Re: [PATCH v4 2/2] dma: add IOMMU static calls with clear default ops
From: Nícolas F. R. A. Prado
Date: Wed Sep 04 2024 - 11:06:15 EST
On Wed, Jul 24, 2024 at 09:04:49PM +0300, Leon Romanovsky wrote:
> From: Leon Romanovsky <leonro@xxxxxxxxxx>
>
> Most of the arch DMA ops (which often, but not always, involve
> some sort of IOMMU) are using the same DMA operations, but for all
> modern platforms dma-iommu implementation is really matters.
>
> So let's make sure to call them directly without need to perform
> function pointers dereference.
>
> During system initialization, the arch can set its own DMA and in such
> case, the default DMA operations will be overridden.
>
> Signed-off-by: Leon Romanovsky <leonro@xxxxxxxxxx>
> Signed-off-by: Leon Romanovsky <leon@xxxxxxxxxx>
> ---
Hi,
KernelCI has identified a boot regression originating from this patch. I've
verified that reverting the patch fixes the issue.
Affected platforms:
* sc7180-trogdor-kingoftown
* sc7180-trogdor-lazor-limozeen
Relevant kernel log:
[ 5.790809] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000040
[ 5.799844] Mem abort info:
[ 5.799846] ESR = 0x0000000096000006
[ 5.808708] EC = 0x25: DABT (current EL), IL = 32 bits
[ 5.808712] SET = 0, FnV = 0
[ 5.808714] EA = 0, S1PTW = 0
[ 5.818465] FSC = 0x06: level 2 translation fault
[ 5.818468] Data abort info:
[ 5.818469] ISV = 0, ISS = 0x00000006, ISS2 = 0x00000000
[ 5.827063] CM = 0, WnR = 0, TnD = 0, TagAccess = 0
[ 5.827065] GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
[ 5.838768] user pgtable: 4k pages, 48-bit VAs, pgdp=00000000d20bb000
[ 5.838771] [0000000000000040] pgd=08000000d20c1003
[ 5.863071] , p4d=08000000d20c1003
[ 5.898011] , pud=08000000d20c2003, pmd=0000000000000000
[ 5.898014] Internal error: Oops: 0000000096000006 [#1] PREEMPT SMP
[ 5.898016] Modules linked in: ipv6 hci_uart venus_core btqca v4l2_mem2mem btrtl qcom_spmi_adc5 sbs_battery btbcm qcom_vadc_common cros_ec_typec videobuf2_v4l2 leds_cros_ec cros_kbd_led_backlight cros_ec_chardev videodev elan_i2c videobuf2_common qcom_stats mc bluetooth coresight_stm stm_core ecdh_generic ecc pwrseq_core panel_edp icc_bwmon ath10k_snoc ath10k_core ath mac80211 phy_qcom_qmp_combo aux_bridge libarc4 coresight_replicator coresight_etm4x coresight_tmc coresight_funnel cfg80211 rfkill coresight qcom_wdt cbmem ramoops reed_solomon pwm_bl coreboot_table backlight crct10dif_ce
[ 5.898057] CPU: 7 UID: 0 PID: 70 Comm: kworker/u32:4 Not tainted 6.11.0-rc6-next-20240903-00003-gdfc6015d0711 #660
[ 5.898061] Hardware name: Google Lazor Limozeen without Touchscreen (rev5 - rev8) (DT)
[ 5.898062] Workqueue: events_unbound deferred_probe_work_func
[ 5.904227] hub 2-1:1.0: 4 ports detected
[ 5.906827]
[ 5.906828] pstate: 80400009 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[ 5.906831] pc : dma_common_alloc_pages+0x54/0x1b4
[ 5.906837] lr : dma_common_alloc_pages+0x4c/0x1b4
[ 5.906839] sp : ffff8000807d3730
[ 5.906840] x29: ffff8000807d3730 x28: ffff02a7d312f880 x27: 0000000000000001
[ 5.906843] x26: 000000000000c000 x25: 0000000000000000 x24: 0000000000000001
[ 5.906845] x23: ffff02a7d23b6898 x22: 0000000000006cc0 x21: 000000000000c000
[ 5.906847] x20: ffff02a7858bf410 x19: fffffe0a60006000 x18: 0000000000000001
[ 5.906850] x17: 00000000000000d5 x16: 1fffe054f0bcc261 x15: 0000000000000001
[ 5.906852] x14: ffff02a7844dc680 x13: 0000000000100180 x12: dead000000000100
[ 5.906855] x11: dead000000000122 x10: 00000000001001ff x9 : ffff02a87f7b7b00
[ 5.906857] x8 : ffff02a87f7b7b00 x7 : ffff405977d6b000 x6 : ffff8000807d3310
[ 5.906860] x5 : ffff02a87f6b6398 x4 : 0000000000000001 x3 : ffff405977d6b000
[ 6.092491] x2 : ffff02a7844dc600 x1 : 0000000100000000 x0 : fffffe0a60006000
[ 6.099809] Call trace:
[ 6.102327] dma_common_alloc_pages+0x54/0x1b4
[ 6.106895] __dma_alloc_pages+0x68/0x90
[ 6.110921] dma_alloc_pages+0x10/0x1c
[ 6.114772] snd_dma_noncoherent_alloc+0x28/0x8c
[ 6.119514] __snd_dma_alloc_pages+0x30/0x50
[ 6.123897] snd_dma_alloc_dir_pages+0x40/0x80
[ 6.128465] do_alloc_pages+0xb8/0x13c
[ 6.132315] preallocate_pcm_pages+0x6c/0xf8
[ 6.132317] preallocate_pages+0x160/0x1a4
[ 6.132319] snd_pcm_set_managed_buffer_all+0x64/0xb0
[ 6.152964] lpass_platform_pcm_new+0xc0/0xe8
[ 6.157443] snd_soc_pcm_component_new+0x3c/0xc8
[ 6.162184] soc_new_pcm+0x4fc/0x668
[ 6.165853] snd_soc_bind_card+0xabc/0xbac
[ 6.170063] snd_soc_register_card+0xf0/0x108
[ 6.174533] devm_snd_soc_register_card+0x4c/0xa4
[ 6.179361] sc7180_snd_platform_probe+0x180/0x224
[ 6.184285] platform_probe+0x68/0xc0
[ 6.188050] really_probe+0xbc/0x298
[ 6.191717] __driver_probe_device+0x78/0x12c
[ 6.196186] driver_probe_device+0x3c/0x15c
[ 6.200481] __device_attach_driver+0xb8/0x134
[ 6.205047] bus_for_each_drv+0x84/0xe0
[ 6.208985] __device_attach+0x9c/0x188
[ 6.212924] device_initial_probe+0x14/0x20
[ 6.217219] bus_probe_device+0xac/0xb0
[ 6.221157] deferred_probe_work_func+0x88/0xc0
[ 6.225810] process_one_work+0x14c/0x28c
[ 6.229923] worker_thread+0x2cc/0x3d4
[ 6.233773] kthread+0x114/0x118
[ 6.237093] ret_from_fork+0x10/0x20
[ 6.240763] Code: f9411c19 940000c9 aa0003f3 b4000460 (f9402326)
[ 6.247012] ---[ end trace 0000000000000000 ]---
See below for the suspicious hunk.
[..]
> diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
> index 6832fd6f0796..02451e27e0b1 100644
> --- a/kernel/dma/mapping.c
> +++ b/kernel/dma/mapping.c
[..]
> @@ -611,6 +662,8 @@ static struct page *__dma_alloc_pages(struct device *dev, size_t size,
> size = PAGE_ALIGN(size);
> if (dma_alloc_direct(dev, ops))
> return dma_direct_alloc_pages(dev, size, dma_handle, dir, gfp);
> + if (use_dma_iommu(dev))
> + return dma_common_alloc_pages(dev, size, dma_handle, dir, gfp);
Is this check correct? dma_common_alloc_pages uses the dma_ops, but the comment
in dma_iommu said it meant that dma_ops wouldn't be used.
And similarly for dma_common_free_pages below.
> if (!ops->alloc_pages_op)
> return NULL;
> return ops->alloc_pages_op(dev, size, dma_handle, dir, gfp);
> @@ -635,6 +688,8 @@ static void __dma_free_pages(struct device *dev, size_t size, struct page *page,
> size = PAGE_ALIGN(size);
> if (dma_alloc_direct(dev, ops))
> dma_direct_free_pages(dev, size, page, dma_handle, dir);
> + else if (use_dma_iommu(dev))
> + dma_common_free_pages(dev, size, page, dma_handle, dir);
> else if (ops->free_pages)
> ops->free_pages(dev, size, page, dma_handle, dir);
> }
[..]
Please add
Reported-by: Nícolas F. R. A. Prado <nfraprado@xxxxxxxxxxxxx> #KernelCI
when fixing this.
Happy to provide any other details necessary.
#regzbot introduced: next-20240822..20240823
#regzbot title: Null pointer dereference in dma_common_alloc_pages() for sc7180 platforms
Thanks,
Nícolas