4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Paul Burton <paul.burton@xxxxxxxxxx> [ Upstream commit 3f00f4d8f083bc61005d0a1ef592b149f5c88bbd ] When clearing the .bss section in kernel_entry we do so using LONG_S instructions, and branch whilst the current write address doesn't equal the end of the .bss section minus the size of a long integer. The .bss section always begins at a long-aligned address and we always increment the write pointer by the size of a long integer - we therefore rely upon the .bss section ending at a long-aligned address. If this is not the case then the long-aligned write address can never be equal to the non-long-aligned end address & we will continue to increment past the end of the .bss section, attempting to zero the rest of memory. Despite this requirement that .bss end at a long-aligned address we pass 0 as the end alignment requirement to the BSS_SECTION macro and thus don't guarantee any particular alignment, allowing us to hit the error condition described above. Fix this by instead passing 8 bytes as the end alignment argument to the BSS_SECTION macro, ensuring that the end of the .bss section is always at least long-aligned. Signed-off-by: Paul Burton <paul.burton@xxxxxxxxxx> Cc: linux-mips@xxxxxxxxxxxxxx Patchwork: https://patchwork.linux-mips.org/patch/14526/ Signed-off-by: Ralf Baechle <ralf@xxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/mips/kernel/vmlinux.lds.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/mips/kernel/vmlinux.lds.S +++ b/arch/mips/kernel/vmlinux.lds.S @@ -182,7 +182,7 @@ SECTIONS * Force .bss to 64K alignment so that .bss..swapper_pg_dir * gets that alignment. .sbss should be empty, so there will be * no holes after __init_end. */ - BSS_SECTION(0, 0x10000, 0) + BSS_SECTION(0, 0x10000, 8) _end = . ;
