From: Shuicheng Lin Date: Fri, 5 Dec 2025 23:47:17 +0000 (+0000) Subject: drm/xe: Limit num_syncs to prevent oversized allocations X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8e461304009135270e9ccf2d7e2dfe29daec9b60;p=thirdparty%2Flinux.git drm/xe: Limit num_syncs to prevent oversized allocations The exec and vm_bind ioctl allow userspace to specify an arbitrary num_syncs value. Without bounds checking, a very large num_syncs can force an excessively large allocation, leading to kernel warnings from the page allocator as below. Introduce DRM_XE_MAX_SYNCS (set to 1024) and reject any request exceeding this limit. " ------------[ cut here ]------------ WARNING: CPU: 0 PID: 1217 at mm/page_alloc.c:5124 __alloc_frozen_pages_noprof+0x2f8/0x2180 mm/page_alloc.c:5124 ... Call Trace: alloc_pages_mpol+0xe4/0x330 mm/mempolicy.c:2416 ___kmalloc_large_node+0xd8/0x110 mm/slub.c:4317 __kmalloc_large_node_noprof+0x18/0xe0 mm/slub.c:4348 __do_kmalloc_node mm/slub.c:4364 [inline] __kmalloc_noprof+0x3d4/0x4b0 mm/slub.c:4388 kmalloc_noprof include/linux/slab.h:909 [inline] kmalloc_array_noprof include/linux/slab.h:948 [inline] xe_exec_ioctl+0xa47/0x1e70 drivers/gpu/drm/xe/xe_exec.c:158 drm_ioctl_kernel+0x1f1/0x3e0 drivers/gpu/drm/drm_ioctl.c:797 drm_ioctl+0x5e7/0xc50 drivers/gpu/drm/drm_ioctl.c:894 xe_drm_ioctl+0x10b/0x170 drivers/gpu/drm/xe/xe_device.c:224 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:598 [inline] __se_sys_ioctl fs/ioctl.c:584 [inline] __x64_sys_ioctl+0x18b/0x210 fs/ioctl.c:584 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xbb/0x380 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f ... " v2: Add "Reported-by" and Cc stable kernels. v3: Change XE_MAX_SYNCS from 64 to 1024. (Matt & Ashutosh) v4: s/XE_MAX_SYNCS/DRM_XE_MAX_SYNCS/ (Matt) v5: Do the check at the top of the exec func. (Matt) Fixes: dd08ebf6c352 ("drm/xe: Introduce a new DRM driver for Intel GPUs") Reported-by: Koen Koning Reported-by: Peter Senna Tschudin Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/6450 Cc: # v6.12+ Cc: Matthew Brost Cc: Michal Mrozek Cc: Carl Zhang Cc: José Roberto de Souza Cc: Lionel Landwerlin Cc: Ivan Briano Cc: Thomas Hellström Cc: Ashutosh Dixit Signed-off-by: Shuicheng Lin Reviewed-by: Matthew Brost Signed-off-by: Matthew Brost Link: https://patch.msgid.link/20251205234715.2476561-5-shuicheng.lin@intel.com (cherry picked from commit b07bac9bd708ec468cd1b8a5fe70ae2ac9b0a11c) Signed-off-by: Thomas Hellström --- diff --git a/drivers/gpu/drm/xe/xe_exec.c b/drivers/gpu/drm/xe/xe_exec.c index 4d81210e41f52..fd94800317506 100644 --- a/drivers/gpu/drm/xe/xe_exec.c +++ b/drivers/gpu/drm/xe/xe_exec.c @@ -132,7 +132,8 @@ int xe_exec_ioctl(struct drm_device *dev, void *data, struct drm_file *file) if (XE_IOCTL_DBG(xe, args->extensions) || XE_IOCTL_DBG(xe, args->pad[0] || args->pad[1] || args->pad[2]) || - XE_IOCTL_DBG(xe, args->reserved[0] || args->reserved[1])) + XE_IOCTL_DBG(xe, args->reserved[0] || args->reserved[1]) || + XE_IOCTL_DBG(xe, args->num_syncs > DRM_XE_MAX_SYNCS)) return -EINVAL; q = xe_exec_queue_lookup(xef, args->exec_queue_id); diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c index 7cac646bdf1c0..c93155c6c6272 100644 --- a/drivers/gpu/drm/xe/xe_vm.c +++ b/drivers/gpu/drm/xe/xe_vm.c @@ -3324,6 +3324,9 @@ static int vm_bind_ioctl_check_args(struct xe_device *xe, struct xe_vm *vm, if (XE_IOCTL_DBG(xe, args->extensions)) return -EINVAL; + if (XE_IOCTL_DBG(xe, args->num_syncs > DRM_XE_MAX_SYNCS)) + return -EINVAL; + if (args->num_binds > 1) { u64 __user *bind_user = u64_to_user_ptr(args->vector_of_binds); diff --git a/include/uapi/drm/xe_drm.h b/include/uapi/drm/xe_drm.h index 47853659a705e..f64dc0eff0e67 100644 --- a/include/uapi/drm/xe_drm.h +++ b/include/uapi/drm/xe_drm.h @@ -1463,6 +1463,7 @@ struct drm_xe_exec { /** @exec_queue_id: Exec queue ID for the batch buffer */ __u32 exec_queue_id; +#define DRM_XE_MAX_SYNCS 1024 /** @num_syncs: Amount of struct drm_xe_sync in array. */ __u32 num_syncs;