From: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> This patch has been added to the 3.12 stable tree. If you have any objections, please let us know. =============== commit 07a46ed27dc6344de831a450df82336270a157a9 upstream. Andrew Morton noted http://lkml.kernel.org/r/20141104142027.a7a0d010772d84560b445f59@xxxxxxxxxxxxxxxxxxxx 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 <dave.hansen@xxxxxxxxxxxxxxx> Cc: Manfred Spraul <manfred@xxxxxxxxxxxxxxxx> Cc: Davidlohr Bueso <dave@xxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Jiri Slaby <jslaby@xxxxxxx> --- ipc/shm.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/ipc/shm.c b/ipc/shm.c index b039a85e2b8d..623bc3877118 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 -- 2.3.3 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html