Re: [PATCH] xen: Fix two possible sleep-in-atomic-context bugs in create_active()

[Juergen Gross]

On 20/06/18 04:38, Jia-Ju Bai wrote:
> The driver may sleep with holding a spinlock.
> The function call paths (from bottom to top) in Linux-4.16.7 are:
> 
> [FUNC] __get_free_pages(GFP_KERNEL)
> drivers/xen/pvcalls-front.c, 351: __get_free_pages in create_active
> drivers/xen/pvcalls-front.c, 800: create_active in pvcalls_front_accept
> drivers/xen/pvcalls-front.c, 783: spin_lock in pvcalls_front_accept
> 
> [FUNC] __get_free_pages(GFP_KERNEL)
> drivers/xen/pvcalls-front.c, 347: __get_free_pages in create_active
> drivers/xen/pvcalls-front.c, 800: create_active in pvcalls_front_accept
> drivers/xen/pvcalls-front.c, 783: spin_lock in pvcalls_front_accept
> 
> To fix these bugs, GFP_KERNEL is replaced with GFP_ATOMIC.
> 
> These bugs are found by my static analysis tool (DSAC-2) and checked by my
> code review.
> 
> Signed-off-by: Jia-Ju Bai <baijiaju1990@xxxxxxxxx>

Reviewed-by: Juergen Gross <jgross@xxxxxxxx>


Juergen