From fe316bf2d5847bc5dd975668671a7b1067603bc7 Mon Sep 17 00:00:00 2001 From: Jun'ichi Nomura Date: Fri, 2 Mar 2012 10:38:33 +0100 Subject: block: Fix NULL pointer dereference in sd_revalidate_disk Since 2.6.39 (1196f8b), when a driver returns -ENOMEDIUM for open(), __blkdev_get() calls rescan_partitions() to remove in-kernel partition structures and raise KOBJ_CHANGE uevent. However it ends up calling driver's revalidate_disk without open and could cause oops. In the case of SCSI: process A process B ---------------------------------------------- sys_open __blkdev_get sd_open returns -ENOMEDIUM scsi_remove_device rescan_partitions sd_revalidate_disk Oopses are reported here: http://marc.info/?l=linux-scsi&m=132388619710052 This patch separates the partition invalidation from rescan_partitions() and use it for -ENOMEDIUM case. Reported-by: Huajun Li Signed-off-by: Jun'ichi Nomura Acked-by: Tejun Heo Cc: stable@kernel.org Signed-off-by: Jens Axboe --- fs/block_dev.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) (limited to 'fs/block_dev.c') diff --git a/fs/block_dev.c b/fs/block_dev.c index 0e575d1304b4..5e9f198f7712 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -1183,8 +1183,12 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part) * The latter is necessary to prevent ghost * partitions on a removed medium. */ - if (bdev->bd_invalidated && (!ret || ret == -ENOMEDIUM)) - rescan_partitions(disk, bdev); + if (bdev->bd_invalidated) { + if (!ret) + rescan_partitions(disk, bdev); + else if (ret == -ENOMEDIUM) + invalidate_partitions(disk, bdev); + } if (ret) goto out_clear; } else { @@ -1214,8 +1218,12 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part) if (bdev->bd_disk->fops->open) ret = bdev->bd_disk->fops->open(bdev, mode); /* the same as first opener case, read comment there */ - if (bdev->bd_invalidated && (!ret || ret == -ENOMEDIUM)) - rescan_partitions(bdev->bd_disk, bdev); + if (bdev->bd_invalidated) { + if (!ret) + rescan_partitions(bdev->bd_disk, bdev); + else if (ret == -ENOMEDIUM) + invalidate_partitions(bdev->bd_disk, bdev); + } if (ret) goto out_unlock_bdev; } -- cgit v1.2.1