On 7.05.19 г. 10:36 ч., Andreas Schwab wrote:
> When a user mode process accesses an address in the vmalloc area
> do_page_fault tries to unlock the mmap semaphore when it isn't locked.
>
> Signed-off-by: Andreas Schwab <sch...@suse.de>
> ---
> arch/riscv/mm/fault.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c
> index 88401d5125bc..c51878e5a66a 100644
> --- a/arch/riscv/mm/fault.c
> +++ b/arch/riscv/mm/fault.c
> @@ -181,6 +181,7 @@ asmlinkage void do_page_fault(struct pt_regs *regs)
> up_read(&mm->mmap_sem);
> /* User mode accesses just cause a SIGSEGV */
> if (user_mode(regs)) {
> +bad_area_do_trap:
> do_trap(regs, SIGSEGV, code, addr, tsk);
> return;
> }
> @@ -230,7 +231,7 @@ asmlinkage void do_page_fault(struct pt_regs *regs)
> int index;
>
> if (user_mode(regs))
> - goto bad_area;
> + goto bad_area_do_trap;
>
> /*
> * Synchronize this task's top level page-table
>
In this case I think it will be a lot cleaner if you just duplicated the
do_trap call. On a slightly different note - is there any reason why
do_page_fault is such a spaghetti mess? At the very least the code under
no_context label could go into it's own function since it just kills the
process and never returns? Furthermore the whole vmalloc_fault just
cries for being factored out in a function, it's explicitly in it's own
block.
