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4e9e920035
This patch fixes crashes when usbmon attempts to access GART aperture. The old code attempted to take a bus address and convert it into a virtual address, which clearly was impossible on systems with actual IOMMUs. Let us not persist in this foolishness, and use transfer_buffer in all cases instead. I think downsides are negligible. The ones I see are: - A driver may pass an address of one buffer down as transfer_buffer, and entirely different entity mapped for DMA, resulting in misleading output of usbmon. Note, however, that PIO based controllers would do transfer the same data that usbmon sees here. - Out of tree drivers may crash usbmon if they store garbage in transfer_buffer. I inspected the in-tree drivers, and clarified the documentation in comments. - Drivers that use get_user_pages will not be possible to monitor. I only found one driver with this problem (drivers/staging/rspiusb). - Same happens with with usb_storage transferring from highmem, but it works fine on 64-bit systems, so I think it's not a concern. At least we don't crash anymore. Why didn't we do this in 2.6.10? That's because back in those days it was popular not to fill in transfer_buffer, so almost all traffic would be invisible (e.g. all of HID was like that). But now, the tree is almost 100% PIO friendly, so we can do the right thing at last. Signed-off-by: Pete Zaitcev <zaitcev@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
76 lines
1.9 KiB
C
76 lines
1.9 KiB
C
/*
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* The USB Monitor, inspired by Dave Harding's USBMon.
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*
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* Copyright (C) 2005 Pete Zaitcev (zaitcev@redhat.com)
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*/
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#ifndef __USB_MON_H
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#define __USB_MON_H
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#include <linux/list.h>
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#include <linux/slab.h>
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#include <linux/kref.h>
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/* #include <linux/usb.h> */ /* We use struct pointers only in this header */
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#define TAG "usbmon"
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struct mon_bus {
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struct list_head bus_link;
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spinlock_t lock;
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struct usb_bus *u_bus;
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int text_inited;
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int bin_inited;
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struct dentry *dent_s; /* Debugging file */
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struct dentry *dent_t; /* Text interface file */
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struct dentry *dent_u; /* Second text interface file */
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struct device *classdev; /* Device in usbmon class */
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/* Ref */
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int nreaders; /* Under mon_lock AND mbus->lock */
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struct list_head r_list; /* Chain of readers (usually one) */
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struct kref ref; /* Under mon_lock */
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/* Stats */
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unsigned int cnt_events;
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unsigned int cnt_text_lost;
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};
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/*
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* An instance of a process which opened a file (but can fork later)
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*/
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struct mon_reader {
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struct list_head r_link;
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struct mon_bus *m_bus;
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void *r_data; /* Use container_of instead? */
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void (*rnf_submit)(void *data, struct urb *urb);
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void (*rnf_error)(void *data, struct urb *urb, int error);
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void (*rnf_complete)(void *data, struct urb *urb, int status);
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};
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void mon_reader_add(struct mon_bus *mbus, struct mon_reader *r);
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void mon_reader_del(struct mon_bus *mbus, struct mon_reader *r);
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struct mon_bus *mon_bus_lookup(unsigned int num);
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int /*bool*/ mon_text_add(struct mon_bus *mbus, const struct usb_bus *ubus);
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void mon_text_del(struct mon_bus *mbus);
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int /*bool*/ mon_bin_add(struct mon_bus *mbus, const struct usb_bus *ubus);
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void mon_bin_del(struct mon_bus *mbus);
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int __init mon_text_init(void);
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void mon_text_exit(void);
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int __init mon_bin_init(void);
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void mon_bin_exit(void);
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/*
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*/
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extern struct mutex mon_lock;
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extern const struct file_operations mon_fops_stat;
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extern struct mon_bus mon_bus0; /* Only for redundant checks */
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#endif /* __USB_MON_H */
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