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| author | Alex Xie <AlexBin.Xie@amd.com> | 2017-07-20 00:02:08 -0400 |
|---|---|---|
| committer | Alex Deucher <alexander.deucher@amd.com> | 2017-07-25 16:15:46 -0400 |
| commit | b7ae412c6f7050b917d8b0bf2dadb212d740d8a5 (patch) | |
| tree | c5604b2d05a12af4015a0580899f730f3a2c0455 /drivers | |
| parent | cfd10811080f5bb0592e21d0b197d445f133ba9e (diff) | |
| download | linux-b7ae412c6f7050b917d8b0bf2dadb212d740d8a5.tar.bz2 | |
drm/amdgpu: Fix blocking in RCU critical section(v2)
In RCU read-side critical sections, blocking or sleeping is prohibited.
v2: Unlock RCU for the code path where result==NULL. (David Zhou)
Update subject
Tested-by and reported by: Dave Airlie <airlied@redhat.com>
[ 141.965723] =============================
[ 141.965724] WARNING: suspicious RCU usage
[ 141.965726] 4.12.0-rc7 #221 Not tainted
[ 141.965727] -----------------------------
[ 141.965728] /home/airlied/devel/kernel/linux-2.6/include/linux/rcupdate.h:531
Illegal context switch in RCU read-side critical section!
[ 141.965730]
other info that might help us debug this:
[ 141.965731]
rcu_scheduler_active = 2, debug_locks = 0
[ 141.965732] 1 lock held by amdgpu_cs:0/1332:
[ 141.965733] #0: (rcu_read_lock){......}, at: [<ffffffffa01a0d07>]
amdgpu_bo_list_get+0x0/0x109 [amdgpu]
[ 141.965774]
stack backtrace:
[ 141.965776] CPU: 6 PID: 1332 Comm: amdgpu_cs:0 Not tainted 4.12.0-rc7 #221
[ 141.965777] Hardware name: To be filled by O.E.M. To be filled by
O.E.M./M5A97 R2.0, BIOS 2603 06/26/2015
[ 141.965778] Call Trace:
[ 141.965782] dump_stack+0x68/0x92
[ 141.965785] lockdep_rcu_suspicious+0xf7/0x100
[ 141.965788] ___might_sleep+0x56/0x1fc
[ 141.965790] __might_sleep+0x68/0x6f
[ 141.965793] __mutex_lock+0x4e/0x7b5
[ 141.965817] ? amdgpu_bo_list_get+0xa4/0x109 [amdgpu]
[ 141.965820] ? lock_acquire+0x125/0x1b9
[ 141.965844] ? amdgpu_bo_list_set+0x464/0x464 [amdgpu]
[ 141.965846] mutex_lock_nested+0x16/0x18
[ 141.965848] ? mutex_lock_nested+0x16/0x18
[ 141.965872] amdgpu_bo_list_get+0xa4/0x109 [amdgpu]
[ 141.965895] amdgpu_cs_ioctl+0x4a0/0x17dd [amdgpu]
[ 141.965898] ? radix_tree_node_alloc.constprop.11+0x77/0xab
[ 141.965916] drm_ioctl+0x264/0x393 [drm]
[ 141.965939] ? amdgpu_cs_find_mapping+0x83/0x83 [amdgpu]
[ 141.965942] ? trace_hardirqs_on_caller+0x16a/0x186
Signed-off-by: Alex Xie <AlexBin.Xie@amd.com>
Reviewed-by: Chunming Zhou <david1.zhou@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c index f621ee115c98..5e771bc11b00 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c @@ -198,12 +198,16 @@ amdgpu_bo_list_get(struct amdgpu_fpriv *fpriv, int id) result = idr_find(&fpriv->bo_list_handles, id); if (result) { - if (kref_get_unless_zero(&result->refcount)) + if (kref_get_unless_zero(&result->refcount)) { + rcu_read_unlock(); mutex_lock(&result->lock); - else + } else { + rcu_read_unlock(); result = NULL; + } + } else { + rcu_read_unlock(); } - rcu_read_unlock(); return result; } |