diff options
author | Chuck Lever <chuck.lever@oracle.com> | 2020-11-25 03:15:18 +0300 |
---|---|---|
committer | Anna Schumaker <Anna.Schumaker@Netapp.com> | 2020-12-11 00:48:03 +0300 |
commit | 1c87b85162975627d684a234d7347ef630f0e3aa (patch) | |
tree | 25c149a3d63fa8c3f2a96024597a3f4ea0fb84ae /fs | |
parent | 63e2fffa59a9dd91e443b08832656399fd80b7f0 (diff) | |
download | linux-1c87b85162975627d684a234d7347ef630f0e3aa.tar.xz |
NFS: Fix rpcrdma_inline_fixup() crash with new LISTXATTRS operation
By switching to an XFS-backed export, I am able to reproduce the
ibcomp worker crash on my client with xfstests generic/013.
For the failing LISTXATTRS operation, xdr_inline_pages() is called
with page_len=12 and buflen=128.
- When ->send_request() is called, rpcrdma_marshal_req() does not
set up a Reply chunk because buflen is smaller than the inline
threshold. Thus rpcrdma_convert_iovs() does not get invoked at
all and the transport's XDRBUF_SPARSE_PAGES logic is not invoked
on the receive buffer.
- During reply processing, rpcrdma_inline_fixup() tries to copy
received data into rq_rcv_buf->pages because page_len is positive.
But there are no receive pages because rpcrdma_marshal_req() never
allocated them.
The result is that the ibcomp worker faults and dies. Sometimes that
causes a visible crash, and sometimes it results in a transport hang
without other symptoms.
RPC/RDMA's XDRBUF_SPARSE_PAGES support is not entirely correct, and
should eventually be fixed or replaced. However, my preference is
that upper-layer operations should explicitly allocate their receive
buffers (using GFP_KERNEL) when possible, rather than relying on
XDRBUF_SPARSE_PAGES.
Reported-by: Olga kornievskaia <kolga@netapp.com>
Suggested-by: Olga kornievskaia <kolga@netapp.com>
Fixes: c10a75145feb ("NFSv4.2: add the extended attribute proc functions.")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Olga kornievskaia <kolga@netapp.com>
Reviewed-by: Frank van der Linden <fllinden@amazon.com>
Tested-by: Olga kornievskaia <kolga@netapp.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Diffstat (limited to 'fs')
-rw-r--r-- | fs/nfs/nfs42proc.c | 21 | ||||
-rw-r--r-- | fs/nfs/nfs42xdr.c | 1 |
2 files changed, 13 insertions, 9 deletions
diff --git a/fs/nfs/nfs42proc.c b/fs/nfs/nfs42proc.c index 2b2211d1234e..4fc61e3d098d 100644 --- a/fs/nfs/nfs42proc.c +++ b/fs/nfs/nfs42proc.c @@ -1241,12 +1241,13 @@ static ssize_t _nfs42_proc_listxattrs(struct inode *inode, void *buf, .rpc_resp = &res, }; u32 xdrlen; - int ret, np; + int ret, np, i; + ret = -ENOMEM; res.scratch = alloc_page(GFP_KERNEL); if (!res.scratch) - return -ENOMEM; + goto out; xdrlen = nfs42_listxattr_xdrsize(buflen); if (xdrlen > server->lxasize) @@ -1254,9 +1255,12 @@ static ssize_t _nfs42_proc_listxattrs(struct inode *inode, void *buf, np = xdrlen / PAGE_SIZE + 1; pages = kcalloc(np, sizeof(struct page *), GFP_KERNEL); - if (pages == NULL) { - __free_page(res.scratch); - return -ENOMEM; + if (!pages) + goto out_free_scratch; + for (i = 0; i < np; i++) { + pages[i] = alloc_page(GFP_KERNEL); + if (!pages[i]) + goto out_free_pages; } arg.xattr_pages = pages; @@ -1271,14 +1275,15 @@ static ssize_t _nfs42_proc_listxattrs(struct inode *inode, void *buf, *eofp = res.eof; } +out_free_pages: while (--np >= 0) { if (pages[np]) __free_page(pages[np]); } - - __free_page(res.scratch); kfree(pages); - +out_free_scratch: + __free_page(res.scratch); +out: return ret; } diff --git a/fs/nfs/nfs42xdr.c b/fs/nfs/nfs42xdr.c index 6e060a88f98c..8432bd6b95f0 100644 --- a/fs/nfs/nfs42xdr.c +++ b/fs/nfs/nfs42xdr.c @@ -1528,7 +1528,6 @@ static void nfs4_xdr_enc_listxattrs(struct rpc_rqst *req, rpc_prepare_reply_pages(req, args->xattr_pages, 0, args->count, hdr.replen); - req->rq_rcv_buf.flags |= XDRBUF_SPARSE_PAGES; encode_nops(&hdr); } |