On Fri, Jun 10, 2016 at 10:54:32AM +0200, Jiri Slaby wrote: > Modules which register drivers via standard path (driver_register) in > parallel can cause a warning: > WARNING: CPU: 2 PID: 3492 at ../fs/sysfs/dir.c:31 sysfs_warn_dup+0x62/0x80 > sysfs: cannot create duplicate filename '/module/saa7146/drivers' > Modules linked in: hexium_gemini(+) mxb(+) ... > ... > Call Trace: > ... > [<ffffffff812e63a2>] sysfs_warn_dup+0x62/0x80 > [<ffffffff812e6487>] sysfs_create_dir_ns+0x77/0x90 > [<ffffffff8140f2c4>] kobject_add_internal+0xb4/0x340 > [<ffffffff8140f5b8>] kobject_add+0x68/0xb0 > [<ffffffff8140f631>] kobject_create_and_add+0x31/0x70 > [<ffffffff8157a703>] module_add_driver+0xc3/0xd0 > [<ffffffff8155e5d4>] bus_add_driver+0x154/0x280 > [<ffffffff815604c0>] driver_register+0x60/0xe0 > [<ffffffff8145bed0>] __pci_register_driver+0x60/0x70 > [<ffffffffa0273e14>] saa7146_register_extension+0x64/0x90 [saa7146] > [<ffffffffa0033011>] hexium_init_module+0x11/0x1000 [hexium_gemini] > ... > > As can be (mostly) seen, driver_register causes this call sequence: > -> bus_add_driver > -> module_add_driver > -> module_create_drivers_dir > The last one creates "drivers" directory in /sys/module/<...>. When > this is done in parallel, the directory is attempted to be created > twice at the same time. > > This can be easily reproduced by loading mxb and hexium_gemini in > parallel: > while :; do > modprobe mxb & > modprobe hexium_gemini > wait > rmmod mxb hexium_gemini saa7146_vv saa7146 > done > > saa7146 calls pci_register_driver for both mxb and hexium_gemini, > which means /sys/module/saa7146/drivers is to be created for both of > them. Wow, good catch, I would never have expected that. I'll go queue this up soon, thanks. greg k-h -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html