From: Guo Ren guoren@linux.alibaba.com

In COMPAT mode, the STACK_TOP is DEFAULT_MAP_WINDOW (0x80000000), but the TASK_SIZE is 0x7fff000. When the user stack is upon 0x7fff000, it will cause a user segment fault. Sometimes, it would cause boot failure when the whole rootfs is rv32.

Freeing unused kernel image (initmem) memory: 2236K Run /sbin/init as init process Starting init: /sbin/init exists but couldn't execute it (error -14) Run /etc/init as init process ...

Increase the TASK_SIZE to cover STACK_TOP.

Cc: stable@vger.kernel.org Fixes: add2cc6b6515 ("RISC-V: mm: Restrict address space for sv39,sv48,sv57") Reviewed-by: Leonardo Bras leobras@redhat.com Reviewed-by: Charlie Jenkins charlie@rivosinc.com Signed-off-by: Guo Ren guoren@linux.alibaba.com Signed-off-by: Guo Ren guoren@kernel.org --- arch/riscv/include/asm/pgtable.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h index ab00235b018f..74ffb2178f54 100644 --- a/arch/riscv/include/asm/pgtable.h +++ b/arch/riscv/include/asm/pgtable.h @@ -881,7 +881,7 @@ static inline pte_t pte_swp_clear_exclusive(pte_t pte) #define TASK_SIZE_MIN (PGDIR_SIZE_L3 * PTRS_PER_PGD / 2)

#ifdef CONFIG_COMPAT -#define TASK_SIZE_32 (_AC(0x80000000, UL) - PAGE_SIZE) +#define TASK_SIZE_32 (_AC(0x80000000, UL)) #define TASK_SIZE (test_thread_flag(TIF_32BIT) ? \ TASK_SIZE_32 : TASK_SIZE_64) #else