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ipc/shm.c add ->pagesize function to shm_vm_ops

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Commit 05ea88608d ("mm, hugetlbfs: introduce ->pagesize() to
vm_operations_struct") adds a new ->pagesize() function to
hugetlb_vm_ops, intended to cover all hugetlbfs backed files.

With System V shared memory model, if "huge page" is specified, the
"shared memory" is backed by hugetlbfs files, but the mappings initiated
via shmget/shmat have their original vm_ops overwritten with shm_vm_ops,
so we need to add a ->pagesize function to shm_vm_ops.  Otherwise,
vma_kernel_pagesize() returns PAGE_SIZE given a hugetlbfs backed vma,
result in below BUG:

  fs/hugetlbfs/inode.c
        443             if (unlikely(page_mapped(page))) {
        444                     BUG_ON(truncate_op);

resulting in

  hugetlbfs: oracle (4592): Using mlock ulimits for SHM_HUGETLB is deprecated
  ------------[ cut here ]------------
  kernel BUG at fs/hugetlbfs/inode.c:444!
  Modules linked in: nfsv3 rpcsec_gss_krb5 nfsv4 ...
  CPU: 35 PID: 5583 Comm: oracle_5583_sbt Not tainted 4.14.35-1829.el7uek.x86_64 #2
  RIP: 0010:remove_inode_hugepages+0x3db/0x3e2
  ....
  Call Trace:
    hugetlbfs_evict_inode+0x1e/0x3e
    evict+0xdb/0x1af
    iput+0x1a2/0x1f7
    dentry_unlink_inode+0xc6/0xf0
    __dentry_kill+0xd8/0x18d
    dput+0x1b5/0x1ed
    __fput+0x18b/0x216
    ____fput+0xe/0x10
    task_work_run+0x90/0xa7
    exit_to_usermode_loop+0xdd/0x116
    do_syscall_64+0x187/0x1ae
    entry_SYSCALL_64_after_hwframe+0x150/0x0

[[email protected]: relocate comment]
  Link: http://lkml.kernel.org/r/[email protected]
Link: http://lkml.kernel.org/r/[email protected]
Fixes: 05ea88608d ("mm, hugetlbfs: introduce ->pagesize() to vm_operations_struct")
Signed-off-by: Jane Chu <[email protected]>
Suggested-by: Mike Kravetz <[email protected]>
Reviewed-by: Mike Kravetz <[email protected]>
Acked-by: Davidlohr Bueso <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Cc: Dan Williams <[email protected]>
Cc: Jan Kara <[email protected]>
Cc: Jérôme Glisse <[email protected]>
Cc: Manfred Spraul <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
This commit is contained in:
Jane Chu 2018-08-02 15:36:05 -07:00 • committed by Linus Torvalds
commit eec3636ad1
2 changed files with 19 additions and 0 deletions
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12
ipc/shm.c
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@ -427,6 +427,17 @@ static int shm_split(struct vm_area_struct *vma, unsigned long addr)
return 0;
}
static unsigned long shm_pagesize(struct vm_area_struct *vma)
{
struct file *file = vma->vm_file;
struct shm_file_data *sfd = shm_file_data(file);
if (sfd->vm_ops->pagesize)
return sfd->vm_ops->pagesize(vma);
return PAGE_SIZE;
}
#ifdef CONFIG_NUMA
static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
{
@ -554,6 +565,7 @@ static const struct vm_operations_struct shm_vm_ops = {
.close = shm_close, /* callback for when the vm-area is released */
.fault = shm_fault,
.split = shm_split,
.pagesize = shm_pagesize,
#if defined(CONFIG_NUMA)
.set_policy = shm_set_policy,
.get_policy = shm_get_policy,