From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793831289; b=kxjU9+Mf4lHF0gTpIHMpJPaI0rqw3u2Vheqm6AGnuPpUzk2cgMejRJqpmRcYrjLKjHIR dADOI4Zjxyrkg55vdY7MSsYkmDnynqwa5nI+7VdMKrHV3Cr81V+BAVXwI5jgwpCkBGyRp ITJpo2UjAbqrp6O6QsvJQlqKH7agPO1gvc+2zwVcXfrvz16I6W38uHNIRisxe7v1zLFDf xxDmpRvaxp9GEetyC1kQsgKv5Siq47NlCnTSMPXNT5U+/wNKqIAkMPYUdETNGHz07a6kn RYtblE7CnzTPQ56xmU7QvrIaVyrosP7lT8urxFxeds+Bt81bx6tQjiDX7g8kygZVnBw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793831289; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=5QDwNASLE7l0iT8oUo7RS72LkTC9IqZ8CNBbxeAzadQ=; b=cHa6+q87l+JXXJLlY4ctdnYK2Qx+CS6Gy/u27Vg/Fk+XE2SFnjAf3mCBoXYPRcmvx14a /BXbYIROT/rM8QOyKeIiYx8fKN7zp/g5i9pfDgnB5CA+yHUDV5VyBZk8oJUmsUINZvl70 PHaoaKcTyCHVSUEHi4kNNS/mBklubDoSj+gLKmN2QwfHzKsquvf4T0FS3hhbP7XmSpW+s 4LBjx1V+nBVxE9l/Iki7eJb2bi0bDkEUYULz3GQ+pHotjYyEJ+80o3XStdR1LW4OaUBKv 8jAplc7MpX9+MnNY4DAUOOAlMqvKupTN31DIJBl4qeElqxoxMmhGD7mKA4ciIFBk/qA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=K4EZ7aSa; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 793A9606AC1C; Wed, 4 Nov 2026 22:28:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=K4EZ7aSa Received: by smtp.kernel.org (Postfix) with ESMTPSA id A66CB1F000C1; Wed, 4 Nov 2026 22:28:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793831289; bh=5QDwNASLE7l0iT8oUo7RS72LkTC9IqZ8CNBbxeAzadQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=K4EZ7aSaH8RgUs97gCooEy2KluKOlh5TIHwRK/eXXBd3DjBnJqC9NvA7BIxSSJH+y kAPD/QEIGOIvf7y6LvDed0ddTC38ipir8RHzlECI+Zh8v89zsZ8FSy4aOZ7T+dTbSa rd53E7xRaBig78Qmu/oEm6AGmJ+CRiM0/D0qumZw= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Hari Mishal , Fangzhi Zuo , Daniel Wheeler , Alex Deucher , Sasha Levin Subject: [PATCH 6.18 0613/1005] drm/amd/display: guard dc_sink dereferences in MST mode validation Date: Wed, 4 Nov 2026 16:05:46 -0500 Message-ID: <20261104211101.011671296@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261104211043.516122098@linuxfoundation.org> References: <20261104211043.516122098@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Hari Mishal [ Upstream commit 217f64f348c90cba62164e7ff38e0ccf78a5ca09 ] dm_dp_mst_is_port_support_mode() reads aconnector->dc_sink->dsc_caps... for the DSC branch-throughput check, and get_conv_frl_bw()'s HDMI-PCON FRL-bandwidth path reads aconnector->dc_sink->edid_caps.max_frl_rate, both without a NULL check. dc_sink is cleared asynchronously on MST unplug, and both functions run from paths that the driver's own comments document as racing that teardown: the connector probe worker's ->mode_valid callback and a compositor's atomic check, neither of which holds the MST manager lock that the teardown path uses. The former does have an existing dsc_aux NULL check, but dsc_aux isn't reliably cleared in every path that clears dc_sink, so it doesn't cover this. Fail the port-support check and skip the FRL conversion path when the sink is already gone. Fixes: f04d275d94e1 ("drm/amd/display: add mst port output bw check") Fixes: 5c9b8b27a883 ("drm/amd/display: Tie FRL support into amdgpu_dm") Assisted-by: gkh_clanker_t1000 Signed-off-by: Hari Mishal Reviewed-by: Fangzhi Zuo Tested-by: Daniel Wheeler Signed-off-by: Alex Deucher (cherry picked from commit 7c3db8da4e039698ae198c870712428644e965c7) Cc: stable@vger.kernel.org [ sashal: Dropped the FRL hunk because the HDMI 2.1 FRL code isn't present, and applied only the dc_sink NULL check in dm_dp_mst_is_port_support_mode(). ] Signed-off-by: Sasha Levin --- drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c index 2e0895f4f9b10..642248a251149 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c @@ -1867,6 +1867,9 @@ enum dc_status dm_dp_mst_is_port_support_mode( struct dc_dsc_config_options dsc_options = {0}; uint32_t stream_kbps; + if (!aconnector->dc_sink) + return DC_FAIL_BANDWIDTH_VALIDATE; + /* DSC unnecessary case * Check if timing could be supported within end-to-end BW */ -- 2.53.0