On Wed, 12 Apr 2017 10:52:54 +0200,
Ville Syrjälä wrote:
>
> On Wed, Apr 12, 2017 at 09:31:39AM +0100, Chris Wilson wrote:
> > [31908.547136] BUG: KASAN: use-after-free in intel_lpe_audio_teardown+0x78/0xb0 [i915] at addr ffff8801f7788358
> > [31908.547297] Read of size 8 by task drv_selftest/3781
> > [31908.547405] CPU: 0 PID: 3781 Comm: drv_selftest Tainted: G BU W 4.10.0+ #451
> > [31908.547553] Hardware name: / , BIOS PYBSWCEL.86A.0027.2015.0507.1758 05/07/2015
> > [31908.547682] Call Trace:
> > [31908.547772] dump_stack+0x68/0x9f
> > [31908.547857] kasan_object_err+0x1c/0x70
> > [31908.547947] kasan_report_error+0x1f1/0x4f0
> > [31908.548038] ? kfree+0xaa/0x170
> > [31908.548121] kasan_report+0x34/0x40
> > [31908.548211] ? klist_children_get+0x20/0x30
> > [31908.548472] ? intel_lpe_audio_teardown+0x78/0xb0 [i915]
> > [31908.548567] __asan_load8+0x5e/0x70
> > [31908.548824] intel_lpe_audio_teardown+0x78/0xb0 [i915]
> > [31908.549080] intel_audio_deinit+0x28/0x80 [i915]
> > [31908.549315] i915_driver_unload+0xe4/0x360 [i915]
> > [31908.549551] ? i915_driver_load+0x1d70/0x1d70 [i915]
> > [31908.549651] ? trace_hardirqs_on+0xd/0x10
> > [31908.549885] i915_pci_remove+0x23/0x30 [i915]
> > [31908.549978] pci_device_remove+0x5c/0x100
> > [31908.550069] device_release_driver_internal+0x1db/0x2e0
> > [31908.550165] driver_detach+0x68/0xc0
> > [31908.550256] bus_remove_driver+0x8b/0x150
> > [31908.550346] driver_unregister+0x3e/0x60
> > [31908.550439] pci_unregister_driver+0x1d/0x110
> > [31908.550531] ? find_module_all+0x7a/0xa0
> > [31908.550791] i915_exit+0x1a/0x87 [i915]
> > [31908.550881] SyS_delete_module+0x264/0x2c0
> > [31908.550971] ? free_module+0x430/0x430
> > [31908.551064] ? trace_hardirqs_off_caller+0x16/0x110
> > [31908.551159] ? trace_hardirqs_on_caller+0x16/0x280
> > [31908.551256] ? trace_hardirqs_on_thunk+0x1a/0x1c
> > [31908.551350] entry_SYSCALL_64_fastpath+0x1c/0xb1
> > [31908.551440] RIP: 0033:0x7f1d67312ec7
> > [31908.551520] RSP: 002b:00007ffebe34e888 EFLAGS: 00000206 ORIG_RAX: 00000000000000b0
> > [31908.551650] RAX: ffffffffffffffda RBX: ffffffff811123f6 RCX: 00007f1d67312ec7
> > [31908.551743] RDX: 0000000000000000 RSI: 0000000000000800 RDI: 0000560d0af476b8
> > [31908.551837] RBP: ffff880233d87f98 R08: 0000000000000000 R09: 00007ffebe34e8b8
> > [31908.551930] R10: 00007f1d68adf8c0 R11: 0000000000000206 R12: 0000000000000000
> > [31908.552023] R13: 0000560d0af46440 R14: 0000000000000034 R15: 00007ffebe34d860
> > [31908.552121] ? trace_hardirqs_off_caller+0x16/0x110
> > [31908.552217] Object at ffff8801f7788000, in cache kmalloc-2048 size: 2048
> > [31908.552306] Allocated:
> > [31908.552377] PID = 3781
> > [31908.552456] save_stack_trace+0x16/0x20
> > [31908.552539] kasan_kmalloc+0xee/0x190
> > [31908.552627] __kmalloc+0xdb/0x1b0
> > [31908.552713] platform_device_alloc+0x27/0x90
> > [31908.552804] platform_device_register_full+0x36/0x220
> > [31908.553066] intel_lpe_audio_init+0x41e/0x570 [i915]
> > [31908.553320] intel_audio_init+0xd/0x40 [i915]
> > [31908.553552] i915_driver_load+0x13f5/0x1d70 [i915]
> > [31908.553788] i915_pci_probe+0x65/0xe0 [i915]
> > [31908.553881] pci_device_probe+0xda/0x140
> > [31908.553969] driver_probe_device+0x400/0x660
> > [31908.554058] __driver_attach+0x11c/0x120
> > [31908.554147] bus_for_each_dev+0xe6/0x150
> > [31908.554237] driver_attach+0x26/0x30
> > [31908.554325] bus_add_driver+0x26b/0x3b0
> > [31908.554412] driver_register+0xce/0x190
> > [31908.554502] __pci_register_driver+0xaf/0xc0
> > [31908.554589] 0xffffffffa0550063
> > [31908.554675] do_one_initcall+0x8b/0x1e0
> > [31908.554764] do_init_module+0x102/0x325
> > [31908.554852] load_module+0x3aad/0x45e0
> > [31908.554944] SyS_finit_module+0x169/0x1a0
> > [31908.555033] entry_SYSCALL_64_fastpath+0x1c/0xb1
> > [31908.555119] Freed:
> > [31908.555188] PID = 3781
> > [31908.555266] save_stack_trace+0x16/0x20
> > [31908.555349] kasan_slab_free+0xb0/0x180
> > [31908.555436] kfree+0xaa/0x170
> > [31908.555520] platform_device_release+0x76/0x80
> > [31908.555610] device_release+0x45/0xe0
> > [31908.555698] kobject_put+0x11f/0x260
> > [31908.555785] put_device+0x12/0x20
> > [31908.555871] platform_device_unregister+0x1b/0x20
> > [31908.556135] intel_lpe_audio_teardown+0x5c/0xb0 [i915]
> > [31908.556390] intel_audio_deinit+0x28/0x80 [i915]
> > [31908.556622] i915_driver_unload+0xe4/0x360 [i915]
> > [31908.556858] i915_pci_remove+0x23/0x30 [i915]
> > [31908.556948] pci_device_remove+0x5c/0x100
> > [31908.557037] device_release_driver_internal+0x1db/0x2e0
> > [31908.557129] driver_detach+0x68/0xc0
> > [31908.557217] bus_remove_driver+0x8b/0x150
> > [31908.557304] driver_unregister+0x3e/0x60
> > [31908.557394] pci_unregister_driver+0x1d/0x110
> > [31908.557653] i915_exit+0x1a/0x87 [i915]
> > [31908.557741] SyS_delete_module+0x264/0x2c0
> > [31908.557834] entry_SYSCALL_64_fastpath+0x1c/0xb1
> > [31908.557919] Memory state around the buggy address:
> > [31908.558005] ffff8801f7788200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> > [31908.558127] ffff8801f7788280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> > [31908.558255] >ffff8801f7788300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> > [31908.558374] ^
> > [31908.558467] ffff8801f7788380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> > [31908.558595] ffff8801f7788400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> >
> > v2: Just leak the memory (8 bytes) as freeing it ourselves is not safe,
> > and we need to coordinate a proper fix in platform_device itself.
> > v3: Use dma_coerce_mask_and_coherent() to skip the kmalloc
> >
> > Fixes: eef57324d926 ("drm/i915: setup bridge for HDMI LPE audio driver")
> > Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
> > Cc: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>
> > Cc: Jerome Anand <jerome.anand@xxxxxxxxx>
> > Cc: Jani Nikula <jani.nikula@xxxxxxxxx>
> > Cc: Takashi Iwai <tiwai@xxxxxxx>
> > Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> > Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
> > ---
> > drivers/gpu/drm/i915/intel_lpe_audio.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/intel_lpe_audio.c b/drivers/gpu/drm/i915/intel_lpe_audio.c
> > index d8ca187ae001..dace2fb3154f 100644
> > --- a/drivers/gpu/drm/i915/intel_lpe_audio.c
> > +++ b/drivers/gpu/drm/i915/intel_lpe_audio.c
> > @@ -108,7 +108,6 @@ lpe_audio_platdev_create(struct drm_i915_private *dev_priv)
> > pinfo.num_res = 2;
> > pinfo.data = pdata;
> > pinfo.size_data = sizeof(*pdata);
> > - pinfo.dma_mask = DMA_BIT_MASK(32);
> >
> > spin_lock_init(&pdata->lpe_audio_slock);
> >
> > @@ -119,6 +118,8 @@ lpe_audio_platdev_create(struct drm_i915_private *dev_priv)
> > goto err;
> > }
> >
> > + dma_coerce_mask_and_coherent(&platdev->dev, DMA_BIT_MASK(32));
> > +
>
> Not sure how racy that is since we've already registered the platdev at
> that point. The whole platform_register_full() API looks misdesigned to
> me since you can't do stuff between alloc and register.
>
> We could shovel the dma_coerce_mask_and_coherent() call into
> platform_register_full() itself I suppose. Or we just stop using the
> register_full() stuff and do each step ourselves, but that looks a bit
> tedious.
Agreed. Through a quick glance, I couldn't find any caller that uses
dev_mask and coherent_mask individually. We can clean up the whole
mess like below.
The platform_device_register_full() doesn't necessarily support all
use-cases. If anyone really needs the separated dev_mask from the
coherent_dma_mask, they should do manually.
thanks,
Takashi
---
diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index c4af00385502..d7e160b212b2 100644
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c
@@ -504,21 +504,8 @@ struct platform_device *platform_device_register_full(
pdev->dev.parent = pdevinfo->parent;
pdev->dev.fwnode = pdevinfo->fwnode;
- if (pdevinfo->dma_mask) {
- /*
- * This memory isn't freed when the device is put,
- * I don't have a nice idea for that though. Conceptually
- * dma_mask in struct device should not be a pointer.
- * See http://thread.gmane.org/gmane.linux.kernel.pci/9081
- */
- pdev->dev.dma_mask =
- kmalloc(sizeof(*pdev->dev.dma_mask), GFP_KERNEL);
- if (!pdev->dev.dma_mask)
- goto err;
-
- *pdev->dev.dma_mask = pdevinfo->dma_mask;
- pdev->dev.coherent_dma_mask = pdevinfo->dma_mask;
- }
+ if (pdevinfo->dma_mask)
+ dma_coerce_mask_and_coherent(&pdev->dev, pdevinfo->dma_mask);
ret = platform_device_add_resources(pdev,
pdevinfo->res, pdevinfo->num_res);
@@ -541,7 +528,6 @@ struct platform_device *platform_device_register_full(
if (ret) {
err:
ACPI_COMPANION_SET(&pdev->dev, NULL);
- kfree(pdev->dev.dma_mask);
err_alloc:
platform_device_put(pdev);
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