[PATCH v2] drm/ttm: Fix dummy res NULL ptr deref bug
Arunpravin Paneer Selvam
arunpravin.paneerselvam at amd.com
Thu Jul 28 07:04:13 UTC 2022
Hi Andre,
On 7/27/2022 8:56 PM, André Almeida wrote:
> Hi Arunpravin,
>
> Às 02:30 de 27/07/22, Arunpravin Paneer Selvam escreveu:
>> Check the bo->resource value before accessing the resource
>> mem_type.
>>
>> v2: Fix commit description unwrapped warning
>>
>> <log snip>
>> [ 40.191227][ T184] general protection fault, probably for non-canonical address 0xdffffc0000000002: 0000 [#1] SMP KASAN PTI
>> [ 40.192995][ T184] KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017]
>> [ 40.194411][ T184] CPU: 1 PID: 184 Comm: systemd-udevd Not tainted 5.19.0-rc4-00721-gb297c22b7070 #1
>> [ 40.196063][ T184] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.0-debian-1.16.0-4 04/01/2014
>> [ 40.199605][ T184] RIP: 0010:ttm_bo_validate+0x1b3/0x240 [ttm]
>> [ 40.200754][ T184] Code: e8 72 c5 ff ff 83 f8 b8 74 d4 85 c0 75 54 49 8b 9e 58 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 8d 7b 10 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 04 3c 03 7e 44 8b 53 10 31 c0 85 d2 0f 85 58
>> [ 40.203685][ T184] RSP: 0018:ffffc900006df0c8 EFLAGS: 00010202
>> [ 40.204630][ T184] RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 1ffff1102f4bb71b
>> [ 40.205864][ T184] RDX: 0000000000000002 RSI: ffffc900006df208 RDI: 0000000000000010
>> [ 40.207102][ T184] RBP: 1ffff920000dbe1a R08: ffffc900006df208 R09: 0000000000000000
>> [ 40.208394][ T184] R10: ffff88817a5f0000 R11: 0000000000000001 R12: ffffc900006df110
>> [ 40.209692][ T184] R13: ffffc900006df0f0 R14: ffff88817a5db800 R15: ffffc900006df208
>> [ 40.210862][ T184] FS: 00007f6b1d16e8c0(0000) GS:ffff88839d700000(0000) knlGS:0000000000000000
>> [ 40.212250][ T184] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> [ 40.213275][ T184] CR2: 000055a1001d4ff0 CR3: 00000001700f4000 CR4: 00000000000006e0
>> [ 40.214469][ T184] Call Trace:
>> [ 40.214974][ T184] <TASK>
>> [ 40.215438][ T184] ? ttm_bo_bounce_temp_buffer+0x140/0x140 [ttm]
>> [ 40.216572][ T184] ? mutex_spin_on_owner+0x240/0x240
>> [ 40.217456][ T184] ? drm_vma_offset_add+0xaa/0x100 [drm]
>> [ 40.218457][ T184] ttm_bo_init_reserved+0x3d6/0x540 [ttm]
>> [ 40.219410][ T184] ? shmem_get_inode+0x744/0x980
>> [ 40.220231][ T184] ttm_bo_init_validate+0xb1/0x200 [ttm]
>> [ 40.221172][ T184] ? bo_driver_evict_flags+0x340/0x340 [drm_vram_helper]
>> [ 40.222530][ T184] ? ttm_bo_init_reserved+0x540/0x540 [ttm]
>> [ 40.223643][ T184] ? __do_sys_finit_module+0x11a/0x1c0
>> [ 40.224654][ T184] ? __shmem_file_setup+0x102/0x280
>> [ 40.234764][ T184] drm_gem_vram_create+0x305/0x480 [drm_vram_helper]
>> [ 40.235766][ T184] ? bo_driver_evict_flags+0x340/0x340 [drm_vram_helper]
>> [ 40.236846][ T184] ? __kasan_slab_free+0x108/0x180
>> [ 40.237650][ T184] drm_gem_vram_fill_create_dumb+0x134/0x340 [drm_vram_helper]
>> [ 40.238864][ T184] ? local_pci_probe+0xdf/0x180
>> [ 40.239674][ T184] ? drmm_vram_helper_init+0x400/0x400 [drm_vram_helper]
>> [ 40.240826][ T184] drm_client_framebuffer_create+0x19c/0x400 [drm]
>> [ 40.241955][ T184] ? drm_client_buffer_delete+0x200/0x200 [drm]
>> [ 40.243001][ T184] ? drm_client_pick_crtcs+0x554/0xb80 [drm]
>> [ 40.244030][ T184] drm_fb_helper_generic_probe+0x23f/0x940 [drm_kms_helper]
>> [ 40.245226][ T184] ? __cond_resched+0x1c/0xc0
>> [ 40.245987][ T184] ? drm_fb_helper_memory_range_to_clip+0x180/0x180 [drm_kms_helper]
>> [ 40.247316][ T184] ? mutex_unlock+0x80/0x100
>> [ 40.248005][ T184] ? __mutex_unlock_slowpath+0x2c0/0x2c0
>> [ 40.249083][ T184] drm_fb_helper_single_fb_probe+0x907/0xf00 [drm_kms_helper]
>> [ 40.250314][ T184] ? drm_fb_helper_check_var+0x1180/0x1180 [drm_kms_helper]
>> [ 40.251540][ T184] ? __cond_resched+0x1c/0xc0
>> [ 40.252321][ T184] ? mutex_lock+0x9f/0x100
>> [ 40.253062][ T184] __drm_fb_helper_initial_config_and_unlock+0xb9/0x2c0 [drm_kms_helper]
>> [ 40.254394][ T184] drm_fbdev_client_hotplug+0x56f/0x840 [drm_kms_helper]
>> [ 40.255477][ T184] drm_fbdev_generic_setup+0x165/0x3c0 [drm_kms_helper]
>> [ 40.256607][ T184] bochs_pci_probe+0x6b7/0x900 [bochs]
>> [ 40.257515][ T184] ? _raw_spin_lock_irqsave+0x87/0x100
>> [ 40.258312][ T184] ? bochs_hw_init+0x480/0x480 [bochs]
>> [ 40.259244][ T184] ? bochs_hw_init+0x480/0x480 [bochs]
>> [ 40.260186][ T184] local_pci_probe+0xdf/0x180
>> [ 40.260928][ T184] pci_call_probe+0x15f/0x500
>> [ 40.265798][ T184] ? _raw_spin_lock+0x81/0x100
>> [ 40.266508][ T184] ? pci_pm_suspend_noirq+0x980/0x980
>> [ 40.267322][ T184] ? pci_assign_irq+0x81/0x280
>> [ 40.268096][ T184] ? pci_match_device+0x351/0x6c0
>> [ 40.268883][ T184] ? kernfs_put+0x18/0x40
>> [ 40.269611][ T184] pci_device_probe+0xee/0x240
>> [ 40.270352][ T184] really_probe+0x435/0xa80
>> [ 40.271021][ T184] __driver_probe_device+0x2ab/0x480
>> [ 40.271828][ T184] driver_probe_device+0x49/0x140
>> [ 40.272627][ T184] __driver_attach+0x1bd/0x4c0
>> [ 40.273372][ T184] ? __device_attach_driver+0x240/0x240
>> [ 40.274273][ T184] bus_for_each_dev+0x11e/0x1c0
>> [ 40.275080][ T184] ? subsys_dev_iter_exit+0x40/0x40
>> [ 40.275951][ T184] ? klist_add_tail+0x132/0x280
>> [ 40.276767][ T184] bus_add_driver+0x39b/0x580
>> [ 40.277574][ T184] driver_register+0x20f/0x3c0
>> [ 40.278281][ T184] ? 0xffffffffc04a2000
>> [ 40.278894][ T184] do_one_initcall+0x8a/0x300
>> [ 40.279642][ T184] ? trace_event_raw_event_initcall_level+0x1c0/0x1c0
>> [ 40.280707][ T184] ? kasan_unpoison+0x23/0x80
>> [ 40.281479][ T184] ? kasan_unpoison+0x23/0x80
>> [ 40.282197][ T184] do_init_module+0x190/0x640
>> [ 40.282926][ T184] load_module+0x221b/0x2780
>> [ 40.283611][ T184] ? layout_and_allocate+0x5c0/0x5c0
>> [ 40.284401][ T184] ? kernel_read_file+0x286/0x6c0
>> [ 40.285216][ T184] ? __x64_sys_fspick+0x2c0/0x2c0
>> [ 40.286043][ T184] ? mmap_region+0x4e7/0x1300
>> [ 40.286832][ T184] ? __do_sys_finit_module+0x11a/0x1c0
>> [ 40.287743][ T184] __do_sys_finit_module+0x11a/0x1c0
>> [ 40.288636][ T184] ? __ia32_sys_init_module+0xc0/0xc0
>> [ 40.289557][ T184] ? __seccomp_filter+0x15e/0xc80
>> [ 40.290341][ T184] ? vm_mmap_pgoff+0x185/0x240
>> [ 40.291060][ T184] do_syscall_64+0x3b/0xc0
>> [ 40.291763][ T184] entry_SYSCALL_64_after_hwframe+0x46/0xb0
>> [ 40.292678][ T184] RIP: 0033:0x7f6b1d6279b9
>> [ 40.293438][ T184] Code: 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d a7 54 0c 00 f7 d8 64 89 01 48
>> [ 40.296302][ T184] RSP: 002b:00007ffe7f51b798 EFLAGS: 00000246 ORIG_RAX: 0000000000000139
>> [ 40.297633][ T184] RAX: ffffffffffffffda RBX: 00005642dcca2880 RCX: 00007f6b1d6279b9
>> [ 40.298890][ T184] RDX: 0000000000000000 RSI: 00007f6b1d7b2e2d RDI: 0000000000000016
>> [ 40.300199][ T184] RBP: 0000000000020000 R08: 0000000000000000 R09: 00005642dccd5530
>> [ 40.301547][ T184] R10: 0000000000000016 R11: 0000000000000246 R12: 00007f6b1d7b2e2d
>> [ 40.302698][ T184] R13: 0000000000000000 R14: 00005642dcca4230 R15: 00005642dcca2880
>>
>> Signed-off-by: Arunpravin Paneer Selvam <Arunpravin.PaneerSelvam at amd.com>
>> Reported-by: kernel test robot <oliver.sang at intel.com>
>> ---
>> drivers/gpu/drm/ttm/ttm_bo.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
>> index c1bd006a5525..590110fdf59c 100644
>> --- a/drivers/gpu/drm/ttm/ttm_bo.c
>> +++ b/drivers/gpu/drm/ttm/ttm_bo.c
>> @@ -912,7 +912,7 @@ int ttm_bo_validate(struct ttm_buffer_object *bo,
>> /*
>> * We might need to add a TTM.
>> */
>> - if (bo->resource->mem_type == TTM_PL_SYSTEM) {
>> + if (!bo->resource || bo->resource->mem_type == TTM_PL_SYSTEM) {
>> ret = ttm_tt_create(bo, true);
>> if (ret)
>> return ret;
>
> bo->resource is accessed a bit earlier in the same function at
>
> ttm_resource_compat(bo->resource, placement)
>
> I wonder if this would need to be check for NULL as well.
In the earlier condition, if bo->resource is NULL, it enters the if
condition and I suspect it
didn't return, hence the control hits the next if condition and access
the bo->resource->mem_type
which results in NULL pointer deference.
Thanks,
Arun
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