From: Adrian Huang <ahuang12@xxxxxxxxxx>
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:
<TASK>
? _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 <hch@xxxxxx>
Signed-off-by: Adrian Huang <ahuang12@xxxxxxxxxx>
---
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));
--
2.25.1
