From 70f7ca9a0262784d0b80727860a63d64ab228e7b Mon Sep 17 00:00:00 2001 From: Jiri Slaby Date: Wed, 15 Jun 2016 15:56:11 +0200 Subject: usb: devio, do not warn when allocation fails usbdev_mmap allocates a buffer. The size of the buffer is determined by a user. So with this code (no need to be root): int fd = open("/dev/bus/usb/001/001", O_RDONLY); mmap(NULL, 0x800000, PROT_READ, MAP_SHARED, fd, 0); we can see a warning: WARNING: CPU: 0 PID: 21771 at ../mm/page_alloc.c:3563 __alloc_pages_slowpath+0x1036/0x16e0() ... Call Trace: [] ? warn_slowpath_null+0x2e/0x40 [] ? __alloc_pages_slowpath+0x1036/0x16e0 [] ? warn_alloc_failed+0x250/0x250 [] ? get_page_from_freelist+0x75b/0x28b0 [] ? __alloc_pages_nodemask+0x583/0x6b0 [] ? __alloc_pages_slowpath+0x16e0/0x16e0 [] ? dma_generic_alloc_coherent+0x104/0x220 [] ? hcd_buffer_alloc+0x1d6/0x3e0 [usbcore] [] ? hcd_buffer_destroy+0xa0/0xa0 [usbcore] [] ? usb_alloc_coherent+0x65/0x90 [usbcore] [] ? usbdev_mmap+0x1a5/0x770 [usbcore] ... Allocations like this one should be marked as __GFP_NOWARN. So do so. The size could be also clipped by something like: if (size >= (1 << (MAX_ORDER + PAGE_SHIFT - 1))) return -ENOMEM; But I think the overall limit of 16M (by usbfs_increase_memory_usage) is enough, so that we only silence the warning here. Signed-off-by: Jiri Slaby Cc: Greg Kroah-Hartman Cc: Alan Stern Cc: Steinar H. Gunderson Cc: Markus Rechberger Fixes: f7d34b445a (USB: Add support for usbfs zerocopy.) Cc: 4.6+ Signed-off-by: Greg Kroah-Hartman --- drivers/usb/core/devio.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'drivers/usb/core') diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c index e9f5043a2167..472cbcdf7456 100644 --- a/drivers/usb/core/devio.c +++ b/drivers/usb/core/devio.c @@ -241,7 +241,8 @@ static int usbdev_mmap(struct file *file, struct vm_area_struct *vma) goto error_decrease_mem; } - mem = usb_alloc_coherent(ps->dev, size, GFP_USER, &dma_handle); + mem = usb_alloc_coherent(ps->dev, size, GFP_USER | __GFP_NOWARN, + &dma_handle); if (!mem) { ret = -ENOMEM; goto error_free_usbm; -- cgit v1.2.3-58-ga151