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authorJeff Moyer <jmoyer@redhat.com>2017-12-14 00:33:09 +0300
committerDan Williams <dan.j.williams@intel.com>2018-01-20 04:01:29 +0300
commitd08cd5e0eb632eef7819ba911c09d89a767f2d0c (patch)
treec68a2d91c3265b0b3752618db864180c4f0bcc17 /drivers/nvdimm/btt.c
parented07c4338dd5ceadb5ffed0a5be03488ac54f5d2 (diff)
downloadlinux-d08cd5e0eb632eef7819ba911c09d89a767f2d0c.tar.xz
libnvdimm, btt: fix uninitialized err_lock
When a sector mode namespace is initially created, the arena's err_lock is not initialized. If, on the other hand, the namespace already exists, the mutex is initialized. To fix the issue, I moved the mutex initialization into the arena_alloc, which is called by both discover_arenas and create_arenas. This was discovered on an older kernel where mutex_trylock checks the count to determine whether the lock is held. Because the data structure is kzalloc-d, that count was 0 (held), and I/O to the device would hang forever waiting for the lock to be released (see btt_write_pg, for example). Current kernels have a different mutex implementation that checks for a non-null owner, and so this doesn't show up as a problem. If that lock were ever contended, it might cause issues, but you'd have to be really unlucky, I think. Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'drivers/nvdimm/btt.c')
-rw-r--r--drivers/nvdimm/btt.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/nvdimm/btt.c b/drivers/nvdimm/btt.c
index e949e3302af4..5860f99113c6 100644
--- a/drivers/nvdimm/btt.c
+++ b/drivers/nvdimm/btt.c
@@ -630,6 +630,7 @@ static struct arena_info *alloc_arena(struct btt *btt, size_t size,
return NULL;
arena->nd_btt = btt->nd_btt;
arena->sector_size = btt->sector_size;
+ mutex_init(&arena->err_lock);
if (!size)
return arena;
@@ -758,7 +759,6 @@ static int discover_arenas(struct btt *btt)
arena->external_lba_start = cur_nlba;
parse_arena_meta(arena, super, cur_off);
- mutex_init(&arena->err_lock);
ret = btt_freelist_init(arena);
if (ret)
goto out;