Hi Greg,
On Sat, Aug 26, 2023 at 07:43:42PM +0200, gregkh@linuxfoundation.org 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@vger.kernel.org.
This version applies to 5.15-stable:
From 582bd7a69533d8b3b5ad3e1df93cb382d25407d8 Mon Sep 17 00:00:00 2001 From: Rik van Riel riel@surriel.com 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@kernel.org Signed-off-by: Rik van Riel riel@surriel.com Suggested-by: Mike Rappoport rppt@kernel.org Link: https://lore.kernel.org/r/20230817135759.0888e5ef@imladris.surriel.com Signed-off-by: Rob Herring robh@kernel.org (cherry picked from commit f0362a253606e2031f8d61c74195d4d6556e12a4) Signed-off-by: Mike Rappoport (IBM) rppt@kernel.org --- 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; }
/**