62 lines
2.7 KiB
Diff
62 lines
2.7 KiB
Diff
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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Chuck Lever <chuck.lever@oracle.com>
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Date: Wed, 3 Apr 2024 10:36:25 -0400
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Subject: [PATCH] SUNRPC: Fix a slow server-side memory leak with RPC-over-TCP
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Jan Schunk reports that his small NFS servers suffer from memory
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exhaustion after just a few days. A bisect shows that commit
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e18e157bb5c8 ("SUNRPC: Send RPC message on TCP with a single
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sock_sendmsg() call") is the first bad commit.
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That commit assumed that sock_sendmsg() releases all the pages in
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the underlying bio_vec array, but the reality is that it doesn't.
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svc_xprt_release() releases the rqst's response pages, but the
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record marker page fragment isn't one of those, so it is never
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released.
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This is a narrow fix that can be applied to stable kernels. A
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more extensive fix is in the works.
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Reported-by: Jan Schunk <scpcom@gmx.de>
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Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218671
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Fixes: e18e157bb5c8 ("SUNRPC: Send RPC message on TCP with a single sock_sendmsg() call")
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Cc: Alexander Duyck <alexander.duyck@gmail.com>
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Cc: Jakub Kacinski <kuba@kernel.org>
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Cc: David Howells <dhowells@redhat.com>
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Reviewed-by: David Howells <dhowells@redhat.com>
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Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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(cherry picked from commit 05258a0a69b3c5d2c003f818702c0a52b6fea861)
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Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
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---
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net/sunrpc/svcsock.c | 10 +---------
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1 file changed, 1 insertion(+), 9 deletions(-)
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diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
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index 545017a3daa4..6b3f01beb294 100644
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--- a/net/sunrpc/svcsock.c
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+++ b/net/sunrpc/svcsock.c
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@@ -1206,15 +1206,6 @@ static int svc_tcp_recvfrom(struct svc_rqst *rqstp)
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* MSG_SPLICE_PAGES is used exclusively to reduce the number of
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* copy operations in this path. Therefore the caller must ensure
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* that the pages backing @xdr are unchanging.
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- *
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- * Note that the send is non-blocking. The caller has incremented
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- * the reference count on each page backing the RPC message, and
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- * the network layer will "put" these pages when transmission is
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- * complete.
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- *
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- * This is safe for our RPC services because the memory backing
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- * the head and tail components is never kmalloc'd. These always
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- * come from pages in the svc_rqst::rq_pages array.
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*/
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static int svc_tcp_sendmsg(struct svc_sock *svsk, struct svc_rqst *rqstp,
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rpc_fraghdr marker, unsigned int *sentp)
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@@ -1244,6 +1235,7 @@ static int svc_tcp_sendmsg(struct svc_sock *svsk, struct svc_rqst *rqstp,
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iov_iter_bvec(&msg.msg_iter, ITER_SOURCE, rqstp->rq_bvec,
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1 + count, sizeof(marker) + rqstp->rq_res.len);
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ret = sock_sendmsg(svsk->sk_sock, &msg);
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+ page_frag_free(buf);
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if (ret < 0)
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return ret;
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*sentp += ret;
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