6.6-stable review patch. If anyone has any objections, please let me know.
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From: baozhu.liu lucas.liu@siengine.com
[ Upstream commit 19ecbe8325a2a7ffda5ff4790955b84eaccba49f ]
If komeda_pipeline_unbound_components() returns -EDEADLK, it means that a deadlock happened in the locking context. Currently, komeda is not dealing with the deadlock properly,producing the following output when CONFIG_DEBUG_WW_MUTEX_SLOWPATH is enabled:
------------[ cut here ]------------ [ 26.103984] WARNING: CPU: 2 PID: 345 at drivers/gpu/drm/arm/display/komeda/komeda_pipeline_state.c:1248 komeda_release_unclaimed_resources+0x13c/0x170 [ 26.117453] Modules linked in: [ 26.120511] CPU: 2 PID: 345 Comm: composer@2.1-se Kdump: loaded Tainted: G W 5.10.110-SE-SDK1.8-dirty #16 [ 26.131374] Hardware name: Siengine Se1000 Evaluation board (DT) [ 26.137379] pstate: 20400009 (nzCv daif +PAN -UAO -TCO BTYPE=--) [ 26.143385] pc : komeda_release_unclaimed_resources+0x13c/0x170 [ 26.149301] lr : komeda_release_unclaimed_resources+0xbc/0x170 [ 26.155130] sp : ffff800017b8b8d0 [ 26.158442] pmr_save: 000000e0 [ 26.161493] x29: ffff800017b8b8d0 x28: ffff000cf2f96200 [ 26.166805] x27: ffff000c8f5a8800 x26: 0000000000000000 [ 26.172116] x25: 0000000000000038 x24: ffff8000116a0140 [ 26.177428] x23: 0000000000000038 x22: ffff000cf2f96200 [ 26.182739] x21: ffff000cfc300300 x20: ffff000c8ab77080 [ 26.188051] x19: 0000000000000003 x18: 0000000000000000 [ 26.193362] x17: 0000000000000000 x16: 0000000000000000 [ 26.198672] x15: b400e638f738ba38 x14: 0000000000000000 [ 26.203983] x13: 0000000106400a00 x12: 0000000000000000 [ 26.209294] x11: 0000000000000000 x10: 0000000000000000 [ 26.214604] x9 : ffff800012f80000 x8 : ffff000ca3308000 [ 26.219915] x7 : 0000000ff3000000 x6 : ffff80001084034c [ 26.225226] x5 : ffff800017b8bc40 x4 : 000000000000000f [ 26.230536] x3 : ffff000ca3308000 x2 : 0000000000000000 [ 26.235847] x1 : 0000000000000000 x0 : ffffffffffffffdd [ 26.241158] Call trace: [ 26.243604] komeda_release_unclaimed_resources+0x13c/0x170 [ 26.249175] komeda_crtc_atomic_check+0x68/0xf0 [ 26.253706] drm_atomic_helper_check_planes+0x138/0x1f4 [ 26.258929] komeda_kms_check+0x284/0x36c [ 26.262939] drm_atomic_check_only+0x40c/0x714 [ 26.267381] drm_atomic_nonblocking_commit+0x1c/0x60 [ 26.272344] drm_mode_atomic_ioctl+0xa3c/0xb8c [ 26.276787] drm_ioctl_kernel+0xc4/0x120 [ 26.280708] drm_ioctl+0x268/0x534 [ 26.284109] __arm64_sys_ioctl+0xa8/0xf0 [ 26.288030] el0_svc_common.constprop.0+0x80/0x240 [ 26.292817] do_el0_svc+0x24/0x90 [ 26.296132] el0_svc+0x20/0x30 [ 26.299185] el0_sync_handler+0xe8/0xf0 [ 26.303018] el0_sync+0x1a4/0x1c0 [ 26.306330] irq event stamp: 0 [ 26.309384] hardirqs last enabled at (0): [<0000000000000000>] 0x0 [ 26.315650] hardirqs last disabled at (0): [<ffff800010056d34>] copy_process+0x5d0/0x183c [ 26.323825] softirqs last enabled at (0): [<ffff800010056d34>] copy_process+0x5d0/0x183c [ 26.331997] softirqs last disabled at (0): [<0000000000000000>] 0x0 [ 26.338261] ---[ end trace 20ae984fa860184a ]--- [ 26.343021] ------------[ cut here ]------------ [ 26.347646] WARNING: CPU: 3 PID: 345 at drivers/gpu/drm/drm_modeset_lock.c:228 drm_modeset_drop_locks+0x84/0x90 [ 26.357727] Modules linked in: [ 26.360783] CPU: 3 PID: 345 Comm: composer@2.1-se Kdump: loaded Tainted: G W 5.10.110-SE-SDK1.8-dirty #16 [ 26.371645] Hardware name: Siengine Se1000 Evaluation board (DT) [ 26.377647] pstate: 20400009 (nzCv daif +PAN -UAO -TCO BTYPE=--) [ 26.383649] pc : drm_modeset_drop_locks+0x84/0x90 [ 26.388351] lr : drm_mode_atomic_ioctl+0x860/0xb8c [ 26.393137] sp : ffff800017b8bb10 [ 26.396447] pmr_save: 000000e0 [ 26.399497] x29: ffff800017b8bb10 x28: 0000000000000001 [ 26.404807] x27: 0000000000000038 x26: 0000000000000002 [ 26.410115] x25: ffff000cecbefa00 x24: ffff000cf2f96200 [ 26.415423] x23: 0000000000000001 x22: 0000000000000018 [ 26.420731] x21: 0000000000000001 x20: ffff800017b8bc10 [ 26.426039] x19: 0000000000000000 x18: 0000000000000000 [ 26.431347] x17: 0000000002e8bf2c x16: 0000000002e94c6b [ 26.436655] x15: 0000000002ea48b9 x14: ffff8000121f0300 [ 26.441963] x13: 0000000002ee2ca8 x12: ffff80001129cae0 [ 26.447272] x11: ffff800012435000 x10: ffff000ed46b5e88 [ 26.452580] x9 : ffff000c9935e600 x8 : 0000000000000000 [ 26.457888] x7 : 000000008020001e x6 : 000000008020001f [ 26.463196] x5 : ffff80001085fbe0 x4 : fffffe0033a59f20 [ 26.468504] x3 : 000000008020001e x2 : 0000000000000000 [ 26.473813] x1 : 0000000000000000 x0 : ffff000c8f596090 [ 26.479122] Call trace: [ 26.481566] drm_modeset_drop_locks+0x84/0x90 [ 26.485918] drm_mode_atomic_ioctl+0x860/0xb8c [ 26.490359] drm_ioctl_kernel+0xc4/0x120 [ 26.494278] drm_ioctl+0x268/0x534 [ 26.497677] __arm64_sys_ioctl+0xa8/0xf0 [ 26.501598] el0_svc_common.constprop.0+0x80/0x240 [ 26.506384] do_el0_svc+0x24/0x90 [ 26.509697] el0_svc+0x20/0x30 [ 26.512748] el0_sync_handler+0xe8/0xf0 [ 26.516580] el0_sync+0x1a4/0x1c0 [ 26.519891] irq event stamp: 0 [ 26.522943] hardirqs last enabled at (0): [<0000000000000000>] 0x0 [ 26.529207] hardirqs last disabled at (0): [<ffff800010056d34>] copy_process+0x5d0/0x183c [ 26.537379] softirqs last enabled at (0): [<ffff800010056d34>] copy_process+0x5d0/0x183c [ 26.545550] softirqs last disabled at (0): [<0000000000000000>] 0x0 [ 26.551812] ---[ end trace 20ae984fa860184b ]---
According to the call trace information,it can be located to be WARN_ON(IS_ERR(c_st)) in the komeda_pipeline_unbound_components function; Then follow the function. komeda_pipeline_unbound_components -> komeda_component_get_state_and_set_user -> komeda_pipeline_get_state_and_set_crtc -> komeda_pipeline_get_state ->drm_atomic_get_private_obj_state -> drm_atomic_get_private_obj_state -> drm_modeset_lock
komeda_pipeline_unbound_components -> komeda_component_get_state_and_set_user -> komeda_component_get_state -> drm_atomic_get_private_obj_state -> drm_modeset_lock
ret = drm_modeset_lock(&obj->lock, state->acquire_ctx); if (ret) return ERR_PTR(ret); Here it return -EDEADLK.
deal with the deadlock as suggested by [1], using the function drm_modeset_backoff(). [1] https://docs.kernel.org/gpu/drm-kms.html?highlight=kms#kms-locking
Therefore, handling this problem can be solved by adding return -EDEADLK back to the drm_modeset_backoff processing flow in the drm_mode_atomic_ioctl function.
Signed-off-by: baozhu.liu lucas.liu@siengine.com Signed-off-by: menghui.huang menghui.huang@siengine.com Reviewed-by: Liviu Dudau liviu.dudau@arm.com Signed-off-by: Liviu Dudau liviu.dudau@arm.com Link: https://patchwork.freedesktop.org/patch/msgid/20230804013117.6870-1-menghui.... Signed-off-by: Sasha Levin sashal@kernel.org --- .../gpu/drm/arm/display/komeda/komeda_pipeline_state.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_pipeline_state.c b/drivers/gpu/drm/arm/display/komeda/komeda_pipeline_state.c index 4618687a8f4d6..f3e744172673c 100644 --- a/drivers/gpu/drm/arm/display/komeda/komeda_pipeline_state.c +++ b/drivers/gpu/drm/arm/display/komeda/komeda_pipeline_state.c @@ -1223,7 +1223,7 @@ int komeda_build_display_data_flow(struct komeda_crtc *kcrtc, return 0; }
-static void +static int komeda_pipeline_unbound_components(struct komeda_pipeline *pipe, struct komeda_pipeline_state *new) { @@ -1243,8 +1243,12 @@ komeda_pipeline_unbound_components(struct komeda_pipeline *pipe, c = komeda_pipeline_get_component(pipe, id); c_st = komeda_component_get_state_and_set_user(c, drm_st, NULL, new->crtc); + if (PTR_ERR(c_st) == -EDEADLK) + return -EDEADLK; WARN_ON(IS_ERR(c_st)); } + + return 0; }
/* release unclaimed pipeline resource */ @@ -1266,9 +1270,8 @@ int komeda_release_unclaimed_resources(struct komeda_pipeline *pipe, if (WARN_ON(IS_ERR_OR_NULL(st))) return -EINVAL;
- komeda_pipeline_unbound_components(pipe, st); + return komeda_pipeline_unbound_components(pipe, st);
- return 0; }
/* Since standalone disabled components must be disabled separately and in the