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authorAtsushi Nemoto <anemo@mba.ocn.ne.jp>2007-01-26 00:56:54 -0800
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-01-26 13:50:58 -0800
commit1e9a51dca19dc1d8807c63cb3bd4413d3f95aaf5 (patch)
tree941d5039c0dfb5aeb8a499e9cbebda0a1e80d8a8
parent863c47028eb469c9e6c4e4287b01bea2bbf78766 (diff)
[PATCH] SPI: alternative fix for spi_busnum_to_master
If a SPI master device exists, udev (udevtrigger) causes kernel crash, due to wrong kobj pointer in kobject_uevent_env(). This problem was not in 2.6.19. The backtrace (on MIPS) was: [<8024db6c>] kobject_uevent_env+0x54c/0x5e8 [<802a8264>] store_uevent+0x1c/0x3c (in drivers/class.c) [<801cb14c>] subsys_attr_store+0x2c/0x50 [<801cb80c>] flush_write_buffer+0x38/0x5c [<801cb900>] sysfs_write_file+0xd0/0x190 [<80181444>] vfs_write+0xc4/0x1a0 [<80181cdc>] sys_write+0x54/0xa0 [<8010dae4>] stack_done+0x20/0x3c flush_write_buffer() passes kobject of spi_master_class.subsys to subsys_addr_store(), then subsys_addr_store() passes a pointer to a struct subsystem to store_uevent() which expects a pointer to a struct class_device. The problem seems subsys_attr_store() called instead of class_device_attr_store(). This mismatch was caused by commit 3bd0f6943520e459659d10f3282285e43d3990f1, which overrides kset of master class. This made spi_master_class.subsys.kset.ktype NULL so subsys_sysfs_ops is used instead of class_dev_sysfs_ops. The commit was to fix spi_busnum_to_master(). Here is a patch fixes this function in other way, just searching children list of class_device. Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp> Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--drivers/spi/spi.c23
1 files changed, 14 insertions, 9 deletions
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 270e6211c2e..6307428d2c9 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -366,7 +366,6 @@ spi_alloc_master(struct device *dev, unsigned size)
class_device_initialize(&master->cdev);
master->cdev.class = &spi_master_class;
- kobj_set_kset_s(&master->cdev, spi_master_class.subsys);
master->cdev.dev = get_device(dev);
spi_master_set_devdata(master, &master[1]);
@@ -466,14 +465,20 @@ EXPORT_SYMBOL_GPL(spi_unregister_master);
*/
struct spi_master *spi_busnum_to_master(u16 bus_num)
{
- char name[9];
- struct kobject *bus;
-
- snprintf(name, sizeof name, "spi%u", bus_num);
- bus = kset_find_obj(&spi_master_class.subsys.kset, name);
- if (bus)
- return container_of(bus, struct spi_master, cdev.kobj);
- return NULL;
+ struct class_device *cdev;
+ struct spi_master *master = NULL;
+ struct spi_master *m;
+
+ down(&spi_master_class.sem);
+ list_for_each_entry(cdev, &spi_master_class.children, node) {
+ m = container_of(cdev, struct spi_master, cdev);
+ if (m->bus_num == bus_num) {
+ master = spi_master_get(m);
+ break;
+ }
+ }
+ up(&spi_master_class.sem);
+ return master;
}
EXPORT_SYMBOL_GPL(spi_busnum_to_master);