From b0907cadabcae6f1248f37a32a6e777f9ff6d4aa Mon Sep 17 00:00:00 2001 From: Adrian Huang Date: Tue, 10 Jan 2023 09:45:12 +0800 Subject: md: fix incorrect declaration about claim_rdev in md_import_device Commit fb541ca4c365 ("md: remove lock_bdev / unlock_bdev") removes wrappers for blkdev_get/blkdev_put. However, the uninitialized local static variable of pointer type 'claim_rdev' in md_import_device() is NULL, which leads to the following warning call trace: WARNING: CPU: 22 PID: 1037 at block/bdev.c:577 bd_prepare_to_claim+0x131/0x150 CPU: 22 PID: 1037 Comm: mdadm Not tainted 6.2.0-rc3+ #69 .. RIP: 0010:bd_prepare_to_claim+0x131/0x150 .. Call Trace: ? _raw_spin_unlock+0x15/0x30 ? iput+0x6a/0x220 blkdev_get_by_dev.part.0+0x4b/0x300 md_import_device+0x126/0x1d0 new_dev_store+0x184/0x240 md_attr_store+0x80/0xf0 kernfs_fop_write_iter+0x128/0x1c0 vfs_write+0x2be/0x3c0 ksys_write+0x5f/0xe0 do_syscall_64+0x38/0x90 entry_SYSCALL_64_after_hwframe+0x72/0xdc It turns out the md device cannot be used: md: could not open device unknown-block(259,0). md: md127 stopped. Fix the issue by declaring the local static variable of struct type and passing the pointer of the variable to blkdev_get_by_dev(). Fixes: fb541ca4c365 ("md: remove lock_bdev / unlock_bdev") Cc: Christoph Hellwig Signed-off-by: Adrian Huang Reviewed-by: Christoph Hellwig Signed-off-by: Song Liu --- drivers/md/md.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/md/md.c b/drivers/md/md.c index 8af639296b3c..02b0240e7c71 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -3644,7 +3644,7 @@ EXPORT_SYMBOL_GPL(md_rdev_init); */ static struct md_rdev *md_import_device(dev_t newdev, int super_format, int super_minor) { - static struct md_rdev *claim_rdev; /* just for claiming the bdev */ + static struct md_rdev claim_rdev; /* just for claiming the bdev */ struct md_rdev *rdev; sector_t size; int err; @@ -3662,7 +3662,7 @@ static struct md_rdev *md_import_device(dev_t newdev, int super_format, int supe rdev->bdev = blkdev_get_by_dev(newdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL, - super_format == -2 ? claim_rdev : rdev); + super_format == -2 ? &claim_rdev : rdev); if (IS_ERR(rdev->bdev)) { pr_warn("md: could not open device unknown-block(%u,%u).\n", MAJOR(newdev), MINOR(newdev)); -- cgit v1.2.3