From: Wentao Liang <vulab@iscas.ac.cn>
To: anna@kernel.org
Cc: linux-kernel@vger.kernel.org, linux-nfs@vger.kernel.org,
trondmy@kernel.org, Wentao Liang <vulab@iscas.ac.cn>,
stable@vger.kernel.org
Subject: [PATCH] NFS: Fix layout header use-after-free in pnfs_update_layout()
Date: Thu, 17 Sep 2026 16:29:50 +0000 [thread overview]
Message-ID: <20260917162950.2162357-1-vulab@iscas.ac.cn> (raw)
When waiting for an in-progress layoutreturn to complete, the retry path
drops the reference on the layout header with pnfs_put_layout_hdr() and
only then passes the layout header to trace_pnfs_update_layout(). If
that was the last reference, for example because the layout was torn
down while the task slept in pnfs_prepare_to_retry_layoutget(), the
tracepoint dereferences freed memory.
Move the pnfs_put_layout_hdr() call after the tracepoint so the layout
header is still valid while it is being traced.
Fixes: 2c8d5fc37fe2 ("pNFS: Stricter ordering of layoutget and layoutreturn")
Cc: stable@vger.kernel.org
Signed-off-by: Wentao Liang <vulab@iscas.ac.cn>
---
fs/nfs/pnfs.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index 743467e9ba20..aee523134c0f 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -2229,11 +2229,11 @@ pnfs_update_layout(struct inode *ino,
dprintk("%s wait for layoutreturn\n", __func__);
lseg = ERR_PTR(pnfs_prepare_to_retry_layoutget(lo));
if (!IS_ERR(lseg)) {
- pnfs_put_layout_hdr(lo);
dprintk("%s retrying\n", __func__);
trace_pnfs_update_layout(ino, pos, count, iomode, lo,
lseg,
PNFS_UPDATE_LAYOUT_RETRY);
+ pnfs_put_layout_hdr(lo);
goto lookup_again;
}
trace_pnfs_update_layout(ino, pos, count, iomode, lo, lseg,
--
2.34.1
next reply other threads:[~2026-09-17 16:29 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-17 16:29 Wentao Liang [this message]
2026-09-17 17:49 ` Anna Schumaker
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