This is a note to let you know that I've just added the patch titled MIPS: Ensure bss section ends on a long-aligned address to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: mips-ensure-bss-section-ends-on-a-long-aligned-address.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From foo@baz Thu Oct 5 10:49:14 CEST 2017 From: Paul Burton <paul.burton@xxxxxxxxxx> Date: Mon, 7 Nov 2016 11:52:19 +0000 Subject: MIPS: Ensure bss section ends on a long-aligned address 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 @@ -159,7 +159,7 @@ 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 = . ; Patches currently in stable-queue which might be from paul.burton@xxxxxxxxxx are queue-4.4/mips-irq-stack-unwind-irq-stack-onto-task-stack.patch queue-4.4/mips-ensure-bss-section-ends-on-a-long-aligned-address.patch