/* mountpoint management * * Copyright (C) 2002 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. */ #include #include #include #include #include #include #include #include #include "internal.h" static struct dentry *afs_mntpt_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags); static int afs_mntpt_open(struct inode *inode, struct file *file); static void afs_mntpt_expiry_timed_out(struct work_struct *work); const struct file_operations afs_mntpt_file_operations = { .open = afs_mntpt_open, .llseek = noop_llseek, }; const struct inode_operations afs_mntpt_inode_operations = { .lookup = afs_mntpt_lookup, .readlink = page_readlink, .getattr = afs_getattr, }; const struct inode_operations afs_autocell_inode_operations = { .getattr = afs_getattr, }; static LIST_HEAD(afs_vfsmounts); static DECLARE_DELAYED_WORK(afs_mntpt_expiry_timer, afs_mntpt_expiry_timed_out); static unsigned long afs_mntpt_expiry_timeout = 10 * 60; /* * check a symbolic link to see whether it actually encodes a mountpoint * - sets the AFS_VNODE_MOUNTPOINT flag on the vnode appropriately */ int afs_mntpt_check_symlink(struct afs_vnode *vnode, struct key *key) { struct page *page; size_t size; char *buf; int ret; _enter("{%x:%u,%u}", vnode->fid.vid, vnode->fid.vnode, vnode->fid.unique); /* read the contents of the symlink into the pagecache */ page = read_cache_page(AFS_VNODE_TO_I(vnode)->i_mapping, 0, afs_page_filler, key); if (IS_ERR(page)) { ret = PTR_ERR(page); goto out; } ret = -EIO; if (PageError(page)) goto out_free; buf = kmap(page); /* examine the symlink's contents */ size = vnode->status.size; _debug("symlink to %*.*s", (int) size, (int) size, buf); if (size > 2 && (buf[0] == '%' || buf[0] == '#') && buf[size - 1] == '.' ) { _debug("symlink is a mountpoint"); spin_lock(&vnode->lock); set_bit(AFS_VNODE_MOUNTPOINT, &vnode->flags); vnode->vfs_inode.i_flags |= S_AUTOMOUNT; spin_unlock(&vnode->lock); } ret = 0; kunmap(page); out_free: put_page(page); out: _leave(" = %d", ret); return ret; } /* * no valid lookup procedure on this sort of dir */ static struct dentry *afs_mntpt_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) { _enter("%p,%p{%pd2}", dir, dentry, dentry); return ERR_PTR(-EREMOTE); } /* * no valid open procedure on this sort of dir */ static int afs_mntpt_open(struct inode *inode, struct file *file) { _enter("%p,%p{%pD2}", inode, file, file); return -EREMOTE; } /* * create a vfsmount to be automounted */ static struct vfsmount *afs_mntpt_do_automount(struct dentry *mntpt) { struct afs_super_info *super; struct vfsmount *mnt; struct afs_vnode *vnode; struct page *page; char *devname, *options; bool rwpath = false; int ret; _enter("{%pd}", mntpt); BUG_ON(!d_inode(mntpt)); ret = -ENOMEM; devname = (char *) get_zeroed_page(GFP_KERNEL); if (!devname) goto error_no_devname; options = (char *) get_zeroed_page(GFP_KERNEL); if (!options) goto error_no_options; vnode = AFS_FS_I(d_inode(mntpt)); if (test_bit(AFS_VNODE_PSEUDODIR, &vnode->flags)) { /* if the directory is a pseudo directory, use the d_name */ static const char afs_root_cell[] = ":root.cell."; unsigned size = mntpt->d_name.len; ret = -ENOENT; if (size < 2 || size > AFS_MAXCELLNAME) goto error_no_page; if (mntpt->d_name.name[0] == '.') { devname[0] = '#'; memcpy(devname + 1, mntpt->d_name.name, size - 1); memcpy(devname + size, afs_root_cell, sizeof(afs_root_cell)); rwpath = true; } else { devname[0] = '%'; memcpy(devname + 1, mntpt->d_name.name, size); memcpy(devname + size + 1, afs_root_cell, sizeof(afs_root_cell)); } } else { /* read the contents of the AFS special symlink */ loff_t size = i_size_read(d_inode(mntpt)); char *buf; ret = -EINVAL; if (size > PAGE_SIZE - 1) goto error_no_page; page = read_mapping_page(d_inode(mntpt)->i_mapping, 0, NULL); if (IS_ERR(page)) { ret = PTR_ERR(page); goto error_no_page; } ret = -EIO; if (PageError(page)) goto error; buf = kmap_atomic(page); memcpy(devname, buf, size); kunmap_atomic(buf); put_page(page); page = NULL; } /* work out what options we want */ super = AFS_FS_S(mntpt->d_sb); memcpy(options, "cell=", 5); strcpy(options + 5, super->volume->cell->name); if (super->volume->type == AFSVL_RWVOL || rwpath) strcat(options, ",rwpath"); /* try and do the mount */ _debug("--- attempting mount %s -o %s ---", devname, options); mnt = vfs_kern_mount(&afs_fs_type, 0, devname, options); _debug("--- mount result %p ---", mnt); free_page((unsigned long) devname); free_page((unsigned long) options); _leave(" = %p", mnt); return mnt; error: put_page(page); error_no_page: free_page((unsigned long) options); error_no_options: free_page((unsigned long) devname); error_no_devname: _leave(" = %d", ret); return ERR_PTR(ret); } /* * handle an automount point */ struct vfsmount *afs_d_automount(struct path *path) { struct vfsmount *newmnt; _enter("{%pd}", path->dentry); newmnt = afs_mntpt_do_automount(path->dentry); if (IS_ERR(newmnt)) return newmnt; mntget(newmnt); /* prevent immediate expiration */ mnt_set_expiry(newmnt, &afs_vfsmounts); queue_delayed_work(afs_wq, &afs_mntpt_expiry_timer, afs_mntpt_expiry_timeout * HZ); _leave(" = %p", newmnt); return newmnt; } /* * handle mountpoint expiry timer going off */ static void afs_mntpt_expiry_timed_out(struct work_struct *work) { _enter(""); if (!list_empty(&afs_vfsmounts)) { mark_mounts_for_expiry(&afs_vfsmounts); queue_delayed_work(afs_wq, &afs_mntpt_expiry_timer, afs_mntpt_expiry_timeout * HZ); } _leave(""); } /* * kill the AFS mountpoint timer if it's still running */ void afs_mntpt_kill_timer(void) { _enter(""); ASSERT(list_empty(&afs_vfsmounts)); cancel_delayed_work_sync(&afs_mntpt_expiry_timer); } it. It seems to be some race condition where the object is going away at shutdown time, since both times happened when shutting down the X server. The call chains were different: - VT ioctl(KDSETMODE, KD_TEXT): intel_cleanup_plane_fb+0x5b/0xa0 [i915] drm_atomic_helper_cleanup_planes+0x6f/0x90 [drm_kms_helper] intel_atomic_commit_tail+0x749/0xfe0 [i915] intel_atomic_commit+0x3cb/0x4f0 [i915] drm_atomic_commit+0x4b/0x50 [drm] restore_fbdev_mode+0x14c/0x2a0 [drm_kms_helper] drm_fb_helper_restore_fbdev_mode_unlocked+0x34/0x80 [drm_kms_helper] drm_fb_helper_set_par+0x2d/0x60 [drm_kms_helper] intel_fbdev_set_par+0x18/0x70 [i915] fb_set_var+0x236/0x460 fbcon_blank+0x30f/0x350 do_unblank_screen+0xd2/0x1a0 vt_ioctl+0x507/0x12a0 tty_ioctl+0x355/0xc30 do_vfs_ioctl+0xa3/0x5e0 SyS_ioctl+0x79/0x90 entry_SYSCALL_64_fastpath+0x13/0x94 - i915 unpin_work workqueue: intel_unpin_work_fn+0x58/0x140 [i915] process_one_work+0x1f1/0x480 worker_thread+0x48/0x4d0 kthread+0x101/0x140 and this patch purely papers over the issue by adding a NULL pointer check and a WARN_ON_ONCE() to avoid the oops that would then generally make the machine unresponsive. Other callers of i915_gem_object_to_ggtt() seem to also check for the returned pointer being NULL and warn about it, so this clearly has happened before in other places. [ Reported it originally to the i915 developers on Jan 8, applying the ugly workaround on my own now after triggering the problem for the second time with no feedback. This is likely to be the same bug reported as https://bugs.freedesktop.org/show_bug.cgi?id=98829 https://bugs.freedesktop.org/show_bug.cgi?id=99134 which has a patch for the underlying problem, but it hasn't gotten to me, so I'm applying the workaround. ] Cc: Daniel Vetter <daniel.vetter@intel.com> Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: Imre Deak <imre.deak@intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/usb/usbip/vhci_rx.c')