summaryrefslogtreecommitdiffstats
path: root/block/genhd.c
diff options
context:
space:
mode:
authorDan Williams <dan.j.williams@intel.com>2017-02-01 14:05:23 -0800
committerJens Axboe <axboe@fb.com>2017-02-02 08:23:19 -0700
commit0dba1314d4f81115dce711292ec7981d17231064 (patch)
tree969d76a99b715aae4bb9cb819851d0fb01daa12b /block/genhd.c
parentefa7c9f97e3ef624e9a398bf69c15f58eea9f0e8 (diff)
downloadlinux-0-day-0dba1314d4f81115dce711292ec7981d17231064.tar.gz
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/genhd.c')
-rw-r--r--block/genhd.c21
1 files changed, 21 insertions, 0 deletions
diff --git a/block/genhd.c b/block/genhd.c
index d9ccd42..3631cd4 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));