On Tue, Jul 23, 2024 at 01:52:46PM -0500, Dan Carpenter wrote: > tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master > head: dee7f101b64219f512bb2f842227bd04c14efe30 > commit: 61ac035361ae555ee5a17a7667fe96afdde3d59a [13298/13495] drm/xe: Drop xe_gt_tlb_invalidation_wait > config: i386-randconfig-141-20240722 (https://download.01.org/0day-ci/archive/20240723/202407231049.esig0Fkb-lkp@xxxxxxxxx/config) > compiler: clang version 18.1.5 (https://github.com/llvm/llvm-project 617a15a9eac96088ae5e9134248d8236e34b91b1) > > If you fix the issue in a separate patch/commit (i.e. not just a new version of > the same patch/commit), kindly add following tags > | Reported-by: kernel test robot <lkp@xxxxxxxxx> > | Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> > | Closes: https://lore.kernel.org/r/202407231049.esig0Fkb-lkp@xxxxxxxxx/ > > New smatch warnings: > drivers/gpu/drm/xe/xe_gt_tlb_invalidation.c:183 send_tlb_invalidation() warn: variable dereferenced before check 'fence' (see line 178) > > vim +/fence +183 drivers/gpu/drm/xe/xe_gt_tlb_invalidation.c > > fc108a8b759f52 Matthew Brost 2023-01-17 159 static int send_tlb_invalidation(struct xe_guc *guc, > 332dd0116c82a7 Matthew Brost 2023-01-24 160 struct xe_gt_tlb_invalidation_fence *fence, > 332dd0116c82a7 Matthew Brost 2023-01-24 161 u32 *action, int len) > a9351846d94568 Matthew Brost 2023-01-17 162 { > a9351846d94568 Matthew Brost 2023-01-17 163 struct xe_gt *gt = guc_to_gt(guc); > 501c4255c40935 Radhakrishna Sripada 2024-06-07 164 struct xe_device *xe = gt_to_xe(gt); > a9351846d94568 Matthew Brost 2023-01-17 165 int seqno; > a9351846d94568 Matthew Brost 2023-01-17 166 int ret; > a9351846d94568 Matthew Brost 2023-01-17 167 > 61ac035361ae55 Matthew Brost 2024-07-19 168 xe_gt_assert(gt, fence); We assert the fence is not NULL here. It is invalid call with a NULL fence. > 61ac035361ae55 Matthew Brost 2024-07-19 169 > a9351846d94568 Matthew Brost 2023-01-17 170 /* > a9351846d94568 Matthew Brost 2023-01-17 171 * XXX: The seqno algorithm relies on TLB invalidation being processed > a9351846d94568 Matthew Brost 2023-01-17 172 * in order which they currently are, if that changes the algorithm will > a9351846d94568 Matthew Brost 2023-01-17 173 * need to be updated. > a9351846d94568 Matthew Brost 2023-01-17 174 */ > 565ce72e1c2d54 Matthew Auld 2023-05-24 175 > a9351846d94568 Matthew Brost 2023-01-17 176 mutex_lock(&guc->ct.lock); > 62ad062150c2ab Matthew Brost 2023-01-17 177 seqno = gt->tlb_invalidation.seqno; > fc108a8b759f52 Matthew Brost 2023-01-17 @178 fence->seqno = seqno; > ^^^^^^^^^^^^^^^^^^^^ > Dereference > > 501c4255c40935 Radhakrishna Sripada 2024-06-07 179 trace_xe_gt_tlb_invalidation_fence_send(xe, fence); > a9351846d94568 Matthew Brost 2023-01-17 180 action[1] = seqno; > 332dd0116c82a7 Matthew Brost 2023-01-24 181 ret = xe_guc_ct_send_locked(&guc->ct, action, len, > a9351846d94568 Matthew Brost 2023-01-17 182 G2H_LEN_DW_TLB_INVALIDATE, 1); > 38224c00d9c284 Matthew Brost 2023-01-24 @183 if (!ret && fence) { > ^^^^^ > Checked too late > This check is not needed. Let me post a patch to remove this. Thanks, Matt > 35c8a964398e1c Matthew Auld 2023-07-10 184 spin_lock_irq(>->tlb_invalidation.pending_lock); > 35c8a964398e1c Matthew Auld 2023-07-10 185 /* > 35c8a964398e1c Matthew Auld 2023-07-10 186 * We haven't actually published the TLB fence as per > 35c8a964398e1c Matthew Auld 2023-07-10 187 * pending_fences, but in theory our seqno could have already > 35c8a964398e1c Matthew Auld 2023-07-10 188 * been written as we acquired the pending_lock. In such a case > 35c8a964398e1c Matthew Auld 2023-07-10 189 * we can just go ahead and signal the fence here. > 35c8a964398e1c Matthew Auld 2023-07-10 190 */ > 35c8a964398e1c Matthew Auld 2023-07-10 191 if (tlb_invalidation_seqno_past(gt, seqno)) { > > -- > 0-DAY CI Kernel Test Service > https://github.com/intel/lkp-tests/wiki >
