[PATCH] KVM: riscv: Fix infinite loop in NACL hfence entry allocation

Zongmin Zhou <[email protected]> Thu, 16 Jul 2026 15:37:56 +0800
Newsgroups org.infradead.lists.kvm-riscv,org.infradead.lists.linux-riscv,org.kernel.vger.kvm,org.kernel.vger.linux-kernel
Message-ID <[email protected]>
From: Zongmin Zhou <[email protected]>

try_count is initialized to 5 but never decremented in the retry path,
making the `if (try_count)` check always true. If all NACL shared memory
hfence entries remain in the pending state after sync, the function loops
forever, causing a soft lockup. Decrement try_count on each retry so the
fallback warning and return become reachable.

Fixes: d466c19cead5 ("RISC-V: KVM: Add common nested acceleration support")
Signed-off-by: Zongmin Zhou <[email protected]>
---
 arch/riscv/kvm/nacl.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/riscv/kvm/nacl.c b/arch/riscv/kvm/nacl.c
index 6f9f8963e9dd..9aff03c4f667 100644
--- a/arch/riscv/kvm/nacl.c
+++ b/arch/riscv/kvm/nacl.c
@@ -33,7 +33,7 @@ void __kvm_riscv_nacl_hfence(void *shmem,
 	}
 
 	if (ent < 0) {
-		if (try_count) {
+		if (try_count--) {
 			nacl_sync_hfence(-1UL);
 			goto again;
 		} else {
-- 
2.34.1


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