Hello Hari,

On 23/01/25 15:34, Hari Bathini wrote:


On 21/01/25 5:24 pm, Sourabh Jain wrote:
kexec_elf_load() loads an ELF executable and sets the address of the
lowest PT_LOAD section to the address held by the lowest_load_addr
function argument.

To determine the lowest PT_LOAD address, a local variable lowest_addr
(type unsigned long) is initialized to UINT_MAX. After loading each
PT_LOAD, its address is compared to lowest_addr. If a loaded PT_LOAD
address is lower, lowest_addr is updated. However, setting lowest_addr
to UINT_MAX won't work when the kernel image is loaded above 4G, as the
returned lowest PT_LOAD address would be invalid. This is resolved by
initializing lowest_addr to ULONG_MAX instead.

This issue was discovered while implementing crashkernel high/low
reservation on the PowerPC architecture.


Acked-by: Hari Bathini <hbath...@linux.ibm.com>


Thanks for the Ack!

- Sourabh Jain



Fixes: a0458284f062 ("powerpc: Add support code for kexec_file_load()")
Cc: Andrew Morton <a...@linux-foundation.org>
Cc: Hari Bathini <hbath...@linux.ibm.com>
Cc: Madhavan Srinivasan <ma...@linux.ibm.com>
Cc: Mahesh Salgaonkar <mah...@linux.ibm.com>
Cc: Michael Ellerman <m...@ellerman.id.au>
Cc: ke...@lists.infradead.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-ker...@vger.kernel.org
Acked-by: Baoquan He <b...@redhat.com>
Signed-off-by: Sourabh Jain <sourabhj...@linux.ibm.com>
---
  kernel/kexec_elf.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/kexec_elf.c b/kernel/kexec_elf.c
index d3689632e8b9..3a5c25b2adc9 100644
--- a/kernel/kexec_elf.c
+++ b/kernel/kexec_elf.c
@@ -390,7 +390,7 @@ int kexec_elf_load(struct kimage *image, struct elfhdr *ehdr,
               struct kexec_buf *kbuf,
               unsigned long *lowest_load_addr)
  {
-    unsigned long lowest_addr = UINT_MAX;
+    unsigned long lowest_addr = ULONG_MAX;
      int ret;
      size_t i;



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