lwn.git/drivers/android, branch master

Merge tag 'mm-stable-2026-04-13-21-45' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2026-04-15T19:59:16+00:00

Pull MM updates from Andrew Morton: - "maple_tree: Replace big node with maple copy" (Liam Howlett) Mainly prepararatory work for ongoing development but it does reduce stack usage and is an improvement. - "mm, swap: swap table phase III: remove swap_map" (Kairui Song) Offers memory savings by removing the static swap_map. It also yields some CPU savings and implements several cleanups. - "mm: memfd_luo: preserve file seals" (Pratyush Yadav) File seal preservation to LUO's memfd code - "mm: zswap: add per-memcg stat for incompressible pages" (Jiayuan Chen) Additional userspace stats reportng to zswap - "arch, mm: consolidate empty_zero_page" (Mike Rapoport) Some cleanups for our handling of ZERO_PAGE() and zero_pfn - "mm/kmemleak: Improve scan_should_stop() implementation" (Zhongqiu Han) A robustness improvement and some cleanups in the kmemleak code - "Improve khugepaged scan logic" (Vernon Yang) Improve khugepaged scan logic and reduce CPU consumption by prioritizing scanning tasks that access memory frequently - "Make KHO Stateless" (Jason Miu) Simplify Kexec Handover by transitioning KHO from an xarray-based metadata tracking system with serialization to a radix tree data structure that can be passed directly to the next kernel - "mm: vmscan: add PID and cgroup ID to vmscan tracepoints" (Thomas Ballasi and Steven Rostedt) Enhance vmscan's tracepointing - "mm: arch/shstk: Common shadow stack mapping helper and VM_NOHUGEPAGE" (Catalin Marinas) Cleanup for the shadow stack code: remove per-arch code in favour of a generic implementation - "Fix KASAN support for KHO restored vmalloc regions" (Pasha Tatashin) Fix a WARN() which can be emitted the KHO restores a vmalloc area - "mm: Remove stray references to pagevec" (Tal Zussman) Several cleanups, mainly udpating references to "struct pagevec", which became folio_batch three years ago - "mm: Eliminate fake head pages from vmemmap optimization" (Kiryl Shutsemau) Simplify the HugeTLB vmemmap optimization (HVO) by changing how tail pages encode their relationship to the head page - "mm/damon/core: improve DAMOS quota efficiency for core layer filters" (SeongJae Park) Improve two problematic behaviors of DAMOS that makes it less efficient when core layer filters are used - "mm/damon: strictly respect min_nr_regions" (SeongJae Park) Improve DAMON usability by extending the treatment of the min_nr_regions user-settable parameter - "mm/page_alloc: pcp locking cleanup" (Vlastimil Babka) The proper fix for a previously hotfixed SMP=n issue. Code simplifications and cleanups ensued - "mm: cleanups around unmapping / zapping" (David Hildenbrand) A bunch of cleanups around unmapping and zapping. Mostly simplifications, code movements, documentation and renaming of zapping functions - "support batched checking of the young flag for MGLRU" (Baolin Wang) Batched checking of the young flag for MGLRU. It's part cleanups; one benchmark shows large performance benefits for arm64 - "memcg: obj stock and slab stat caching cleanups" (Johannes Weiner) memcg cleanup and robustness improvements - "Allow order zero pages in page reporting" (Yuvraj Sakshith) Enhance free page reporting - it is presently and undesirably order-0 pages when reporting free memory. - "mm: vma flag tweaks" (Lorenzo Stoakes) Cleanup work following from the recent conversion of the VMA flags to a bitmap - "mm/damon: add optional debugging-purpose sanity checks" (SeongJae Park) Add some more developer-facing debug checks into DAMON core - "mm/damon: test and document power-of-2 min_region_sz requirement" (SeongJae Park) An additional DAMON kunit test and makes some adjustments to the addr_unit parameter handling - "mm/damon/core: make passed_sample_intervals comparisons overflow-safe" (SeongJae Park) Fix a hard-to-hit time overflow issue in DAMON core - "mm/damon: improve/fixup/update ratio calculation, test and documentation" (SeongJae Park) A batch of misc/minor improvements and fixups for DAMON - "mm: move vma_(kernel|mmu)_pagesize() out of hugetlb.c" (David Hildenbrand) Fix a possible issue with dax-device when CONFIG_HUGETLB=n. Some code movement was required. - "zram: recompression cleanups and tweaks" (Sergey Senozhatsky) A somewhat random mix of fixups, recompression cleanups and improvements in the zram code - "mm/damon: support multiple goal-based quota tuning algorithms" (SeongJae Park) Extend DAMOS quotas goal auto-tuning to support multiple tuning algorithms that users can select - "mm: thp: reduce unnecessary start_stop_khugepaged()" (Breno Leitao) Fix the khugpaged sysfs handling so we no longer spam the logs with reams of junk when starting/stopping khugepaged - "mm: improve map count checks" (Lorenzo Stoakes) Provide some cleanups and slight fixes in the mremap, mmap and vma code - "mm/damon: support addr_unit on default monitoring targets for modules" (SeongJae Park) Extend the use of DAMON core's addr_unit tunable - "mm: khugepaged cleanups and mTHP prerequisites" (Nico Pache) Cleanups to khugepaged and is a base for Nico's planned khugepaged mTHP support - "mm: memory hot(un)plug and SPARSEMEM cleanups" (David Hildenbrand) Code movement and cleanups in the memhotplug and sparsemem code - "mm: remove CONFIG_ARCH_ENABLE_MEMORY_HOTREMOVE and cleanup CONFIG_MIGRATION" (David Hildenbrand) Rationalize some memhotplug Kconfig support - "change young flag check functions to return bool" (Baolin Wang) Cleanups to change all young flag check functions to return bool - "mm/damon/sysfs: fix memory leak and NULL dereference issues" (Josh Law and SeongJae Park) Fix a few potential DAMON bugs - "mm/vma: convert vm_flags_t to vma_flags_t in vma code" (Lorenzo Stoakes) Convert a lot of the existing use of the legacy vm_flags_t data type to the new vma_flags_t type which replaces it. Mainly in the vma code. - "mm: expand mmap_prepare functionality and usage" (Lorenzo Stoakes) Expand the mmap_prepare functionality, which is intended to replace the deprecated f_op->mmap hook which has been the source of bugs and security issues for some time. Cleanups, documentation, extension of mmap_prepare into filesystem drivers - "mm/huge_memory: refactor zap_huge_pmd()" (Lorenzo Stoakes) Simplify and clean up zap_huge_pmd(). Additional cleanups around vm_normal_folio_pmd() and the softleaf functionality are performed. * tag 'mm-stable-2026-04-13-21-45' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (369 commits) mm: fix deferred split queue races during migration mm/khugepaged: fix issue with tracking lock mm/huge_memory: add and use has_deposited_pgtable() mm/huge_memory: add and use normal_or_softleaf_folio_pmd() mm: add softleaf_is_valid_pmd_entry(), pmd_to_softleaf_folio() mm/huge_memory: separate out the folio part of zap_huge_pmd() mm/huge_memory: use mm instead of tlb->mm mm/huge_memory: remove unnecessary sanity checks mm/huge_memory: deduplicate zap deposited table call mm/huge_memory: remove unnecessary VM_BUG_ON_PAGE() mm/huge_memory: add a common exit path to zap_huge_pmd() mm/huge_memory: handle buggy PMD entry in zap_huge_pmd() mm/huge_memory: have zap_huge_pmd return a boolean, add kdoc mm/huge: avoid big else branch in zap_huge_pmd() mm/huge_memory: simplify vma_is_specal_huge() mm: on remap assert that input range within the proposed VMA mm: add mmap_action_map_kernel_pages[_full]() uio: replace deprecated mmap hook with mmap_prepare in uio_info drivers: hv: vmbus: replace deprecated mmap hook with mmap_prepare mm: allow handling of stacked mmap_prepare hooks in more drivers ...

Merge tag 'rust-7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux

2026-04-13T16:54:20+00:00

Pull Rust updates from Miguel Ojeda: "Toolchain and infrastructure: - Bump the minimum Rust version to 1.85.0 (and 'bindgen' to 0.71.1). As proposed in LPC 2025 and the Maintainers Summit [1], we are going to follow Debian Stable's Rust versions as our minimum versions. Debian Trixie was released on 2025-08-09 with a Rust 1.85.0 and 'bindgen' 0.71.1 toolchain, which is a fair amount of time for e.g. kernel developers to upgrade. Other major distributions support a Rust version that is high enough as well, including: + Arch Linux. + Fedora Linux. + Gentoo Linux. + Nix. + openSUSE Slowroll and openSUSE Tumbleweed. + Ubuntu 25.10 and 26.04 LTS. In addition, 24.04 LTS using their versioned packages. The merged patch series comes with the associated cleanups and simplifications treewide that can be performed thanks to both bumps, as well as documentation updates. In addition, start using 'bindgen''s '--with-attribute-custom-enum' feature to set the 'cfi_encoding' attribute for the 'lru_status' enum used in Binder. Link: https://lwn.net/Articles/1050174/ [1] - Add experimental Kconfig option ('CONFIG_RUST_INLINE_HELPERS') that inlines C helpers into Rust. Essentially, it performs a step similar to LTO, but just for the helpers, i.e. very local and fast. It relies on 'llvm-link' and its '--internalize' flag, and requires a compatible LLVM between Clang and 'rustc' (i.e. same major version, 'CONFIG_RUSTC_CLANG_LLVM_COMPATIBLE'). It is only enabled for two architectures for now. The result is a measurable speedup in different workloads that different users have tested. For instance, for the null block driver, it amounts to a 2%. - Support global per-version flags. While we already have per-version flags in many places, we didn't have a place to set global ones that depend on the compiler version, i.e. in 'rust_common_flags', which sometimes is needed to e.g. tweak the lints set per version. Use that to allow the 'clippy::precedence' lint for Rust < 1.86.0, since it had a change in behavior. - Support overriding the crate name and apply it to Rust Binder, which wanted the module to be called 'rust_binder'. - Add the remaining '__rust_helper' annotations (started in the previous cycle). 'kernel' crate: - Introduce the 'const_assert!' macro: a more powerful version of 'static_assert!' that can refer to generics inside functions or implementation bodies, e.g.: fn f() { const_assert!(N > 1); } fn g() { const_assert!(size_of::() > 0, "T cannot be ZST"); } In addition, reorganize our set of build-time assertion macros ('{build,const,static_assert}!') to live in the 'build_assert' module. Finally, improve the docs as well to clarify how these are different from one another and how to pick the right one to use, and their equivalence (if any) to the existing C ones for extra clarity. - 'sizes' module: add 'SizeConstants' trait. This gives us typed 'SZ_*' constants (avoiding casts) for use in device address spaces where the address width depends on the hardware (e.g. 32-bit MMIO windows, 64-bit GPU framebuffers, etc.), e.g.: let gpu_heap = 14 * u64::SZ_1M; let mmio_window = u32::SZ_16M; - 'clk' module: implement 'Send' and 'Sync' for 'Clk' and thus simplify the users in Tyr and PWM. - 'ptr' module: add 'const_align_up'. - 'str' module: improve the documentation of the 'c_str!' macro to explain that one should only use it for non-literal cases (for the other case we instead use C string literals, e.g. 'c"abc"'). - Disallow the use of 'CStr::{as_ptr,from_ptr}' and clean one such use in the 'task' module. - 'sync' module: finish the move of 'ARef' and 'AlwaysRefCounted' outside of the 'types' module, i.e. update the last remaining instances and finally remove the re-exports. - 'error' module: clarify that 'from_err_ptr' can return 'Ok(NULL)', including runtime-tested examples. The intention is to hopefully prevent UB that assumes the result of the function is not 'NULL' if successful. This originated from a case of UB I noticed in 'regulator' that created a 'NonNull' on it. Timekeeping: - Expand the example section in the 'HrTimer' documentation. - Mark the 'ClockSource' trait as unsafe to ensure valid values for 'ktime_get()'. - Add 'Delta::from_nanos()'. 'pin-init' crate: - Replace the 'Zeroable' impls for 'Option' with impls of 'ZeroableOption' for 'NonZero*'. - Improve feature gate handling for unstable features. - Declutter the documentation of implementations of 'Zeroable' for tuples. - Replace uses of 'addr_of[_mut]!' with '&raw [mut]'. rust-analyzer: - Add type annotations to 'generate_rust_analyzer.py'. - Add support for scripts written in Rust ('generate_rust_target.rs', 'rustdoc_test_builder.rs', 'rustdoc_test_gen.rs'). - Refactor 'generate_rust_analyzer.py' to explicitly identify host and target crates, improve readability, and reduce duplication. And some other fixes, cleanups and improvements" * tag 'rust-7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux: (79 commits) rust: sizes: add SizeConstants trait for device address space constants rust: kernel: update `file_with_nul` comment rust: kbuild: allow `clippy::precedence` for Rust < 1.86.0 rust: kbuild: support global per-version flags rust: declare cfi_encoding for lru_status docs: rust: general-information: use real example docs: rust: general-information: simplify Kconfig example docs: rust: quick-start: remove GDB/Binutils mention docs: rust: quick-start: remove Nix "unstable channel" note docs: rust: quick-start: remove Gentoo "testing" note docs: rust: quick-start: add Ubuntu 26.04 LTS and remove subsection title docs: rust: quick-start: update minimum Ubuntu version docs: rust: quick-start: update Ubuntu versioned packages docs: rust: quick-start: openSUSE provides `rust-src` package nowadays rust: kbuild: remove "dummy parameter" workaround for `bindgen` < 0.71.1 rust: kbuild: update `bindgen --rust-target` version and replace comment rust: rust_is_available: remove warning for `bindgen` < 0.69.5 && libclang >= 19.1 rust: rust_is_available: remove warning for `bindgen` 0.66.[01] rust: bump `bindgen` minimum supported version to 0.71.1 (Debian Trixie) rust: block: update `const_refs_to_static` MSRV TODO comment ...

Merge tag 'rust-timekeeping-for-v7.1' of https://github.com/Rust-for-Linux/linux into rust-next

2026-04-08T08:44:11+00:00

Pull timekeeping updates from Andreas Hindborg: - Expand the example section in the 'HrTimer' documentation. - Mark the 'ClockSource' trait as unsafe to ensure valid values for 'ktime_get()'. - Add 'Delta::from_nanos()'. This is a back merge since the pull request has a newer base -- we will avoid that in the future. And, given it is a back merge, it happens to resolve the "subtle" conflict around '--remap-path-{prefix,scope}' that I discussed in linux-next [1], plus a few other common conflicts. The result matches what we did for next-20260407. The actual diffstat (i.e. using a temporary merge of upstream first) is: rust/kernel/time.rs | 32 ++++- rust/kernel/time/hrtimer.rs | 336 ++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 362 insertions(+), 6 deletions(-) Link: https://lore.kernel.org/linux-next/CANiq72kdxB=W3_CV1U44oOK3SssztPo2wLDZt6LP94TEO+Kj4g@mail.gmail.com/ [1] * tag 'rust-timekeeping-for-v7.1' of https://github.com/Rust-for-Linux/linux: hrtimer: add usage examples to documentation rust: time: make ClockSource unsafe trait rust/time: Add Delta::from_nanos()

rust: declare cfi_encoding for lru_status

2026-04-07T08:00:25+00:00

By default bindgen will convert 'enum lru_status' into a typedef for an integer. For the most part, an integer of the same size as the enum results in the correct ABI, but in the specific case of CFI, that is not the case. The CFI encoding is supposed to be the same as a struct called 'lru_status' rather than the name of the underlying native integer type. To fix this, tell bindgen to generate a newtype and set the CFI type explicitly. Note that we need to set the CFI attribute explicitly as bindgen is using repr(transparent), which is otherwise identical to the inner type for ABI purposes. This allows us to remove the page range helper C function in Binder without risking a CFI failure when list_lru_walk calls the provided function pointer. The --with-attribute-custom-enum argument requires bindgen v0.71 or greater. [ In particular, the feature was added in 0.71.0 [1][2]. In addition, `feature(cfi_encoding)` has been available since Rust 1.71.0 [3]. Link: https://github.com/rust-lang/rust-bindgen/issues/2520 [1] Link: https://github.com/rust-lang/rust-bindgen/pull/2866 [2] Link: https://github.com/rust-lang/rust/pull/105452 [3] - Miguel ] My testing procedure was to add this to the android17-6.18 branch and verify that rust_shrink_free_page is successfully called without crash, and verify that it does in fact crash when the cfi_encoding is set to other values. Note that I couldn't test this on android16-6.12 as that branch uses a bindgen version that is too old. Signed-off-by: Alice Ryhl Link: https://patch.msgid.link/20260223-cfi-lru-status-v2-1-89c6448a63a4@google.com [ Rebased on top of the minimum Rust version bump series which provide the required `bindgen` version. - Miguel ] Reviewed-by: Gary Guo Link: https://patch.msgid.link/20260405235309.418950-32-ojeda@kernel.org Signed-off-by: Miguel Ojeda

mm: rename zap_page_range_single() to zap_vma_range()

2026-04-05T20:53:15+00:00

Let's rename it to make it better match our new naming scheme. While at it, polish the kerneldoc. [akpm@linux-foundation.org: fix rustfmtcheck] Link: https://lkml.kernel.org/r/20260227200848.114019-15-david@kernel.org Signed-off-by: David Hildenbrand (Arm) Reviewed-by: Lorenzo Stoakes (Oracle) Acked-by: Puranjay Mohan Cc: Alexander Gordeev Cc: Alexei Starovoitov Cc: Alice Ryhl Cc: Andrii Nakryiko Cc: Andy Lutomirski Cc: Arnaldo Carvalho de Melo Cc: Arnd Bergmann Cc: Arve Cc: "Borislav Petkov (AMD)" Cc: Carlos Llamas Cc: Christian Borntraeger Cc: Christian Brauner Cc: Claudio Imbrenda Cc: Daniel Borkman Cc: Dave Airlie Cc: David Ahern Cc: David Rientjes Cc: David S. Miller Cc: Dimitri Sivanich Cc: Eric Dumazet Cc: Gerald Schaefer Cc: Greg Kroah-Hartman Cc: Hartley Sweeten Cc: Heiko Carstens Cc: Ian Abbott Cc: Ingo Molnar Cc: Jakub Kacinski Cc: Jani Nikula Cc: Jann Horn Cc: Janosch Frank Cc: Jarkko Sakkinen Cc: Jason Gunthorpe Cc: Jonas Lahtinen Cc: Leon Romanovsky Cc: Liam Howlett Cc: Madhavan Srinivasan Cc: Matthew Wilcox (Oracle) Cc: Michael Ellerman Cc: Michal Hocko Cc: Miguel Ojeda Cc: Mike Rapoport Cc: Namhyung kim Cc: Neal Cardwell Cc: Paolo Abeni Cc: Pedro Falcato Cc: Peter Zijlstra Cc: Rodrigo Vivi Cc: Shakeel Butt Cc: Suren Baghdasaryan Cc: Todd Kjos Cc: Tvrtko Ursulin Cc: Vasily Gorbik Cc: Vincenzo Frascino Signed-off-by: Andrew Morton

mm/memory: remove "zap_details" parameter from zap_page_range_single()

2026-04-05T20:53:13+00:00

Nobody except memory.c should really set that parameter to non-NULL. So let's just drop it and make unmap_mapping_range_vma() use zap_page_range_single_batched() instead. [david@kernel.org: format on a single line] Link: https://lkml.kernel.org/r/8a27e9ac-2025-4724-a46d-0a7c90894ba7@kernel.org Link: https://lkml.kernel.org/r/20260227200848.114019-3-david@kernel.org Signed-off-by: David Hildenbrand (Arm) Reviewed-by: Lorenzo Stoakes (Oracle) Acked-by: Puranjay Mohan Cc: Alexander Gordeev Cc: Alexei Starovoitov Cc: Alice Ryhl Cc: Andrii Nakryiko Cc: Andy Lutomirski Cc: Arnaldo Carvalho de Melo Cc: Arnd Bergmann Cc: Arve Cc: "Borislav Petkov (AMD)" Cc: Carlos Llamas Cc: Christian Borntraeger Cc: Christian Brauner Cc: Claudio Imbrenda Cc: Daniel Borkman Cc: Dave Airlie Cc: David Ahern Cc: David Rientjes Cc: David S. Miller Cc: Dimitri Sivanich Cc: Eric Dumazet Cc: Gerald Schaefer Cc: Greg Kroah-Hartman Cc: Hartley Sweeten Cc: Heiko Carstens Cc: Ian Abbott Cc: Ingo Molnar Cc: Jakub Kacinski Cc: Jani Nikula Cc: Jann Horn Cc: Janosch Frank Cc: Jarkko Sakkinen Cc: Jason Gunthorpe Cc: Jonas Lahtinen Cc: Leon Romanovsky Cc: Liam Howlett Cc: Madhavan Srinivasan Cc: Matthew Wilcox (Oracle) Cc: Michael Ellerman Cc: Michal Hocko Cc: Miguel Ojeda Cc: Mike Rapoport Cc: Namhyung kim Cc: Neal Cardwell Cc: Paolo Abeni Cc: Pedro Falcato Cc: Peter Zijlstra Cc: Rodrigo Vivi Cc: Shakeel Butt Cc: Suren Baghdasaryan Cc: Todd Kjos Cc: Tvrtko Ursulin Cc: Vasily Gorbik Cc: Vincenzo Frascino Signed-off-by: Andrew Morton

rust_binder: override crate name to rust_binder

2026-04-03T09:57:35+00:00

The Rust Binder object file is called rust_binder_main.o because the name rust_binder.o is used for the result of linking together rust_binder_main.o with rust_binderfs.o and a few others. However, the crate name is supposed to be rust_binder without a _main suffix. Thus, override the crate name accordingly. Signed-off-by: Alice Ryhl Acked-by: Gary Guo Acked-by: Greg Kroah-Hartman Link: https://patch.msgid.link/20260402-binder-crate-name-v4-2-ec3919b87909@google.com Signed-off-by: Miguel Ojeda

rust_binder: use AssertSync for BINDER_VM_OPS

2026-03-31T12:58:56+00:00

When declaring an immutable global variable in Rust, the compiler checks that it looks thread safe, because it is generally safe to access said global variable. When using C bindings types for these globals, we don't really want this check, because it is conservative and assumes pointers are not thread safe. In the case of BINDER_VM_OPS, this is a challenge when combined with the patch 'userfaultfd: introduce vm_uffd_ops' [1], which introduces a pointer field to vm_operations_struct. It previously only held function pointers, which are considered thread safe. Rust Binder should not be assuming that vm_operations_struct contains no pointer fields, so to fix this, use AssertSync (which Rust Binder has already declared for another similar global of type struct file_operations with the same problem). This ensures that even if another commit adds a pointer field to vm_operations_struct, this does not cause problems. Fixes: 8ef2c15aeae0 ("rust_binder: check ownership before using vma") Cc: stable Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202603121235.tpnRxFKO-lkp@intel.com/ Link: https://lore.kernel.org/r/20260306171815.3160826-8-rppt@kernel.org [1] Signed-off-by: Alice Ryhl Reviewed-by: Gary Guo Link: https://patch.msgid.link/20260314111951.4139029-1-aliceryhl@google.com Signed-off-by: Greg Kroah-Hartman

rust_binder: use lock_vma_under_rcu() in use_page_slow()

2026-02-27T05:34:14+00:00

There's no reason to lock the whole mm when we are doing operations on the vma if we can help it, so to reduce contention, use the lock_vma_under_rcu() abstraction. Signed-off-by: Alice Ryhl Reviewed-by: Jann Horn Reviewed-by: Liam R. Howlett Link: https://patch.msgid.link/20260218-binder-vma-rcu-v1-1-8bd45b2b1183@google.com Signed-off-by: Greg Kroah-Hartman

rust_binder: call set_notification_done() without proc lock

2026-02-27T05:33:03+00:00

Consider the following sequence of events on a death listener: 1. The remote process dies and sends a BR_DEAD_BINDER message. 2. The local process invokes the BC_CLEAR_DEATH_NOTIFICATION command. 3. The local process then invokes the BC_DEAD_BINDER_DONE. Then, the kernel will reply to the BC_DEAD_BINDER_DONE command with a BR_CLEAR_DEATH_NOTIFICATION_DONE reply using push_work_if_looper(). However, this can result in a deadlock if the current thread is not a looper. This is because dead_binder_done() still holds the proc lock during set_notification_done(), which called push_work_if_looper(). Normally, push_work_if_looper() takes the thread lock, which is fine to take under the proc lock. But if the current thread is not a looper, then it falls back to delivering the reply to the process work queue, which involves taking the proc lock. Since the proc lock is already held, this is a deadlock. Fix this by releasing the proc lock during set_notification_done(). It was not intentional that it was held during that function to begin with. I don't think this ever happens in Android because BC_DEAD_BINDER_DONE is only invoked in response to BR_DEAD_BINDER messages, and the kernel always delivers BR_DEAD_BINDER to a looper. So there's no scenario where Android userspace will call BC_DEAD_BINDER_DONE on a non-looper thread. Cc: stable Fixes: eafedbc7c050 ("rust_binder: add Rust Binder driver") Reported-by: syzbot+c8287e65a57a89e7fb72@syzkaller.appspotmail.com Tested-by: syzbot+c8287e65a57a89e7fb72@syzkaller.appspotmail.com Signed-off-by: Alice Ryhl Reviewed-by: Gary Guo Reviewed-by: Andreas Hindborg Link: https://patch.msgid.link/20260224-binder-dead-binder-done-proc-lock-v1-1-bbe1b8a6e74a@google.com Signed-off-by: Greg Kroah-Hartman