This is a note to let you know that I've just added the patch titled drm/amd/display: fix shift-out-of-bounds in CalculateVMAndRowBytes to the 5.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: drm-amd-display-fix-shift-out-of-bounds-in-calculate.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit ea0d24fdcbc505856e1eff19b53b1a7184407442 Author: Alex Hung <alex.hung@xxxxxxx> Date: Wed Jan 11 09:54:11 2023 -0700 drm/amd/display: fix shift-out-of-bounds in CalculateVMAndRowBytes [ Upstream commit 031f196d1b1b6d5dfcb0533b431e3ab1750e6189 ] [WHY] When PTEBufferSizeInRequests is zero, UBSAN reports the following warning because dml_log2 returns an unexpected negative value: shift exponent 4294966273 is too large for 32-bit type 'int' [HOW] In the case PTEBufferSizeInRequests is zero, skip the dml_log2() and assign the result directly. Reviewed-by: Jun Lei <Jun.Lei@xxxxxxx> Acked-by: Qingqing Zhuo <qingqing.zhuo@xxxxxxx> Signed-off-by: Alex Hung <alex.hung@xxxxxxx> Tested-by: Daniel Wheeler <daniel.wheeler@xxxxxxx> Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/gpu/drm/amd/display/dc/dml/dcn30/display_mode_vba_30.c b/drivers/gpu/drm/amd/display/dc/dml/dcn30/display_mode_vba_30.c index e427f4ffa0807..e5b1002d7f3f0 100644 --- a/drivers/gpu/drm/amd/display/dc/dml/dcn30/display_mode_vba_30.c +++ b/drivers/gpu/drm/amd/display/dc/dml/dcn30/display_mode_vba_30.c @@ -1868,7 +1868,10 @@ static unsigned int CalculateVMAndRowBytes( } if (SurfaceTiling == dm_sw_linear) { - *dpte_row_height = dml_min(128, 1 << (unsigned int) dml_floor(dml_log2(PTEBufferSizeInRequests * *PixelPTEReqWidth / Pitch), 1)); + if (PTEBufferSizeInRequests == 0) + *dpte_row_height = 1; + else + *dpte_row_height = dml_min(128, 1 << (unsigned int) dml_floor(dml_log2(PTEBufferSizeInRequests * *PixelPTEReqWidth / Pitch), 1)); *dpte_row_width_ub = (dml_ceil(((double) SwathWidth - 1) / *PixelPTEReqWidth, 1) + 1) * *PixelPTEReqWidth; *PixelPTEBytesPerRow = *dpte_row_width_ub / *PixelPTEReqWidth * *PTERequestSize; } else if (ScanDirection != dm_vert) {