From 731572d39fcd3498702eda4600db4c43d51e0b26 Mon Sep 17 00:00:00 2001 From: Alan Cox Date: Wed, 29 Oct 2008 14:01:20 -0700 Subject: 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 Acked-by: James Morris Signed-off-by: Alan Cox Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/shmem.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'mm/shmem.c') 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) */ static inline int shmem_acct_size(unsigned long flags, loff_t size) { - return (flags & VM_ACCOUNT)? - security_vm_enough_memory(VM_ACCT(size)): 0; + return (flags & VM_ACCOUNT) ? + security_vm_enough_memory_kern(VM_ACCT(size)) : 0; } static 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) */ static inline int shmem_acct_block(unsigned long flags) { - return (flags & VM_ACCOUNT)? - 0: security_vm_enough_memory(VM_ACCT(PAGE_CACHE_SIZE)); + return (flags & VM_ACCOUNT) ? + 0 : security_vm_enough_memory_kern(VM_ACCT(PAGE_CACHE_SIZE)); } static inline void shmem_unacct_blocks(unsigned long flags, long pages) -- cgit v1.2.3