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authorAlan Cox <alan@redhat.com>2008-10-29 17:01:20 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2008-10-30 14:38:47 -0400
commit731572d39fcd3498702eda4600db4c43d51e0b26 (patch)
treef892907ae20539845f353d72d2a2bf202b67e007 /mm/shmem.c
parent6c89161b10f5771ee0b51ada0fce0e8835e72ade (diff)
nfsd: fix vm overcommit crash
Junjiro R. Okajima reported a problem where knfsd crashes if you are using it to export shmemfs objects and run strict overcommit. In this situation the current->mm based modifier to the overcommit goes through a NULL pointer. We could simply check for NULL and skip the modifier but we've caught other real bugs in the past from mm being NULL here - cases where we did need a valid mm set up (eg the exec bug about a year ago). To preserve the checks and get the logic we want shuffle the checking around and add a new helper to the vm_ security wrappers Also fix a current->mm reference in nommu that should use the passed mm [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: fix build] Reported-by: Junjiro R. Okajima <hooanon05@yahoo.co.jp> Acked-by: James Morris <jmorris@namei.org> Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/shmem.c')
-rw-r--r--mm/shmem.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/mm/shmem.c b/mm/shmem.c
index d38d7e61fcd..0ed075215e5 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -161,8 +161,8 @@ static inline struct shmem_sb_info *SHMEM_SB(struct super_block *sb)
161 */ 161 */
162static inline int shmem_acct_size(unsigned long flags, loff_t size) 162static inline int shmem_acct_size(unsigned long flags, loff_t size)
163{ 163{
164 return (flags & VM_ACCOUNT)? 164 return (flags & VM_ACCOUNT) ?
165 security_vm_enough_memory(VM_ACCT(size)): 0; 165 security_vm_enough_memory_kern(VM_ACCT(size)) : 0;
166} 166}
167 167
168static inline void shmem_unacct_size(unsigned long flags, loff_t size) 168static inline void shmem_unacct_size(unsigned long flags, loff_t size)
@@ -179,8 +179,8 @@ static inline void shmem_unacct_size(unsigned long flags, loff_t size)
179 */ 179 */
180static inline int shmem_acct_block(unsigned long flags) 180static inline int shmem_acct_block(unsigned long flags)
181{ 181{
182 return (flags & VM_ACCOUNT)? 182 return (flags & VM_ACCOUNT) ?
183 0: security_vm_enough_memory(VM_ACCT(PAGE_CACHE_SIZE)); 183 0 : security_vm_enough_memory_kern(VM_ACCT(PAGE_CACHE_SIZE));
184} 184}
185 185
186static inline void shmem_unacct_blocks(unsigned long flags, long pages) 186static inline void shmem_unacct_blocks(unsigned long flags, long pages)