5.15-stable review patch. If anyone has any objections, please let me know.
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From: Rik van Riel riel@surriel.com
commit f0362a253606e2031f8d61c74195d4d6556e12a4 upstream.
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 Signed-off-by: Mike Rappoport (IBM) rppt@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/of/kexec.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- 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; }
/**