From a2b992c828f7651db369ba8f0eb0818d70232636 Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Thu, 9 Jul 2020 17:42:44 -0700 Subject: debugfs: make sure we can remove u32_array files cleanly debugfs_create_u32_array() allocates a small structure to wrap the data and size information about the array. If users ever try to remove the file this leads to a leak since nothing ever frees this wrapper. That said there are no upstream users of debugfs_create_u32_array() that'd remove a u32 array file (we only have one u32 array user in CMA), so there is no real bug here. Make callers pass a wrapper they allocated. This way the lifetime management of the wrapper is on the caller, and we can avoid the potential leak in debugfs. CC: Chucheng Luo Signed-off-by: Jakub Kicinski Reviewed-by: Greg Kroah-Hartman Signed-off-by: David S. Miller --- mm/cma.h | 3 +++ mm/cma_debug.c | 7 ++++--- 2 files changed, 7 insertions(+), 3 deletions(-) (limited to 'mm') diff --git a/mm/cma.h b/mm/cma.h index 33c0b517733c..6698fa63279b 100644 --- a/mm/cma.h +++ b/mm/cma.h @@ -2,6 +2,8 @@ #ifndef __MM_CMA_H__ #define __MM_CMA_H__ +#include + struct cma { unsigned long base_pfn; unsigned long count; @@ -11,6 +13,7 @@ struct cma { #ifdef CONFIG_CMA_DEBUGFS struct hlist_head mem_head; spinlock_t mem_head_lock; + struct debugfs_u32_array dfs_bitmap; #endif const char *name; }; diff --git a/mm/cma_debug.c b/mm/cma_debug.c index 4e6cbe2f586e..d5bf8aa34fdc 100644 --- a/mm/cma_debug.c +++ b/mm/cma_debug.c @@ -164,7 +164,6 @@ static void cma_debugfs_add_one(struct cma *cma, struct dentry *root_dentry) { struct dentry *tmp; char name[16]; - int u32s; scnprintf(name, sizeof(name), "cma-%s", cma->name); @@ -180,8 +179,10 @@ static void cma_debugfs_add_one(struct cma *cma, struct dentry *root_dentry) debugfs_create_file("used", 0444, tmp, cma, &cma_used_fops); debugfs_create_file("maxchunk", 0444, tmp, cma, &cma_maxchunk_fops); - u32s = DIV_ROUND_UP(cma_bitmap_maxno(cma), BITS_PER_BYTE * sizeof(u32)); - debugfs_create_u32_array("bitmap", 0444, tmp, (u32 *)cma->bitmap, u32s); + cma->dfs_bitmap.array = (u32 *)cma->bitmap; + cma->dfs_bitmap.n_elements = DIV_ROUND_UP(cma_bitmap_maxno(cma), + BITS_PER_BYTE * sizeof(u32)); + debugfs_create_u32_array("bitmap", 0444, tmp, &cma->dfs_bitmap); } static int __init cma_debugfs_init(void) -- cgit v1.2.3