[PATCH v5 0/9] Fix missing fops.owner in Rust DRM/misc abstractions
Alvin Sun <[email protected]>
| Newsgroups | org.kernel.vger.linux-modules,dev.linux.lists.driver-core,dev.linux.lists.nova-gpu,org.freedesktop.lists.dri-devel,org.kernel.feeds.b4-sent,org.kernel.vger.linux-block,org.kernel.vger.linux-kernel,org.kernel.vger.linux-kselftest,org.kernel.vger.linux-pci,org.kernel.vger.netdev,org.kernel.vger.rust-for-linux |
|---|---|
| Message-ID | <[email protected]> |
During tyr debugfs development, a kernel NULL pointer dereference was encountered after `rmmod tyr` while gnome-shell still held /dev/card1 open: ``` [158827.868132] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 [158827.868918] Mem abort info: [158827.869177] ESR = 0x0000000086000004 [158827.869519] EC = 0x21: IABT (current EL), IL = 32 bits [158827.870000] SET = 0, FnV = 0 [158827.870281] EA = 0, S1PTW = 0 [158827.870571] FSC = 0x04: level 0 translation fault [158827.871043] user pgtable: 4k pages, 48-bit VAs, pgdp=0000000108dec000 [158827.871623] [0000000000000000] pgd=0000000000000000, p4d=0000000000000000 [158827.872242] Internal error: Oops: 0000000086000004 [#1] SMP [158827.872246] Modules linked in: tyr sunrpc snd_soc_simple_card rk805_pwrkey snd_soc_simple_card_utils rtw88_8822bu display_connector rtw88_usb rtw88_8822b snd_soc_rockchip_i2s_tdm snd_soc_hdmi_codec rtw88_core] [158827.872337] CPU: 4 UID: 1000 PID: 11276 Comm: gnome-s:disk$0 Tainted: G N 7.1.0-rc1+ #331 PREEMPT [158827.880534] Tainted: [N]=TEST [158827.880535] Hardware name: FriendlyElec NanoPi R6C/NanoPi R6C, BIOS v1.1 04/09/2025 [158827.880538] pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [158827.880542] pc : 0x0 [158827.880547] lr : _RNvNtCs257m05FHVbX_3tyr2vm8pt_unmap+0x8c/0x12c [tyr] [158827.880578] sp : ffff800083c236b0 [158827.880579] x29: ffff800083c236d0 x28: ffff00013f8a0000 x27: 0000000000000000 [158827.880585] x26: 000000000000007c x25: ffff000108e6ed80 x24: 0000000000401000 [158827.880590] x23: 0000000000000000 x22: 0000000040000000 x21: 0000000000001000 [158827.880595] x20: ffff00010f778138 x19: 0000000000400000 x18: 00000000ffffffff [158827.880600] x17: 000000040044ffff x16: 045000f2b5503510 x15: 0720072007200720 [158827.880606] x14: 0720072007200720 x13: 0000000000401000 x12: 0000000000400000 [158827.880611] x11: ffff800083c239d0 x10: ffff000141e4fd88 x9 : 0000000000000000 [158827.880615] x8 : 0000000000000000 x7 : 0000000000000000 x6 : 0000000000400000 [158827.880620] x5 : ffff00013f8a0000 x4 : 0000000000000000 x3 : 0000000000000001 [158827.880625] x2 : 0000000000001000 x1 : 0000000000400000 x0 : ffff00010f778138 [158827.880630] Call trace: [158827.880632] 0x0 (P) [158827.880635] _RNvXs6_NtCs257m05FHVbX_3tyr2vmNtB5_9GpuVmDataNtNtNtCsgmSOfgXi5CZ_6kernel3drm5gpuvm11DriverGpuVm13sm_step_unmap+0x3c/0x120 [tyr] [158827.891166] _RNvMs4_NtNtNtCsgmSOfgXi5CZ_6kernel3drm5gpuvm6sm_opsINtB7_5GpuVmNtNtCs257m05FHVbX_3tyr2vm9GpuVmDataE13sm_step_unmapB13_+0x18/0x34 [tyr] [158827.891187] op_unmap_cb+0x78/0xb0 [158827.891196] __drm_gpuvm_sm_unmap+0x18c/0x1b4 [158827.891204] drm_gpuvm_sm_unmap+0x38/0x4c [158827.891209] _RNvMs5_NtCs257m05FHVbX_3tyr2vmNtB5_2Vm7exec_op+0x1cc/0x254 [tyr] [158827.894085] _RNvMs5_NtCs257m05FHVbX_3tyr2vmNtB5_2Vm11unmap_range+0x124/0x188 [tyr] [158827.894105] _RINvNtCs5hGKnPbRUFW_4core3ptr13drop_in_placeNtNtCs257m05FHVbX_3tyr3gem8KernelBoEBK_+0x44/0xd8 [tyr] [158827.894125] _RINvNtCs5hGKnPbRUFW_4core3ptr13drop_in_placeINtNtNtCsgmSOfgXi5CZ_6kernel5alloc4kvec3VecNtNtCs257m05FHVbX_3tyr2fw7SectionNtNtBL_9allocator7KmallocEEB1r_+0x3c/0x100 [tyr] [158827.894147] _RINvNtCs5hGKnPbRUFW_4core3ptr13drop_in_placeINtNtNtCsgmSOfgXi5CZ_6kernel4sync3arc3ArcNtNtCs257m05FHVbX_3tyr2fw8FirmwareEEB1p_+0x94/0x190 [tyr] [158827.894167] _RNvMs4_NtNtCsgmSOfgXi5CZ_6kernel3drm6deviceINtB5_6DeviceNtNtCs257m05FHVbX_3tyr6driver12TyrDrmDriverE7releaseBW_+0x30/0x98 [tyr] [158827.899550] drm_dev_put.part.0+0x88/0xc0 [158827.899557] drm_minor_release+0x18/0x28 [158827.899562] drm_release+0x144/0x170 [158827.899567] __fput+0xe4/0x30c [158827.899573] ____fput+0x14/0x20 [158827.899579] task_work_run+0x7c/0xe8 [158827.899586] do_exit+0x2a8/0xac4 [158827.899590] do_group_exit+0x34/0x90 [158827.899594] get_signal+0xaac/0xabc [158827.899599] arch_do_signal_or_restart+0x90/0x3e8 [158827.899606] exit_to_user_mode_loop+0x140/0x1d0 [158827.899613] el0_svc+0x2f4/0x2f8 [158827.899620] el0t_64_sync_handler+0xa0/0xe4 [158827.899627] el0t_64_sync+0x198/0x19c [158827.899632] ---[ end trace 0000000000000000 ]--- ``` The root cause: `fops.owner` was `NULL` in Rust DRM drivers, so the kernel never blocked module unloading while file descriptors were open. This leads to use-after-free when drm_release (or other fops) is called on freed module code. The series moves `THIS_MODULE` into the `ModuleMetadata` as a const, threads it through `#[vtable]` to set `fops.owner` in DRM/miscdevice, and updates configfs and rnull to use `this_module::<LocalModule>()`. Assisted-by: opencode:glm-5.2 Signed-off-by: Alvin Sun <[email protected]> --- Changes in v5: - Add `#[inline]` to the `this_module()` helper. - Fix configfs doc comment to reference `crate::LocalModule` instead of bare `LocalModule`. - Link to v4: https://lore.kernel.org/r/[email protected] Changes in v4: - Move module-related types into a new `rust/kernel/module.rs`. - Migrate binder from the `module!`-generated `THIS_MODULE` static to `this_module::<LocalModule>()`. - Reorganise the series so that every commit builds independently, and drop the legacy `THIS_MODULE` static once all users are migrated. - Link to v3: https://lore.kernel.org/r/[email protected] Changes in v3: - Renamed vtable associated type `ThisModule` to `OwnerModule` - Added `this_module()` helper for ergonomic `THIS_MODULE` access - Refined vtable macro implementation: one-liner detection and single `defined_items` set - Reordered commits to place doctest fallback before vtable auto-insert - Link to v2: https://lore.kernel.org/r/[email protected] Changes in v2: - Merged old `static THIS_MODULE` and v1's `MODULE_PTR` into a single `ModuleMetadata::THIS_MODULE` const - `#[vtable]` macro now auto-inserts `type ThisModule`, removing all per-driver manual patches from v1 - Added configfs & rnull usage site updates and doctest `LocalModule` fallback - Link to v1: https://lore.kernel.org/r/[email protected] --- Alvin Sun (9): rust: module: move module types into `module.rs` rust: module: add `THIS_MODULE` const to `ModuleMetadata` trait rust: doctest: add LocalModule fallback for #[vtable] ThisModule rust: macros: auto-insert OwnerModule in #[vtable] rust: drm: set fops.owner from driver module pointer rust: miscdevice: set fops.owner from driver module pointer rust: configfs: use `LocalModule` for `THIS_MODULE` rust: binder: use `LocalModule` for `THIS_MODULE` rust: macros: remove `THIS_MODULE` static from `module!` drivers/android/binder/rust_binder_main.rs | 3 +- drivers/block/rnull/configfs.rs | 6 +-- rust/kernel/auxiliary.rs | 2 +- rust/kernel/configfs.rs | 8 +-- rust/kernel/drm/device.rs | 3 +- rust/kernel/drm/gem/mod.rs | 4 +- rust/kernel/i2c.rs | 2 +- rust/kernel/lib.rs | 75 +++------------------------- rust/kernel/miscdevice.rs | 4 +- rust/kernel/module.rs | 80 ++++++++++++++++++++++++++++++ rust/kernel/net/phy.rs | 6 ++- rust/kernel/pci.rs | 2 +- rust/kernel/platform.rs | 2 +- rust/kernel/usb.rs | 2 +- rust/macros/lib.rs | 6 +++ rust/macros/module.rs | 34 ++++++------- rust/macros/vtable.rs | 41 +++++++++++++-- scripts/rustdoc_test_gen.rs | 16 ++++++ 18 files changed, 188 insertions(+), 108 deletions(-) --- base-commit: b7e5ac83cb16f7ffd11dc23736f84276602100ed change-id: 20260519-fix-fops-owner-e3a77bb27c6c prerequisite-change-id: 20260519-miscdev-use-format-9ab7e83b1c11:v3 prerequisite-patch-id: 405b334ff0d48ad350014f05a2321bdbaa025400 prerequisite-patch-id: 604b631c81d5423f4ebb2e12ba2d22e9ce371bfc prerequisite-patch-id: cb550d94cefe01920e0d3ced2b2bcbecd76f3907 prerequisite-patch-id: 3bc830839742591460cb86d9472c04f4686dc600 prerequisite-patch-id: 571058244bc8c7088638d2e3225713011246c7e9 prerequisite-patch-id: 347c5a3c6dbef9832bfce8419fc23e6e08ba477f prerequisite-patch-id: 3e202d988b56b88446f7535e90d3f00cf5f15701 Best regards, -- Alvin Sun <[email protected]>