This series fixes a lockdep "possible recursive locking" splat in amdgpu_devcoredump_format() that fires on every GPU timeout once a job with a PASID context is involved. With amdgpu.gpu_recovery=0 the timeout handler refires every ~2 s, so the splat repeats until it drowns the kernel ring buffer. It is also a real self-deadlock for IB BOs that share their dma_resv with the root PD (the always-valid case).
The root cause: amdgpu_devcoredump_format() holds the VM root PD's reservation and then reserves each IB BO on top of it, nesting two reservation_ww_class_mutex acquires without a ww_acquire_ctx.
The fix teaches amdgpu_vm_lock_by_pasid() to lock the root PD in a drm_exec context, so the devcoredump path can lock the root PD and all the IB BOs together in one ww ticket. Because amdgpu_vm_lock_by_pasid() has a second caller in the page-fault path, the series is split so each patch builds and works on its own:
1/2 Convert amdgpu_vm_lock_by_pasid() to take a drm_exec context and lock the root PD with drm_exec_lock_obj(). The drm_exec context holds the root BO reference, so the root output parameter is dropped. Updates the existing caller, amdgpu_vm_handle_fault(). Pure refactor, no functional change to the page-fault path. (Reviewed-by Christian on v5.)
2/2 Move the IB dumping into a separate helper that locks the root PD and every IB BO together in one drm_exec ticket. The per-IB amdgpu_bo_reserve() nesting is gone, along with a BO refcount leak on the old reserve-failure path. This is the actual bug fix and carries the Fixes: tag.
Tested on Linux 7.1-rc4 + this series, Radeon RX 7900 XTX (gfx1100), KASAN + PROVE_LOCKING enabled, using a small libdrm_amdgpu reproducer that submits a GFX IB chained at GPU VA 0 and waits for the hang. Before the series the splat fires on every TDR; after it the dmesg is clean across repeated timeouts and the devcoredump IB dump is produced correctly.
v1: https://lore.kernel.org/amd-gfx/20260429143743.50743-1-mikhail.v.gavrilov@gm... v2: https://lore.kernel.org/amd-gfx/20260519161541.19994-1-mikhail.v.gavrilov@gm... v3: https://lore.kernel.org/amd-gfx/20260520151741.50575-1-mikhail.v.gavrilov@gm... v4: https://lore.kernel.org/amd-gfx/20260521104335.28978-1-mikhail.v.gavrilov@gm... v5: https://lore.kernel.org/amd-gfx/20260521150841.20625-1-mikhail.v.gavrilov@gm...
Changes since v5 (all in patch 2, per Christian's review): - Trim the commit message: drop the reproducer paragraph, keep the problem description and the solution. - Move the IB dumping out of amdgpu_devcoredump_format() into a separate amdgpu_devcoredump_print_ibs() helper. - Use goto error handling inside drm_exec_until_all_locked() instead of break, and drop the now-superfluous `locked` variable. drm_exec_fini() is called once at the end of the helper, not in the locking path. - Patch 1 is unchanged from v5 and keeps Christian's Reviewed-by.
A note on one review point I couldn't fully confirm before respinning (asked on the v5 thread [1], no reply yet): in the locking loop, when amdgpu_vm_bo_lookup_mapping() returns no mapping for an IB, this version treats it as non-fatal -- there is simply nothing to lock for that IB, so the loop continues, and the content loop still emits the "IB #N <addr>" header without a body. goto-abort is reserved for real errors (VM not found, drm_exec_lock_obj() failure). If a missing mapping should instead abort the whole dump, I'll change it.
[1] https://lore.kernel.org/amd-gfx/CABXGCsPPY3qX7Ad-a7==nmA5R7aejCTCrmWYpn-9OQQ...
Changes since v4: - Pass nr=1 to drm_exec_init() in amdgpu_vm_handle_fault() (Christian). - Picked up Christian's Reviewed-by on patch 1.
Changes since v3: - Lock the root PD with drm_exec_lock_obj() instead of amdgpu_vm_lock_pd(); drop the root output parameter; unlock with drm_exec_unlock_obj() on the VM-recheck-failed path (Christian). - Resolves the docutils warning the kernel test robot reported on v3.
Changes since v2: - Reworked along the lines Christian suggested: amdgpu_vm_lock_by_pasid() takes a drm_exec context directly (patch 1), devcoredump locks the root PD and all IB BOs in one ticket (patch 2). The v2 helper struct and the three collect/lock/release helpers are gone.
Changes since v1: - Switched from per-IB amdgpu_bo_reserve() to drm_exec. - Dropped the Cc: stable tag: the regression only landed in 7.1-rc1, so the fix reaches 7.1 via drm-fixes without a stable backport.
Mikhail Gavrilov (2): drm/amdgpu: convert amdgpu_vm_lock_by_pasid() to drm_exec drm/amdgpu: fix recursive ww_mutex acquire in amdgpu_devcoredump_format
.../gpu/drm/amd/amdgpu/amdgpu_dev_coredump.c | 215 ++++++++++-------- drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 91 +++++--- drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h | 2 +- 3 files changed, 184 insertions(+), 124 deletions(-)