From 78c8f780d3f0d6d17aa93d6f99ff72960080fdd7 Mon Sep 17 00:00:00 2001 From: Gavin Shan Date: Mon, 16 Sep 2024 09:31:17 +1000 Subject: [PATCH] hostmem: Apply merge property after the memory region is initialized The semantic change has been introduced by commit 5becdc0ab0 ("hostmem: simplify the code for merge and dump properties") even it clarifies that no senmatic change has been introduced. After the commit, the merge property can be applied even the corresponding memory region isn't initialized yet. This leads to crash dump by the following command lines. # /home/gavin/sandbox/qemu.main/build/qemu-system-aarch64 \ -accel kvm -machine virt -cpu host \ -object memory-backend-ram,id=mem-memN0,size=4096M,merge=off : qemu-system-aarch64: ../system/memory.c:2419: memory_region_get_ram_ptr: \ Assertion `mr->ram_block' failed. Fix it by applying the merge property only when the memory region is initialized. Message-ID: <20240915233117.478169-1-gshan@redhat.com> Fixes: 5becdc0ab083 ("hostmem: simplify the code for merge and dump properties") Reported-by: Zhenyu Zhang Tested-by: Zhenyu Zhang Signed-off-by: Gavin Shan Signed-off-by: David Hildenbrand --- backends/hostmem.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/backends/hostmem.c b/backends/hostmem.c index 4e5576a4ad..181446626a 100644 --- a/backends/hostmem.c +++ b/backends/hostmem.c @@ -178,7 +178,7 @@ static void host_memory_backend_set_merge(Object *obj, bool value, Error **errp) return; } - if (!host_memory_backend_mr_inited(backend) && + if (host_memory_backend_mr_inited(backend) && value != backend->merge) { void *ptr = memory_region_get_ram_ptr(&backend->mr); uint64_t sz = memory_region_size(&backend->mr);