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drm/amdkfd: Avoid topology_lock in kfd_mmap

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Use process-local GPU lookup in kfd_mmap() instead of kfd_device_by_id(),
so mmap path does not take topology_lock while holding mmap_lock.

Lockdep warning: possible circular locking dependency detected.
Chain:
  &topology_lock -> &root->kernfs_rwsem -> &mm->mmap_lock

Backtrace #0 (&topology_lock):
  down_read+0x8b/0x490
  kfd_device_by_id+0x1d/0xf0 [amdgpu]
  kfd_mmap+0x11e/0x750 [amdgpu]
  __mmap_region+0x101f/0x25e0
  mmap_region+0x228/0x2e0
  do_mmap+0x9f2/0x1070
  vm_mmap_pgoff+0x25d/0x430

Backtrace #1 (&root->kernfs_rwsem):
  down_write+0x80/0x200
  kernfs_add_one+0x30/0x6a0
  kernfs_create_dir_ns+0xd2/0x160
  sysfs_create_dir_ns+0x12c/0x2a0
  kobject_add_internal+0x280/0x8e0
  kfd_topology_update_sysfs+0xb85/0x1970 [amdgpu]

Backtrace #2 (&mm->mmap_lock):
  down_read_killable+0x8e/0x510
  lock_mm_and_find_vma+0x299/0xb00
  do_user_addr_fault+0x3fc/0xf80
  exc_page_fault+0x73/0x110
  filldir64+0x1aa/0x610
  kernfs_fop_readdir+0x3c2/0x810

Signed-off-by: Philip Yang <Philip.Yang@amd.com>
Reviewed-by: Felix Kuehling <felix.kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This commit is contained in:
Philip Yang 2026-06-21 11:46:37 -04:00 committed by Alex Deucher
parent 7e1b4bdb0e
commit 2c381b75fa
1 changed files with 5 additions and 3 deletions
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8
drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
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@ -3722,10 +3722,10 @@ static int kfd_mmio_mmap(struct kfd_node *dev, struct kfd_process *process,
vma->vm_page_prot);
}
static int kfd_mmap(struct file *filep, struct vm_area_struct *vma)
{
struct kfd_process *process;
struct kfd_process_device *pdd;
struct kfd_node *dev = NULL;
unsigned long mmap_offset;
unsigned int gpu_id;
@ -3739,8 +3739,10 @@ static int kfd_mmap(struct file *filep, struct vm_area_struct *vma)
mmap_offset = vma->vm_pgoff << PAGE_SHIFT;
gpu_id = KFD_MMAP_GET_GPU_ID(mmap_offset);
if (gpu_id)
dev = kfd_device_by_id(gpu_id);
pdd = kfd_process_device_data_by_id(process, gpu_id);
if (pdd)
dev = pdd->dev;
switch (mmap_offset & KFD_MMAP_TYPE_MASK) {
case KFD_MMAP_TYPE_DOORBELL: