> -----Original Message----- > From: amd-gfx [mailto:amd-gfx-bounces at lists.freedesktop.org] On Behalf > Of Alex Xie > Sent: Wednesday, July 19, 2017 10:28 PM > To: amd-gfx at lists.freedesktop.org > Cc: Xie, AlexBin > Subject: [PATCH] drm/amdgpu: Fix error RCU usage > > In RCU read-side critical sections, blocking or sleeping is prohibited. > > Reported by: Dave Airlie > > [ 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 at amd.com> > --- > drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c | 9 ++++++--- > 1 file changed, 6 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 dc87962..565ca90 100644 > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c > @@ -198,12 +198,15 @@ 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 { Coding style, open paren should be on same line as else. E.g., } else { Alex > + rcu_read_unlock(); > result = NULL; > + } > } > - rcu_read_unlock(); > > return result; > } > -- > 2.7.4 > > _______________________________________________ > amd-gfx mailing list > amd-gfx at lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/amd-gfx
