diff --git a/sys/kern/uipc_syscalls.c b/sys/kern/uipc_syscalls.c
index 459082b18c9a..ce83a9380eaa 100644
--- a/sys/kern/uipc_syscalls.c
+++ b/sys/kern/uipc_syscalls.c
@@ -2126,18 +2126,25 @@ kern_sendfile(struct thread *td, struct sendfile_args *uap,
 			}
 
 			/*
-			 * Get a sendfile buf.  We usually wait as long
-			 * as necessary, but this wait can be interrupted.
+			 * Get a sendfile buf.  When allocating the
+			 * first buffer for mbuf chain, we usually
+			 * wait as long as necessary, but this wait
+			 * can be interrupted.  For consequent
+			 * buffers, do not sleep, since several
+			 * threads might exhaust the buffers and then
+			 * deadlock.
 			 */
-			if ((sf = sf_buf_alloc(pg,
-			    (mnw ? SFB_NOWAIT : SFB_CATCH))) == NULL) {
+			sf = sf_buf_alloc(pg, (mnw || m != NULL) ? SFB_NOWAIT :
+			    SFB_CATCH);
+			if (sf == NULL) {
 				mbstat.sf_allocfail++;
 				vm_page_lock(pg);
 				vm_page_unwire(pg, 0);
 				KASSERT(pg->object != NULL,
 				    ("kern_sendfile: object disappeared"));
 				vm_page_unlock(pg);
-				error = (mnw ? EAGAIN : EINTR);
+				if (m == NULL)
+					error = (mnw ? EAGAIN : EINTR);
 				break;
 			}