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@vger.kernel.org Signed-off-by: Jarkko Nikula jarkko.nikula@linux.intel.com --- 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);