From 231345d9109bcc6601d570e9e04585493b125b67 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= Date: Fri, 29 Nov 2024 09:29:23 +0000 Subject: [PATCH] hw/virtio: fix crash in processing balloon stats MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit balloon_stats_get_all will iterate over guest stats upto the max VIRTIO_BALLOON_S_NR value, calling visit_type_uint64 to populate the QObject dict. The dict keys are obtained from the static array balloon_stat_names which is VIRTIO_BALLOON_S_NR in size. Unfortunately the way that array is declared results in any unassigned stats getting a NULL name, which will then cause visit_type_uint64 to trigger an assert in qobject_output_add_obj. The balloon_stat_names array was fortunately fully populated with names until recently: commit 0d2eeef77a33315187df8519491a900bde4a3d83 Author: Bibo Mao Date: Mon Oct 28 10:38:09 2024 +0800 linux-headers: Update to Linux v6.12-rc5 pulled a change to include/standard-headers/linux/virtio_balloon.h which increased VIRTIO_BALLOON_S_NR by 6, and failed to add the new names to balloon_stat_names. This commit fills in the missing names, and uses a static assert to guarantee that any future changes to VIRTIO_BALLOON_S_NR will cause a build failure until balloon_stat_names is updated. This problem was detected by the Cockpit Project's automated integration tests on QEMU 9.2.0-rc1. Fixes: 0d2eeef77a33315187df8519491a900bde4a3d83 Reported-by: Martin Pitt Signed-off-by: Daniel P. Berrangé --- hw/virtio/virtio-balloon.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c index 609e39a821..afd2ad6dd6 100644 --- a/hw/virtio/virtio-balloon.c +++ b/hw/virtio/virtio-balloon.c @@ -167,19 +167,33 @@ static void balloon_deflate_page(VirtIOBalloon *balloon, } } +/* + * All stats upto VIRTIO_BALLOON_S_NR /must/ have a + * non-NULL name declared here, since these are used + * as keys for populating the QDict with stats + */ static const char *balloon_stat_names[] = { [VIRTIO_BALLOON_S_SWAP_IN] = "stat-swap-in", [VIRTIO_BALLOON_S_SWAP_OUT] = "stat-swap-out", [VIRTIO_BALLOON_S_MAJFLT] = "stat-major-faults", [VIRTIO_BALLOON_S_MINFLT] = "stat-minor-faults", [VIRTIO_BALLOON_S_MEMFREE] = "stat-free-memory", + [VIRTIO_BALLOON_S_MEMTOT] = "stat-total-memory", [VIRTIO_BALLOON_S_AVAIL] = "stat-available-memory", [VIRTIO_BALLOON_S_CACHES] = "stat-disk-caches", [VIRTIO_BALLOON_S_HTLB_PGALLOC] = "stat-htlb-pgalloc", [VIRTIO_BALLOON_S_HTLB_PGFAIL] = "stat-htlb-pgfail", - [VIRTIO_BALLOON_S_NR] = NULL + + [VIRTIO_BALLOON_S_OOM_KILL] = "stat-oom-kills", + [VIRTIO_BALLOON_S_ALLOC_STALL] = "stat-alloc-stalls", + [VIRTIO_BALLOON_S_ASYNC_SCAN] = "stat-async-scans", + [VIRTIO_BALLOON_S_DIRECT_SCAN] = "stat-direct-scans", + [VIRTIO_BALLOON_S_ASYNC_RECLAIM] = "stat-async-reclaims", + + [VIRTIO_BALLOON_S_DIRECT_RECLAIM] = "stat-direct-reclaims", }; +G_STATIC_ASSERT(G_N_ELEMENTS(balloon_stat_names) == VIRTIO_BALLOON_S_NR); /* * reset_stats - Mark all items in the stats array as unset -- 2.46.0