/* sis_drv.h -- Private header for sis driver -*- linux-c -*- */ /* * Copyright 2005 Eric Anholt * All Rights Reserved. * * Permission is hereby granted, free of charge, to any person obtaining a * copy of this software and associated documentation files (the "Software"), * to deal in the Software without restriction, including without limitation * the rights to use, copy, modify, merge, publish, distribute, sublicense, * and/or sell copies of the Software, and to permit persons to whom the * Software is furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice (including the next * paragraph) shall be included in all copies or substantial portions of the * Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE * SOFTWARE. * */ #ifndef __SIS_DRM_H__ #define __SIS_DRM_H__ #include "drm.h" #if defined(__cplusplus) extern "C" { #endif /* SiS specific ioctls */ #define NOT_USED_0_3 #define DRM_SIS_FB_ALLOC 0x04 #define DRM_SIS_FB_FREE 0x05 #define NOT_USED_6_12 #define DRM_SIS_AGP_INIT 0x13 #define DRM_SIS_AGP_ALLOC 0x14 #define DRM_SIS_AGP_FREE 0x15 #define DRM_SIS_FB_INIT 0x16 #define DRM_IOCTL_SIS_FB_ALLOC DRM_IOWR(DRM_COMMAND_BASE + DRM_SIS_FB_ALLOC, drm_sis_mem_t) #define DRM_IOCTL_SIS_FB_FREE DRM_IOW( DRM_COMMAND_BASE + DRM_SIS_FB_FREE, drm_sis_mem_t) #define DRM_IOCTL_SIS_AGP_INIT DRM_IOWR(DRM_COMMAND_BASE + DRM_SIS_AGP_INIT, drm_sis_agp_t) #define DRM_IOCTL_SIS_AGP_ALLOC DRM_IOWR(DRM_COMMAND_BASE + DRM_SIS_AGP_ALLOC, drm_sis_mem_t) #define DRM_IOCTL_SIS_AGP_FREE DRM_IOW( DRM_COMMAND_BASE + DRM_SIS_AGP_FREE, drm_sis_mem_t) #define DRM_IOCTL_SIS_FB_INIT DRM_IOW( DRM_COMMAND_BASE + DRM_SIS_FB_INIT, drm_sis_fb_t) /* #define DRM_IOCTL_SIS_FLIP DRM_IOW( 0x48, drm_sis_flip_t) #define DRM_IOCTL_SIS_FLIP_INIT DRM_IO( 0x49) #define DRM_IOCTL_SIS_FLIP_FINAL DRM_IO( 0x50) */ typedef struct { int context; unsigned long offset; unsigned long size; unsigned long free; } drm_sis_mem_t; typedef struct { unsigned long offset, size; } drm_sis_agp_t; typedef struct { unsigned long offset, size; } drm_sis_fb_t; #if defined(__cplusplus) } #endif #endif /* __SIS_DRM_H__ */ ommitter
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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 /include/trace
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>
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