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| author | Dan Williams <dan.j.williams@intel.com> | 2020-09-18 12:51:15 -0700 |
|---|---|---|
| committer | Dan Williams <dan.j.williams@intel.com> | 2020-09-20 08:33:56 -0700 |
| commit | 02186d8897d49b0afd3c80b6cf23437d91024065 (patch) | |
| tree | f715793734ad13cc07e8c5159668a2164f8244fc | |
| parent | 856deb866d16e29bd65952e0289066f6078af773 (diff) | |
| download | linux-02186d8897d49b0afd3c80b6cf23437d91024065.tar.gz linux-02186d8897d49b0afd3c80b6cf23437d91024065.tar.bz2 linux-02186d8897d49b0afd3c80b6cf23437d91024065.zip | |
dm/dax: Fix table reference counts
A recent fix to the dm_dax_supported() flow uncovered a latent bug. When
dm_get_live_table() fails it is still required to drop the
srcu_read_lock(). Without this change the lvm2 test-suite triggers this
warning:
# lvm2-testsuite --only pvmove-abort-all.sh
WARNING: lock held when returning to user space!
5.9.0-rc5+ #251 Tainted: G OE
------------------------------------------------
lvm/1318 is leaving the kernel with locks still held!
1 lock held by lvm/1318:
#0: ffff9372abb5a340 (&md->io_barrier){....}-{0:0}, at: dm_get_live_table+0x5/0xb0 [dm_mod]
...and later on this hang signature:
INFO: task lvm:1344 blocked for more than 122 seconds.
Tainted: G OE 5.9.0-rc5+ #251
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:lvm state:D stack: 0 pid: 1344 ppid: 1 flags:0x00004000
Call Trace:
__schedule+0x45f/0xa80
? finish_task_switch+0x249/0x2c0
? wait_for_completion+0x86/0x110
schedule+0x5f/0xd0
schedule_timeout+0x212/0x2a0
? __schedule+0x467/0xa80
? wait_for_completion+0x86/0x110
wait_for_completion+0xb0/0x110
__synchronize_srcu+0xd1/0x160
? __bpf_trace_rcu_utilization+0x10/0x10
__dm_suspend+0x6d/0x210 [dm_mod]
dm_suspend+0xf6/0x140 [dm_mod]
Fixes: 7bf7eac8d648 ("dax: Arrange for dax_supported check to span multiple devices")
Cc: <stable@vger.kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Reported-by: Adrian Huang <ahuang12@lenovo.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Tested-by: Adrian Huang <ahuang12@lenovo.com>
Link: https://lore.kernel.org/r/160045867590.25663.7548541079217827340.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
| -rw-r--r-- | drivers/md/dm.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c index fb0255d25e4b..4a40df8af7d3 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -1136,15 +1136,16 @@ static bool dm_dax_supported(struct dax_device *dax_dev, struct block_device *bd { struct mapped_device *md = dax_get_private(dax_dev); struct dm_table *map; + bool ret = false; int srcu_idx; - bool ret; map = dm_get_live_table(md, &srcu_idx); if (!map) - return false; + goto out; ret = dm_table_supports_dax(map, device_supports_dax, &blocksize); +out: dm_put_live_table(md, srcu_idx); return ret; |