From a23780ea9db3f3cadbb52ff6151384bff89d95d2 Mon Sep 17 00:00:00 2001 From: Vincent Donnefort Date: Thu, 21 May 2026 13:46:12 +0100 Subject: [PATCH] KVM: arm64: Fix rollback in hyp_trace_buffer_share_hyp() When sharing the trace buffer with the hypervisor, if sharing a page fails, the rollback path in hyp_trace_buffer_share_hyp() misses unsharing the metadata page (meta_va) which was successfully shared before entering the page sharing loop. Additionally, if a failure occurs, the cleanup calls hyp_trace_buffer_unshare_hyp() with an incorrect CPU index. Since that CPU's pages were already rolled back locally in the loop, this leads to duplicate unsharing attempts. Fix both issues affecting the rollback. Fixes: 3aed038aac8d ("KVM: arm64: Add trace remote for the nVHE/pKVM hyp") Reported-by: Sashiko Signed-off-by: Vincent Donnefort Link: https://patch.msgid.link/20260521124613.911067-3-vdonnefort@google.com Signed-off-by: Marc Zyngier --- arch/arm64/kvm/hyp_trace.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kvm/hyp_trace.c b/arch/arm64/kvm/hyp_trace.c index 06805b426101..8595f9bdb3dc 100644 --- a/arch/arm64/kvm/hyp_trace.c +++ b/arch/arm64/kvm/hyp_trace.c @@ -212,14 +212,15 @@ static int hyp_trace_buffer_share_hyp(struct hyp_trace_buffer *trace_buffer) } if (ret) { - for (p--; p >= 0; p--) + while (--p >= 0) __unshare_page(rb_desc->page_va[p]); + __unshare_page(rb_desc->meta_va); break; } } if (ret) - hyp_trace_buffer_unshare_hyp(trace_buffer, cpu--); + hyp_trace_buffer_unshare_hyp(trace_buffer, --cpu); return ret; }