CVE-2022-49675

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> tick/nohz: unexport __init-annotated tick_nohz_full_setup()<br /> <br /> EXPORT_SYMBOL and __init is a bad combination because the .init.text<br /> section is freed up after the initialization. Hence, modules cannot<br /> use symbols annotated __init. The access to a freed symbol may end up<br /> with kernel panic.<br /> <br /> modpost used to detect it, but it had been broken for a decade.<br /> <br /> Commit 28438794aba4 ("modpost: fix section mismatch check for exported<br /> init/exit sections") fixed it so modpost started to warn it again, then<br /> this showed up:<br /> <br /> MODPOST vmlinux.symvers<br /> WARNING: modpost: vmlinux.o(___ksymtab_gpl+tick_nohz_full_setup+0x0): Section mismatch in reference from the variable __ksymtab_tick_nohz_full_setup to the function .init.text:tick_nohz_full_setup()<br /> The symbol tick_nohz_full_setup is exported and annotated __init<br /> Fix this by removing the __init annotation of tick_nohz_full_setup or drop the export.<br /> <br /> Drop the export because tick_nohz_full_setup() is only called from the<br /> built-in code in kernel/sched/isolation.c.