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NFSv4: Fix a NULL pointer dereference in pnfs_mark_matching_lsegs_return() 

commit a421d218603ffa822a0b8045055c03eae394a7eb upstream.

Commit de144ff4234f changes _pnfs_return_layout() to call
pnfs_mark_matching_lsegs_return() passing NULL as the struct
pnfs_layout_range argument. Unfortunately,
pnfs_mark_matching_lsegs_return() doesn't check if we have a value here
before dereferencing it, causing an oops.

I'm able to hit this crash consistently when running connectathon basic
tests on NFS v4.1/v4.2 against Ontap.

Fixes: de144ff4234f ("NFSv4: Don't discard segments marked for return in _pnfs_return_layout()")
Cc: stable@vger.kernel.org
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Anna Schumaker 2021-05-19 12:54:51 -04:00 committed by Greg Kroah-Hartman
parent f2a35ade22
commit aba3c7795f
1 changed files with 7 additions and 8 deletions
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15
fs/nfs/pnfs.c
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@ -1285,6 +1285,11 @@ _pnfs_return_layout(struct inode *ino)
{
struct pnfs_layout_hdr *lo = NULL;
struct nfs_inode *nfsi = NFS_I(ino);
struct pnfs_layout_range range = {
.iomode = IOMODE_ANY,
.offset = 0,
.length = NFS4_MAX_UINT64,
};
LIST_HEAD(tmp_list);
nfs4_stateid stateid;
int status = 0;
@ -1311,16 +1316,10 @@ _pnfs_return_layout(struct inode *ino)
}
valid_layout = pnfs_layout_is_valid(lo);
pnfs_clear_layoutcommit(ino, &tmp_list);
pnfs_mark_matching_lsegs_return(lo, &tmp_list, NULL, 0);
pnfs_mark_matching_lsegs_return(lo, &tmp_list, &range, 0);
if (NFS_SERVER(ino)->pnfs_curr_ld->return_range) {
struct pnfs_layout_range range = {
.iomode = IOMODE_ANY,
.offset = 0,
.length = NFS4_MAX_UINT64,
};
if (NFS_SERVER(ino)->pnfs_curr_ld->return_range)
NFS_SERVER(ino)->pnfs_curr_ld->return_range(lo, &range);
}
/* Don't send a LAYOUTRETURN if list was initially empty */
if (!test_bit(NFS_LAYOUT_RETURN_REQUESTED, &lo->plh_flags) ||