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| author | Chuck Lever <chuck.lever@oracle.com> | 2024-04-03 16:36:25 +0200 |
|---|---|---|
| committer | Chuck Lever <chuck.lever@oracle.com> | 2024-04-04 15:43:02 +0200 |
| commit | 05258a0a69b3c5d2c003f818702c0a52b6fea861 (patch) | |
| tree | c76a5d2475d8a7f76086cb491949bc2e7619dbad /net/sunrpc/svcsock.c | |
| parent | NFSD: CREATE_SESSION must never cache NFS4ERR_DELAY replies (diff) | |
| download | linux-05258a0a69b3c5d2c003f818702c0a52b6fea861.tar.xz linux-05258a0a69b3c5d2c003f818702c0a52b6fea861.zip | |
SUNRPC: Fix a slow server-side memory leak with RPC-over-TCP
Jan Schunk reports that his small NFS servers suffer from memory
exhaustion after just a few days. A bisect shows that commit
e18e157bb5c8 ("SUNRPC: Send RPC message on TCP with a single
sock_sendmsg() call") is the first bad commit.
That commit assumed that sock_sendmsg() releases all the pages in
the underlying bio_vec array, but the reality is that it doesn't.
svc_xprt_release() releases the rqst's response pages, but the
record marker page fragment isn't one of those, so it is never
released.
This is a narrow fix that can be applied to stable kernels. A
more extensive fix is in the works.
Reported-by: Jan Schunk <scpcom@gmx.de>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218671
Fixes: e18e157bb5c8 ("SUNRPC: Send RPC message on TCP with a single sock_sendmsg() call")
Cc: Alexander Duyck <alexander.duyck@gmail.com>
Cc: Jakub Kacinski <kuba@kernel.org>
Cc: David Howells <dhowells@redhat.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Diffstat (limited to '')
| -rw-r--r-- | net/sunrpc/svcsock.c | 10 |
1 files changed, 1 insertions, 9 deletions
diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c index 545017a3daa4..6b3f01beb294 100644 --- a/net/sunrpc/svcsock.c +++ b/net/sunrpc/svcsock.c @@ -1206,15 +1206,6 @@ err_noclose: * MSG_SPLICE_PAGES is used exclusively to reduce the number of * copy operations in this path. Therefore the caller must ensure * that the pages backing @xdr are unchanging. - * - * Note that the send is non-blocking. The caller has incremented - * the reference count on each page backing the RPC message, and - * the network layer will "put" these pages when transmission is - * complete. - * - * This is safe for our RPC services because the memory backing - * the head and tail components is never kmalloc'd. These always - * come from pages in the svc_rqst::rq_pages array. */ static int svc_tcp_sendmsg(struct svc_sock *svsk, struct svc_rqst *rqstp, rpc_fraghdr marker, unsigned int *sentp) @@ -1244,6 +1235,7 @@ static int svc_tcp_sendmsg(struct svc_sock *svsk, struct svc_rqst *rqstp, iov_iter_bvec(&msg.msg_iter, ITER_SOURCE, rqstp->rq_bvec, 1 + count, sizeof(marker) + rqstp->rq_res.len); ret = sock_sendmsg(svsk->sk_sock, &msg); + page_frag_free(buf); if (ret < 0) return ret; *sentp += ret; |