Hello Baoquan and Eric,
On 12/12/24 08:25, Baoquan he wrote:
On 12/10/24 at 02:43pm, 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.
Fixes: a0458284f062 ("powerpc: Add support code for kexec_file_load()")
Cc: Baoquan he <b...@redhat.com>
Cc: Hari Bathini <hbath...@linux.ibm.com>
CC: Madhavan Srinivasan <ma...@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
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;
Great catch.
Acked-by: Baoquan He <b...@redhat.com>
Thank you for the Ack! The upcoming two patch series, which aim to
enable generic crashkernel reservation, depends on this fix. One of them
is already posted for upstream review:
https://lore.kernel.org/all/20250108101458.406806-1-sourabhj...@linux.ibm.com/
I was wondering if you could guide us on how to get this fix pushed to
the mainline tree.
Thanks,
Sourabh Jain
