From: Dave Hansen Date: Sat, 13 Dec 2014 00:58:22 +0000 (-0800) Subject: shmdt: use i_size_read() instead of ->i_size X-Git-Tag: v3.12.40~78 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3301500b05e0b060ccc1eb870355530ec7da6778;p=thirdparty%2Fkernel%2Fstable.git shmdt: use i_size_read() instead of ->i_size commit 07a46ed27dc6344de831a450df82336270a157a9 upstream. 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: Dave Hansen Cc: Manfred Spraul Cc: Davidlohr Bueso Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Jiri Slaby --- diff --git a/ipc/shm.c b/ipc/shm.c index b039a85e2b8de..623bc3877118f 100644 --- a/ipc/shm.c +++ b/ipc/shm.c @@ -218,7 +218,8 @@ 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); } @@ -1278,7 +1279,7 @@ 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