XPost: linux.debian.bugs.dist   
   From: carnil@debian.org   
      
   Control: tags -1 + moreinfo   
      
   Hi Vincent,   
      
   On Mon, Sep 29, 2025 at 05:56:05PM +0200, Vincent Lefevre wrote:   
   > Package: src:linux   
   > Version: 6.16.8-1   
   > Severity: important   
   >   
   > When logging out:   
   >   
   > Sep 29 10:01:20 qaa kernel: ------------[ cut here ]------------   
   > Sep 29 10:01:20 qaa kernel: UBSAN: shift-out-of-bounds in /bui   
   d/reproducible-path/linux-6.16.8/drivers/gpu/drm/display/drm_dp_   
   st_topology.c:4574:36   
   > Sep 29 10:01:20 qaa kernel: shift exponent -1 is negative   
   > Sep 29 10:01:20 qaa kernel: CPU: 4 UID: 0 PID: 490795 Comm: Xorg Not tainted   
   6.16.8+deb14-amd64 #1 PREEMPT(lazy)  Debian 6.16.8-1   
   > Sep 29 10:01:20 qaa kernel: Hardware name: Dell Inc. Precision 5570/01Y4G1,   
   BIOS 1.32.1 04/28/2025   
   > Sep 29 10:01:20 qaa kernel: Call Trace:   
   > Sep 29 10:01:20 qaa kernel:     
   > Sep 29 10:01:20 qaa kernel:  dump_stack_lvl+0x5d/0x80   
   > Sep 29 10:01:20 qaa kernel:  ubsan_epilogue+0x5/0x2b   
   > Sep 29 10:01:20 qaa kernel:  __ubsan_handle_shift_out_of_bound   
   .cold+0x5e/0x113   
   > Sep 29 10:01:20 qaa kernel:  drm_dp_atomic_release_time_slots.cold+0x18/0x61   
   [drm_display_helper]   
   > Sep 29 10:01:20 qaa kernel:  drm_atomic_helper_check_modeset+0x484/0xe30   
   [drm_kms_helper]   
   > Sep 29 10:01:20 qaa kernel:  intel_atomic_check+0xec/0x2b10 [i915]   
   > Sep 29 10:01:20 qaa kernel:  drm_atomic_check_only+0x63a/0xab0 [drm]   
   > Sep 29 10:01:20 qaa kernel:  drm_atomic_commit+0x71/0xe0 [drm]   
   > Sep 29 10:01:20 qaa kernel:  ? __pfx___drm_printfn_info+0x10/0x10 [drm]   
   > Sep 29 10:01:20 qaa kernel:  drm_client_modeset_commit_atomic+0x201/0x250   
   [drm]   
   > Sep 29 10:01:20 qaa kernel:  drm_client_modeset_commit_locked+0x5a/0x160   
   [drm]   
   > Sep 29 10:01:20 qaa kernel:  ? drm_setup_crtcs_fb+0xfa/0x150 [drm_kms_helper]   
   > Sep 29 10:01:20 qaa kernel:  __drm_fb_helper_restore_fbdev_mod   
   _unlocked+0x5e/0xd0 [drm_kms_helper]   
   > Sep 29 10:01:20 qaa kernel:  drm_fb_helper_hotplug_event+0xe6/0x100   
   [drm_kms_helper]   
   > Sep 29 10:01:20 qaa kernel:  __drm_fb_helper_restore_fbdev_mod   
   _unlocked+0xbd/0xd0 [drm_kms_helper]   
   > Sep 29 10:01:20 qaa kernel:  drm_fb_helper_set_par+0x30/0x40 [drm_kms_helper]   
   > Sep 29 10:01:20 qaa kernel:  intel_fbdev_set_par+0x38/0x80 [i915]   
   > Sep 29 10:01:20 qaa kernel:  fb_set_var+0x248/0x430   
   > Sep 29 10:01:20 qaa kernel:  ? __slab_free+0xdf/0x310   
   > Sep 29 10:01:20 qaa kernel:  ? __slab_free+0xdf/0x310   
   > Sep 29 10:01:20 qaa kernel:  ? __slab_free+0xdf/0x310   
   > Sep 29 10:01:20 qaa kernel:  fbcon_blank+0x28e/0x390   
   > Sep 29 10:01:20 qaa kernel:  do_unblank_screen+0xd6/0x1e0   
   > Sep 29 10:01:20 qaa kernel:  vt_ioctl+0x583/0x15b0   
   > Sep 29 10:01:20 qaa kernel:  tty_ioctl+0xe8/0x8c0   
   > Sep 29 10:01:20 qaa kernel:  __x64_sys_ioctl+0x93/0xe0   
   > Sep 29 10:01:20 qaa kernel:  do_syscall_64+0x84/0x320   
   > Sep 29 10:01:20 qaa kernel:  ? __x64_sys_close+0x3d/0x80   
   > Sep 29 10:01:20 qaa kernel:  ? kmem_cache_free+0x3a3/0x450   
   > Sep 29 10:01:20 qaa kernel:  ? do_syscall_64+0x30c/0x320   
   > Sep 29 10:01:20 qaa kernel:  ? do_user_addr_fault+0x2c3/0x7f0   
   > Sep 29 10:01:20 qaa kernel:  entry_SYSCALL_64_after_hwframe+0x76/0x7e   
   > Sep 29 10:01:20 qaa kernel: RIP: 0033:0x7f8285d648db   
   > Sep 29 10:01:20 qaa kernel: Code: 00 48 89 44 24 18 31 c0 48 8d 44 24 60 c7   
   04 24 10 00 00 00 48 89 44 24 08 48 8d 44 24 20 48 89 44 24 10 b8 10 00 00 00   
   0f 05 <89> c2 3d 00 f0 ff ff 77 1c 48 8b 44 24 18 64 48 2b 04 25 28 00 00   
   > Sep 29 10:01:20 qaa kernel: RSP: 002b:00007ffec1647a00 EFLAGS: 00000246   
   ORIG_RAX: 0000000000000010   
   > Sep 29 10:01:20 qaa kernel: RAX: ffffffffffffffda RBX: 000055fbd6e6ab80 RCX:   
   00007f8285d648db   
   > Sep 29 10:01:20 qaa kernel: RDX: 0000000000000000 RSI: 0000000000004b3a RDI:   
   000000000000000e   
   > Sep 29 10:01:20 qaa kernel: RBP: 0000000000000000 R08: 0000000000000000 R09:   
   0000000000000000   
   > Sep 29 10:01:20 qaa kernel: R10: 0000000000000000 R11: 0000000000000246 R12:   
   000055fbd6ea5794   
   > Sep 29 10:01:20 qaa kernel: R13: 00007ffec1647c48 R14: 000055fbd6e90c10 R15:   
   000055fbd6e90bf8   
   > Sep 29 10:01:20 qaa kernel:     
   > Sep 29 10:01:20 qaa kernel: ---[ end trace ]---   
   >   
   > What I did:   
   >   * Earlier, the laptop was connected to a dock.   
   >   * I logged out.   
   >   * I disconnected the machine from the dock.   
   >   * I closed the lid, which suspended the machine as expected:   
   >     Sep 29 09:19:53 qaa systemd-logind[1241]: Lid closed.   
   >     Sep 29 09:19:53 qaa systemd-logind[1241]: Suspending...   
   >   
   > The above occurred after I opened the lid.   
      
   Assuming you can reproduce this, can you test the patch from   
   https://lore.kernel.org/all/20251119094650.799135-1-suraj.kandpal@intel.com/   
   and report back if that fixes the issue?   
      
   In case it does, can you please followup to the upstream patch   
   sumission adding your Tested-by (and ideally get as well a Closes tag   
   for this bug for easier tracking).   
      
   I might be completely wrong on it.   
      
   Regards,   
   Salvatore   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)