Hi Greg,
On Sat, Aug 26, 2023 at 07:43:42PM +0200, gregkh@xxxxxxxxxxxxxxxxxxx wrote:
>
> The patch below does not apply to the 5.15-stable tree.
> If someone wants it applied there, or to any other stable or longterm
> tree, then please email the backport, including the original git commit
> id to <stable@xxxxxxxxxxxxxxx>.
This version applies to 5.15-stable:
>From 582bd7a69533d8b3b5ad3e1df93cb382d25407d8 Mon Sep 17 00:00:00 2001
From: Rik van Riel <riel@xxxxxxxxxxx>
Date: Thu, 17 Aug 2023 13:57:59 -0400
Subject: [PATCH] mm,ima,kexec,of: use memblock_free_late from
ima_free_kexec_buffer
The code calling ima_free_kexec_buffer runs long after the memblock
allocator has already been torn down, potentially resulting in a use
after free in memblock_isolate_range.
With KASAN or KFENCE, this use after free will result in a BUG
from the idle task, and a subsequent kernel panic.
Switch ima_free_kexec_buffer over to memblock_free_late to avoid
that issue.
Fixes: fee3ff99bc67 ("powerpc: Move arch independent ima kexec functions to drivers/of/kexec.c")
Cc: stable@xxxxxxxxxx
Signed-off-by: Rik van Riel <riel@xxxxxxxxxxx>
Suggested-by: Mike Rappoport <rppt@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20230817135759.0888e5ef@xxxxxxxxxxxxxxxxxxxx
Signed-off-by: Rob Herring <robh@xxxxxxxxxx>
(cherry picked from commit f0362a253606e2031f8d61c74195d4d6556e12a4)
Signed-off-by: Mike Rappoport (IBM) <rppt@xxxxxxxxxx>
---
drivers/of/kexec.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/of/kexec.c b/drivers/of/kexec.c
index 52bb68fb2216..3a07cc58e7d7 100644
--- a/drivers/of/kexec.c
+++ b/drivers/of/kexec.c
@@ -187,8 +187,8 @@ int ima_free_kexec_buffer(void)
if (ret)
return ret;
- return memblock_free(addr, size);
-
+ memblock_free_late(addr, size);
+ return 0;
}
/**
--
2.39.2
