Messages in this thread Patch in this message | ![/](/images/icornerl.gif) | | From | H Hartley Sweeten <> | Date | Fri, 2 Apr 2010 17:41:25 -0500 | Subject | RE: BUG: physmap modprobe & rmmod |
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On Friday, April 02, 2010 3:16 PM, H Hartley Sweeten wrote: > On Friday, April 02, 2010 2:47 PM, Randy Dunlap wrote: >>> 2.6.34-rc2 kernel: >>> >>> Boot up on a common PC, then: modprobe physmap ; rmmod physmap >>> and bang. > > [snip] > >> This is with close to an allmodconfig on x86_64, including: >> >> CONFIG_MTD_PHYSMAP=m >> CONFIG_MTD_PHYSMAP_COMPAT=y >> CONFIG_MTD_PHYSMAP_START=0x8000000 >> CONFIG_MTD_PHYSMAP_LEN=0 >> CONFIG_MTD_PHYSMAP_BANKWIDTH=2 > > That's probably the cause of the BUG. > > If your not run-time calling physmap_configure(), your resource will > be created as: > > static struct physmap_flash_data physmap_flash_data = { > .width = CONFIG_MTD_PHYSMAP_BANKWIDTH, > }; > > static struct resource physmap_flash_resource = { > .start = CONFIG_MTD_PHYSMAP_START, > .end = CONFIG_MTD_PHYSMAP_START + CONFIG_MTD_PHYSMAP_LEN - 1, > .flags = IORESOURCE_MEM, > }; > > In other words: > > static struct physmap_flash_data physmap_flash_data = { > .width = 2, > }; > > static struct resource physmap_flash_resource = { > .start = 0x8000000, > .end = 0x8000000 + 0 - 1, > .flags = IORESOURCE_MEM, > };
I traced this down to kernel/resource.c. When __request_resource is finally called, because of the platform_device_register, it ends up returning a conflict due to:
resource_size_t start = new->start; resource_size_t end = new->end; struct resource *tmp, **p;
if (end < start) return root;
This ends up causing an -EBUSY error code. The patch below should be correct to fix this.
I changed the commit message a bit.
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mtd/maps/physmap: catch failure to register MTD_PHYSMAP_COMPAT device
If the default Kconfig values are used with MTD_PHYSMAP_COMPAT you end up with a resource where end < start. This causes __request_resource to return a conflict which then returns an -EBUSY error code. The current physmap.c code just assumes that the platfom_device_register will always succeed.
Catch this failure during the physmap_init and propogate the error.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
---
diff --git a/drivers/mtd/maps/physmap.c b/drivers/mtd/maps/physmap.c index d9603f7..426461a 100644 --- a/drivers/mtd/maps/physmap.c +++ b/drivers/mtd/maps/physmap.c @@ -264,8 +264,11 @@ static int __init physmap_init(void) err = platform_driver_register(&physmap_flash_driver); #ifdef CONFIG_MTD_PHYSMAP_COMPAT - if (err == 0) - platform_device_register(&physmap_flash); + if (err == 0) { + err = platform_device_register(&physmap_flash); + if (err) + platform_driver_unregister(&physmap_flash_driver); + } #endif return err; ______________________________________________________ Linux MTD discussion mailing list http://lists.infradead.org/mailman/listinfo/linux-mtd/
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