Hi, andy_purcell@xxxxxxxxxxxx writes: > Hello Felipe, > >> > >> > I have a second issue with a functionfs USB-device implementation. >> > >> > The scenario is this: >> > 1) USB-device app starts up, runs fine >> > 2) ssh to the device, kill the app with CTRL-C >> > 3) try to start the USB-device app 2nd time >> > >> > PANIC >> > >> > dmesg output: >> > [ 2553.870000] ------------[ cut here ]------------ [ 2553.870000] >> > kernel BUG at /var/lib/jenkins/workspace/Complete_PXYZ/.../kernel- >> source/fs/sysfs/file.c:332! >> > >> > [ 2553.870000] Internal error: Oops - BUG: 0 [#1] PREEMPT ARM [ >> > 2553.870000] Modules linked in: designware_udc usb_f_fs libcomposite >> > udc_core fuse configfs autofs4 >> >> what is this designware_udc? We don't have that in mainline > > It is a driver for a very old ST Micro processor. > I now believe it is the cause of the problem. > The same user-space code for starting and stopping our USB function works on another platform. > So now I must look at the source code for this old ST Micro processor and compare it to our other platform. > > Any hints about what to look for? > Must be something to do with functionfs and starting and stopping, binding and unbinding? I'd start sprinkling trace_printk() around in the driver. Frankly, though, the best approach would be to either ping the company forcing you to use this out-of-tree driver, or convince them to support the mainline version (drivers/usb/gadget/udc/snps_udc_core.c). Best of luck :-) -- balbi
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