Commit 9b61e302210e (spi: Pick spi bus number from Linux idr or spi alias)
ceased to unregister SPI buses with fixed bus numbers. Moreover this is
visible only if CONFIG_SPI_DEBUG=y is set or when trying to re-register
the same SPI controller.
rmmod spi_pxa2xx_platform (with CONFIG_SPI_DEBUG=y):
[ 26.788362] spi_master spi1: attempting to delete unregistered controller [spi1]
modprobe spi_pxa2xx_platform:
[ 37.883137] sysfs: cannot create duplicate filename '/devices/pci0000:00/0000:00:19.0/pxa2xx-spi.12/spi_master/spi1'
[ 37.894984] CPU: 1 PID: 1467 Comm: modprobe Not tainted 4.16.0-rc4+ #21
[ 37.902384] Call Trace:
...
[ 38.122680] kobject_add_internal failed for spi1 with -EEXIST, don't try to register things with the same name in the same directory.
[ 38.136154] WARNING: CPU: 1 PID: 1467 at lib/kobject.c:238 kobject_add_internal+0x2a5/0x2f0
...
[ 38.513817] pxa2xx-spi pxa2xx-spi.12: problem registering spi master
[ 38.521036] pxa2xx-spi: probe of pxa2xx-spi.12 failed with error -17
Fix this by not returning immediately from spi_unregister_controller() if
idr_find() doesn't find controller with given ID/bus number. It finds
only those controllers that were registered with dynamic SPI bus
numbers. Only conditional cleanup between dynamic and fixed bus numbers
is to remove allocated IDR.
Fixes: 9b61e302210e (spi: Pick spi bus number from Linux idr or spi alias)
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Jarkko Nikula <jarkko.nikula@xxxxxxxxxxxxxxx>
---
This doesn't apply to v4.14 without commit 67f7b2781faf ("spi: fix
use-after-free at controller deregistration").
---
drivers/spi/spi.c | 9 ++-------
1 file changed, 2 insertions(+), 7 deletions(-)
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index b33a727a0158..e90fd442b3f0 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -2254,12 +2254,6 @@ void spi_unregister_controller(struct spi_controller *ctlr)
mutex_lock(&board_lock);
found = idr_find(&spi_master_idr, id);
mutex_unlock(&board_lock);
- if (found != ctlr) {
- dev_dbg(&ctlr->dev,
- "attempting to delete unregistered controller [%s]\n",
- dev_name(&ctlr->dev));
- return;
- }
if (ctlr->queued) {
if (spi_destroy_queue(ctlr))
dev_err(&ctlr->dev, "queue remove failed\n");
@@ -2272,7 +2266,8 @@ void spi_unregister_controller(struct spi_controller *ctlr)
device_unregister(&ctlr->dev);
/* free bus id */
mutex_lock(&board_lock);
- idr_remove(&spi_master_idr, id);
+ if (found == ctlr)
+ idr_remove(&spi_master_idr, id);
mutex_unlock(&board_lock);
}
EXPORT_SYMBOL_GPL(spi_unregister_controller);
--
2.16.2