scan_labels() leaks memory when label scanning fails and it falls back
to just creating a default "seed" namespace for userspace to configure.
Root can force the kernel to leak memory.
Allocate the minimum resources unconditionally and release them when
unneeded to avoid the memory leak.
A kmemleak reports:
unreferenced object 0xffff88800dda1980 (size 16):
comm "kworker/u10:5", pid 69, jiffies 4294671781
hex dump (first 16 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace (crc 0):
[<00000000c5dea560>] __kmalloc+0x32c/0x470
[<000000009ed43c83>] nd_region_register_namespaces+0x6fb/0x1120 [libnvdimm]
[<000000000e07a65c>] nd_region_probe+0xfe/0x210 [libnvdimm]
[<000000007b79ce5f>] nvdimm_bus_probe+0x7a/0x1e0 [libnvdimm]
[<00000000a5f3da2e>] really_probe+0xc6/0x390
[<00000000129e2a69>] __driver_probe_device+0x78/0x150
[<000000002dfed28b>] driver_probe_device+0x1e/0x90
[<00000000e7048de2>] __device_attach_driver+0x85/0x110
[<0000000032dca295>] bus_for_each_drv+0x85/0xe0
[<00000000391c5a7d>] __device_attach+0xbe/0x1e0
[<0000000026dabec0>] bus_probe_device+0x94/0xb0
[<00000000c590d936>] device_add+0x656/0x870
[<000000003d69bfaa>] nd_async_device_register+0xe/0x50 [libnvdimm]
[<000000003f4c52a4>] async_run_entry_fn+0x2e/0x110
[<00000000e201f4b0>] process_one_work+0x1ee/0x600
[<000000006d90d5a9>] worker_thread+0x183/0x350
Cc: Dave Jiang <dave.ji...@intel.com>
Cc: Ira Weiny <ira.we...@intel.com>
Fixes: 1b40e09a1232 ("libnvdimm: blk labels and namespace instantiation")
Suggested-by: Dan Williams <dan.j.willi...@intel.com>
Signed-off-by: Li Zhijian <lizhij...@fujitsu.com>
Reviewed-by: Dan Williams <dan.j.willi...@intel.com>
---
V3:
update commit log and allocate the minimum(2 *dev) unconditionally. # Dan
V2:
update description and comment
Signed-off-by: Li Zhijian <lizhij...@fujitsu.com>
---
drivers/nvdimm/namespace_devs.c | 34 ++++++++++++++++-----------------
1 file changed, 17 insertions(+), 17 deletions(-)
diff --git a/drivers/nvdimm/namespace_devs.c b/drivers/nvdimm/namespace_devs.c
index d6d558f94d6b..35d9f3cc2efa 100644
--- a/drivers/nvdimm/namespace_devs.c
+++ b/drivers/nvdimm/namespace_devs.c
@@ -1937,12 +1937,16 @@ static int cmp_dpa(const void *a, const void *b)
static struct device **scan_labels(struct nd_region *nd_region)
{
int i, count = 0;
- struct device *dev, **devs = NULL;
+ struct device *dev, **devs;
struct nd_label_ent *label_ent, *e;
struct nd_mapping *nd_mapping = &nd_region->mapping[0];
struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
resource_size_t map_end = nd_mapping->start + nd_mapping->size - 1;
+ devs = kcalloc(2, sizeof(dev), GFP_KERNEL);
+ if (!devs)
+ return NULL;
+
/* "safe" because create_namespace_pmem() might list_move() label_ent */
list_for_each_entry_safe(label_ent, e, &nd_mapping->labels, list) {
struct nd_namespace_label *nd_label = label_ent->label;
@@ -1961,12 +1965,14 @@ static struct device **scan_labels(struct nd_region
*nd_region)
goto err;
if (i < count)
continue;
- __devs = kcalloc(count + 2, sizeof(dev), GFP_KERNEL);
- if (!__devs)
- goto err;
- memcpy(__devs, devs, sizeof(dev) * count);
- kfree(devs);
- devs = __devs;
+ if (count) {
+ __devs = kcalloc(count + 2, sizeof(dev), GFP_KERNEL);
+ if (!__devs)
+ goto err;
+ memcpy(__devs, devs, sizeof(dev) * count);
+ kfree(devs);
+ devs = __devs;
+ }
dev = create_namespace_pmem(nd_region, nd_mapping, nd_label);
if (IS_ERR(dev)) {
@@ -1993,11 +1999,6 @@ static struct device **scan_labels(struct nd_region
*nd_region)
/* Publish a zero-sized namespace for userspace to configure. */
nd_mapping_free_labels(nd_mapping);
-
- devs = kcalloc(2, sizeof(dev), GFP_KERNEL);
- if (!devs)
- goto err;
-
nspm = kzalloc(sizeof(*nspm), GFP_KERNEL);
if (!nspm)
goto err;
@@ -2036,11 +2037,10 @@ static struct device **scan_labels(struct nd_region
*nd_region)
return devs;
err:
- if (devs) {
- for (i = 0; devs[i]; i++)
- namespace_pmem_release(devs[i]);
- kfree(devs);
- }
+ for (i = 0; devs[i]; i++)
+ namespace_pmem_release(devs[i]);
+ kfree(devs);
+
return NULL;
}
--
2.29.2
