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Commit 07a46ed2 authored by Dave Hansen's avatar Dave Hansen Committed by Linus Torvalds
Browse files

shmdt: use i_size_read() instead of ->i_size 

Andrew Morton noted

	http://lkml.kernel.org/r/20141104142027.a7a0d010772d84560b445f59@linux-foundation.org



that the shmdt uses inode->i_size outside of i_mutex being held.
There is one more case in shm.c in shm_destroy().  This converts
both users over to use i_size_read().

Signed-off-by: default avatarDave Hansen <dave.hansen@linux.intel.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent d3c97900

ipc/shm.c

+3 −2
Original line number Diff line number Diff line
@@ -219,7 +219,8 @@ static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp) 
	if (!is_file_hugepages(shm_file))

		shmem_lock(shm_file, 0, shp->mlock_user);

	else if (shp->mlock_user)

		user_shm_unlock(file_inode(shm_file)->i_size, shp->mlock_user);

		user_shm_unlock(i_size_read(file_inode(shm_file)),

				shp->mlock_user);

	fput(shm_file);

	ipc_rcu_putref(shp, shm_rcu_free);

}
@@ -1280,7 +1281,7 @@ SYSCALL_DEFINE1(shmdt, char __user *, shmaddr) 
			 * in the range we are unmapping.

			 */

			file = vma->vm_file;

			size = file_inode(file)->i_size;

			size = i_size_read(file_inode(vma->vm_file));

			do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);

			/*

			 * We discovered the size of the shm segment, so