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From: Zongmin Zhou <min_halo@163.com>
To: anup@brainfault.org, atish.patra@linux.dev, pjw@kernel.org,
	palmer@dabbelt.com, aou@eecs.berkeley.edu, alex@ghiti.fr
Cc: kvm@vger.kernel.org, kvm-riscv@lists.infradead.org,
	linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
	Zongmin Zhou <zhouzongmin@kylinos.cn>
Subject: [PATCH] KVM: riscv: Fix infinite loop in NACL hfence entry allocation
Date: Thu, 16 Jul 2026 15:37:56 +0800	[thread overview]
Message-ID: <20260716073756.44153-1-min_halo@163.com> (raw)

From: Zongmin Zhou <zhouzongmin@kylinos.cn>

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 <zhouzongmin@kylinos.cn>
---
 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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             reply	other threads:[~2026-07-16  7:39 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-07-16  7:37 Zongmin Zhou [this message]
2026-07-16  7:55 ` [PATCH] KVM: riscv: Fix infinite loop in NACL hfence entry allocation sashiko-bot

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