no useful information relative to their
> size so often obscure the relevant content in your message. If part of the
> backtrace is usefully illustrative (it often is for search engines if nothing 
> else)
> then it's usually better to pull out the relevant sections.

Hi Mark,

Thank you very much for reminding. 
I will remove the redundant part when I meet similar situations in the future. 

Best Regards,
Clark Wang

Re: [PATCH V2 1/4] spi: lpspi: Fix kernel warning dump when probe fail after calling spi_register

2020-07-27 Thread Mark Brown 
On Mon, Jul 27, 2020 at 11:14:46AM +0800, Clark Wang wrote:
> Calling devm_spi_register_controller() too early will cause problem.
> When probe failed occurs after calling devm_spi_register_controller(),
> the call of spi_controller_put() will trigger the following warning dump.
> 
> [2.092138] [ cut here ]
> [2.096876] kernfs: can not remove 'uevent', no directory
> [2.102440] WARNING: CPU: 0 PID: 181 at fs/kernfs/dir.c:1503 
> kernfs_remove_by_name_ns+0xa0/0xb0
> [2.42] Modules linked in:
> [2.114207] CPU: 0 PID: 181 Comm: kworker/0:7 Not tainted 
> 5.4.24-05024-g775c6e8a738c-dirty #1314
> [2.122991] Hardware name: Freescale i.MX8DXL EVK (DT)
> [2.128141] Workqueue: events deferred_probe_work_func

Please think hard before including complete backtraces in upstream
reports, they are very large and contain almost no useful information
relative to their size so often obscure the relevant content in your
message. If part of the backtrace is usefully illustrative (it often is
for search engines if nothing else) then it's usually better to pull out
the relevant sections.


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[PATCH V2 1/4] spi: lpspi: Fix kernel warning dump when probe fail after calling spi_register

2020-07-26 Thread Clark Wang 
Calling devm_spi_register_controller() too early will cause problem.
When probe failed occurs after calling devm_spi_register_controller(),
the call of spi_controller_put() will trigger the following warning dump.

[2.092138] [ cut here ]
[2.096876] kernfs: can not remove 'uevent', no directory
[2.102440] WARNING: CPU: 0 PID: 181 at fs/kernfs/dir.c:1503 
kernfs_remove_by_name_ns+0xa0/0xb0
[2.42] Modules linked in:
[2.114207] CPU: 0 PID: 181 Comm: kworker/0:7 Not tainted 
5.4.24-05024-g775c6e8a738c-dirty #1314
[2.122991] Hardware name: Freescale i.MX8DXL EVK (DT)
[2.128141] Workqueue: events deferred_probe_work_func
[2.133281] pstate: 6005 (nZCv daif -PAN -UAO)
[2.138076] pc : kernfs_remove_by_name_ns+0xa0/0xb0
[2.142958] lr : kernfs_remove_by_name_ns+0xa0/0xb0
[2.147837] sp : 8000122bba70
[2.151145] x29: 8000122bba70 x28: 8000119d6000
[2.156462] x27:  x26: 800011edbce8
[2.161779] x25:  x24: 3ae4f700
[2.167096] x23: 10184c10 x22: 3a3d6200
[2.172412] x21: 800011a464a8 x20: 10126a68
[2.177729] x19: 3ae5c800 x18: 000e
[2.183046] x17: 0001 x16: 0019
[2.188362] x15: 0004 x14: 004c
[2.193679] x13:  x12: 0001
[2.198996] x11:  x10: 09c0
[2.204313] x9 : 8000122bb7a0 x8 : 3a3d6c20
[2.209630] x7 : 3a3d6380 x6 : 0001
[2.214946] x5 : 0001 x4 : 3a05eb18
[2.220263] x3 : 0005 x2 : 8000119f1c48
[2.225580] x1 : 2bcbda323bf5a800 x0 : 
[2.230898] Call trace:
[2.233345]  kernfs_remove_by_name_ns+0xa0/0xb0
[2.237879]  sysfs_remove_file_ns+0x14/0x20
[2.242065]  device_del+0x12c/0x348
[2.24]  device_unregister+0x14/0x30
[2.249492]  spi_unregister_controller+0xac/0x120
[2.254201]  devm_spi_unregister+0x10/0x18
[2.258304]  release_nodes+0x1a8/0x220
[2.262055]  devres_release_all+0x34/0x58
[2.266069]  really_probe+0x1b8/0x318
[2.269733]  driver_probe_device+0x54/0xe8
[2.273833]  __device_attach_driver+0x80/0xb8
[2.278194]  bus_for_each_drv+0x74/0xc0
[2.282034]  __device_attach+0xdc/0x138
[2.285876]  device_initial_probe+0x10/0x18
[2.290063]  bus_probe_device+0x90/0x98
[2.293901]  deferred_probe_work_func+0x64/0x98
[2.298442]  process_one_work+0x198/0x320
[2.302451]  worker_thread+0x1f0/0x420
[2.306208]  kthread+0xf0/0x120
[2.309352]  ret_from_fork+0x10/0x18
[2.312927] ---[ end trace 58abcdfae01bd3c7 ]---

So put this function at the end of the probe sequence.

Signed-off-by: Clark Wang 
---
Changes:
V2:
 - redo the patch base on the new code.
---
 drivers/spi/spi-fsl-lpspi.c | 12 ++--
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/spi/spi-fsl-lpspi.c b/drivers/spi/spi-fsl-lpspi.c
index a4a42e85e132..b0a1bb62f10a 100644
--- a/drivers/spi/spi-fsl-lpspi.c
+++ b/drivers/spi/spi-fsl-lpspi.c
@@ -850,12 +850,6 @@ static int fsl_lpspi_probe(struct platform_device *pdev)
if (!fsl_lpspi->is_slave)
controller->use_gpio_descriptors = true;
 
-   ret = devm_spi_register_controller(>dev, controller);
-   if (ret < 0) {
-   dev_err(>dev, "spi_register_controller error.\n");
-   goto out_controller_put;
-   }
-
init_completion(_lpspi->xfer_done);
 
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
@@ -913,6 +907,12 @@ static int fsl_lpspi_probe(struct platform_device *pdev)
if (ret < 0)
dev_err(>dev, "dma setup error %d, use pio\n", ret);
 
+   ret = devm_spi_register_controller(>dev, controller);
+   if (ret < 0) {
+   dev_err(>dev, "spi_register_controller error.\n");
+   goto out_pm_get;
+   }
+
pm_runtime_mark_last_busy(fsl_lpspi->dev);
pm_runtime_put_autosuspend(fsl_lpspi->dev);
 
-- 
2.17.1