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| author | Cong Wang <xiyou.wangcong@gmail.com> | 2016-06-08 16:20:16 (GMT) |
|---|---|---|
| committer | Shaohua Li <shli@fb.com> | 2016-06-09 16:37:23 (GMT) |
| commit | 5b1f5bc3323ece3726206a46ce64a92ace2c8df8 (patch) | |
| tree | 1c6561610b3ae91e9d76c92ebd27e5610f7739fe | |
| parent | db76767213be6c6db1b1344621511e27e9984fbb (diff) | |
| download | linux-5b1f5bc3323ece3726206a46ce64a92ace2c8df8.tar.xz | |
md: use a mutex to protect a global list
We saw a list corruption in the list all_detected_devices:
WARNING: CPU: 16 PID: 226 at lib/list_debug.c:29 __list_add+0x3c/0xa9()
list_add corruption. next->prev should be prev (ffff880859d58320), but was ffff880859ce74c0. (next=ffffffff81abfdb0).
Modules linked in: ahci libahci libata sd_mod scsi_mod
CPU: 16 PID: 226 Comm: kworker/u241:4 Not tainted 4.1.20 #1
Hardware name: Dell Inc. PowerEdge C6220/04GD66, BIOS 2.2.3 11/07/2013
Workqueue: events_unbound async_run_entry_fn
0000000000000000 ffff880859a5baf8 ffffffff81502872 ffff880859a5bb48
0000000000000009 ffff880859a5bb38 ffffffff810692a5 ffff880859ee8828
ffffffff812ad02c ffff880859d58320 ffffffff81abfdb0 ffff880859eb90c0
Call Trace:
[<ffffffff81502872>] dump_stack+0x4d/0x63
[<ffffffff810692a5>] warn_slowpath_common+0xa1/0xbb
[<ffffffff812ad02c>] ? __list_add+0x3c/0xa9
[<ffffffff81069305>] warn_slowpath_fmt+0x46/0x48
[<ffffffff812ad02c>] __list_add+0x3c/0xa9
[<ffffffff81406f28>] md_autodetect_dev+0x41/0x62
[<ffffffff81285862>] rescan_partitions+0x25f/0x29d
[<ffffffff81506372>] ? mutex_lock+0x13/0x31
[<ffffffff811a090f>] __blkdev_get+0x1aa/0x3cd
[<ffffffff811a0b91>] blkdev_get+0x5f/0x294
[<ffffffff81377ceb>] ? put_device+0x17/0x19
[<ffffffff8128227c>] ? disk_put_part+0x12/0x14
[<ffffffff812836f3>] add_disk+0x29d/0x407
[<ffffffff81384345>] ? __pm_runtime_use_autosuspend+0x5c/0x64
[<ffffffffa004a724>] sd_probe_async+0x115/0x1af [sd_mod]
[<ffffffff81083177>] async_run_entry_fn+0x72/0x12c
[<ffffffff8107c44c>] process_one_work+0x198/0x2ce
[<ffffffff8107cac7>] worker_thread+0x1dd/0x2bb
[<ffffffff8107c8ea>] ? cancel_delayed_work_sync+0x15/0x15
[<ffffffff8107c8ea>] ? cancel_delayed_work_sync+0x15/0x15
[<ffffffff81080d9c>] kthread+0xae/0xb6
[<ffffffff81080000>] ? param_array_set+0x40/0xfa
[<ffffffff81080cee>] ? __kthread_parkme+0x61/0x61
[<ffffffff81508152>] ret_from_fork+0x42/0x70
[<ffffffff81080cee>] ? __kthread_parkme+0x61/0x61
I suspect it is because there is no lock protecting this
global list, autostart_arrays() is called in ioctl() path
where there is no lock.
Cc: Shaohua Li <shli@kernel.org>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Shaohua Li <shli@fb.com>
| -rw-r--r-- | drivers/md/md.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/drivers/md/md.c b/drivers/md/md.c index 459f189..43728a4 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -8797,6 +8797,7 @@ EXPORT_SYMBOL(md_reload_sb); * at boot time. */ +static DEFINE_MUTEX(detected_devices_mutex); static LIST_HEAD(all_detected_devices); struct detected_devices_node { struct list_head list; @@ -8810,7 +8811,9 @@ void md_autodetect_dev(dev_t dev) node_detected_dev = kzalloc(sizeof(*node_detected_dev), GFP_KERNEL); if (node_detected_dev) { node_detected_dev->dev = dev; + mutex_lock(&detected_devices_mutex); list_add_tail(&node_detected_dev->list, &all_detected_devices); + mutex_unlock(&detected_devices_mutex); } else { printk(KERN_CRIT "md: md_autodetect_dev: kzalloc failed" ", skipping dev(%d,%d)\n", MAJOR(dev), MINOR(dev)); @@ -8829,6 +8832,7 @@ static void autostart_arrays(int part) printk(KERN_INFO "md: Autodetecting RAID arrays.\n"); + mutex_lock(&detected_devices_mutex); while (!list_empty(&all_detected_devices) && i_scanned < INT_MAX) { i_scanned++; node_detected_dev = list_entry(all_detected_devices.next, @@ -8847,6 +8851,7 @@ static void autostart_arrays(int part) list_add(&rdev->same_set, &pending_raid_disks); i_passed++; } + mutex_unlock(&detected_devices_mutex); printk(KERN_INFO "md: Scanned %d and added %d devices.\n", i_scanned, i_passed); |