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Re: [PATCH v3 01/18] ASoC: dt-bindings: mediatek,mt8365-afe: Add audio afe document

by Krzysztof Kozlowski

On 09/04/2024 15:41, Alexandre Mergnat wrote: > Add MT8365 audio front-end bindings > > Signed-off-by: Alexandre Mergnat <amergnat(a)baylibre.com> > --- > +properties: > + compatible: > + const: mediatek,mt8365-afe-pcm > + > + reg: > + maxItems: 1 > + > + "#sound-dai-cells": > + const: 0 > + > + clocks: > + items: > + - description: 26M clock > + - description: mux for audio clock > + - description: audio i2s0 mck > + - description: audio i2s1 mck > + - description: audio i2s2 mck > + - description: audio i2s3 mck > + - description: engen 1 clock > + - description: engen 2 clock > + - description: audio 1 clock > + - description: audio 2 clock > + - description: mux for i2s0 > + - description: mux for i2s1 > + - description: mux for i2s2 > + - description: mux for i2s3 > + > + clock-names: > + items: > + - const: top_clk26m_clk > + - const: top_audio_sel > + - const: audio_i2s0_m > + - const: audio_i2s1_m > + - const: audio_i2s2_m > + - const: audio_i2s3_m > + - const: engen1 > + - const: engen2 > + - const: aud1 > + - const: aud2 > + - const: i2s0_m_sel > + - const: i2s1_m_sel > + - const: i2s2_m_sel > + - const: i2s3_m_sel > + > + interrupts: > + maxItems: 1 > + > + power-domains: > + maxItems: 1 > + > + mediatek,dmic-mode: > + $ref: /schemas/types.yaml#/definitions/uint32 > + description: > + Indicates how many data pins are used to transmit two channels of PDM > + signal. 1 means two wires, 0 means one wire. Default value is 0. > + enum: > + - 0 # one wire > + - 1 # two wires > + > + mediatek,topckgen: > + $ref: /schemas/types.yaml#/definitions/phandle > + description: The phandle of the mediatek topckgen controller Nothing improved, so again, so something which is not obvious. What is it used for? Why AFE needs topckgen for example? > + > +required: > + - compatible > + - reg > + - clocks > + - clock-names > + - interrupts > + - power-domains > + - mediatek,topckgen > + > +additionalProperties: false > + > +examples: > + - | > + #include <dt-bindings/clock/mediatek,mt8365-clk.h> > + #include <dt-bindings/interrupt-controller/arm-gic.h> > + #include <dt-bindings/interrupt-controller/irq.h> > + #include <dt-bindings/power/mediatek,mt8365-power.h> > + > + soc { > + #address-cells = <2>; > + #size-cells = <2>; > + > + afe@11220000 { Did you implement the comment or decided to keep afe? BTW, whatever "consistency" you have in mind, it does not really matter that much for that example. And for sure do not add incorrect code intentionally just to fix it in next patch. Best regards, Krzysztof

1 month, 1 week

Re: [PATCH] dma-buf: add DMA_BUF_IOCTL_SYNC_PARTIAL support

by Christian König

Am 09.04.24 um 09:32 schrieb Rong Qianfeng: > > 在 2024/4/8 15:58, Christian König 写道: >> Am 07.04.24 um 09:50 schrieb Rong Qianfeng: >>> [SNIP] >>>> Am 13.11.21 um 07:22 schrieb Jianqun Xu: >>>>> Add DMA_BUF_IOCTL_SYNC_PARTIAL support for user to sync dma-buf with >>>>> offset and len. >>>> >>>> You have not given an use case for this so it is a bit hard to >>>> review. And from the existing use cases I don't see why this should >>>> be necessary. >>>> >>>> Even worse from the existing backend implementation I don't even >>>> see how drivers should be able to fulfill this semantics. >>>> >>>> Please explain further, >>>> Christian. >>> Here is a practical case: >>> The user space can allocate a large chunk of dma-buf for >>> self-management, used as a shared memory pool. >>> Small dma-buf can be allocated from this shared memory pool and >>> released back to it after use, thus improving the speed of dma-buf >>> allocation and release. >>> Additionally, custom functionalities such as memory statistics and >>> boundary checking can be implemented in the user space. >>> Of course, the above-mentioned functionalities require the >>> implementation of a partial cache sync interface. >> >> Well that is obvious, but where is the code doing that? >> >> You can't send out code without an actual user of it. That will >> obviously be rejected. >> >> Regards, >> Christian. > > In fact, we have already used the user-level dma-buf memory pool in > the camera shooting scenario on the phone. > > From the test results, The execution time of the photo shooting > algorithm has been reduced from 3.8s to 3s. > > To be honest, I didn't understand your concern "...how drivers should > be able to fulfill this semantics." Can you please help explain it in > more detail? Well you don't give any upstream driver code which actually uses this interface. If you want to suggest some changes to the core Linux kernel your driver actually needs to be upstream. As long as that isn't the case this approach here is a completely no-go. Regards, Christian. > > Thanks, > > Rong Qianfeng. > >> >>> >>> Thanks >>> Rong Qianfeng. >>

1 month, 1 week

Re: [PATCH v3 2/2] misc: sram: Add DMA-BUF Heap exporting of SRAM areas

by Andrew Davis

On 4/9/24 7:06 AM, Pascal FONTAIN wrote: > From: Andrew Davis <afd(a)ti.com> > > This new export type exposes to userspace the SRAM area as a DMA-BUF > Heap, > this allows for allocations of DMA-BUFs that can be consumed by various > DMA-BUF supporting devices. > > Signed-off-by: Andrew Davis <afd(a)ti.com> > Tested-by: Pascal Fontain <pascal.fontain(a)bachmann.info> > --- The last time I posted this I got this comment[0], for which I didn't really have a good response and so haven't reposted this since then. Bacically this driver is backed by something other than "normal" memory. So we really need to be careful here, the page pointer is really just a cookie to keep track for the real mappings. We might be able to use something similar to dma_get_sgtable() to hide that, but under the hood it would still a bit unsafe[1]. Andrew [0] https://patchwork.kernel.org/project/linux-media/patch/20230713191316.11601… [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/ker… > drivers/misc/Kconfig | 7 + > drivers/misc/Makefile | 1 + > drivers/misc/sram-dma-heap.c | 246 +++++++++++++++++++++++++++++++++++ > drivers/misc/sram.c | 6 + > drivers/misc/sram.h | 16 +++ > 5 files changed, 276 insertions(+) > create mode 100644 drivers/misc/sram-dma-heap.c > > diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig > index 9e4ad4d61f06..e6674e913168 100644 > --- a/drivers/misc/Kconfig > +++ b/drivers/misc/Kconfig > @@ -448,6 +448,13 @@ config SRAM > config SRAM_EXEC > bool > > +config SRAM_DMA_HEAP > + bool "Export on-chip SRAM pools using DMA-Heaps" > + depends on DMABUF_HEAPS && SRAM > + help > + This driver allows the export of on-chip SRAM marked as both pool > + and exportable to userspace using the DMA-Heaps interface. > + > config DW_XDATA_PCIE > depends on PCI > tristate "Synopsys DesignWare xData PCIe driver" > diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile > index cdc6405584e3..63effdde5163 100644 > --- a/drivers/misc/Makefile > +++ b/drivers/misc/Makefile > @@ -47,6 +47,7 @@ obj-$(CONFIG_VMWARE_VMCI) += vmw_vmci/ > obj-$(CONFIG_LATTICE_ECP3_CONFIG) += lattice-ecp3-config.o > obj-$(CONFIG_SRAM) += sram.o > obj-$(CONFIG_SRAM_EXEC) += sram-exec.o > +obj-$(CONFIG_SRAM_DMA_HEAP) += sram-dma-heap.o > obj-$(CONFIG_GENWQE) += genwqe/ > obj-$(CONFIG_ECHO) += echo/ > obj-$(CONFIG_CXL_BASE) += cxl/ > diff --git a/drivers/misc/sram-dma-heap.c b/drivers/misc/sram-dma-heap.c > new file mode 100644 > index 000000000000..e5a0bafe8cb9 > --- /dev/null > +++ b/drivers/misc/sram-dma-heap.c > @@ -0,0 +1,246 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * SRAM DMA-Heap userspace exporter > + * > + * Copyright (C) 2019-2022 Texas Instruments Incorporated - https://www.ti.com/ > + * Andrew Davis <afd(a)ti.com> > + */ > + > +#include <linux/dma-mapping.h> > +#include <linux/err.h> > +#include <linux/genalloc.h> > +#include <linux/io.h> > +#include <linux/mm.h> > +#include <linux/scatterlist.h> > +#include <linux/slab.h> > +#include <linux/dma-buf.h> > +#include <linux/dma-heap.h> > + > +#include "sram.h" > + > +struct sram_dma_heap { > + struct dma_heap *heap; > + struct gen_pool *pool; > +}; > + > +struct sram_dma_heap_buffer { > + struct gen_pool *pool; > + struct list_head attachments; > + struct mutex attachments_lock; > + unsigned long len; > + void *vaddr; > + phys_addr_t paddr; > +}; > + > +struct dma_heap_attachment { > + struct device *dev; > + struct sg_table *table; > + struct list_head list; > +}; > + > +static int dma_heap_attach(struct dma_buf *dmabuf, > + struct dma_buf_attachment *attachment) > +{ > + struct sram_dma_heap_buffer *buffer = dmabuf->priv; > + struct dma_heap_attachment *a; > + struct sg_table *table; > + > + a = kzalloc(sizeof(*a), GFP_KERNEL); > + if (!a) > + return -ENOMEM; > + > + table = kmalloc(sizeof(*table), GFP_KERNEL); > + if (!table) { > + kfree(a); > + return -ENOMEM; > + } > + if (sg_alloc_table(table, 1, GFP_KERNEL)) { > + kfree(table); > + kfree(a); > + return -ENOMEM; > + } > + sg_set_page(table->sgl, pfn_to_page(PFN_DOWN(buffer->paddr)), buffer->len, 0); > + > + a->table = table; > + a->dev = attachment->dev; > + INIT_LIST_HEAD(&a->list); > + > + attachment->priv = a; > + > + mutex_lock(&buffer->attachments_lock); > + list_add(&a->list, &buffer->attachments); > + mutex_unlock(&buffer->attachments_lock); > + > + return 0; > +} > + > +static void dma_heap_detatch(struct dma_buf *dmabuf, > + struct dma_buf_attachment *attachment) > +{ > + struct sram_dma_heap_buffer *buffer = dmabuf->priv; > + struct dma_heap_attachment *a = attachment->priv; > + > + mutex_lock(&buffer->attachments_lock); > + list_del(&a->list); > + mutex_unlock(&buffer->attachments_lock); > + > + sg_free_table(a->table); > + kfree(a->table); > + kfree(a); > +} > + > +static struct sg_table *dma_heap_map_dma_buf(struct dma_buf_attachment *attachment, > + enum dma_data_direction direction) > +{ > + struct dma_heap_attachment *a = attachment->priv; > + struct sg_table *table = a->table; > + > + /* > + * As this heap is backed by uncached SRAM memory we do not need to > + * perform any sync operations on the buffer before allowing device > + * domain access. For this reason we use SKIP_CPU_SYNC and also do > + * not use or provide begin/end_cpu_access() dma-buf functions. > + */ > + if (!dma_map_sg_attrs(attachment->dev, table->sgl, table->nents, > + direction, DMA_ATTR_SKIP_CPU_SYNC)) > + return ERR_PTR(-ENOMEM); > + > + return table; > +} > + > +static void dma_heap_unmap_dma_buf(struct dma_buf_attachment *attachment, > + struct sg_table *table, > + enum dma_data_direction direction) > +{ > + dma_unmap_sg_attrs(attachment->dev, table->sgl, table->nents, > + direction, DMA_ATTR_SKIP_CPU_SYNC); > +} > + > +static void dma_heap_dma_buf_release(struct dma_buf *dmabuf) > +{ > + struct sram_dma_heap_buffer *buffer = dmabuf->priv; > + > + gen_pool_free(buffer->pool, (unsigned long)buffer->vaddr, buffer->len); > + kfree(buffer); > +} > + > +static int dma_heap_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma) > +{ > + struct sram_dma_heap_buffer *buffer = dmabuf->priv; > + int ret; > + > + /* SRAM mappings are not cached */ > + vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot); > + > + ret = vm_iomap_memory(vma, buffer->paddr, buffer->len); > + if (ret) > + pr_err("Could not map buffer to userspace\n"); > + > + return ret; > +} > + > +static int dma_heap_vmap(struct dma_buf *dmabuf, struct iosys_map *map) > +{ > + struct sram_dma_heap_buffer *buffer = dmabuf->priv; > + > + iosys_map_set_vaddr(map, buffer->vaddr); > + > + return 0; > +} > + > +static const struct dma_buf_ops sram_dma_heap_buf_ops = { > + .attach = dma_heap_attach, > + .detach = dma_heap_detatch, > + .map_dma_buf = dma_heap_map_dma_buf, > + .unmap_dma_buf = dma_heap_unmap_dma_buf, > + .release = dma_heap_dma_buf_release, > + .mmap = dma_heap_mmap, > + .vmap = dma_heap_vmap, > +}; > + > +static struct dma_buf *sram_dma_heap_allocate(struct dma_heap *heap, > + unsigned long len, > + unsigned long fd_flags, > + unsigned long heap_flags) > +{ > + struct sram_dma_heap *sram_dma_heap = dma_heap_get_drvdata(heap); > + struct sram_dma_heap_buffer *buffer; > + > + DEFINE_DMA_BUF_EXPORT_INFO(exp_info); > + struct dma_buf *dmabuf; > + int ret; > + > + buffer = kzalloc(sizeof(*buffer), GFP_KERNEL); > + if (!buffer) > + return ERR_PTR(-ENOMEM); > + buffer->pool = sram_dma_heap->pool; > + INIT_LIST_HEAD(&buffer->attachments); > + mutex_init(&buffer->attachments_lock); > + buffer->len = len; > + > + buffer->vaddr = (void *)gen_pool_alloc(buffer->pool, buffer->len); > + if (!buffer->vaddr) { > + ret = -ENOMEM; > + goto free_buffer; > + } > + > + buffer->paddr = gen_pool_virt_to_phys(buffer->pool, (unsigned long)buffer->vaddr); > + if (buffer->paddr == -1) { > + ret = -ENOMEM; > + goto free_pool; > + } > + > + /* create the dmabuf */ > + exp_info.exp_name = dma_heap_get_name(heap); > + exp_info.ops = &sram_dma_heap_buf_ops; > + exp_info.size = buffer->len; > + exp_info.flags = fd_flags; > + exp_info.priv = buffer; > + dmabuf = dma_buf_export(&exp_info); > + if (IS_ERR(dmabuf)) { > + ret = PTR_ERR(dmabuf); > + goto free_pool; > + } > + > + return dmabuf; > + > +free_pool: > + gen_pool_free(buffer->pool, (unsigned long)buffer->vaddr, buffer->len); > +free_buffer: > + kfree(buffer); > + > + return ERR_PTR(ret); > +} > + > +static struct dma_heap_ops sram_dma_heap_ops = { > + .allocate = sram_dma_heap_allocate, > +}; > + > +int sram_add_dma_heap(struct sram_dev *sram, > + struct sram_reserve *block, > + phys_addr_t start, > + struct sram_partition *part) > +{ > + struct sram_dma_heap *sram_dma_heap; > + struct dma_heap_export_info exp_info; > + > + dev_info(sram->dev, "Exporting SRAM Heap '%s'\n", block->label); > + > + sram_dma_heap = kzalloc(sizeof(*sram_dma_heap), GFP_KERNEL); > + if (!sram_dma_heap) > + return -ENOMEM; > + sram_dma_heap->pool = part->pool; > + > + exp_info.name = kasprintf(GFP_KERNEL, "sram_%s", block->label); > + exp_info.ops = &sram_dma_heap_ops; > + exp_info.priv = sram_dma_heap; > + sram_dma_heap->heap = dma_heap_add(&exp_info); > + if (IS_ERR(sram_dma_heap->heap)) { > + int ret = PTR_ERR(sram_dma_heap->heap); > + > + kfree(sram_dma_heap); > + return ret; > + } > + > + return 0; > +} > diff --git a/drivers/misc/sram.c b/drivers/misc/sram.c > index 632f90d9bcea..643c77598beb 100644 > --- a/drivers/misc/sram.c > +++ b/drivers/misc/sram.c > @@ -120,6 +120,12 @@ static int sram_add_partition(struct sram_dev *sram, struct sram_reserve *block, > ret = sram_add_pool(sram, block, start, part); > if (ret) > return ret; > + > + if (block->export) { > + ret = sram_add_dma_heap(sram, block, start, part); > + if (ret) > + return ret; > + } > } > if (block->export) { > ret = sram_add_export(sram, block, start, part); > diff --git a/drivers/misc/sram.h b/drivers/misc/sram.h > index 397205b8bf6f..062bdd25fa06 100644 > --- a/drivers/misc/sram.h > +++ b/drivers/misc/sram.h > @@ -60,4 +60,20 @@ static inline int sram_add_protect_exec(struct sram_partition *part) > return -ENODEV; > } > #endif /* CONFIG_SRAM_EXEC */ > + > +#ifdef CONFIG_SRAM_DMA_HEAP > +int sram_add_dma_heap(struct sram_dev *sram, > + struct sram_reserve *block, > + phys_addr_t start, > + struct sram_partition *part); > +#else > +static inline int sram_add_dma_heap(struct sram_dev *sram, > + struct sram_reserve *block, > + phys_addr_t start, > + struct sram_partition *part) > +{ > + return 0; > +} > +#endif /* CONFIG_SRAM_DMA_HEAP */ > + > #endif /* __SRAM_H */

1 month, 1 week

Re: [PATCH v2 04/18] ASoC: dt-bindings: mt6357: Add audio codec document

by Rob Herring

On Tue, 09 Apr 2024 12:13:25 +0200, Alexandre Mergnat wrote: > Add MT8365 audio codec bindings to set required > and optional voltage properties between the codec and the board. > The properties are: > - phandle of the requiered power supply. > - Setup of microphone bias voltage. > - Setup of the speaker pin pull-down. > > Signed-off-by: Alexandre Mergnat <amergnat(a)baylibre.com> > --- > .../devicetree/bindings/sound/mt6357.yaml | 54 ++++++++++++++++++++++ > 1 file changed, 54 insertions(+) > My bot found errors running 'make DT_CHECKER_FLAGS=-m dt_binding_check' on your patch (DT_CHECKER_FLAGS is new in v5.13): yamllint warnings/errors: dtschema/dtc warnings/errors: /builds/robherring/dt-review-ci/linux/Documentation/devicetree/bindings/sound/mt6357.yaml: properties:vaud28-supply: '$ref' is not one of ['description', 'deprecated'] from schema $id: http://devicetree.org/meta-schemas/core.yaml# doc reference errors (make refcheckdocs): See https://patchwork.ozlabs.org/project/devicetree-bindings/patch/20240226-aud… The base for the series is generally the latest rc1. A different dependency should be noted in *this* patch. If you already ran 'make dt_binding_check' and didn't see the above error(s), then make sure 'yamllint' is installed and dt-schema is up to date: pip3 install dtschema --upgrade Please check and re-submit after running the above command yourself. Note that DT_SCHEMA_FILES can be set to your schema file to speed up checking your schema. However, it must be unset to test all examples with your schema.

1 month, 1 week

Re: [PATCH v2 03/18] dt-bindings: mfd: mediatek: Add codec property for MT6357 PMIC

by Rob Herring

On Tue, 09 Apr 2024 12:13:24 +0200, Alexandre Mergnat wrote: > Add the audio codec sub-device. This sub-device is used to set required > and optional voltage properties between the codec and the board. > > Signed-off-by: Alexandre Mergnat <amergnat(a)baylibre.com> > --- > Documentation/devicetree/bindings/mfd/mediatek,mt6357.yaml | 5 +++++ > 1 file changed, 5 insertions(+) > My bot found errors running 'make DT_CHECKER_FLAGS=-m dt_binding_check' on your patch (DT_CHECKER_FLAGS is new in v5.13): yamllint warnings/errors: dtschema/dtc warnings/errors: /builds/robherring/dt-review-ci/linux/Documentation/devicetree/bindings/mfd/mediatek,mt6357.yaml: Error in referenced schema matching $id: http://devicetree.org/schemas/sound/mt6357.yaml doc reference errors (make refcheckdocs): See https://patchwork.ozlabs.org/project/devicetree-bindings/patch/20240226-aud… The base for the series is generally the latest rc1. A different dependency should be noted in *this* patch. If you already ran 'make dt_binding_check' and didn't see the above error(s), then make sure 'yamllint' is installed and dt-schema is up to date: pip3 install dtschema --upgrade Please check and re-submit after running the above command yourself. Note that DT_SCHEMA_FILES can be set to your schema file to speed up checking your schema. However, it must be unset to test all examples with your schema.

1 month, 1 week

Re: [PATCH] dma-buf: add DMA_BUF_IOCTL_SYNC_PARTIAL support

by Christian König

Am 07.04.24 um 09:50 schrieb Rong Qianfeng: > [SNIP] >> Am 13.11.21 um 07:22 schrieb Jianqun Xu: >>> Add DMA_BUF_IOCTL_SYNC_PARTIAL support for user to sync dma-buf with >>> offset and len. >> >> You have not given an use case for this so it is a bit hard to >> review. And from the existing use cases I don't see why this should >> be necessary. >> >> Even worse from the existing backend implementation I don't even see >> how drivers should be able to fulfill this semantics. >> >> Please explain further, >> Christian. > Here is a practical case: > The user space can allocate a large chunk of dma-buf for > self-management, used as a shared memory pool. > Small dma-buf can be allocated from this shared memory pool and > released back to it after use, thus improving the speed of dma-buf > allocation and release. > Additionally, custom functionalities such as memory statistics and > boundary checking can be implemented in the user space. > Of course, the above-mentioned functionalities require the > implementation of a partial cache sync interface. Well that is obvious, but where is the code doing that? You can't send out code without an actual user of it. That will obviously be rejected. Regards, Christian. > > Thanks > Rong Qianfeng.

1 month, 1 week

[PATCH v9 0/6] iio: new DMABUF based API

by Paul Cercueil

Hi Jonathan, Here's the final-er version of the IIO DMABUF patchset. This v9 fixes the few issues reported by the kernel bot. This was based on next-20240308. Changelog: - [3/6]: - Select DMA_SHARED_BUFFER in Kconfig - Remove useless forward declaration of 'iio_dma_fence' - Import DMA-BUF namespace - Add missing __user tag to iio_buffer_detach_dmabuf() argument Cheers, -Paul Paul Cercueil (6): dmaengine: Add API function dmaengine_prep_peripheral_dma_vec() dmaengine: dma-axi-dmac: Implement device_prep_peripheral_dma_vec iio: core: Add new DMABUF interface infrastructure iio: buffer-dma: Enable support for DMABUFs iio: buffer-dmaengine: Support new DMABUF based userspace API Documentation: iio: Document high-speed DMABUF based API Documentation/iio/iio_dmabuf_api.rst | 54 ++ Documentation/iio/index.rst | 1 + drivers/dma/dma-axi-dmac.c | 40 ++ drivers/iio/Kconfig | 1 + drivers/iio/buffer/industrialio-buffer-dma.c | 181 ++++++- .../buffer/industrialio-buffer-dmaengine.c | 59 ++- drivers/iio/industrialio-buffer.c | 462 ++++++++++++++++++ include/linux/dmaengine.h | 27 + include/linux/iio/buffer-dma.h | 31 ++ include/linux/iio/buffer_impl.h | 30 ++ include/uapi/linux/iio/buffer.h | 22 + 11 files changed, 891 insertions(+), 17 deletions(-) create mode 100644 Documentation/iio/iio_dmabuf_api.rst -- 2.43.0

1 month, 1 week

Re: [PATCH] dmabuf: fix dmabuf file poll uaf issue

by Christian König

Am 02.04.24 um 08:49 schrieb zhiguojiang: >> As far as I can see that's not because of the DMA-buf code, but >> because you are somehow using this interface incorrectly. >> >> When dma_buf_poll() is called it is mandatory for the caller to hold >> a reference to the file descriptor on which the poll operation is >> executed. >> >> So adding code like "if (!file_count(file))" in the beginning of >> dma_buf_poll() is certainly broken. >> >> My best guess is that you have some unbalanced >> dma_buf_get()/dma_buf_put() somewhere instead. >> >> > Hi Christian, > > The kernel dma_buf_poll() code shound not cause system crashes due to > the user mode usage logical issues ? What user mode logical issues are you talking about? Closing a file while polling on it is perfectly valid. dma_buf_poll() is called by the filesystem layer and it's the filesystem layer which should make sure that a file can't be closed while polling for an event. If that doesn't work then you have stumbled over a massive bug in the fs layer. And I have some doubts that this is actually the case. What is more likely is that some driver messes up the reference count and because of this you see an UAF. Anyway as far as I can see the DMA-buf code is correct regarding this. Regards, Christian. > > Thanks > > > 在 2024/4/1 20:22, Christian König 写道: >> Am 27.03.24 um 03:29 schrieb Zhiguo Jiang: >>> The issue is a UAF issue of dmabuf file fd. Throght debugging, we found >>> that the dmabuf file fd is added to the epoll event listener list, and >>> when it is released, it is not removed from the epoll list, which leads >>> to the UAF(Use-After-Free) issue. >> >> As far as I can see that's not because of the DMA-buf code, but >> because you are somehow using this interface incorrectly. >> >> When dma_buf_poll() is called it is mandatory for the caller to hold >> a reference to the file descriptor on which the poll operation is >> executed. >> >> So adding code like "if (!file_count(file))" in the beginning of >> dma_buf_poll() is certainly broken. >> >> My best guess is that you have some unbalanced >> dma_buf_get()/dma_buf_put() somewhere instead. >> >> Regards, >> Christian. >> >>> >>> The UAF issue can be solved by checking dmabuf file->f_count value and >>> skipping the poll operation for the closed dmabuf file in the >>> dma_buf_poll(). We have tested this solved patch multiple times and >>> have not reproduced the uaf issue. >>> >>> crash dump: >>> list_del corruption, ffffff8a6f143a90->next is LIST_POISON1 >>> (dead000000000100) >>> ------------[ cut here ]------------ >>> kernel BUG at lib/list_debug.c:55! >>> Internal error: Oops - BUG: 00000000f2000800 [#1] PREEMPT SMP >>> pc : __list_del_entry_valid+0x98/0xd4 >>> lr : __list_del_entry_valid+0x98/0xd4 >>> sp : ffffffc01d413d00 >>> x29: ffffffc01d413d00 x28: 00000000000000c0 x27: 0000000000000020 >>> x26: 0000000000000000 x25: 0000000000000000 x24: 0000000000080007 >>> x23: ffffff8b22e5dcc0 x22: ffffff88a6be12d0 x21: ffffff8b22e572b0 >>> x20: ffffff80254ed0a0 x19: ffffff8a6f143a00 x18: ffffffda5efed3c0 >>> x17: 6165642820314e4f x16: 53494f505f545349 x15: 4c20736920747865 >>> x14: 6e3e2d3039613334 x13: 2930303130303030 x12: 0000000000000018 >>> x11: ffffff8b6c188000 x10: 00000000ffffffff x9 : 6c8413a194897b00 >>> x8 : 6c8413a194897b00 x7 : 74707572726f6320 x6 : 6c65645f7473696c >>> x5 : ffffff8b6c3b2a3e x4 : ffffff8b6c3b2a40 x3 : ffff103000001005 >>> x2 : 0000000000000001 x1 : 00000000000000c0 x0 : 000000000000004e >>> Call trace: >>> __list_del_entry_valid+0x98/0xd4 >>> dma_buf_file_release+0x48/0x90 >>> __fput+0xf4/0x280 >>> ____fput+0x10/0x20 >>> task_work_run+0xcc/0xf4 >>> do_notify_resume+0x2a0/0x33c >>> el0_svc+0x5c/0xa4 >>> el0t_64_sync_handler+0x68/0xb4 >>> el0t_64_sync+0x1a0/0x1a4 >>> Code: d0006fe0 912c5000 f2fbd5a2 94231a01 (d4210000) >>> ---[ end trace 0000000000000000 ]--- >>> Kernel panic - not syncing: Oops - BUG: Fatal exception >>> SMP: stopping secondary CPUs >>> >>> Signed-off-by: Zhiguo Jiang <justinjiang(a)vivo.com> >>> --- >>> drivers/dma-buf/dma-buf.c | 28 ++++++++++++++++++++++++---- >>> 1 file changed, 24 insertions(+), 4 deletions(-) >>> mode change 100644 => 100755 drivers/dma-buf/dma-buf.c >>> >>> diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c >>> index 8fe5aa67b167..e469dd9288cc >>> --- a/drivers/dma-buf/dma-buf.c >>> +++ b/drivers/dma-buf/dma-buf.c >>> @@ -240,6 +240,10 @@ static __poll_t dma_buf_poll(struct file *file, >>> poll_table *poll) >>> struct dma_resv *resv; >>> __poll_t events; >>> + /* Check if the file exists */ >>> + if (!file_count(file)) >>> + return EPOLLERR; >>> + >>> dmabuf = file->private_data; >>> if (!dmabuf || !dmabuf->resv) >>> return EPOLLERR; >>> @@ -266,8 +270,15 @@ static __poll_t dma_buf_poll(struct file *file, >>> poll_table *poll) >>> spin_unlock_irq(&dmabuf->poll.lock); >>> if (events & EPOLLOUT) { >>> - /* Paired with fput in dma_buf_poll_cb */ >>> - get_file(dmabuf->file); >>> + /* >>> + * Paired with fput in dma_buf_poll_cb, >>> + * Skip poll for the closed file. >>> + */ >>> + if (!get_file_rcu(&dmabuf->file)) { >>> + events &= ~EPOLLOUT; >>> + dcb->active = 0; >>> + goto clear_out_event; >>> + } >>> if (!dma_buf_poll_add_cb(resv, true, dcb)) >>> /* No callback queued, wake up any other waiters */ >>> @@ -277,6 +288,7 @@ static __poll_t dma_buf_poll(struct file *file, >>> poll_table *poll) >>> } >>> } >>> +clear_out_event: >>> if (events & EPOLLIN) { >>> struct dma_buf_poll_cb_t *dcb = &dmabuf->cb_in; >>> @@ -289,8 +301,15 @@ static __poll_t dma_buf_poll(struct file >>> *file, poll_table *poll) >>> spin_unlock_irq(&dmabuf->poll.lock); >>> if (events & EPOLLIN) { >>> - /* Paired with fput in dma_buf_poll_cb */ >>> - get_file(dmabuf->file); >>> + /* >>> + * Paired with fput in dma_buf_poll_cb, >>> + * Skip poll for the closed file. >>> + */ >>> + if (!get_file_rcu(&dmabuf->file)) { >>> + events &= ~EPOLLIN; >>> + dcb->active = 0; >>> + goto clear_in_event; >>> + } >>> if (!dma_buf_poll_add_cb(resv, false, dcb)) >>> /* No callback queued, wake up any other waiters */ >>> @@ -300,6 +319,7 @@ static __poll_t dma_buf_poll(struct file *file, >>> poll_table *poll) >>> } >>> } >>> +clear_in_event: >>> dma_resv_unlock(resv); >>> return events; >>> } >> >

1 month, 2 weeks

Re: [PATCH] dma-buf: Do not build debugfs related code when !CONFIG_DEBUG_FS

by Christian König

Am 01.04.24 um 14:39 schrieb Tvrtko Ursulin: > > On 29/03/2024 00:00, T.J. Mercier wrote: >> On Thu, Mar 28, 2024 at 7:53 AM Tvrtko Ursulin <tursulin(a)igalia.com> >> wrote: >>> >>> From: Tvrtko Ursulin <tursulin(a)ursulin.net> >>> >>> There is no point in compiling in the list and mutex operations >>> which are >>> only used from the dma-buf debugfs code, if debugfs is not compiled in. >>> >>> Put the code in questions behind some kconfig guards and so save >>> some text >>> and maybe even a pointer per object at runtime when not enabled. >>> >>> Signed-off-by: Tvrtko Ursulin <tursulin(a)ursulin.net> >> >> Reviewed-by: T.J. Mercier <tjmercier(a)google.com> > > Thanks! > > How would patches to dma-buf be typically landed? Via what tree I > mean? drm-misc-next? That should go through drm-misc-next. And feel free to add Reviewed-by: Christian König <christian.koenig(a)amd.com> as well. Regards, Christian. > > Regards, > > Tvrtko

1 month, 2 weeks

Re: [PATCH] dmabuf: fix dmabuf file poll uaf issue

by Christian König

Am 27.03.24 um 03:29 schrieb Zhiguo Jiang: > The issue is a UAF issue of dmabuf file fd. Throght debugging, we found > that the dmabuf file fd is added to the epoll event listener list, and > when it is released, it is not removed from the epoll list, which leads > to the UAF(Use-After-Free) issue. As far as I can see that's not because of the DMA-buf code, but because you are somehow using this interface incorrectly. When dma_buf_poll() is called it is mandatory for the caller to hold a reference to the file descriptor on which the poll operation is executed. So adding code like "if (!file_count(file))" in the beginning of dma_buf_poll() is certainly broken. My best guess is that you have some unbalanced dma_buf_get()/dma_buf_put() somewhere instead. Regards, Christian. > > The UAF issue can be solved by checking dmabuf file->f_count value and > skipping the poll operation for the closed dmabuf file in the > dma_buf_poll(). We have tested this solved patch multiple times and > have not reproduced the uaf issue. > > crash dump: > list_del corruption, ffffff8a6f143a90->next is LIST_POISON1 > (dead000000000100) > ------------[ cut here ]------------ > kernel BUG at lib/list_debug.c:55! > Internal error: Oops - BUG: 00000000f2000800 [#1] PREEMPT SMP > pc : __list_del_entry_valid+0x98/0xd4 > lr : __list_del_entry_valid+0x98/0xd4 > sp : ffffffc01d413d00 > x29: ffffffc01d413d00 x28: 00000000000000c0 x27: 0000000000000020 > x26: 0000000000000000 x25: 0000000000000000 x24: 0000000000080007 > x23: ffffff8b22e5dcc0 x22: ffffff88a6be12d0 x21: ffffff8b22e572b0 > x20: ffffff80254ed0a0 x19: ffffff8a6f143a00 x18: ffffffda5efed3c0 > x17: 6165642820314e4f x16: 53494f505f545349 x15: 4c20736920747865 > x14: 6e3e2d3039613334 x13: 2930303130303030 x12: 0000000000000018 > x11: ffffff8b6c188000 x10: 00000000ffffffff x9 : 6c8413a194897b00 > x8 : 6c8413a194897b00 x7 : 74707572726f6320 x6 : 6c65645f7473696c > x5 : ffffff8b6c3b2a3e x4 : ffffff8b6c3b2a40 x3 : ffff103000001005 > x2 : 0000000000000001 x1 : 00000000000000c0 x0 : 000000000000004e > Call trace: > __list_del_entry_valid+0x98/0xd4 > dma_buf_file_release+0x48/0x90 > __fput+0xf4/0x280 > ____fput+0x10/0x20 > task_work_run+0xcc/0xf4 > do_notify_resume+0x2a0/0x33c > el0_svc+0x5c/0xa4 > el0t_64_sync_handler+0x68/0xb4 > el0t_64_sync+0x1a0/0x1a4 > Code: d0006fe0 912c5000 f2fbd5a2 94231a01 (d4210000) > ---[ end trace 0000000000000000 ]--- > Kernel panic - not syncing: Oops - BUG: Fatal exception > SMP: stopping secondary CPUs > > Signed-off-by: Zhiguo Jiang <justinjiang(a)vivo.com> > --- > drivers/dma-buf/dma-buf.c | 28 ++++++++++++++++++++++++---- > 1 file changed, 24 insertions(+), 4 deletions(-) > mode change 100644 => 100755 drivers/dma-buf/dma-buf.c > > diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c > index 8fe5aa67b167..e469dd9288cc > --- a/drivers/dma-buf/dma-buf.c > +++ b/drivers/dma-buf/dma-buf.c > @@ -240,6 +240,10 @@ static __poll_t dma_buf_poll(struct file *file, poll_table *poll) > struct dma_resv *resv; > __poll_t events; > > + /* Check if the file exists */ > + if (!file_count(file)) > + return EPOLLERR; > + > dmabuf = file->private_data; > if (!dmabuf || !dmabuf->resv) > return EPOLLERR; > @@ -266,8 +270,15 @@ static __poll_t dma_buf_poll(struct file *file, poll_table *poll) > spin_unlock_irq(&dmabuf->poll.lock); > > if (events & EPOLLOUT) { > - /* Paired with fput in dma_buf_poll_cb */ > - get_file(dmabuf->file); > + /* > + * Paired with fput in dma_buf_poll_cb, > + * Skip poll for the closed file. > + */ > + if (!get_file_rcu(&dmabuf->file)) { > + events &= ~EPOLLOUT; > + dcb->active = 0; > + goto clear_out_event; > + } > > if (!dma_buf_poll_add_cb(resv, true, dcb)) > /* No callback queued, wake up any other waiters */ > @@ -277,6 +288,7 @@ static __poll_t dma_buf_poll(struct file *file, poll_table *poll) > } > } > > +clear_out_event: > if (events & EPOLLIN) { > struct dma_buf_poll_cb_t *dcb = &dmabuf->cb_in; > > @@ -289,8 +301,15 @@ static __poll_t dma_buf_poll(struct file *file, poll_table *poll) > spin_unlock_irq(&dmabuf->poll.lock); > > if (events & EPOLLIN) { > - /* Paired with fput in dma_buf_poll_cb */ > - get_file(dmabuf->file); > + /* > + * Paired with fput in dma_buf_poll_cb, > + * Skip poll for the closed file. > + */ > + if (!get_file_rcu(&dmabuf->file)) { > + events &= ~EPOLLIN; > + dcb->active = 0; > + goto clear_in_event; > + } > > if (!dma_buf_poll_add_cb(resv, false, dcb)) > /* No callback queued, wake up any other waiters */ > @@ -300,6 +319,7 @@ static __poll_t dma_buf_poll(struct file *file, poll_table *poll) > } > } > > +clear_in_event: > dma_resv_unlock(resv); > return events; > }

1 month, 2 weeks

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