diff options
| author | Dan Williams <dan.j.williams@intel.com> | 2017-02-01 23:05:23 +0100 |
|---|---|---|
| committer | Jens Axboe <axboe@fb.com> | 2017-02-02 16:23:19 +0100 |
| commit | 0dba1314d4f81115dce711292ec7981d17231064 (patch) | |
| tree | 969d76a99b715aae4bb9cb819851d0fb01daa12b /block | |
| parent | block: Get rid of blk_get_backing_dev_info() (diff) | |
| download | linux-0dba1314d4f81115dce711292ec7981d17231064.tar.xz linux-0dba1314d4f81115dce711292ec7981d17231064.zip | |
scsi, block: fix duplicate bdi name registration crashes
Warnings of the following form occur because scsi reuses a devt number
while the block layer still has it referenced as the name of the bdi
[1]:
WARNING: CPU: 1 PID: 93 at fs/sysfs/dir.c:31 sysfs_warn_dup+0x62/0x80
sysfs: cannot create duplicate filename '/devices/virtual/bdi/8:192'
[..]
Call Trace:
dump_stack+0x86/0xc3
__warn+0xcb/0xf0
warn_slowpath_fmt+0x5f/0x80
? kernfs_path_from_node+0x4f/0x60
sysfs_warn_dup+0x62/0x80
sysfs_create_dir_ns+0x77/0x90
kobject_add_internal+0xb2/0x350
kobject_add+0x75/0xd0
device_add+0x15a/0x650
device_create_groups_vargs+0xe0/0xf0
device_create_vargs+0x1c/0x20
bdi_register+0x90/0x240
? lockdep_init_map+0x57/0x200
bdi_register_owner+0x36/0x60
device_add_disk+0x1bb/0x4e0
? __pm_runtime_use_autosuspend+0x5c/0x70
sd_probe_async+0x10d/0x1c0
async_run_entry_fn+0x39/0x170
This is a brute-force fix to pass the devt release information from
sd_probe() to the locations where we register the bdi,
device_add_disk(), and unregister the bdi, blk_cleanup_queue().
Thanks to Omar for the quick reproducer script [2]. This patch survives
where an unmodified kernel fails in a few seconds.
[1]: https://marc.info/?l=linux-scsi&m=147116857810716&w=4
[2]: http://marc.info/?l=linux-block&m=148554717109098&w=2
Cc: James Bottomley <James.Bottomley@hansenpartnership.com>
Cc: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Jan Kara <jack@suse.cz>
Reported-by: Omar Sandoval <osandov@osandov.com>
Tested-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'block')
| -rw-r--r-- | block/blk-core.c | 1 | ||||
| -rw-r--r-- | block/genhd.c | 21 |
2 files changed, 22 insertions, 0 deletions
diff --git a/block/blk-core.c b/block/blk-core.c index a3c29270807e..a5726e01f839 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -572,6 +572,7 @@ void blk_cleanup_queue(struct request_queue *q) spin_unlock_irq(lock); bdi_unregister(q->backing_dev_info); + put_disk_devt(q->disk_devt); /* @q is and will stay empty, shutdown and put */ blk_put_queue(q); diff --git a/block/genhd.c b/block/genhd.c index d9ccd42f3675..3631cd480295 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -572,6 +572,20 @@ exit: disk_part_iter_exit(&piter); } +void put_disk_devt(struct disk_devt *disk_devt) +{ + if (disk_devt && atomic_dec_and_test(&disk_devt->count)) + disk_devt->release(disk_devt); +} +EXPORT_SYMBOL(put_disk_devt); + +void get_disk_devt(struct disk_devt *disk_devt) +{ + if (disk_devt) + atomic_inc(&disk_devt->count); +} +EXPORT_SYMBOL(get_disk_devt); + /** * device_add_disk - add partitioning information to kernel list * @parent: parent device for the disk @@ -612,6 +626,13 @@ void device_add_disk(struct device *parent, struct gendisk *disk) disk_alloc_events(disk); + /* + * Take a reference on the devt and assign it to queue since it + * must not be reallocated while the bdi is registered + */ + disk->queue->disk_devt = disk->disk_devt; + get_disk_devt(disk->disk_devt); + /* Register BDI before referencing it from bdev */ bdi = disk->queue->backing_dev_info; bdi_register_owner(bdi, disk_to_dev(disk)); |