diff options
| author | Shang XiaoJing <shangxiaojing@huawei.com> | 2022-11-19 14:39:15 +0800 |
|---|---|---|
| committer | Miquel Raynal <miquel.raynal@bootlin.com> | 2022-11-24 12:32:16 +0100 |
| commit | 56570bdad5e31c5c538cd6efff5c4510256e1bb4 (patch) | |
| tree | f8615218dbdc596c71b87611235284616ceb7720 /drivers/mtd | |
| parent | 085679b15b5af65f9610f619afde41da0f966194 (diff) | |
mtd: core: Fix refcount error in del_mtd_device()
del_mtd_device() will call of_node_put() to mtd_get_of_node(mtd), which
is mtd->dev.of_node. However, memset(&mtd->dev, 0) is called before
of_node_put(). As the result, of_node_put() won't do anything in
del_mtd_device(), and causes the refcount leak.
del_mtd_device()
memset(&mtd->dev, 0, sizeof(mtd->dev) # clear mtd->dev
of_node_put()
mtd_get_of_node(mtd) # mtd->dev is cleared, can't locate of_node
# of_node_put(NULL) won't do anything
Fix the error by caching the pointer of the device_node.
OF: ERROR: memory leak, expected refcount 1 instead of 2,
of_node_get()/of_node_put() unbalanced - destroy cset entry: attach
overlay node /spi/spi-sram@0
CPU: 3 PID: 275 Comm: python3 Tainted: G N 6.1.0-rc3+ #54
0d8a1edddf51f172ff5226989a7565c6313b08e2
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014
Call Trace:
<TASK>
dump_stack_lvl+0x67/0x83
kobject_get+0x155/0x160
of_node_get+0x1f/0x30
of_fwnode_get+0x43/0x70
fwnode_handle_get+0x54/0x80
fwnode_get_nth_parent+0xc9/0xe0
fwnode_full_name_string+0x3f/0xa0
device_node_string+0x30f/0x750
pointer+0x598/0x7a0
vsnprintf+0x62d/0x9b0
...
cfs_overlay_release+0x30/0x90
config_item_release+0xbe/0x1a0
config_item_put+0x5e/0x80
configfs_rmdir+0x3bd/0x540
vfs_rmdir+0x18c/0x320
do_rmdir+0x198/0x330
__x64_sys_rmdir+0x2c/0x40
do_syscall_64+0x37/0x90
entry_SYSCALL_64_after_hwframe+0x63/0xcd
Fixes: 00596576a051 ("mtd: core: clear out unregistered devices a bit more")
Signed-off-by: Shang XiaoJing <shangxiaojing@huawei.com>
[<miquel.raynal@bootlin.com>: Light reword of the commit log]
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20221119063915.11108-1-shangxiaojing@huawei.com
Diffstat (limited to 'drivers/mtd')
| -rw-r--r-- | drivers/mtd/mtdcore.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c index 6c4683a5e531..0feacb9fbdac 100644 --- a/drivers/mtd/mtdcore.c +++ b/drivers/mtd/mtdcore.c @@ -780,6 +780,7 @@ int del_mtd_device(struct mtd_info *mtd) { int ret; struct mtd_notifier *not; + struct device_node *mtd_of_node; mutex_lock(&mtd_table_mutex); @@ -798,6 +799,7 @@ int del_mtd_device(struct mtd_info *mtd) mtd->index, mtd->name, mtd->usecount); ret = -EBUSY; } else { + mtd_of_node = mtd_get_of_node(mtd); debugfs_remove_recursive(mtd->dbg.dfs_dir); /* Try to remove the NVMEM provider */ @@ -809,7 +811,7 @@ int del_mtd_device(struct mtd_info *mtd) memset(&mtd->dev, 0, sizeof(mtd->dev)); idr_remove(&mtd_idr, mtd->index); - of_node_put(mtd_get_of_node(mtd)); + of_node_put(mtd_of_node); module_put(THIS_MODULE); ret = 0; |