From 4134be5d463b7ba9503652ed622dc1e97fef2c32 Mon Sep 17 00:00:00 2001 From: Tomas Henzl Date: Thu, 7 Feb 2013 12:27:58 +1100 Subject: [PATCH] block: fix ext_devt_idr handling While adding and removing a lot of disks disks and partitions this sometimes shows up: WARNING: at fs/sysfs/dir.c:512 sysfs_add_one+0xc9/0x130() (Not tainted) Hardware name: sysfs: cannot create duplicate filename '/dev/block/259:751' Modules linked in: raid1 autofs4 bnx2fc cnic uio fcoe libfcoe libfc 8021q scsi_transport_fc scsi_tgt garp stp llc sunrpc cpufreq_ondemand powernow_k8 freq_table mperf ipv6 dm_mirror dm_region_hash dm_log power_meter microcode dcdbas serio_raw amd64_edac_mod edac_core edac_mce_amd i2c_piix4 i2c_core k10temp bnx2 sg ixgbe dca mdio ext4 mbcache jbd2 dm_round_robin sr_mod cdrom sd_mod crc_t10dif ata_generic pata_acpi pata_atiixp ahci mptsas mptscsih mptbase scsi_transport_sas dm_multipath dm_mod [last unloaded: scsi_wait_scan] Pid: 44103, comm: async/16 Not tainted 2.6.32-195.el6.x86_64 #1 Call Trace: [] ? warn_slowpath_common+0x87/0xc0 [] ? warn_slowpath_fmt+0x46/0x50 [] ? sysfs_add_one+0xc9/0x130 [] ? sysfs_do_create_link+0x12b/0x170 [] ? sysfs_create_link+0x13/0x20 [] ? device_add+0x317/0x650 [] ? idr_get_new+0x13/0x50 [] ? add_partition+0x21c/0x390 [] ? rescan_partitions+0x32b/0x470 [] ? sd_open+0x81/0x1f0 [sd_mod] [] ? __blkdev_get+0x1b6/0x3c0 [] ? blkdev_get+0x10/0x20 [] ? register_disk+0x155/0x170 [] ? add_disk+0xa6/0x160 [] ? sd_probe_async+0x13b/0x210 [sd_mod] [] ? add_wait_queue+0x46/0x60 [] ? async_thread+0x102/0x250 [] ? default_wake_function+0x0/0x20 [] ? async_thread+0x0/0x250 [] ? kthread+0x96/0xa0 [] ? child_rip+0xa/0x20 [] ? kthread+0x0/0xa0 [] ? child_rip+0x0/0x20 This most likely happens because dev_t is freed while the number is still used and idr_get_new() is not protected on every use. The fix adds a mutex where it wasn't before and moves the dev_t free function so it is called after device del. Signed-off-by: Tomas Henzl Cc: Jens Axboe Cc: Signed-off-by: Andrew Morton --- block/genhd.c | 6 +++++- block/partition-generic.c | 2 +- 2 files changed, 6 insertions(+), 2 deletions(-) diff --git a/block/genhd.c b/block/genhd.c index 2eb64a34b949..8cc500944d20 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -423,14 +423,18 @@ int blk_alloc_devt(struct hd_struct *part, dev_t *devt) do { if (!idr_pre_get(&ext_devt_idr, GFP_KERNEL)) return -ENOMEM; + mutex_lock(&ext_devt_mutex); rc = idr_get_new(&ext_devt_idr, part, &idx); + mutex_unlock(&ext_devt_mutex); } while (rc == -EAGAIN); if (rc) return rc; if (idx > MAX_EXT_DEVT) { + mutex_lock(&ext_devt_mutex); idr_remove(&ext_devt_idr, idx); + mutex_unlock(&ext_devt_mutex); return -EBUSY; } @@ -655,7 +659,6 @@ void del_gendisk(struct gendisk *disk) disk_part_iter_exit(&piter); invalidate_partition(disk, 0); - blk_free_devt(disk_to_dev(disk)->devt); set_capacity(disk, 0); disk->flags &= ~GENHD_FL_UP; @@ -674,6 +677,7 @@ void del_gendisk(struct gendisk *disk) sysfs_remove_link(block_depr, dev_name(disk_to_dev(disk))); pm_runtime_set_memalloc_noio(disk_to_dev(disk), false); device_del(disk_to_dev(disk)); + blk_free_devt(disk_to_dev(disk)->devt); } EXPORT_SYMBOL(del_gendisk); diff --git a/block/partition-generic.c b/block/partition-generic.c index f1d14519cc04..1cb4deca1324 100644 --- a/block/partition-generic.c +++ b/block/partition-generic.c @@ -249,11 +249,11 @@ void delete_partition(struct gendisk *disk, int partno) if (!part) return; - blk_free_devt(part_devt(part)); rcu_assign_pointer(ptbl->part[partno], NULL); rcu_assign_pointer(ptbl->last_lookup, NULL); kobject_put(part->holder_dir); device_del(part_to_dev(part)); + blk_free_devt(part_devt(part)); hd_struct_put(part); } -- 2.39.5