[S390] initrd vs bss section clearing. (761cdf6a) · Commits · 戴 / test

In case the initrd is located within the bss section it will be overwritten when the section is cleared. To prevent this just move the initrd right behind the bss section if it starts within the section. The current code already moves the initrd if the bootmem allocator bitmap would overwrite it. With this patch we should be safe against initrd corruptions. Cc: Peter Oberparleiter <peter.oberparleiter@de.ibm.com> Signed-off-by:

Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by:

Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/kernel/early.c

+18 −0

Original line number	Diff line number	Diff line
		@@ -380,6 +380,23 @@ static __init void detect_machine_facilities(void)
		#endif
		}

		static __init void rescue_initrd(void)
		{
		#ifdef CONFIG_BLK_DEV_INITRD
		/*
		* Move the initrd right behind the bss section in case it starts
		* within the bss section. So we don't overwrite it when the bss
		* section gets cleared.
		*/
		if (!INITRD_START \|\| !INITRD_SIZE)
		return;
		if (INITRD_START >= (unsigned long) __bss_stop)
		return;
		memmove(__bss_stop, (void *) INITRD_START, INITRD_SIZE);
		INITRD_START = (unsigned long) __bss_stop;
		#endif
		}

		/*
		* Save ipl parameters, clear bss memory, initialize storage keys
		* and create a kernel NSS at startup if the SAVESYS= parm is defined
		@@ -389,6 +406,7 @@ void __init startup_init(void)
		unsigned long long memsize;

		ipl_save_parameters();
		rescue_initrd();
		clear_bss_section();
		init_kernel_storage_key();
		lockdep_init();

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