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authorJiri Slaby <jslaby@suse.cz>2016-06-15 15:56:11 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-08-09 16:14:18 +0200
commit70f7ca9a0262784d0b80727860a63d64ab228e7b (patch)
tree1a4b50597c4fd4e916fc4f0d2709c10d32588599
parentbc337b51508beb2d039aff5074a76cfe1c212030 (diff)
downloadop-kernel-dev-70f7ca9a0262784d0b80727860a63d64ab228e7b.zip
op-kernel-dev-70f7ca9a0262784d0b80727860a63d64ab228e7b.tar.gz
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: [<ffffffff8117a3ae>] ? warn_slowpath_null+0x2e/0x40 [<ffffffff815178b6>] ? __alloc_pages_slowpath+0x1036/0x16e0 [<ffffffff81516880>] ? warn_alloc_failed+0x250/0x250 [<ffffffff8151226b>] ? get_page_from_freelist+0x75b/0x28b0 [<ffffffff815184e3>] ? __alloc_pages_nodemask+0x583/0x6b0 [<ffffffff81517f60>] ? __alloc_pages_slowpath+0x16e0/0x16e0 [<ffffffff810565d4>] ? dma_generic_alloc_coherent+0x104/0x220 [<ffffffffa0269e56>] ? hcd_buffer_alloc+0x1d6/0x3e0 [usbcore] [<ffffffffa0269c80>] ? hcd_buffer_destroy+0xa0/0xa0 [usbcore] [<ffffffffa0228f05>] ? usb_alloc_coherent+0x65/0x90 [usbcore] [<ffffffffa0275c05>] ? 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 <jslaby@suse.cz> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: Steinar H. Gunderson <sesse@google.com> Cc: Markus Rechberger <mrechberger@gmail.com> Fixes: f7d34b445a (USB: Add support for usbfs zerocopy.) Cc: 4.6+ <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/usb/core/devio.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c
index e9f5043..472cbcd 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;
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