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authorDavidlohr Bueso <davidlohr.bueso@hp.com>2013-09-11 14:26:28 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-09-11 15:59:44 -0700
commit530fcd16d87cd2417c472a581ba5a1e501556c86 (patch)
treec741f07d57e5b6fdf5920c6ba87e59b779073aaf /ipc
parent05603c44a7627793219b0bd9a7b236099dc9cd9d (diff)
downloadlinux-530fcd16d87cd2417c472a581ba5a1e501556c86.tar.gz
ipc, shm: guard against non-existant vma in shmdt(2)
When !CONFIG_MMU there's a chance we can derefence a NULL pointer when the VM area isn't found - check the return value of find_vma(). Also, remove the redundant -EINVAL return: retval is set to the proper return code and *only* changed to 0, when we actually unmap the segments. Signed-off-by: Davidlohr Bueso <davidlohr.bueso@hp.com> Cc: Sedat Dilek <sedat.dilek@gmail.com> Cc: Rik van Riel <riel@redhat.com> Cc: Manfred Spraul <manfred@colorfullife.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'ipc')
-rw-r--r--ipc/shm.c3
1 files changed, 1 insertions, 2 deletions
diff --git a/ipc/shm.c b/ipc/shm.c
index cb2cedaa880..a0ed957cefc 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -1288,8 +1288,7 @@ SYSCALL_DEFINE1(shmdt, char __user *, shmaddr)
#else /* CONFIG_MMU */
/* under NOMMU conditions, the exact address to be destroyed must be
* given */
- retval = -EINVAL;
- if (vma->vm_start == addr && vma->vm_ops == &shm_vm_ops) {
+ if (vma && vma->vm_start == addr && vma->vm_ops == &shm_vm_ops) {
do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
retval = 0;
}