Hi, Alex,
On Thu, Mar 20, 2025 at 10:16 AM Alex Hung <alex.hung@xxxxxxx> wrote:
>
>
>
> On 3/18/25 05:17, Huacai Chen wrote:
> > Commit 7da55c27e76749b9 ("drm/amd/display: Remove incorrect FP context
> > start") removes the FP context protection of dml2_create(), and it said
> > "All the DC_FP_START/END should be used before call anything from DML2".
> >
> > However, dml2_create()/dml2_copy()/dml2_create_copy() are not protected
> > from their callers, causing such errors:
> >
> > do_fpu invoked from kernel context![#1]:
> > CPU: 0 UID: 0 PID: 239 Comm: kworker/0:5 Not tainted 6.14.0-rc6+ #1
> > Workqueue: events work_for_cpu_fn
> > pc ffff80000319de80 ra ffff80000319de5c tp 900000010575c000 sp 900000010575f840
> > a0 0000000000000000 a1 900000012f210130 a2 900000012f000000 a3 ffff80000357e268
> > a4 ffff80000357e260 a5 900000012ea52cf0 a6 0000000400000004 a7 0000012c00001388
> > t0 00001900000015e0 t1 ffff80000379d000 t2 0000000010624dd3 t3 0000006400000014
> > t4 00000000000003e8 t5 0000005000000018 t6 0000000000000020 t7 0000000f00000064
> > t8 000000000000002f u0 5f5e9200f8901912 s9 900000012d380010 s0 900000012ea51fd8
> > s1 900000012f000000 s2 9000000109296000 s3 0000000000000001 s4 0000000000001fd8
> > s5 0000000000000001 s6 ffff800003415000 s7 900000012d390000 s8 ffff800003211f80
> > ra: ffff80000319de5c dml21_apply_soc_bb_overrides+0x3c/0x960 [amdgpu]
> > ERA: ffff80000319de80 dml21_apply_soc_bb_overrides+0x60/0x960 [amdgpu]
> > CRMD: 000000b0 (PLV0 -IE -DA +PG DACF=CC DACM=CC -WE)
> > PRMD: 00000004 (PPLV0 +PIE -PWE)
> > EUEN: 00000000 (-FPE -SXE -ASXE -BTE)
> > ECFG: 00071c1d (LIE=0,2-4,10-12 VS=7)
> > ESTAT: 000f0000 [FPD] (IS= ECode=15 EsubCode=0)
> > PRID: 0014d010 (Loongson-64bit, Loongson-3C6000/S)
> > Process kworker/0:5 (pid: 239, threadinfo=00000000927eadc6, task=000000008fd31682)
> > Stack : 00040dc000003164 0000000000000001 900000012f210130 900000012eabeeb8
> > 900000012f000000 ffff80000319fe48 900000012f210000 900000012f210130
> > 900000012f000000 900000012eabeeb8 0000000000000001 ffff8000031a0064
> > 900000010575f9f0 900000012f210130 900000012eac0000 900000012ea80000
> > 900000012f000000 ffff8000031cefc4 900000010575f9f0 ffff8000035859c0
> > ffff800003414000 900000010575fa78 900000012f000000 ffff8000031b4c50
> > 0000000000000000 9000000101c9d700 9000000109c40000 5f5e9200f8901912
> > 900000012d3c4bd0 900000012d3c5000 ffff8000034aed18 900000012d380010
> > 900000012d3c4bd0 ffff800003414000 900000012d380000 ffff800002ea49dc
> > 0000000000000001 900000012d3c6000 00000000ffffe423 0000000000010000
> > ...
> > Call Trace:
> > [<ffff80000319de80>] dml21_apply_soc_bb_overrides+0x60/0x960 [amdgpu]
> > [<ffff80000319fe44>] dml21_init+0xa4/0x280 [amdgpu]
> > [<ffff8000031a0060>] dml21_create+0x40/0x80 [amdgpu]
> > [<ffff8000031cefc0>] dc_state_create+0x100/0x160 [amdgpu]
> > [<ffff8000031b4c4c>] dc_create+0x44c/0x640 [amdgpu]
> > [<ffff800002ea49d8>] amdgpu_dm_init+0x3f8/0x2060 [amdgpu]
> > [<ffff800002ea6658>] dm_hw_init+0x18/0x60 [amdgpu]
> > [<ffff800002b16738>] amdgpu_device_init+0x1938/0x27e0 [amdgpu]
> > [<ffff800002b18e80>] amdgpu_driver_load_kms+0x20/0xa0 [amdgpu]
> > [<ffff800002b0c8f0>] amdgpu_pci_probe+0x1b0/0x580 [amdgpu]
> > [<900000000448eae4>] local_pci_probe+0x44/0xc0
> > [<9000000003b02b18>] work_for_cpu_fn+0x18/0x40
> > [<9000000003b05da0>] process_one_work+0x160/0x300
> > [<9000000003b06718>] worker_thread+0x318/0x440
> > [<9000000003b11b8c>] kthread+0x12c/0x220
> > [<9000000003ac1484>] ret_from_kernel_thread+0x8/0xa4
> >
> > So protect dml2_create()/dml2_copy()/dml2_create_copy() with DC_FP_START
> > and DC_FP_END.
>
> Hi Huacai,
>
> Can you try to put DC_FP_START DC_FP_END in the
> dml2_create()/dml2_copy()/dml2_create_copy()/dml2_validate() instead?
> The code will be cleaner and less error-prone to future changes.
At first I want to add them in
dml2_create()/dml2_copy()/dml2_create_copy()/dml2_validate(), but
commit 7da55c27e76749b9 ("drm/amd/display: Remove incorrect FP context
start") said
that "All the DC_FP_START/END should be used before call anything from DML2".
Huacai
>
> Thanks.
>
>
> >
> > Cc: stable@xxxxxxxxxxxxxxx
> > Signed-off-by: Huacai Chen <chenhuacai@xxxxxxxxxxx>
> > ---
> > drivers/gpu/drm/amd/display/dc/core/dc_state.c | 16 ++++++++++++++++
> > 1 file changed, 16 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_state.c b/drivers/gpu/drm/amd/display/dc/core/dc_state.c
> > index 1b2cce127981..6e2cac08002d 100644
> > --- a/drivers/gpu/drm/amd/display/dc/core/dc_state.c
> > +++ b/drivers/gpu/drm/amd/display/dc/core/dc_state.c
> > @@ -210,17 +210,23 @@ struct dc_state *dc_state_create(struct dc *dc, struct dc_state_create_params *p
> >
> > #ifdef CONFIG_DRM_AMD_DC_FP
> > if (dc->debug.using_dml2) {
> > + DC_FP_START();
> > +
> > dml2_opt->use_clock_dc_limits = false;
> > if (!dml2_create(dc, dml2_opt, &state->bw_ctx.dml2)) {
> > + DC_FP_END();
> > dc_state_release(state);
> > return NULL;
> > }
> >
> > dml2_opt->use_clock_dc_limits = true;
> > if (!dml2_create(dc, dml2_opt, &state->bw_ctx.dml2_dc_power_source)) {
> > + DC_FP_END();
> > dc_state_release(state);
> > return NULL;
> > }
> > +
> > + DC_FP_END();
> > }
> > #endif
> >
> > @@ -240,6 +246,8 @@ void dc_state_copy(struct dc_state *dst_state, struct dc_state *src_state)
> > dc_state_copy_internal(dst_state, src_state);
> >
> > #ifdef CONFIG_DRM_AMD_DC_FP
> > + DC_FP_START();
> > +
> > dst_state->bw_ctx.dml2 = dst_dml2;
> > if (src_state->bw_ctx.dml2)
> > dml2_copy(dst_state->bw_ctx.dml2, src_state->bw_ctx.dml2);
> > @@ -247,6 +255,8 @@ void dc_state_copy(struct dc_state *dst_state, struct dc_state *src_state)
> > dst_state->bw_ctx.dml2_dc_power_source = dst_dml2_dc_power_source;
> > if (src_state->bw_ctx.dml2_dc_power_source)
> > dml2_copy(dst_state->bw_ctx.dml2_dc_power_source, src_state->bw_ctx.dml2_dc_power_source);
> > +
> > + DC_FP_END();
> > #endif
> >
> > /* context refcount should not be overridden */
> > @@ -268,17 +278,23 @@ struct dc_state *dc_state_create_copy(struct dc_state *src_state)
> > new_state->bw_ctx.dml2 = NULL;
> > new_state->bw_ctx.dml2_dc_power_source = NULL;
> >
> > + DC_FP_START();
> > +
> > if (src_state->bw_ctx.dml2 &&
> > !dml2_create_copy(&new_state->bw_ctx.dml2, src_state->bw_ctx.dml2)) {
> > + DC_FP_END();
> > dc_state_release(new_state);
> > return NULL;
> > }
> >
> > if (src_state->bw_ctx.dml2_dc_power_source &&
> > !dml2_create_copy(&new_state->bw_ctx.dml2_dc_power_source, src_state->bw_ctx.dml2_dc_power_source)) {
> > + DC_FP_END();
> > dc_state_release(new_state);
> > return NULL;
> > }
> > +
> > + DC_FP_END();
> > #endif
> >
> > kref_init(&new_state->refcount);
>
