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[PATCH v2 0/9] vfio/pci: Add mmap() for DMABUFs

by Matt Evans

Hi all, This series is based on previous RFCs/discussions: Tech topic: https://lore.kernel.org/linux-iommu/20250918214425.2677057-1-amastro@fb.com/ RFCv1: https://lore.kernel.org/all/20260226202211.929005-1-mattev@meta.com/ RFCv2: https://lore.kernel.org/kvm/20260312184613.3710705-1-mattev@meta.com/ The background/rationale is covered in more detail in the RFC cover letters. The TL;DR is: The goal is to enable userspace driver designs that use VFIO to export DMABUFs representing subsets of PCI device BARs, and "vend" those buffers from a primary process to other subordinate processes by fd. These processes then mmap() the buffers and their access to the device is isolated to the exported ranges. This is an improvement on sharing the VFIO device fd to subordinate processes, which would allow unfettered access. This is achieved by enabling mmap() of vfio-pci DMABUFs, passed by fd to subordinate processes. Second, a new ioctl()-based revocation mechanism is added to allow the primary process to forcibly revoke access to previously-shared BAR spans, even if the subordinate processes haven't cleanly exited. (The related topic of safe delegation of iommufd control to the subordinate processes is not addressed here, and is follow-up work.) As well as isolation and revocation, another advantage to accessing a BAR through a VMA backed by a DMABUF is that it's straightforward to mmap() the buffer with access attributes, such as write-combining. Feedback from the RFCs requested that, instead of creating DMABUF-specific vm_ops and .fault paths, to go the whole way and migrate the existing VFIO PCI BAR mmap() to be backed by a DMABUF too, resulting in a common vm_ops and fault handler for mmap()s of both the VFIO device and explicitly-exported DMABUFs. This will help future iommufd emulation of VFIO Type1 peer-to-peer, making it easier to get a DMABUF for a VFIO BAR as a DMA target. mmap() conversion to use DMABUF underneath has been done for vfio-pci, but not sub-drivers: nvgrace-gpu's mmap() override path is unchanged; I kept this out of scope for now not least because I don't have a thorough test setup for this system. I would prefer to help the nvgrace-gpu maintainers enable BAR mmap() DMABUFs themselves. Notes on patches ================ PCI/P2PDMA: Add CONFIG_PCI_P2PDMA_CORE Later in the series, vfio-pci's mmap() is going to depend on pcim_p2pdma_provider() which depended on CONFIG_PCI_P2PDMA, which in turn depended on ZONE_DEVICE (which isn't available on 32-bit and some archs, because they lack MEMORY_HOTPLUG and friends). VFIO does _not_ require actual P2P to be present for basic mmap() functionality, only for the optional CONFIG_DMA_SHARED_BUFFER feature. This splits P2PDMA into a CONFIG_PCI_P2PDMA_CORE (which currently contains pcim_p2pdma_provider()) and an optional CONFIG_PCI_P2PDMA (which depends on ZONE_DEVICE etc., and provides P2P functionality). vfio/pci: Add a helper to look up PFNs for DMABUFs vfio/pci: Add a helper to create a DMABUF for a BAR-map VMA The first is for a DMABUF VMA fault handler to determine arbitrary-sized PFNs from ranges in DMABUF. Secondly, refactor DMABUF export for use by the existing export feature and add a new helper that creates a DMABUF corresponding to a VFIO BAR mmap() request. vfio/pci: Convert BAR mmap() to use a DMABUF The vfio-pci core mmap() creates a DMABUF with the helper, and the vm_ops fault handler uses the other helper to resolve the fault. Because this depends on DMABUF structs/code, CONFIG_VFIO_PCI_CORE needs to depend on CONFIG_DMA_SHARED_BUFFER. The CONFIG_VFIO_PCI_DMABUF still conditionally enables the export support code. NOTE: The user mmap()s a device fd, but the resulting VMA's vm_file becomes that of the DMABUF which takes ownership of the device and puts it on release. This maintains the existing behaviour of a VMA keeping the VFIO device open. BAR zapping then happens via the existing vfio_pci_dma_buf_move() path, which now needs to unmap PTEs in the DMABUF's address_space. vfio/pci: Provide a user-facing name for BAR mappings There was a request for decent debug naming in /proc/<pid>/maps etc. comparable to the existing VFIO names: since the VMAs are DMABUFs, they have a "dmabuf:" prefix and can't be 100% identical to before. This is a user-visible change, but this patch at least now gives us extra info on the BDF & BAR being mapped. vfio/pci: Clean up BAR zap and revocation In general (see NOTE!) the vfio_pci_zap_bars() is now obsolete, since it unmaps PTEs in the VFIO device address_space which is now unused. This consolidates all calls (e.g. around reset) with the neighbouring vfio_pci_dma_buf_move()s into new functions, to revoke-zap/unrevoke. !!! NOTE: the nvgrace-gpu driver continues to use its own private vm_ops, fault handler, etc. for its special memregions, and these DO still add PTEs to the VFIO device address_space. So, a temporary flag, vdev->bar_needs_zap, maintains the old behaviour for this use. At least this patch's consolidation makes it easy to remove the remaining zap when this need goes away; a FIXME reminds that this can be removed when nvgrace-gpu is converted. vfio/pci: Support mmap() of a VFIO DMABUF Adds mmap() for a DMABUF fd exported from vfio-pci. It was a goal to keep the VFIO device fd lifetime behaviour unchanged with respect to the DMABUFs. An application can close all device fds, and this will revoke/clean up all DMABUFs; no mappings or other access can be performed now. When enabling mmap() of the DMABUFs, this means access through the VMA is also revoked. This complicates the fault handler because whilst the DMABUF exists, it has no guarantee that the corresponding VFIO device is still alive. Adds synchronisation ensuring the vdev is available before vdev->memory_lock is touched; this holds the device registration so that even if the buffer has been cleaned up, vdev hasn't been freed and so the lock can be safely taken. (I decided against the alternative of preventing cleanup by holding the VFIO device open if any DMABUFs exist, because it's both a change of behaviour and less clean overall.) I've added a chonky comment in place, happy to clarify more if you have ideas. This commit makes VFIO_PCI_CORE depend on PCI_P2PDMA_CORE (commit 1) to bring in (only) the P2PDMA provider code. vfio/pci: Permanently revoke a DMABUF on request By weight, this is mostly a rename of revoked to an enum, status. There are now 3 states for a buffer, usable and revoked temporary/permanent. A new VFIO device ioctl is added, VFIO_DEVICE_PCI_DMABUF_REVOKE, which passes a DMABUF (exported from that device) and permanently revokes it. Thus a userspace driver can guarantee any downstream consumers of a shared fd are prevented from accessing a BAR range, and that range can be reused. The code doing revocation in vfio_pci_dma_buf_move() is moved, unchanged, to a common function for use by _move() and the new ioctl path. Q: I can't think of a good reason to temporarily revoke/unrevoke buffers from userspace, so didn't add a 'flags' field to the ioctl struct. Easy to add if people think it's worthwhile for future use. vfio/pci: Add mmap() attributes to DMABUF feature Adds a new VFIO feature, VFIO_DEVICE_FEATURE_DMA_BUF_MEMATTR. After a DMABUF is exported, this feature ioctl() isused to set a memory attribute that will be used by future mmap()s of the DMABUF fd (i.e. it does nothing for any existing maps). The default is UC, and via the feature one can specify CPU access as WC. The attribute is an enum/scalar rather than bitmap/cumulative. The attributes follow a "try-fail" model where a client can request an attribute and either succeed or fail with ENOTSUPP if it's unknown; if future attributes are platform-specific then their support can be probed. (Since it's just UC/WC for now, there is no reservation or numeric structure to the namespace yet, but we could support system/arch-specific values in future by carving out base + arch-specific + IMPDEF ranges.) Testing ======= (The [RFC ONLY] userspace test program, for QEMU edu-plus, has been dropped from the series, but can be found in the GitHub branch below. It at least illustrates the export, map, revoke, attribute, and close semantics interoperate.) This code has been tested in mapping DMABUFs of single/multiple ranges, aliasing mmap()s, aliasing ranges across DMABUFs, vm_pgoff > 0, revocation, shutdown/cleanup scenarios, and hugepage mappings seem to work correctly. I've lightly tested WC mappings also (by observing resulting PTEs as having the correct attributes...). No regressions observed on the VFIO selftests, or on our internal vfio-pci applications. End === This is based on VFIO next (e.g. at b9285405c5f6). These commits are on GitHub for easier browsing, along with "[RFC ONLY] selftests: vfio: Add standalone vfio_dmabuf_mmap_test": https://github.com/metamev/linux/compare/b9285405c5f6...metamev:linux:dev/m… Thanks for reading, Matt ================================================================================ Change log: v2: - Rebase on VFIO next, picking up Alex's vfio_pci_dma_buf_move()/vfio_pci_dma_buf_cleanup() fixes, and dropping "vfio/pci: Fix vfio_pci_dma_buf_cleanup() double-put" - Added "PCI/P2PDMA: Add CONFIG_PCI_P2PDMA_CORE" so that the newly-added vfio-pci hard dependency on the P2PDMA provider instead pulls in the _CORE variant and not the full-fat CONFIG_PCI_P2PDMA. This means that the core of vfio-pci does not need ZONE_DEVICE, but if it's available then enabling P2PDMA in turn enables DMABUF export. Fixes basic VFIO operation on 32b or other platforms without ZONE_DEVICE. - Fixed comment inaccuracy in vfio_pci_dma_buf_revoke() and cleaned up vdev validity test. - vfio_pci_dma_buf_find_pfn(): use PAGE_ALIGN(), better span variable naming, OVF check - Made vm_pgoffs use consistent (keeping the resource index at the top and masking where offset is used). For BAR mmap, use new vma_pgoff_adjust to create the DMABUF with the exact mmap()ed span instead of from the start of the BAR with an invisible portion before the mapping. - Added VFIO_DEVICE_FEATURE_DMA_BUF_MEMATTR to set memory attributes, instead of using the export `flags` field. - vfio_pci_ioctl_reset: Moved vfio_pci_zap_revoke_bars() (effectively, vfio_pci_dma_buf_move()) back after D0 transition. Note, if a BAR zap is needed, it's done in this function so now happens after this D0 transition with the _move; it was done before it at the time of the memory_lock taking. - Minimised vfio_pci_dma_buf_mmap() (removed redundant span check), added READ_ONCE for memattr - Misc fixes: comment in DMABUF name generation, removed superfluous READ_ONCE from faulthandler v1: https://lore.kernel.org/kvm/20260416131815.2729131-1-mattev@meta.com/ - Cleanup of the common DMABUF-aware VMA vm_ops fault handler and export code. - Fixed a lot of races, particularly faults racing with DMABUF cleanup (if the VFIO device fds close, for example). - Added nicer human-readable names for VFIO mmap() VMAs RFCv2: Respin based on the feedback/suggestions: https://lore.kernel.org/kvm/20260312184613.3710705-1-mattev@meta.com/ - Transform the existing VFIO BAR mmap path to also use DMABUFs behind the scenes, and then simply share that code for explicitly-mapped DMABUFs. Jason wanted to go that direction to enable iommufd VFIO type 1 emulation to pick up a DMABUF for an IO mapping. - Revoke buffers using a VFIO device fd ioctl RFCv1: https://lore.kernel.org/all/20260226202211.929005-1-mattev@meta.com/ Matt Evans (9): PCI/P2PDMA: Add CONFIG_PCI_P2PDMA_CORE vfio/pci: Add a helper to look up PFNs for DMABUFs vfio/pci: Add a helper to create a DMABUF for a BAR-map VMA vfio/pci: Convert BAR mmap() to use a DMABUF vfio/pci: Provide a user-facing name for BAR mappings vfio/pci: Clean up BAR zap and revocation vfio/pci: Support mmap() of a VFIO DMABUF vfio/pci: Permanently revoke a DMABUF on request vfio/pci: Add mmap() attributes to DMABUF feature drivers/pci/Kconfig | 10 +- drivers/pci/Makefile | 2 +- drivers/pci/p2pdma.c | 16 + drivers/vfio/pci/Kconfig | 4 +- drivers/vfio/pci/Makefile | 3 +- drivers/vfio/pci/nvgrace-gpu/main.c | 5 + drivers/vfio/pci/vfio_pci_config.c | 30 +- drivers/vfio/pci/vfio_pci_core.c | 225 +++++++++--- drivers/vfio/pci/vfio_pci_dmabuf.c | 548 ++++++++++++++++++++++++---- drivers/vfio/pci/vfio_pci_priv.h | 57 ++- include/linux/pci-p2pdma.h | 24 +- include/linux/pci.h | 2 +- include/linux/vfio_pci_core.h | 1 + include/uapi/linux/vfio.h | 57 +++ 14 files changed, 815 insertions(+), 169 deletions(-) -- 2.47.3

1 hour, 28 minutes

[PATCH v2] dma-buf: Fix silent overflow for phys vec to sgt

by David Hu

In case MMIO size is bigger than 4G and peer2peer DMA goes through host bridge, we trigger a code path that assigns the total linked IOVA (which is greater than 4G) to mapped_len. Previously, `mapped_len` was declared as 32-bit `unsigned int`. When accumulating `size_t` lengths, this leads to a silent wrap-around. This truncation causes truncated lengths to be passed to functions like `fill_sg_entry()`. Fix this by changing `mapped_len` to `size_t` (64-bit). While at it, fix similar potential overflow issues in `calc_sg_nents` by using `size_t` for `nents` and checking against `UINT_MAX` and using `unsigned int` for the loop iterator in `fill_sg_entry` to match. to mapped_len, and leading to a silent overflow Fixes: 3aa31a8bb11e ("dma-buf: provide phys_vec to scatter-gather mapping routine") Cc: stable(a)vger.kernel.org Cc: iommu(a)lists.linux.dev Reviewed-by: Pranjal Shrivastava <praan(a)google.com> Signed-off-by: David Hu <xuehaohu(a)google.com> --- Changes in v2: Fixed 'IVOA' -> 'IOVA' typo and expanded commit message (Claude Bot). Added Reverse Xmas tree formatting (Pranjal). Folded in extra bounds checking for calc_sg_nents() (Pranjal). Folded in type consistency fix for fill_sg_entry() (Pranjal). Droped unnecessary `nents = 0` initialization (Claude Bot). drivers/dma-buf/dma-buf-mapping.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/drivers/dma-buf/dma-buf-mapping.c b/drivers/dma-buf/dma-buf-mapping.c index 794acff2546a..5bc769fc42ea 100644 --- a/drivers/dma-buf/dma-buf-mapping.c +++ b/drivers/dma-buf/dma-buf-mapping.c @@ -10,7 +10,7 @@ static struct scatterlist *fill_sg_entry(struct scatterlist *sgl, size_t length, dma_addr_t addr) { unsigned int len, nents; - int i; + unsigned int i; nents = DIV_ROUND_UP(length, UINT_MAX); for (i = 0; i < nents; i++) { @@ -36,7 +36,7 @@ static unsigned int calc_sg_nents(struct dma_iova_state *state, struct phys_vec *phys_vec, size_t nr_ranges, size_t size) { - unsigned int nents = 0; + size_t nents = 0; size_t i; if (!state || !dma_use_iova(state)) { @@ -51,6 +51,9 @@ static unsigned int calc_sg_nents(struct dma_iova_state *state, nents = DIV_ROUND_UP(size, UINT_MAX); } + if (nents > UINT_MAX) + return 0; + return nents; } @@ -95,9 +98,10 @@ struct sg_table *dma_buf_phys_vec_to_sgt(struct dma_buf_attachment *attach, size_t nr_ranges, size_t size, enum dma_data_direction dir) { - unsigned int nents, mapped_len = 0; struct dma_buf_dma *dma; struct scatterlist *sgl; + size_t mapped_len = 0; + unsigned int nents; dma_addr_t addr; size_t i; int ret; -- 2.54.0.794.g4f17f83d09-goog

3 hours, 36 minutes

Re: [PATCH] dma-buf: Fix silent overflow for phys vec to sgt

by David Hu

On Tue, May 26, 2026 at 1:33 PM Pranjal Shrivastava <praan(a)google.com> wrote: > > On Mon, May 11, 2026, David Hu wrote: > > In case MMIO size is bigger than 4G, and peer2peer > > dma goes through host bridge, we trigger the code > > path to assign total linked IVOA, greater than 4G > > Nit: s/IVOA/IOVA > > > to mapped_len, and leading to a silent overflow > > > Fixes: 3aa31a8bb11e ("dma-buf: provide phys_vec to scatter-gather mapping routine") > > Signed-off-by: David Hu <xuehaohu(a)google.com> > > --- > > drivers/dma-buf/dma-buf-mapping.c | 3 ++- > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > diff --git a/drivers/dma-buf/dma-buf-mapping.c b/drivers/dma-buf/dma-buf-mapping.c > > index 794acff2546a..658064140357 100644 > > --- a/drivers/dma-buf/dma-buf-mapping.c > > +++ b/drivers/dma-buf/dma-buf-mapping.c > > @@ -95,7 +95,8 @@ struct sg_table *dma_buf_phys_vec_to_sgt(struct dma_buf_attachment *attach, > > size_t nr_ranges, size_t size, > > enum dma_data_direction dir) > > { > > - unsigned int nents, mapped_len = 0; > > + unsigned int nents = 0; > > + size_t mapped_len = 0; > > struct dma_buf_dma *dma; > > struct scatterlist *sgl; > > dma_addr_t addr; > > Minor nit: Let's follow the reverse xmas tree format? > This looks correct to me, for this change: > > Reviewed-by: Pranjal Shrivastava <praan(a)google.com> > > Apart from this, I see similar issues at other places: > > 1. In calc_sg_nents(), nents is accumulated as an unsigned int. [1] > If nr_ranges is very large, nents could also overflow, potentially > leading to a small allocation in sg_alloc_table() and a subsequent > out-of-bounds access in the mapping loop. It might be worth changing > nents to size_t there and adding a check against UINT_MAX. > > 2. In fill_sg_entry(), the loop variable i is an int [2]. Changing > it to unsigned int would be more consistent with the nents type > and safer for extremely large mappings. > > > Maybe, we should also fix these? For example: > > diff --git a/drivers/dma-buf/dma-buf-mapping.c b/drivers/dma-buf/dma-buf-mapping.c > index 794acff2546a..ecf07ffca2b9 100644 > --- a/drivers/dma-buf/dma-buf-mapping.c > +++ b/drivers/dma-buf/dma-buf-mapping.c > @@ -10,7 +10,7 @@ static struct scatterlist *fill_sg_entry(struct scatterlist *sgl, size_t length, > dma_addr_t addr) > { > unsigned int len, nents; > - int i; > + unsigned int i; > > nents = DIV_ROUND_UP(length, UINT_MAX); > for (i = 0; i < nents; i++) { > @@ -36,7 +36,7 @@ static unsigned int calc_sg_nents(struct dma_iova_state *state, > struct phys_vec *phys_vec, size_t nr_ranges, > size_t size) > { > - unsigned int nents = 0; > + size_t nents = 0; > size_t i; > > if (!state || !dma_use_iova(state)) { > @@ -51,6 +51,9 @@ static unsigned int calc_sg_nents(struct dma_iova_state *state, > nents = DIV_ROUND_UP(size, UINT_MAX); > } > > + if (nents > UINT_MAX) > + return 0; > + > return nents; > } > > Thanks, > Praan > > [1] https://elixir.bootlin.com/linux/v7.1-rc3/source/drivers/dma-buf/dma-buf-ma… > [2] https://elixir.bootlin.com/linux/v7.1-rc3/source/drivers/dma-buf/dma-buf-ma… Thank you Pranjal for the review ! Good catch on other potential overflow sites. I have folded in your suggestions for calc_sg_nents(), and fill_sg_entry(), and applied reverse xmas tree formatting. Sending out a v2 shortly.

3 hours, 50 minutes

Re: [PATCH v2 1/9] PCI/P2PDMA: Add CONFIG_PCI_P2PDMA_CORE

by Matt Evans

Hi Logan, On 27/05/2026 17:07, Logan Gunthorpe wrote: > > On 2026-05-27 04:23, Matt Evans wrote: >> The P2PDMA code currently provides two features under the same >> CONFIG_PCI_P2PDMA option: >> >> 1. Locate providers via pcim_p2pdma_provider() >> 2. Manage actual P2P DMA >> >> Other code (such as vfio-pci) depends on 1, without having a hard >> dependency on 2. >> >> A future commit expands the use of DMABUF in vfio-pci for non-P2P >> scenarios, relying on pcim_p2pdma_provider() always being present. If >> that depended on CONFIG_PCI_P2PDMA, it would make vfio-pci only >> available if CONFIG_ZONE_DEVICE is present (e.g. 64-bit systems), even >> when P2P is not needed. >> >> To resolve this, introduce CONFIG_PCI_P2PDMA_CORE which contains the >> basic provider functionality to make it available even if the >> CONFIG_PCI_P2PDMA feature is disabled or unavailable due to >> !CONFIG_ZONE_DEVICE. Users such as vfio-pci can enable their own P2P >> features based off the original CONFIG_PCI_P2PDMA (available when >> CONFIG_ZONE_DEVICE is set). >> >> Signed-off-by: Matt Evans <mattev(a)meta.com> > > Largely this looks good to me. I have one minor nit below that you can > apply or not. Either way, feel free to add: > > Reviewed-by: Logan Gunthorpe <logang(a)deltatee.com> > > >> static void pci_p2pdma_release(void *data) >> { >> struct pci_dev *pdev = data; >> @@ -241,11 +251,13 @@ static void pci_p2pdma_release(void *data) >> synchronize_rcu(); >> xa_destroy(&p2pdma->map_types); >> >> +#ifdef CONFIG_PCI_P2PDMA >> if (!p2pdma->pool) >> return; >> >> gen_pool_destroy(p2pdma->pool); >> sysfs_remove_group(&pdev->dev.kobj, &p2pmem_group); >> +#endif >> } > > I'm personally not a fan of adding #ifdefs inside functions like this. > This instance is small and easy to understand, but it can quickly become > a bit of a mess if we start adding more features. I probably would have > created a pci_p2pdma_release_pool() helper which does the inverse of > pci_p2pdma_setup_pool(), it would be called in pci_p2pdma_release() and > an empty implementation would be provided in the case where > CONFIG_PCI_P2PDMA is not set. That's cleaner, I'll do that. Thanks for the review. Matt

7 hours, 14 minutes

Basketball Stars: Rule the Court and Become the MVP

by joeytribuani0＠gmail.com

Basketball Stars is the perfect game for anyone who loves fast-paced street basketball action! From smooth dribble moves and ankle-breaking crossovers to clutch shots and powerful dunks, every match feels intense and competitive. The game’s easy controls make it simple to start playing, but mastering the timing, defense, and shooting mechanics takes real skill. Whether you’re playing quick one-on-one matches or climbing the ranked leaderboard, Basketball Stars keeps every game exciting. One of the best parts is the character customization. You can unlock new outfits, courts, basketballs, and upgrades to create your own unique style on the court. Playing against real opponents online also adds a fun challenge because every player has a different strategy. If you enjoy basketball games with arcade-style gameplay and nonstop action, Basketball Stars is definitely worth checking out. Step onto the court and show everyone who the real MVP is! WEB: https://basketballstars2026.io

15 hours, 40 minutes

Geometry Dash Lite – A Challenging Rhythm Game That Keeps Players Hooked

by christabbati＠gmail.com

Mobile games come and go, but some titles remain popular for years because of their addictive gameplay and unique style. One of those games is Geometry Dash Lite, the free version of the famous rhythm-based platformer developed by RobTop Games. Even with its simple controls and minimalist design, the game continues to attract millions of players worldwide. Easy to Play, Difficult to Master The gameplay of Geometry Dash Lite is very straightforward. Players control a geometric icon that automatically moves forward through obstacle-filled levels. The main objective is to jump at the correct time to avoid spikes, traps, and dangerous platforms. The controls only require a single tap or click, making the game easy for anyone to pick up. However, the real challenge comes from mastering timing and memorizing level patterns. One small mistake sends you back to the beginning, which can be frustrating but also highly motivating. Rhythm and Music Create the Experience What truly makes Geometry Dash Lite stand out is its connection between gameplay and music. Every level is synchronized with energetic electronic soundtracks that guide the player through obstacles and jumps. The rhythm helps create a fast-paced and immersive experience that feels both exciting and satisfying. As the music intensifies, so does the gameplay. Players must stay focused and react quickly to survive increasingly difficult sections. Colorful Graphics and Creative Design Although the game uses simple geometric visuals, the design is stylish and memorable. Bright neon colors, smooth animations, and creative level layouts give each stage its own personality. Different gameplay mechanics are introduced as players progress, keeping the experience fresh and challenging. Why Players Keep Coming Back One of the biggest strengths of Geometry Dash Lite is the sense of achievement it provides. Completing a difficult level after dozens of failed attempts feels incredibly rewarding. This balance between frustration and satisfaction is what makes the game so addictive. The game is also perfect for short gaming sessions, allowing players to quickly retry levels and improve their skills over time. Final Thoughts Geometry Dash Lite proves that a game does not need complicated mechanics or realistic graphics to become successful. Its combination of rhythm-based gameplay, challenging obstacles, and energetic music creates an experience that is simple, fun, and highly addictive. Whether you are a beginner looking for a fun mobile game or a competitive player seeking a difficult challenge, Geometry Dash Lite offers an exciting adventure that is hard to put down. SITE: https://geometrylite22.io

19 hours, 43 minutes

[PATCH v14 0/6] rust: drm: gem: shmem: Add sg_table() function

by Lyude Paul

(was previously Rust bindings for gem shmem) Most of this patch series has already been pushed upstream, this is just the second half of the patch series that has not been pushed yet + some additional changes which were required to implement changes requested by the mailing list. This patch series is originally from Asahi, previously posted by Daniel Almeida. The previous version of the patch series can be found here: https://patchwork.freedesktop.org/series/164580/ Branch with patches applied available here: https://gitlab.freedesktop.org/lyudess/linux/-/commits/rust/gem-shmem This patch series applies on top of drm-rust-next with the following dependencies applied: https://lkml.org/lkml/2026/5/26/1960 Lyude Paul (6): rust: faux: Allow retrieving a bound Device rust: gem: shmem: Fix Default implementation for ObjectConfig rust: drm: gem: s/device::Device/Device/ for shmem.rs drm/gem/shmem: Introduce __drm_gem_shmem_free_sgt_locked() rust: drm: gem/shmem: Add DmaResvGuard helper rust: drm: gem: Introduce shmem::Object::sg_table() drivers/gpu/drm/drm_gem_shmem_helper.c | 32 ++- include/drm/drm_gem_shmem_helper.h | 1 + rust/kernel/drm/gem/shmem.rs | 264 +++++++++++++++++++++++-- rust/kernel/faux.rs | 7 +- 4 files changed, 279 insertions(+), 25 deletions(-) base-commit: 2cf1840b0fa7637b6731fd554529f8d57ea34c04 prerequisite-patch-id: c8ade07eec6e9c9e875800b114137c459d362e4e prerequisite-patch-id: dc4f750bc885b867842587b994261f43602bc6a8 -- 2.54.0

1 day, 2 hours

Re: [PATCH] iommufd: take dma_resv lock before dma_buf_unpin() in release path

by Jason Gunthorpe

On Tue, May 26, 2026 at 11:10:34AM +0000, Ankit Soni wrote: > dma_buf_unpin() requires the caller to hold the exporter's dma_resv > lock: > > void dma_buf_unpin(struct dma_buf_attachment *attach) > { > ... > dma_resv_assert_held(dmabuf->resv); > ... > } > > iopt_release_pages() calls dma_buf_unpin() without taking that lock, > so every iommufd_ioas_destroy()/iommufd_ioas_unmap() that releases > the last reference on a DMABUF-backed iopt_pages triggers a WARN. > This was hit while running tools/testing/selftests/iommu/iommufd: Any idea why this is comming up now? Did I run the tests without some kind of debug option to turn on that assertion maybe? Jason

1 day, 12 hours

Navigating the Unpredictable: A Dive into Level Devil

by profound.cheetah.kect＠hidingmail.net

If you’re looking for a fun way to spend an evening, trying an interesting game is a great option—especially one that makes you think, explore, or improve your skills without feeling overwhelming. One example that many players enjoy is Level Devil. Even if you’ve never played before, you can approach it like a puzzle: learn the rules, watch what works, and gradually build confidence as levels start to feel more predictable. https://leveldevilfull.com In this article, I’ll walk you through how to experience a game like Level Devil in a friendly, practical way—focusing on what to do first, how to play, and what habits can make the experience smoother. Gameplay When you start Level Devil, your first goal is simply to understand how the game responds to you. Pay attention to the basics: movement controls, timing, and what happens when you try different approaches. Many players get stuck by rushing. Instead, try a short “experiment run” where your only objective is to learn mechanics—no pressure to win quickly. As you progress, the game tends to reward pattern recognition. Levels may ask you to manage obstacles, plan routes, or react under time constraints. A helpful mindset is to think in small steps: What’s the next safe action? What’s the easiest section to master first? If a section feels difficult, pause and observe. Look for consistent cues—visual hints, recurring enemy behavior, or environmental timing. Often, you don’t need a “perfect” run; you need a reliable one. For another way to explore the experience, some players prefer to review the broader game details here: Level Devil. Tips Start with calm attempts. If you’re on your first run, prioritize learning over scoring. Try not to restart too many times in anger—give yourself time to understand the rhythm of a level. Use “fail data.” Each time you die, ask a simple question: Did I misread timing, misjudge distance, or panic too early? That answer helps you choose a better strategy next attempt. Practice the hardest segment, not the whole level. If the game allows repetition, focus on the portion that blocks you. Clearing smaller checkpoints builds momentum. Keep your controls consistent. Sudden changes in how you press buttons or time actions can make you worse temporarily. Once you find a comfortable method, stick with it for a few attempts. Take breaks when you’re frustrated. A five-minute pause can reset your focus. When you return, you’ll often spot a solution you missed before. Conclusion Playing a game like Level Devil is less about having “elite” reflexes and more about learning the game’s patterns and improving step by step. Start by experimenting, approach challenges with curiosity, and use your failures as feedback. With a calm routine—short sessions, focused practice, and mindful breaks—you can enjoy the puzzle-like satisfaction that makes many levels rewarding.

1 day, 21 hours

[PATCH] dma-buf: fix UAF in dma_buf_fd() tracepoint

by David Carlier

Once FD_ADD() returns, the fd is live in the file descriptor table and a thread sharing that table can close() it before DMA_BUF_TRACE() runs. The close drops the last reference, __fput() frees the dma_buf, and the tracepoint then dereferences dmabuf to take dmabuf->name_lock -- slab-use-after-free. Split FD_ADD() back into get_unused_fd_flags() + fd_install() and emit the tracepoint between them. While the fdtable slot is reserved with a NULL file pointer, a racing close() returns -EBADF without entering __fput(), so the dma_buf stays alive across the trace. Same approach as commit 2d76319c4cbb ("dma-buf: fix UAF in dma_buf_put() tracepoint"). This undoes the FD_ADD() conversion done in commit 34dfce523c90 ("dma: convert dma_buf_fd() to FD_ADD()"); FD_ADD() has no place to hook the tracepoint safely. Reported-by: syzbot+7f4987d0afb97dd090cb(a)syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=7f4987d0afb97dd090cb Fixes: 281a22631423 ("dma-buf: add some tracepoints to debug.") Cc: stable(a)vger.kernel.org # 7.0.x Signed-off-by: David Carlier <devnexen(a)gmail.com> --- drivers/dma-buf/dma-buf.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index 71f37544a5c6..d504c636dc29 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -792,9 +792,13 @@ int dma_buf_fd(struct dma_buf *dmabuf, int flags) if (!dmabuf || !dmabuf->file) return -EINVAL; - fd = FD_ADD(flags, dmabuf->file); + fd = get_unused_fd_flags(flags); + if (fd < 0) + return fd; + DMA_BUF_TRACE(trace_dma_buf_fd, dmabuf, fd); + fd_install(fd, dmabuf->file); return fd; } EXPORT_SYMBOL_NS_GPL(dma_buf_fd, "DMA_BUF"); -- 2.53.0

2 days, 5 hours

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