Bug 19512

Summary: kmemcheck reports reads from uninitialized memory in drm_kms_helper when switching vt from X
Product: Drivers Reporter: Sami Liedes (sami.liedes)
Component: Video(DRI - Intel)Assignee: drivers_video-dri-intel (drivers_video-dri-intel)
Status: RESOLVED INSUFFICIENT_DATA    
Severity: normal CC: daniel
Priority: P1    
Hardware: All   
OS: Linux   
Kernel Version: 2.6.35.6 (+ tuxonice patches) Subsystem:
Regression: No Bisected commit-id:

Description Sami Liedes 2010-10-02 10:58:54 UTC 
After starting X in a computer with kmemcheck turned on in kernel config, I get the following warnings when switching to a text console with alt-ctrl-F1:


 WARNING: kmemcheck: Caught 16-bit read from uninitialized memory (ffff880132b57a20)
 0000000000000000000000000000000000000000000000000000000000000000
  u u u u u u u u u u u u u u u u u u u u u u u u u u u u u u u u
  ^
 
 Pid: 3852, comm: Xorg Tainted: G          I 2.6.35.6-tuxonice-debug #2 Aspire 5810T/Aspire 5810T
 RIP: 0010:[<ffffffffa04550a7>]  [<ffffffffa04550a7>] drm_fb_helper_setcmap+0xa7/0x390 [drm_kms_helper]
 RSP: 0018:ffff8801329f3908  EFLAGS: 00010206
 RAX: 0000000000000010 RBX: 0000000000000020 RCX: 0000000000000000
 RDX: ffff880132b57a00 RSI: 000000000000000f RDI: ffff880132b57050
 RBP: ffff8801329f39b8 R08: 0000000000000000 R09: ffff880130158800
 R10: 2222222222222222 R11: 00000000000000ff R12: 0000000000000010
 R13: ffff880132b570b0 R14: ffff880132b57000 R15: 0000000000000010
 FS:  00007fa9d195f700(0000) GS:ffff880002800000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
 CR2: ffff880130158978 CR3: 00000001329a1000 CR4: 00000000000406f0
 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
 DR3: 0000000000000000 DR6: 00000000ffff4ff0 DR7: 0000000000000400
  [<ffffffffa0404805>] fb_set_cmap+0x65/0x150 [fb]
  [<ffffffffa0401672>] fb_set_var+0x1a2/0x390 [fb]
  [<ffffffffa01258cc>] fbcon_blank+0x17c/0x250 [fbcon]
  [<ffffffff81342193>] do_unblank_screen+0xa3/0x170
  [<ffffffff81338029>] complete_change_console+0x59/0xf0
  [<ffffffff81339c52>] vt_ioctl+0x1af2/0x1d90
  [<ffffffff8132e0ad>] tty_ioctl+0x9d/0x9a0
  [<ffffffff8113b4d8>] vfs_ioctl+0x38/0xd0
  [<ffffffff8113b6aa>] do_vfs_ioctl+0x8a/0x580
  [<ffffffff8113bbea>] sys_ioctl+0x4a/0x80
  [<ffffffff81002dab>] system_call_fastpath+0x16/0x1b
  [<ffffffffffffffff>] 0xffffffffffffffff
 WARNING: kmemcheck: Caught 16-bit read from uninitialized memory (ffff880132b57820)
 0000000000000000000000000000000000000000000000000000000000000000
  u u u u u u u u u u u u u u u u u u u u u u u u u u u u u u u u
  ^
 
 Pid: 3852, comm: Xorg Tainted: G          I 2.6.35.6-tuxonice-debug #2 Aspire 5810T/Aspire 5810T
 RIP: 0010:[<ffffffffa04550b2>]  [<ffffffffa04550b2>] drm_fb_helper_setcmap+0xb2/0x390 [drm_kms_helper]
 RSP: 0018:ffff8801329f3908  EFLAGS: 00010206
 RAX: 0000000000000010 RBX: 0000000000000020 RCX: 0000000000000000
 RDX: ffff880132b57800 RSI: 000000000000000f RDI: ffff880132b57050
 RBP: ffff8801329f39b8 R08: 0000000000000000 R09: ffff880130158800
 R10: 2222222222222222 R11: 00000000000000ff R12: 0000000000000010
 R13: ffff880132b570b0 R14: ffff880132b57000 R15: 0000000000000010
 FS:  00007fa9d195f700(0000) GS:ffff880002800000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
 CR2: ffff880130158978 CR3: 00000001329a1000 CR4: 00000000000406f0
 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
 DR3: 0000000000000000 DR6: 00000000ffff4ff0 DR7: 0000000000000400
  [<ffffffffa0404805>] fb_set_cmap+0x65/0x150 [fb]
  [<ffffffffa0401672>] fb_set_var+0x1a2/0x390 [fb]
  [<ffffffffa01258cc>] fbcon_blank+0x17c/0x250 [fbcon]
  [<ffffffff81342193>] do_unblank_screen+0xa3/0x170
  [<ffffffff81338029>] complete_change_console+0x59/0xf0
  [<ffffffff81339c52>] vt_ioctl+0x1af2/0x1d90
  [<ffffffff8132e0ad>] tty_ioctl+0x9d/0x9a0
  [<ffffffff8113b4d8>] vfs_ioctl+0x38/0xd0
  [<ffffffff8113b6aa>] do_vfs_ioctl+0x8a/0x580
  [<ffffffff8113bbea>] sys_ioctl+0x4a/0x80
  [<ffffffff81002dab>] system_call_fastpath+0x16/0x1b
  [<ffffffffffffffff>] 0xffffffffffffffff
 WARNING: kmemcheck: Caught 16-bit read from uninitialized memory (ffff880132b57620)
 0000000000000000000000000000000000000000000000000000000000000000
  u u u u u u u u u u u u u u u u u u u u u u u u u u u u u u u u
  ^
 
 Pid: 3852, comm: Xorg Tainted: G          I 2.6.35.6-tuxonice-debug #2 Aspire 5810T/Aspire 5810T
 RIP: 0010:[<ffffffffa04550bb>]  [<ffffffffa04550bb>] drm_fb_helper_setcmap+0xbb/0x390 [drm_kms_helper]
 RSP: 0018:ffff8801329f3908  EFLAGS: 00010206
 RAX: 0000000000000010 RBX: 0000000000000020 RCX: 0000000000000000
 RDX: ffff880132b57600 RSI: 000000000000000f RDI: ffff880132b57050
 RBP: ffff8801329f39b8 R08: 0000000000000000 R09: ffff880130158800
 R10: 2222222222222222 R11: 0000000000000000 R12: 0000000000000010
 R13: ffff880132b570b0 R14: ffff880132b57000 R15: 0000000000000010
 FS:  00007fa9d195f700(0000) GS:ffff880002800000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
 CR2: ffff880130158978 CR3: 00000001329a1000 CR4: 00000000000406f0
 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
 DR3: 0000000000000000 DR6: 00000000ffff4ff0 DR7: 0000000000000400
  [<ffffffffa0404805>] fb_set_cmap+0x65/0x150 [fb]
  [<ffffffffa0401672>] fb_set_var+0x1a2/0x390 [fb]
  [<ffffffffa01258cc>] fbcon_blank+0x17c/0x250 [fbcon]
  [<ffffffff81342193>] do_unblank_screen+0xa3/0x170
  [<ffffffff81338029>] complete_change_console+0x59/0xf0
  [<ffffffff81339c52>] vt_ioctl+0x1af2/0x1d90
  [<ffffffff8132e0ad>] tty_ioctl+0x9d/0x9a0
  [<ffffffff8113b4d8>] vfs_ioctl+0x38/0xd0
  [<ffffffff8113b6aa>] do_vfs_ioctl+0x8a/0x580
  [<ffffffff8113bbea>] sys_ioctl+0x4a/0x80
  [<ffffffff81002dab>] system_call_fastpath+0x16/0x1b
  [<ffffffffffffffff>] 0xffffffffffffffff
 WARNING: kmemcheck: Caught 16-bit read from uninitialized memory (ffff880132b57a22)
 0000000000000000000000000000000000000000000000000000000000000000
  i i u u u u u u u u u u u u u u u u u u u u u u u u u u u u u u
      ^
 
 Pid: 3852, comm: Xorg Tainted: G          I 2.6.35.6-tuxonice-debug #2 Aspire 5810T/Aspire 5810T
 RIP: 0010:[<ffffffffa04550a7>]  [<ffffffffa04550a7>] drm_fb_helper_setcmap+0xa7/0x390 [drm_kms_helper]
 RSP: 0018:ffff8801329f3908  EFLAGS: 00010212
 RAX: 0000000000000011 RBX: 0000000000000022 RCX: 0000000000000000
 RDX: ffff880132b57a00 RSI: 0000000000000010 RDI: ffff880132b57050
 RBP: ffff8801329f39b8 R08: 0000000000000000 R09: ffff880130158800
 R10: 2222222222222222 R11: 0000000000000000 R12: 0000000000000011
 R13: ffff880132b570b0 R14: ffff880132b57000 R15: 0000000000000011
 FS:  00007fa9d195f700(0000) GS:ffff880002800000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
 CR2: ffff880130158978 CR3: 00000001329a1000 CR4: 00000000000406f0
 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
 DR3: 0000000000000000 DR6: 00000000ffff4ff0 DR7: 0000000000000400
  [<ffffffffa0404805>] fb_set_cmap+0x65/0x150 [fb]
  [<ffffffffa0401672>] fb_set_var+0x1a2/0x390 [fb]
  [<ffffffffa01258cc>] fbcon_blank+0x17c/0x250 [fbcon]
  [<ffffffff81342193>] do_unblank_screen+0xa3/0x170
  [<ffffffff81338029>] complete_change_console+0x59/0xf0
  [<ffffffff81339c52>] vt_ioctl+0x1af2/0x1d90
  [<ffffffff8132e0ad>] tty_ioctl+0x9d/0x9a0
  [<ffffffff8113b4d8>] vfs_ioctl+0x38/0xd0
  [<ffffffff8113b6aa>] do_vfs_ioctl+0x8a/0x580
  [<ffffffff8113bbea>] sys_ioctl+0x4a/0x80
  [<ffffffff81002dab>] system_call_fastpath+0x16/0x1b
  [<ffffffffffffffff>] 0xffffffffffffffff
 WARNING: kmemcheck: Caught 16-bit read from uninitialized memory (ffff880132b57822)
 0000000000000000000000000000000000000000000000000000000000000000
  i i u u u u u u u u u u u u u u u u u u u u u u u u u u u u u u
      ^
 
 Pid: 3852, comm: Xorg Tainted: G          I 2.6.35.6-tuxonice-debug #2 Aspire 5810T/Aspire 5810T
 RIP: 0010:[<ffffffffa04550b2>]  [<ffffffffa04550b2>] drm_fb_helper_setcmap+0xb2/0x390 [drm_kms_helper]
 RSP: 0018:ffff8801329f3908  EFLAGS: 00010212
 RAX: 0000000000000011 RBX: 0000000000000022 RCX: 0000000000000000
 RDX: ffff880132b57800 RSI: 0000000000000010 RDI: ffff880132b57050
 RBP: ffff8801329f39b8 R08: 0000000000000000 R09: ffff880130158800
 R10: 2222222222222222 R11: 0000000000000000 R12: 0000000000000011
 R13: ffff880132b570b0 R14: ffff880132b57000 R15: 0000000000000011
 FS:  00007fa9d195f700(0000) GS:ffff880002800000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
 CR2: ffff880130158978 CR3: 00000001329a1000 CR4: 00000000000406f0
 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
 DR3: 0000000000000000 DR6: 00000000ffff4ff0 DR7: 0000000000000400
  [<ffffffffa0404805>] fb_set_cmap+0x65/0x150 [fb]
  [<ffffffffa0401672>] fb_set_var+0x1a2/0x390 [fb]
  [<ffffffffa01258cc>] fbcon_blank+0x17c/0x250 [fbcon]
  [<ffffffff81342193>] do_unblank_screen+0xa3/0x170
  [<ffffffff81338029>] complete_change_console+0x59/0xf0
  [<ffffffff81339c52>] vt_ioctl+0x1af2/0x1d90
  [<ffffffff8132e0ad>] tty_ioctl+0x9d/0x9a0
  [<ffffffff8113b4d8>] vfs_ioctl+0x38/0xd0
  [<ffffffff8113b6aa>] do_vfs_ioctl+0x8a/0x580
  [<ffffffff8113bbea>] sys_ioctl+0x4a/0x80
  [<ffffffff81002dab>] system_call_fastpath+0x16/0x1b
  [<ffffffffffffffff>] 0xffffffffffffffff
 WARNING: kmemcheck: Caught 16-bit read from uninitialized memory (ffff880132b57622)
 0000000000000000000000000000000000000000000000000000000000000000
  i i u u u u u u u u u u u u u u u u u u u u u u u u u u u u u u
      ^
 
 Pid: 3852, comm: Xorg Tainted: G          I 2.6.35.6-tuxonice-debug #2 Aspire 5810T/Aspire 5810T
 RIP: 0010:[<ffffffffa04550bb>]  [<ffffffffa04550bb>] drm_fb_helper_setcmap+0xbb/0x390 [drm_kms_helper]
 RSP: 0018:ffff8801329f3908  EFLAGS: 00010212
 RAX: 0000000000000011 RBX: 0000000000000022 RCX: 0000000000000000
 RDX: ffff880132b57600 RSI: 0000000000000010 RDI: ffff880132b57050
 RBP: ffff8801329f39b8 R08: 0000000000000000 R09: ffff880130158800
 R10: 2222222222222222 R11: 0000000000000000 R12: 0000000000000011
 R13: ffff880132b570b0 R14: ffff880132b57000 R15: 0000000000000011
 FS:  00007fa9d195f700(0000) GS:ffff880002800000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
 CR2: ffff880130158978 CR3: 00000001329a1000 CR4: 00000000000406f0
 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
 DR3: 0000000000000000 DR6: 00000000ffff4ff0 DR7: 0000000000000400
  [<ffffffffa0404805>] fb_set_cmap+0x65/0x150 [fb]
  [<ffffffffa0401672>] fb_set_var+0x1a2/0x390 [fb]
  [<ffffffffa01258cc>] fbcon_blank+0x17c/0x250 [fbcon]
  [<ffffffff81342193>] do_unblank_screen+0xa3/0x170
  [<ffffffff81338029>] complete_change_console+0x59/0xf0
  [<ffffffff81339c52>] vt_ioctl+0x1af2/0x1d90
  [<ffffffff8132e0ad>] tty_ioctl+0x9d/0x9a0
  [<ffffffff8113b4d8>] vfs_ioctl+0x38/0xd0
  [<ffffffff8113b6aa>] do_vfs_ioctl+0x8a/0x580
  [<ffffffff8113bbea>] sys_ioctl+0x4a/0x80
  [<ffffffff81002dab>] system_call_fastpath+0x16/0x1b
  [<ffffffffffffffff>] 0xffffffffffffffff
Comment 1 Daniel Vetter 2012-03-25 14:23:46 UTC 
Without debug information it's pretty much nigh to impossible to reliably decode these. Also, kernel 2.6.35 is rather old. Please reopen if you have up-to-date traces or if you can do the basic decoding.