mtd: spi-nor: fix memory leak when using debugfs_lookup()
Subsystems (2)
PATCH v3 1/1 mtd: spi-nor: fix memory leak when using debugfs_lookup()
When calling debugfs_lookup() the result must have dput() called on it, otherwise the memory will leak over time. To solve this, remove the lookup and create the directory on the first device found, and then remove it when the module is unloaded.
---
v3: create the directory the first time it is used, and then remove it
if it is present when the module is unloaded. More complex than v2, but correct.
v2: fix up to work when module is removed and added, making the fix
much simpler.
drivers/mtd/spi-nor/core.c | 14 +++++++++++++- drivers/mtd/spi-nor/core.h | 2 ++ drivers/mtd/spi-nor/debugfs.c | 12 +++++++++--- 3 files changed, 24 insertions(+), 4 deletions(-)
drivers/mtd/spi-nor/core.c +13 -1
@@ -3335,7 +3335,19 @@ static struct spi_mem_driver spi_nor_driver = { .remove = spi_nor_remove, .shutdown = spi_nor_shutdown, }; -module_spi_mem_driver (spi_nor_driver); + +static int __init spi_nor_module_init (void ) +{ +return spi_mem_driver_register (&spi_nor_driver); +} +module_init (spi_nor_module_init); + +static void __exit spi_nor_module_exit(void) +{ +spi_nor_debugfs_shutdown (); +spi_mem_driver_unregister (&spi_nor_driver); +} +module_exit (spi_nor_module_exit);MODULE_LICENSE ("GPL v2" );MODULE_AUTHOR ("Huang Shijie <[email protected]>" );
drivers/mtd/spi-nor/core.h +2 -0
@@ -713,8 +713,10 @@ static inline struct spi_nor *mtd_to_spi_nor(struct mtd_info *mtd)#ifdef CONFIG_DEBUG_FS void spi_nor_debugfs_register (struct spi_nor *nor); +void spi_nor_debugfs_shutdown (void );#else static inline void spi_nor_debugfs_register (struct spi_nor *nor) {} +static inline void spi_nor_debugfs_shutdown (void ) {}#endif #endif /* __LINUX_MTD_SPI_NOR_INTERNAL_H */
drivers/mtd/spi-nor/debugfs.c +9 -3
@@ -226,13 +226,13 @@ static void spi_nor_debugfs_unregister(void *data) nor->debugfs_root =NULL ; } +static struct dentry *rootdir; +void spi_nor_debugfs_register (struct spi_nor *nor) { -struct dentry *rootdir, *d; +struct dentry *d;int ret; -/* Create rootdir once. Will never be deleted again. */ - rootdir =debugfs_lookup (SPI_NOR_DEBUGFS_ROOT ,NULL );if (!rootdir) rootdir =debugfs_create_dir (SPI_NOR_DEBUGFS_ROOT ,NULL );
@@ -247,3 +247,9 @@ void spi_nor_debugfs_register(struct spi_nor *nor)debugfs_create_file ("capabilities" ,0444 , d, nor, &spi_nor_capabilities_fops); } + +void spi_nor_debugfs_shutdown (void ) +{ +if (rootdir) +debugfs_remove (rootdir); +}
Signature · 1 line
2.39.1
drivers/mtd/spi-nor/core.c static struct spi_mem_driver spi_nor_driver = { · line 3348
Quoted 4 lines
drivers/mtd/spi-nor/core.c +4
-0+static void __exit spi_nor_module_exit(void) +{ +spi_nor_debugfs_shutdown (); +spi_mem_driver_unregister (&spi_nor_driver);
Hm, does the order matter here? I didn't test it, but this will lead to:
rootdir = debugfs_create_dir("spi-nor", NULL); nor->debugfs_root = debugfs_create_dir("spi0", rootdir); debugfs_remove(rootdir); debugfs_remove(nor->debugfs_root);
If that's ok, then this looks good.
-michael
Quoted 8 lines · Michael Walle
drivers/mtd/spi-nor/core.c static struct spi_mem_driver spi_nor_driver = { · line 3348
Quoted 4 lines
drivers/mtd/spi-nor/core.c +4
-0+static void __exit spi_nor_module_exit(void) +{ +spi_nor_debugfs_shutdown (); +spi_mem_driver_unregister (&spi_nor_driver);Hm, does the order matter here? I didn't test it, but this will lead to:
Quoted 6 lines
rootdir =
debugfs_create_dir("spi-nor", NULL);nor->debugfs_root=debugfs_create_dir("spi0", rootdir);debugfs_remove(rootdir);debugfs_remove(nor->debugfs_root);If that's ok, then this looks good.
It's ok as the last call to debugfs_remove() will just fail as that dentry is long gone. Not the nicest, so I'll reverse them and send out a v4 now.
thanks,
greg k-h
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