Jiri Slaby c705db27ed base: make module_create_drivers_dir race-free ... commit 7e1b1fc4da upstream. 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. Fix this by a new mutex in module_create_drivers_dir which makes the test-and-create "drivers" dir atomic. I inverted the condition and removed 'return' to avoid multiple unlocks or a goto. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Fixes: fe480a2675 (Modules: only add drivers/ direcory if needed) Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2016-07-27 09:47:32 -07:00
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power	PM / sleep: Handle failures in device_suspend_late() consistently	2016-06-07 18:14:37 -07:00
regmap	regmap: spmi: Fix regmap_spmi_ext_read in multi-byte case	2016-05-18 17:06:48 -07:00
attribute_container.c
base.h
bus.c
cacheinfo.c
class.c
component.c
container.c
core.c
cpu.c
dd.c
devcoredump.c
devres.c
devtmpfs.c
dma-coherent.c
dma-contiguous.c
dma-mapping.c
driver.c
firmware_class.c
firmware.c
hypervisor.c
init.c
isa.c
Kconfig
Makefile
map.c
memory.c
module.c	base: make module_create_drivers_dir race-free	2016-07-27 09:47:32 -07:00
node.c
pinctrl.c
platform-msi.c
platform.c
property.c
soc.c
syscore.c
topology.c
transport_class.c