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| author | Qu Wenruo <wqu@suse.com> | 2018-06-20 15:38:58 +0800 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2018-08-06 13:12:38 +0200 |
| commit | 9912bbf6440ba0555e91d3306520da01872c7c1d (patch) | |
| tree | 861abacfd17adf6fba9e9483bcdee438e45da725 /fs/btrfs/check-integrity.c | |
| parent | 43a7e99db6788110fb2bd97bdad5aa5c0c004aff (diff) | |
| download | lwn-9912bbf6440ba0555e91d3306520da01872c7c1d.tar.gz lwn-9912bbf6440ba0555e91d3306520da01872c7c1d.zip | |
btrfs: check-integrity: Fix NULL pointer dereference for degraded mount
Commit f8f84b2dfda5 ("btrfs: index check-integrity state hash by a dev_t")
changed how btrfsic indexes device state.
Now we need to access device->bdev->bd_dev, while for degraded mount
it's completely possible to have device->bdev as NULL, thus it will
trigger a NULL pointer dereference at mount time.
Fix it by checking if the device is degraded before accessing
device->bdev->bd_dev.
There are a lot of other places accessing device->bdev->bd_dev, however
the other call sites have either checked device->bdev, or the
device->bdev is passed from btrfsic_map_block(), so it won't cause harm.
Fixes: f8f84b2dfda5 ("btrfs: index check-integrity state hash by a dev_t")
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs/check-integrity.c')
| -rw-r--r-- | fs/btrfs/check-integrity.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/fs/btrfs/check-integrity.c b/fs/btrfs/check-integrity.c index a3fdb4fe967d..daf45472bef9 100644 --- a/fs/btrfs/check-integrity.c +++ b/fs/btrfs/check-integrity.c @@ -1539,7 +1539,12 @@ static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len, } device = multi->stripes[0].dev; - block_ctx_out->dev = btrfsic_dev_state_lookup(device->bdev->bd_dev); + if (test_bit(BTRFS_DEV_STATE_MISSING, &device->dev_state) || + !device->bdev || !device->name) + block_ctx_out->dev = NULL; + else + block_ctx_out->dev = btrfsic_dev_state_lookup( + device->bdev->bd_dev); block_ctx_out->dev_bytenr = multi->stripes[0].physical; block_ctx_out->start = bytenr; block_ctx_out->len = len; |