diff options
| author | Alan Cox <alan@redhat.com> | 2008-10-29 14:01:20 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2010-05-26 14:27:09 -0700 |
| commit | 3f955fe683ffdda7fd68e0b61779001cb9b50011 (patch) | |
| tree | b226e5056dcd6defc352ffc5ec29b3dd7c091c49 /mm | |
| parent | 0ce0dd4ec9890eefb7b656c74bc5256c60626a85 (diff) | |
nfsd: fix vm overcommit crash
commit 731572d39fcd3498702eda4600db4c43d51e0b26 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/mmap.c | 3 | ||||
| -rw-r--r-- | mm/nommu.c | 3 | ||||
| -rw-r--r-- | mm/shmem.c | 8 |
3 files changed, 8 insertions, 6 deletions
diff --git a/mm/mmap.c b/mm/mmap.c index 8b5aa8ecdfa0..f3e5bfecf7b5 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -178,7 +178,8 @@ int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin) /* Don't let a single process grow too big: leave 3% of the size of this process for other processes */ - allowed -= mm->total_vm / 32; + if (mm) + allowed -= mm->total_vm / 32; /* * cast `allowed' as a signed long because vm_committed_space diff --git a/mm/nommu.c b/mm/nommu.c index 4bf76868150c..7122331aaed5 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -1432,7 +1432,8 @@ int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin) /* Don't let a single process grow too big: leave 3% of the size of this process for other processes */ - allowed -= current->mm->total_vm / 32; + if (mm) + allowed -= mm->total_vm / 32; /* * cast `allowed' as a signed long because vm_committed_space diff --git a/mm/shmem.c b/mm/shmem.c index 04fb4f1ab88e..c088da12059f 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -163,8 +163,8 @@ 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) @@ -181,8 +181,8 @@ 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) |