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drm/amdgpu: Fix lockdep false positive in amdgpu_lockdep_init

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Move fs_reclaim_acquire() to before all lock acquisitions to eliminate
false positive circular locking dependency warning.

This is a 7.2-cycle regression fix suitable for stable backport.

v3: Address Mikhail Gavrilov technical review:
    - Clarify that fs_reclaim_acquire/release pair only REGISTERS the
      fs_reclaim lock class, does NOT create a static edge when called
      with no locks held
    - Explain that the actual fs_reclaim -> notifier_lock edge is
      established at runtime during memory reclaim -> MMU notifier path
    - Add Cc: Arunpravin PaneerSelvam

v2: Address Mikhail Gavrilov review feedback:
    - Fix author name: Michael -> Mikhail Gavrilov in all trailers
    - Add Fixes: tag to link regression to original commit
    - Add Tested-by: Mikhail Gavrilov (tested on RX 7900 XTX)

Fixes: 1d0f5838b1 ("drm/amdgpu: Add lockdep annotations for lock ordering validation")
Reported-by: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
Analyzed-by: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
Test-case-by: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
Tested-by: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
Suggested-by: Christian König <christian.koenig@amd.com>
Tested-by: Vitaly Prosyak <vitaly.prosyak@amd.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Arunpravin PaneerSelvam <Arunpravin.PaneerSelvam@amd.com>
Signed-off-by: Vitaly Prosyak <vitaly.prosyak@amd.com>
Acked-by: Arunpravin Paneer Selvam <Arunpravin.PaneerSelvam@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 70a1e9849e)
Cc: stable@vger.kernel.org
This commit is contained in:
Vitaly Prosyak
2026-07-31 20:18:20 -04:00
committed by Alex Deucher
parent cda6ab11c1
commit 384c1d907e
1 changed files with 15 additions and 6 deletions
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21
drivers/gpu/drm/amd/amdgpu/amdgpu_lockdep.c
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@@ -135,6 +135,21 @@ int amdgpu_lockdep_init(void)
lockdep_set_class(&locks->srbm_mutex, &amdgpu_srbm_lock_key);
lockdep_set_class(&locks->grbm_idx_mutex, &amdgpu_grbm_lock_key);
lockdep_set_class(&locks->mmio_idx_lock, &amdgpu_mmio_lock_key);
/*
* Register fs_reclaim lock class FIRST, before taking any locks.
*
* This acquire/release pair does NOT create a static lockdep edge
* (no locks are held between acquire and release). It only registers
* the fs_reclaim lock class with lockdep.
*
* The actual fs_reclaim -> notifier_lock dependency is established at
* RUNTIME when memory reclaim invokes MMU notifiers:
* fs_reclaim (held by reclaim) -> notifier_lock (acquired in callback)
*/
fs_reclaim_acquire(GFP_KERNEL);
fs_reclaim_release(GFP_KERNEL);
/*
* Take locks in the correct order to train lockdep.
* This establishes the dependency chain.
@@ -154,11 +169,6 @@ int amdgpu_lockdep_init(void)
/* Level 6: Reset control lock */
mutex_lock(&locks->reset_lock);
/*
* Mark potential memory reclaim boundary.
* GPU operations might trigger memory allocation/reclaim.
*/
fs_reclaim_acquire(GFP_KERNEL);
/* Level 7: SRBM register access */
mutex_lock(&locks->srbm_mutex);
@@ -176,7 +186,6 @@ int amdgpu_lockdep_init(void)
spin_unlock_irqrestore(&locks->mmio_idx_lock, flags);
mutex_unlock(&locks->grbm_idx_mutex);
mutex_unlock(&locks->srbm_mutex);
fs_reclaim_release(GFP_KERNEL);
mutex_unlock(&locks->reset_lock);
up_read(&reset_domain->sem);