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authorDmitry Baryshkov <dmitry.baryshkov@linaro.org>2023-02-23 12:57:08 +0300
committerAbhinav Kumar <quic_abhinavk@quicinc.com>2023-03-03 21:04:11 +0300
commit1c1ded39bfb89217947affaa79c4cd1c138c5da2 (patch)
tree620b552382460b2ca8e5d1bab1522eecdb204199 /drivers/gpu
parentd6181c18d55cdbbf37baea0fdd0cacf69b84f6b9 (diff)
downloadlinux-1c1ded39bfb89217947affaa79c4cd1c138c5da2.tar.xz
drm/msm/dpu: fix stack smashing in dpu_hw_ctl_setup_blendstage
The rewritten dpu_hw_ctl_setup_blendstage() can lightly smash the stack when setting the SSPP_NONE pipe. However it was unnoticed until the kernel was tested under AOSP (with some kind of stack protection/check). This fixes the following backtrace: Unexpected kernel BRK exception at EL1 Internal error: BRK handler: 00000000f20003e8 [#1] PREEMPT SMP Hardware name: Thundercomm Dragonboard 845c (DT) pstate: a0400005 (NzCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : dpu_hw_ctl_setup_blendstage+0x26c/0x278 [msm] lr : _dpu_crtc_blend_setup+0x4b4/0x5a0 [msm] sp : ffffffc00bdcb720 x29: ffffffc00bdcb720 x28: ffffff8085debac0 x27: 0000000000000002 x26: ffffffd74af18320 x25: ffffff8083af75a0 x24: ffffffc00bdcb878 x23: 0000000000000001 x22: 0000000000000000 x21: ffffff8085a70000 x20: ffffff8083012dc0 x19: 0000000000000001 x18: 0000000000000000 x17: 000000040044ffff x16: 045000f4b5593519 x15: 0000000000000000 x14: 000000000000000b x13: 0000000000000001 x12: 0000000000000000 x11: 0000000000000001 x10: ffffffc00bdcb764 x9 : ffffffd74af06a08 x8 : 0000000000000001 x7 : 0000000000000001 x6 : 0000000000000000 x5 : ffffffc00bdcb878 x4 : 0000000000000002 x3 : ffffffffffffffff x2 : ffffffc00bdcb878 x1 : 0000000000000000 x0 : 0000000000000002 Call trace: dpu_hw_ctl_setup_blendstage+0x26c/0x278 [msm] _dpu_crtc_blend_setup+0x4b4/0x5a0 [msm] dpu_crtc_atomic_begin+0xd8/0x22c [msm] drm_atomic_helper_commit_planes+0x80/0x208 [drm_kms_helper] msm_atomic_commit_tail+0x134/0x6f0 [msm] commit_tail+0xa4/0x1a4 [drm_kms_helper] drm_atomic_helper_commit+0x170/0x184 [drm_kms_helper] drm_atomic_commit+0xac/0xe8 drm_mode_atomic_ioctl+0xbf0/0xdac drm_ioctl_kernel+0xc4/0x178 drm_ioctl+0x2c8/0x608 __arm64_sys_ioctl+0xa8/0xec invoke_syscall+0x44/0x104 el0_svc_common.constprop.0+0x44/0xec do_el0_svc+0x38/0x98 el0_svc+0x2c/0xb4 el0t_64_sync_handler+0xb8/0xbc el0t_64_sync+0x1a0/0x1a4 Code: 52800016 52800017 52800018 17ffffc7 (d4207d00) Fixes: 4488f71f6373 ("drm/msm/dpu: simplify blend configuration") Reported-by: Amit Pundir <amit.pundir@linaro.org> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org> Tested-by: Amit Pundir <amit.pundir@linaro.org> Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com> Patchwork: https://patchwork.freedesktop.org/patch/523778/ Link: https://lore.kernel.org/r/20230223095708.3688148-1-dmitry.baryshkov@linaro.org Signed-off-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Diffstat (limited to 'drivers/gpu')
-rw-r--r--drivers/gpu/drm/msm/disp/dpu1/dpu_hw_ctl.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_ctl.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_ctl.c
index b88a2f3724e6..6c53ea560ffa 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_ctl.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_ctl.c
@@ -446,7 +446,9 @@ static void dpu_hw_ctl_setup_blendstage(struct dpu_hw_ctl *ctx,
* CTL_LAYER has 3-bit field (and extra bits in EXT register),
* all EXT registers has 4-bit fields.
*/
- if (cfg->idx == 0) {
+ if (cfg->idx == -1) {
+ continue;
+ } else if (cfg->idx == 0) {
mixercfg[0] |= mix << cfg->shift;
mixercfg[1] |= ext << cfg->ext_shift;
} else {