/*
* Mausezahn - A fast versatile traffic generator
* Copyright (C) 2008-2010 Herbert Haas
*
* This program is free software; you can redistribute it and/or modify it under
* the terms of the GNU General Public License version 2 as published by the
* Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
* details.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, see http://www.gnu.org/licenses/gpl-2.0.html
*
*/
#include "mz.h"
#include "mops.h"
// Assigns MPLS tag at position i (starting at zero!) with values:
//
// m ... total number of tags (important to set BoS in last tag)
// Label ... label value
// Exp ... EXP field (typically CoS)
// TTL ... Time To Live
//
// NOTE: Two usage possibilities!
//
// 1.) When called from for-loop to add all tags the total size mpls_s
// is updated continuously and the BoS is set in the last tag.
// Therefore set m = total number of tags!
//
// 2.) But when changing a particular tag within an existing MPLS stack
// the total number of tags does not change, therefore use m=0.
//
// RETURN VALUE: 0 upon success, 1 upon failure
//
int mops_mpls(struct mops *mp, int i, int m, u_int32_t Label, u_int8_t Exp, u_int8_t TTL)
{
u_int8_t *ptr;
if ((m) && (i>=m)) return 1; // label index greater than number of labels!
if (Label > 1048575) return 1;
if (Exp > 7) return 1;
// Create binary tag: Label(20) EXP(3) BoS(1) TTL(8)
Label <<= 4;
ptr = (u_int8_t *) &Label;
mp->mpls[4*i+0] = *(ptr+2);
mp->mpls[4*i+1] = *(ptr+1);
mp->mpls[4*i+2] = *(ptr+0);
Exp <<= 1;
mp->mpls[4*i+2] |= Exp;
mp->mpls[4*i+3] = TTL;
if ((m) && (i==(m-1))) // reached last tag!
{
mp->mpls[4*i+2] |= 0x01; // set BoS in last tag
mp->mpls_s =4*m;
mp->use_MPLS = 1;
if ( (mp->eth_type != 0x8847) && (mp->eth_type != 0x8848) )
{
mp->eth_type_backup = mp->eth_type;
}
mp->eth_type = 0x8847;
}
return 0;
}
// Remove MPLS tags from packet mp
//
// j indicates which tag to be removed (1..n)
// j=0 means: remove all tags!
//
// RETURN VALUE: 1 upon failure, 0 upon success
int mops_mpls_remove (struct mops *mp, int j)
{
int a, b, k;
if (j==0) // remove all tags
{
if (mp->use_MPLS)
{
mp->mpls_s=0;
mp->use_MPLS=0;
mp->eth_type = mp->eth_type_backup; // restore original ethertype
return 0;
}
else
return 1;
}
k = mp->mpls_s/4;
if (j>k) return 1; // The packet only consists of k tag(s)
if (k==1) // only delete the single tag
{
mp->mpls_s=0;
mp->use_MPLS=0;
mp->eth_type = mp->eth_type_backup; // restore original ethertype
return 0;
}
// if we got here we have more than one tag:
if (j==k) // remove last tag (of several)
{
mp->mpls_s -=4;
return 0;
}
// remove some non-ending tag: 0, 1, 2, 3
a = (j-1)*4; // target
b = j*4; // source (what should be copied)
memcpy(&mp->mpls[a], &mp->mpls[b], (k-j)*4);
mp->mpls_s -=4;
return 0;
}
// Set BOS in tag k where k=1..n
int mops_mpls_bos (struct mops *mp, int k)
{
int n;
n = mp->mpls_s/4; // n = total number of tags
if (k>n) return 1;
mp->mpls[(k-1)*4+2] |= 0x01;
return 0;
}
// Unset BOS in tag k where k=1..n
int mops_mpls_nobos (struct mops *mp, int k)
{
int n;
n = mp->mpls_s/4; // n = total number of tags
if (k>n) return 1;
mp->mpls[(k-1)*4+2] &= 0xfe;
return 0;
}
drm/i915: Check for NULL i915_vma in intel_unpin_fb_obj()
I've seen this trigger twice now, where the i915_gem_object_to_ggtt()
call in intel_unpin_fb_obj() returns NULL, resulting in an oops
immediately afterwards as the (inlined) call to i915_vma_unpin_fence()
tries to dereference 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>