CVE-2026-43289

In the Linux kernel, the following vulnerability has been resolved:

kexec: derive purgatory entry from symbol

kexec_load_purgatory() derives image->start by locating e_entry inside an
SHF_EXECINSTR section.  If the purgatory object contains multiple
executable sections with overlapping sh_addr, the entrypoint check can
match more than once and trigger a WARN.

Derive the entry section from the purgatory_start symbol when present and
compute image->start from its final placement.  Keep the existing e_entry
fallback for purgatories that do not expose the symbol.

WARNING: kernel/kexec_file.c:1009 at kexec_load_purgatory+0x395/0x3c0, CPU#10: kexec/1784
Call Trace:
 <TASK>
 bzImage64_load+0x133/0xa00
 __do_sys_kexec_file_load+0x2b3/0x5c0
 do_syscall_64+0x81/0x610
 entry_SYSCALL_64_after_hwframe+0x76/0x7e

[me@linux.beauty: move helper to avoid forward declaration, per Baoquan]