diff options
author | Alan Cox <alan@redhat.com> | 2008-10-29 17:01:20 -0400 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-10-30 14:38:47 -0400 |
commit | 731572d39fcd3498702eda4600db4c43d51e0b26 (patch) | |
tree | f892907ae20539845f353d72d2a2bf202b67e007 /mm/shmem.c | |
parent | 6c89161b10f5771ee0b51ada0fce0e8835e72ade (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.c | 8 |
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 | */ |
162 | static inline int shmem_acct_size(unsigned long flags, loff_t size) | 162 | static 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 | ||
168 | static inline void shmem_unacct_size(unsigned long flags, loff_t size) | 168 | 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) | |||
179 | */ | 179 | */ |
180 | static inline int shmem_acct_block(unsigned long flags) | 180 | static 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 | ||
186 | static inline void shmem_unacct_blocks(unsigned long flags, long pages) | 186 | static inline void shmem_unacct_blocks(unsigned long flags, long pages) |