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authorChristoph Hellwig <hch@lst.de>2023-05-31 14:55:34 +0200
committerJens Axboe <axboe@kernel.dk>2023-06-05 11:10:14 -0600
commit8d03187ee7328af8e18ef1782289e0b034e75485 (patch)
treeae7d1975d46c3280ecdf665602eecd66e92d09b1
parentb2baa57475e3a24bb9ad27bb9047ea3be94627f5 (diff)
mtd: block2mtd: don't call early_lookup_bdev after the system is running
early_lookup_bdev is supposed to only be called from the early boot code, but mdtblock_early_get_bdev is called as a general fallback when lookup_bdev fails, which is problematic because early_lookup_bdev bypasses all normal path based permission checking, and might cause problems with certain container environments renaming devices. Switch to only call early_lookup_bdev when block2mtd is built-in and the system state in not running yet. Note that this strictly speaking changes the kernel ABI as the PARTUUID= and PARTLABEL= style syntax is now not available during a running systems. They never were intended for that, but this breaks things we'll have to figure out a way to make them available again. But if avoidable in any way I'd rather avoid that. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com> Link: https://lore.kernel.org/r/20230531125535.676098-24-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
-rw-r--r--drivers/mtd/devices/block2mtd.c12
1 files changed, 11 insertions, 1 deletions
diff --git a/drivers/mtd/devices/block2mtd.c b/drivers/mtd/devices/block2mtd.c
index 457774eef4d0..218eb2af564a 100644
--- a/drivers/mtd/devices/block2mtd.c
+++ b/drivers/mtd/devices/block2mtd.c
@@ -215,7 +215,11 @@ static void block2mtd_free_device(struct block2mtd_dev *dev)
kfree(dev);
}
-static struct block_device *mdtblock_early_get_bdev(const char *devname,
+/*
+ * This function is marked __ref because it calls the __init marked
+ * early_lookup_bdev when called from the early boot code.
+ */
+static struct block_device __ref *mdtblock_early_get_bdev(const char *devname,
fmode_t mode, int timeout, struct block2mtd_dev *dev)
{
struct block_device *bdev = ERR_PTR(-ENODEV);
@@ -223,6 +227,12 @@ static struct block_device *mdtblock_early_get_bdev(const char *devname,
int i;
/*
+ * We can't use early_lookup_bdev from a running system.
+ */
+ if (system_state >= SYSTEM_RUNNING)
+ return bdev;
+
+ /*
* We might not have the root device mounted at this point.
* Try to resolve the device name by other means.
*/