> On Jul 1, 2019, at 10:33 AM, Sebastian Andrzej Siewior
> <[email protected]> wrote:
>
> The mutex mm->context->lock for init_mm is not initialized for init_mm.
> This wasn't a problem because it remained unused. This changed however
> since commit
> 4fc19708b165c ("x86/alternatives: Initialize temporary mm for patching")
>
> Initialize the mutex for init_mm.
>
> Fixes: 4fc19708b165c ("x86/alternatives: Initialize temporary mm for
> patching")
> Signed-off-by: Sebastian Andrzej Siewior <[email protected]>
> ---
>
> The rwsem `ldt_usr_sem' is also not initialized for init_mm. No idea if
> we want this.
I cannot see why not (but it would need to depend on CONFIG_MODIFY_LDT_SYSCALL)
>
> arch/x86/include/asm/mmu.h | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/arch/x86/include/asm/mmu.h b/arch/x86/include/asm/mmu.h
> index 5ff3e8af2c205..e78c7db878018 100644
> --- a/arch/x86/include/asm/mmu.h
> +++ b/arch/x86/include/asm/mmu.h
> @@ -59,6 +59,7 @@ typedef struct {
> #define INIT_MM_CONTEXT(mm) \
> .context = { \
> .ctx_id = 1, \
> + .lock = __MUTEX_INITIALIZER(mm.context.lock), \
Sorry for my mistake. Thanks for fixing it up. I find it useful to know how
the problem was found or what the impact was - helps me sometimes to avoid
causing similar bugs in the future.
Reviewed-by: Nadav Amit <[email protected]>
