/* * TURBOchannel driver services. * * Copyright (c) 2005 James Simmons * Copyright (c) 2006 Maciej W. Rozycki * * Loosely based on drivers/dio/dio-driver.c and * drivers/pci/pci-driver.c. * * This file is subject to the terms and conditions of the GNU * General Public License. See the file "COPYING" in the main * directory of this archive for more details. */ #include #include #include /** * tc_register_driver - register a new TC driver * @drv: the driver structure to register * * Adds the driver structure to the list of registered drivers * Returns a negative value on error, otherwise 0. * If no error occurred, the driver remains registered even if * no device was claimed during registration. */ int tc_register_driver(struct tc_driver *tdrv) { return driver_register(&tdrv->driver); } EXPORT_SYMBOL(tc_register_driver); /** * tc_unregister_driver - unregister a TC driver * @drv: the driver structure to unregister * * Deletes the driver structure from the list of registered TC drivers, * gives it a chance to clean up by calling its remove() function for * each device it was responsible for, and marks those devices as * driverless. */ void tc_unregister_driver(struct tc_driver *tdrv) { driver_unregister(&tdrv->driver); } EXPORT_SYMBOL(tc_unregister_driver); /** * tc_match_device - tell if a TC device structure has a matching * TC device ID structure * @tdrv: the TC driver to earch for matching TC device ID strings * @tdev: the TC device structure to match against * * Used by a driver to check whether a TC device present in the * system is in its list of supported devices. Returns the matching * tc_device_id structure or %NULL if there is no match. */ const struct tc_device_id *tc_match_device(struct tc_driver *tdrv, struct tc_dev *tdev) { const struct tc_device_id *id = tdrv->id_table; if (id) { while (id->name[0] || id->vendor[0]) { if (strcmp(tdev->name, id->name) == 0 && strcmp(tdev->vendor, id->vendor) == 0) return id; id++; } } return NULL; } EXPORT_SYMBOL(tc_match_device); /** * tc_bus_match - Tell if a device structure has a matching * TC device ID structure * @dev: the device structure to match against * @drv: the device driver to search for matching TC device ID strings * * Used by a driver to check whether a TC device present in the * system is in its list of supported devices. Returns 1 if there * is a match or 0 otherwise. */ static int tc_bus_match(struct device *dev, struct device_driver *drv) { struct tc_dev *tdev = to_tc_dev(dev); struct tc_driver *tdrv = to_tc_driver(drv); const struct tc_device_id *id; id = tc_match_device(tdrv, tdev); if (id) return 1; return 0; } struct bus_type tc_bus_type = { .name = "tc", .match = tc_bus_match, }; EXPORT_SYMBOL(tc_bus_type); static int __init tc_driver_init(void) { return bus_register(&tc_bus_type); } postcore_initcall(tc_driver_init); s-private-remove&id=3895dbf8985f656675b5bde610723a29cbce3fa7'>net/irda/ircomm
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authorEric W. Biederman <ebiederm@xmission.com>2017-01-03 14:18:43 +1300
committerEric W. Biederman <ebiederm@xmission.com>2017-01-10 13:34:43 +1300
commit3895dbf8985f656675b5bde610723a29cbce3fa7 (patch)
tree91d4517f09918fd573998eb40b8f35f08ed1c470 /net/irda/ircomm
parent0c744ea4f77d72b3dcebb7a8f2684633ec79be88 (diff)
mnt: Protect the mountpoint hashtable with mount_lock
Protecting the mountpoint hashtable with namespace_sem was sufficient until a call to umount_mnt was added to mntput_no_expire. At which point it became possible for multiple calls of put_mountpoint on the same hash chain to happen on the same time. Kristen Johansen <kjlx@templeofstupid.com> reported: > This can cause a panic when simultaneous callers of put_mountpoint > attempt to free the same mountpoint. This occurs because some callers > hold the mount_hash_lock, while others hold the namespace lock. Some > even hold both. > > In this submitter's case, the panic manifested itself as a GP fault in > put_mountpoint() when it called hlist_del() and attempted to dereference > a m_hash.pprev that had been poisioned by another thread. Al Viro observed that the simple fix is to switch from using the namespace_sem to the mount_lock to protect the mountpoint hash table. I have taken Al's suggested patch moved put_mountpoint in pivot_root (instead of taking mount_lock an additional time), and have replaced new_mountpoint with get_mountpoint a function that does the hash table lookup and addition under the mount_lock. The introduction of get_mounptoint ensures that only the mount_lock is needed to manipulate the mountpoint hashtable. d_set_mounted is modified to only set DCACHE_MOUNTED if it is not already set. This allows get_mountpoint to use the setting of DCACHE_MOUNTED to ensure adding a struct mountpoint for a dentry happens exactly once. Cc: stable@vger.kernel.org Fixes: ce07d891a089 ("mnt: Honor MNT_LOCKED when detaching mounts") Reported-by: Krister Johansen <kjlx@templeofstupid.com> Suggested-by: Al Viro <viro@ZenIV.linux.org.uk> Acked-by: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Diffstat (limited to 'net/irda/ircomm')