Hi Inki,
On 2015-12-11 10:02, Inki Dae wrote:
Hi Marek,
I found out why NULL point access happened. That was incurred by below your patch, [PATCH] drm/exynos: move dma_addr attribute from exynos plane to exynos fb
When another crtc driver is hotplugged in runtime such as HDMI or VIDI, the drm frambuffer object of fb_helper is set to the plane state of the new crtc driver so the driver should get the drm framebuffer object from the plane's state or exynos_plane->pending_fb which is set by exynos_plane_atomic_update function.
After that, I think the drm framebuffer should be set to drm plane as a current fb which would be scanned out.
Anyway, I can fix it like below if you are ok.
Thanks, Inki Dae
--- a/drivers/gpu/drm/exynos/exynos_drm_vidi.c +++ b/drivers/gpu/drm/exynos/exynos_drm_vidi.c @@ -137,7 +137,7 @@ static void vidi_update_plane(struct exynos_drm_crtc *crtc, if (ctx->suspended) return;
addr = exynos_drm_fb_dma_addr(plane->base.fb, 0);
addr = exynos_drm_fb_dma_addr(plane->pending_fb, 0); DRM_DEBUG_KMS("dma_addr = %pad\n", &addr);plane->base.fb = plane->pending_fb;
plane->base.fb should not be modified. I think that the following fix is more appropriate: --- a/drivers/gpu/drm/exynos/exynos_drm_vidi.c +++ b/drivers/gpu/drm/exynos/exynos_drm_vidi.c @@ -132,12 +132,13 @@ static void vidi_update_plane(struct exynos_drm_crtc *crtc, struct exynos_drm_plane *plane) { struct vidi_context *ctx = crtc->ctx; - dma_addr_t addr; + dma_addr_t addr = 0;
if (ctx->suspended) return;
- addr = exynos_drm_fb_dma_addr(plane->base.fb, 0); + if (plane->base.fb) + addr = exynos_drm_fb_dma_addr(plane->base.fb, 0); DRM_DEBUG_KMS("dma_addr = %pad\n", &addr);
if (ctx->vblank_on)
I will investigate the case of NULL plane->state.fb, because it might be relevant to other crtc drivers as well.
if (ctx->vblank_on)2015년 12월 10일 22:05에 Inki Dae 이(가) 쓴 글:
2015년 11월 30일 22:53에 Marek Szyprowski 이(가) 쓴 글:
DMA address is a framebuffer attribute and the right place for it is exynos_drm_framebuffer not exynos_drm_plane. This patch also introduces helper function for getting dma address of the given framebuffer.
Signed-off-by: Marek Szyprowski m.szyprowski@samsung.com Reviewed-by: Gustavo Padovan gustavo.padovan@collabora.co.uk
drivers/gpu/drm/exynos/exynos5433_drm_decon.c | 13 ++++++++----- drivers/gpu/drm/exynos/exynos7_drm_decon.c | 16 +++++++++------- drivers/gpu/drm/exynos/exynos_drm_drv.h | 3 --- drivers/gpu/drm/exynos/exynos_drm_fb.c | 16 ++++++---------- drivers/gpu/drm/exynos/exynos_drm_fb.h | 3 +-- drivers/gpu/drm/exynos/exynos_drm_fimd.c | 10 ++++++---- drivers/gpu/drm/exynos/exynos_drm_plane.c | 18 ------------------ drivers/gpu/drm/exynos/exynos_drm_vidi.c | 5 ++++- drivers/gpu/drm/exynos/exynos_mixer.c | 7 ++++--- 9 files changed, 38 insertions(+), 53 deletions(-)
<--snip-->
diff --git a/drivers/gpu/drm/exynos/exynos_drm_vidi.c b/drivers/gpu/drm/exynos/exynos_drm_vidi.c index 669362c53f49..3ce141236fad 100644 --- a/drivers/gpu/drm/exynos/exynos_drm_vidi.c +++ b/drivers/gpu/drm/exynos/exynos_drm_vidi.c @@ -24,6 +24,7 @@
#include "exynos_drm_drv.h" #include "exynos_drm_crtc.h" +#include "exynos_drm_fb.h" #include "exynos_drm_plane.h" #include "exynos_drm_vidi.h"
@@ -126,11 +127,13 @@ static void vidi_update_plane(struct exynos_drm_crtc *crtc, struct exynos_drm_plane *plane) { struct vidi_context *ctx = crtc->ctx;
dma_addr_t addr;
if (ctx->suspended) return;
- DRM_DEBUG_KMS("dma_addr = %pad\n", plane->dma_addr);
- addr = exynos_drm_fb_dma_addr(plane->base.fb, 0);
At this point, plane->base.fb is NULL so null pointer access happens like below,
[ 5.969422] Unable to handle kernel NULL pointer dereference at virtual address 00000090 [ 5.977481] pgd = ee590000 [ 5.980142] [00000090] *pgd=6e526831, *pte=00000000, *ppte=00000000 [ 5.986347] Internal error: Oops: 17 [#1] PREEMPT SMP ARM [ 5.991712] Modules linked in: [ 5.994770] CPU: 3 PID: 1598 Comm: sh Not tainted 4.4.0-rc3-00052-gc60d7e2-dirty #199 [ 6.002565] Hardware name: SAMSUNG EXYNOS (Flattened Device Tree) [ 6.008647] task: ef328000 ti: ee4d4000 task.ti: ee4d4000 [ 6.014053] PC is at exynos_drm_fb_dma_addr+0x8/0x14 [ 6.018990] LR is at vidi_update_plane+0x4c/0xc4 [ 6.023581] pc : [<c02b1fb4>] lr : [<c02c3cc4>] psr: 80000013 [ 6.023581] sp : ee4d5d90 ip : 00000001 fp : 00000000 [ 6.035029] r10: 00000000 r9 : c05b965c r8 : ee813e00 [ 6.040241] r7 : 00000000 r6 : ee8e3330 r5 : 00000000 r4 : ee8e3010 [ 6.046749] r3 : 00000000 r2 : 00000000 r1 : 00000024 r0 : 00000000 [ 6.053264] Flags: Nzcv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none [ 6.060379] Control: 10c5387d Table: 6e59004a DAC: 00000051 [ 6.066107] Process sh (pid: 1598, stack limit = 0xee4d4210) [ 6.071748] Stack: (0xee4d5d90 to 0xee4d6000) [ 6.076100] 5d80: 00000000 ee813300 ee476e40 00000005 [ 6.084236] 5da0: ee8e3330 c028ac14 00000008 ee476e40 ee476fc0 ef3b3800 ee476fc0 eeb3e380 [ 6.092395] 5dc0: 00000002 c02b08e4 00000000 eeb3e3a4 ee476fc0 ee476e40 ef3b3800 eeb3e380 [ 6.100554] 5de0: 00000002 c02b12b8 ee854400 00000000 00000001 ee8501a8 00000000 ee476e40 [ 6.108714] 5e00: ef3b3800 00000001 ee476e40 00000050 ee850c80 00000001 ee476e40 ef3b3aac [ 6.116873] 5e20: 00000002 000000ff 00000000 c028e0ec 000a82b4 c02acc50 ee8e36a0 ee476c80 [ 6.125032] 5e40: ef3b3aac ef3b3800 ee476c9c ee850c80 ef3b3800 ef3b3800 ef3b3800 ef3b398c [ 6.133191] 5e60: c088c390 00000002 000a82b4 c028f8d4 00000000 ef3b3800 ef0f4300 c028f948 [ 6.141350] 5e80: ee850c80 c028f864 ef3b3a84 00000001 ef3b3a90 c02853e4 00000001 00000000 [ 6.149509] 5ea0: 000a82b4 ee4d5ec0 00000002 ee8e3010 00000002 00000002 ee4d5f88 00000000 [ 6.157669] 5ec0: 00000000 eeb8df00 000a82b4 c02c4278 00000002 ee476b00 eeb8df0c c01390ac [ 6.165828] 5ee0: 00000000 00000000 ee4e1f00 00000002 000a9540 ee4d5f88 c000f844 ee4d4000 [ 6.173987] 5f00: 00000000 c00dbf70 000a82b4 c00093dc ee4d4000 ee4d5f78 ef328234 c0579bec [ 6.182146] 5f20: 00000001 00000001 ee4d5f3c 00000001 ee45e9c4 00000001 000a82b4 c005ca74 [ 6.190306] 5f40: ee45e9c4 00000002 000a9540 c005cad4 ee4e1f00 00000002 000a9540 ee4d5f88 [ 6.198465] 5f60: c000f844 c00dc770 00000000 00000000 ee4e1f00 ee4e1f00 00000002 000a9540 [ 6.206624] 5f80: c000f844 c00dcf98 00000000 00000000 00000003 000a7c40 00000001 000a9540 [ 6.214783] 5fa0: 00000004 c000f680 000a7c40 00000001 00000001 000a9540 00000002 00000000 [ 6.222942] 5fc0: 000a7c40 00000001 000a9540 00000004 00000020 000a82c8 000a8294 000a82b4 [ 6.231102] 5fe0: 00000000 be8b1624 00012345 b6e94166 40000030 00000001 00000000 00000000 [ 6.239270] [<c02b1fb4>] (exynos_drm_fb_dma_addr) from [<c02c3cc4>] (vidi_update_plane+0x4c/0xc4) [ 6.248122] [<c02c3cc4>] (vidi_update_plane) from [<c028ac14>] (drm_atomic_helper_commit_planes+0x1f4/0x258) [ 6.257928] [<c028ac14>] (drm_atomic_helper_commit_planes) from [<c02b08e4>] (exynos_atomic_commit_complete+0xe4/0x1c4) [ 6.268688] [<c02b08e4>] (exynos_atomic_commit_complete) from [<c02b12b8>] (exynos_atomic_commit+0x180/0x1cc) [ 6.278584] [<c02b12b8>] (exynos_atomic_commit) from [<c028e0ec>] (restore_fbdev_mode+0x260/0x290) [ 6.287525] [<c028e0ec>] (restore_fbdev_mode) from [<c028f8d4>] (drm_fb_helper_restore_fbdev_mode_unlocked+0x30/0x74) [ 6.298111] [<c028f8d4>] (drm_fb_helper_restore_fbdev_mode_unlocked) from [<c028f948>] (drm_fb_helper_set_par+0x30/0x54) [ 6.308961] [<c028f948>] (drm_fb_helper_set_par) from [<c028f864>] (drm_fb_helper_hotplug_event+0x9c/0xdc) [ 6.318595] [<c028f864>] (drm_fb_helper_hotplug_event) from [<c02853e4>] (drm_helper_hpd_irq_event+0xd4/0x160) [ 6.328578] [<c02853e4>] (drm_helper_hpd_irq_event) from [<c02c4278>] (vidi_store_connection+0x94/0xcc) [ 6.337954] [<c02c4278>] (vidi_store_connection) from [<c01390ac>] (kernfs_fop_write+0xb8/0x1bc) [ 6.346723] [<c01390ac>] (kernfs_fop_write) from [<c00dbf70>] (__vfs_write+0x20/0xd8) [ 6.354531] [<c00dbf70>] (__vfs_write) from [<c00dc770>] (vfs_write+0x90/0x164) [ 6.361821] [<c00dc770>] (vfs_write) from [<c00dcf98>] (SyS_write+0x44/0x9c) [ 6.368855] [<c00dcf98>] (SyS_write) from [<c000f680>] (ret_fast_syscall+0x0/0x3c) [ 6.376404] Code: eb0b17f1 eaffffe7 e3510003 d2811024 (d7900101)
When vidi driver is intiated by triggering a connection sysfs file, vidi driver tries modeset binding by calling drm_fb_helper_hotplug_event. However, at this time it seems there is a case that plan->state->crtc exists but plane->fb is NULL, which would be related to vidi driver.
I just looked into this issue roughly so we would need to check this issue in more details.
Thanks, Inki Dae
DRM_DEBUG_KMS("dma_addr = %pad\n", &addr);
if (ctx->vblank_on) schedule_work(&ctx->work);
diff --git a/drivers/gpu/drm/exynos/exynos_mixer.c b/drivers/gpu/drm/exynos/exynos_mixer.c index 47777be1a754..f40de82848dc 100644 --- a/drivers/gpu/drm/exynos/exynos_mixer.c +++ b/drivers/gpu/drm/exynos/exynos_mixer.c @@ -37,6 +37,7 @@
#include "exynos_drm_drv.h" #include "exynos_drm_crtc.h" +#include "exynos_drm_fb.h" #include "exynos_drm_plane.h" #include "exynos_drm_iommu.h"
@@ -422,8 +423,8 @@ static void vp_video_buffer(struct mixer_context *ctx, return; }
- luma_addr[0] = plane->dma_addr[0];
- chroma_addr[0] = plane->dma_addr[1];
luma_addr[0] = exynos_drm_fb_dma_addr(fb, 0);
chroma_addr[0] = exynos_drm_fb_dma_addr(fb, 1);
if (mode->flags & DRM_MODE_FLAG_INTERLACE) { ctx->interlace = true;
@@ -575,7 +576,7 @@ static void mixer_graph_buffer(struct mixer_context *ctx, dst_y_offset = plane->crtc_y;
/* converting dma address base and source offset */
- dma_addr = plane->dma_addr[0]
- dma_addr = exynos_drm_fb_dma_addr(fb, 0)
src_x_offset = 0;
- (plane->src_x * fb->bits_per_pixel >> 3)
- (plane->src_y * fb->pitches[0]);
Best regards