Re: [linux-next:master] [mm] bbcbf2a3f0: kernel_BUG_at_mm/memory.c

[Matthew Wilcox]

On Thu, Dec 21, 2023 at 08:26:37AM +0530, Aithal, Srikanth wrote:
> Starting from next-20231214 until next-20231220 have noted regression where
> kernel hangs randomly while running virtualization tests [multiple
> start-shutdown and reboot] against AMD sev guest type, with below call
> trace:

This is an entirely different problem, already reported and fix sent
about 24 hours ago.

diff --git a/mm/swap_state.c b/mm/swap_state.c
index 793b5b9e4f96..8a3a8f1ab20a 100644
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -894,6 +894,9 @@ struct page *swapin_readahead(swp_entry_t entry, gfp_t gfp_mask,
 		swap_vma_readahead(entry, gfp_mask, mpol, ilx, vmf) :
 		swap_cluster_readahead(entry, gfp_mask, mpol, ilx);
 	mpol_cond_put(mpol);
+
+	if (!folio)
+		return NULL;
 	return folio_file_page(folio, swp_offset(entry));
 }