#include "log.h"
/* shift the packet array by n places. */
static void batadv_bitmap_shift_left(unsigned long *seq_bits, s32 n)
{
if (n <= 0 || n >= BATADV_TQ_LOCAL_WINDOW_SIZE)
return;
bitmap_shift_left(seq_bits, seq_bits, n, BATADV_TQ_LOCAL_WINDOW_SIZE);
}
/**
* batadv_bit_get_packet - receive and process one packet within the sequence
* number window
* @priv: the bat priv with all the soft interface information
* @seq_bits: pointer to the sequence number receive packet
* @seq_num_diff: difference between the current/received sequence number and
* the last sequence number
* @set_mark: whether this packet should be marked in seq_bits
*
* Return: true if the window was moved (either new or very old),
* false if the window was not moved/shifted.
*/
bool batadv_bit_get_packet(void *priv, unsigned long *seq_bits,
s32 seq_num_diff, int set_mark)
{
struct batadv_priv *bat_priv = priv;
/* sequence number is slightly older. We already got a sequence number
* higher than this one, so we just mark it.
*/
if (seq_num_diff <= 0 && seq_num_diff > -BATADV_TQ_LOCAL_WINDOW_SIZE) {
if (set_mark)
batadv_set_bit(seq_bits, -seq_num_diff);
return false;
}
/* sequence number is slightly newer, so we shift the window and
* set the mark if required
*/
if (seq_num_diff > 0 && seq_num_diff < BATADV_TQ_LOCAL_WINDOW_SIZE) {
batadv_bitmap_shift_left(seq_bits, seq_num_diff);
if (set_mark)
batadv_set_bit(seq_bits, 0);
return true;
}
/* sequence number is much newer, probably missed a lot of packets */
if (seq_num_diff >= BATADV_TQ_LOCAL_WINDOW_SIZE &&
seq_num_diff < BATADV_EXPECTED_SEQNO_RANGE) {
batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
"We missed a lot of packets (%i) !\n",
seq_num_diff - 1);
bitmap_zero(seq_bits, BATADV_TQ_LOCAL_WINDOW_SIZE);
if (set_mark)
batadv_set_bit(seq_bits, 0);
return true;
}
/* received a much older packet. The other host either restarted
* or the old packet got delayed somewhere in the network. The
* packet should be dropped without calling this function if the
* seqno window is protected.
*
* seq_num_diff <= -BATADV_TQ_LOCAL_WINDOW_SIZE
* or
* seq_num_diff >= BATADV_EXPECTED_SEQNO_RANGE
*/
batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
"Other host probably restarted!\n");
bitmap_zero(seq_bits, BATADV_TQ_LOCAL_WINDOW_SIZE);
if (set_mark)
batadv_set_bit(seq_bits, 0);
return true;
}
und/pci?h=nds-private-remove&id=d07830db1bdb254e4b50d366010b219286b8c937'>pci/cs5535audio/Makefile
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>