Re: [PATCH v2 1/6] kexec: Initialize ELF lowest address to ULONG_MAX
From: Hari Bathini <hbathini@linux.ibm.com>
Date: 2025-01-23 10:04:33
Also in:
kexec, lkml
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 <hbathini@linux.ibm.com>
quoted hunk ↗ jump to hunk
Fixes: a0458284f062 ("powerpc: Add support code for kexec_file_load()") Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Hari Bathini <hbathini@linux.ibm.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Mahesh Salgaonkar <mahesh@linux.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: kexec@lists.infradead.org Cc: linuxppc-dev@lists.ozlabs.org Cc: linux-kernel@vger.kernel.org Acked-by: Baoquan He <redacted> Signed-off-by: Sourabh Jain <redacted> --- 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;