From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1852338DC62 for ; Thu, 10 Sep 2026 19:42:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789069361; cv=none; b=HQL/v7UyQ+HJYVjb52O2m9RdHGeWUpEdiCBmWXWHz8fkIowmqF/0c+BHR/2wGUcq/G9M45WojUDpCbiijslGlHsplWjlONw+ewPlhmDV19bgItxgQ16JgKoF+kJfa6dn2A/2EfQ/XEVt2vQqR1RkNYvxzotMe80XuERbLvubnhE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789069361; c=relaxed/simple; bh=oii34dkQdH1tLVvgOKCfLB8O1a8EiWK68qIFHjtowYs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=i4wtw5A0Q40FFfGMKo6iPECUTW6LgDE1TKXoP3pN8GSx1NLdJEyS/YCFbQq1eIF8WoSDDNpB2BWQsf2EwdpMkIFGRD4D/9ECVKJhSDeEowfoEXWyZT9dBZdVsUI0L2i4Cmbj9Nq4bDXEmabCRFSBYhFDLwq7fZeDBvyi75CqAks= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=NcFQ1QLM; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="NcFQ1QLM" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4025A1F000FF; Thu, 10 Sep 2026 19:42:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789069359; bh=1YpuzsMRhi760Ioj7E+EsE3lgHmlasBLbVUdVsnHVoM=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=NcFQ1QLMaEuFTTWaRjvunODYs0iB/6XzLrnm+48tSSJXiFG/OonAVmfgodb0YcXIk VPuffIPUdXohdSalmBAjswL5+s6Am8ZHHSqNNgRSNaLwgyV7la2XwP427qkaReB/b7 1PqErcZVu5QYUn7YxT+9y9ZJh3r6m8N9/b1cYxY+E+Q/lLL5rWwPVxFbXauxVGfNIz E8xK8mLgkrqPqyfRPHbRwiamSDA9xDfm58+kMAu73eNbnlG/2KI6QhbPtmAMwz9yP5 8+Y1kFEBdEi0SqKJdeGoz1vdogcrfljqwmIvRpYu+HXiIJym0y+y7IAEXhVoIRDK75 Cdlhy8VcdmqbQ== From: Sasha Levin To: stable@vger.kernel.org Cc: Taimuraz Kaitmazov , Lizhi Hou , Sasha Levin Subject: [PATCH 6.18.y] accel/amdxdna: return early from a zero-length flush Date: Thu, 10 Sep 2026 15:42:37 -0400 Message-ID: <20260910194237.1586329-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026090959-anyhow-crinkly-25f7@gregkh> References: <2026090959-anyhow-crinkly-25f7@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Taimuraz Kaitmazov [ Upstream commit dc14753664240cedf669623b27ae9922b0618b25 ] SYNC_BO does not constrain its size, so a request for zero bytes reaches drm_clflush_virt_range(), which ends with an unconditional clflushopt(end - 1). For an empty range that is the byte before the mapping, and abo->mem.kva comes from vmap(), so the access lands in the guard page below the vmalloc area and faults: BUG: unable to handle page fault for address: ffffd16fbbc70fff #PF: supervisor read access in kernel mode Oops: Oops: 0000 [#1] SMP NOPTI CPU: 7 UID: 1000 Comm: sync_bo_probe RIP: 0010:drm_clflush_virt_range+0x3c/0x70 Call Trace: amdxdna_drm_sync_bo_ioctl+0x124/0x430 [amdxdna] drm_ioctl+0x301/0x4c0 __x64_sys_ioctl+0x115/0x2f0 do_syscall_64+0xa6/0x3d0 Any process that can open the render node can do this. Reproduced 3 of 3 times on a Strix Point NPU (1022:17f0), by calling SYNC_BO with size 0 on an AMDXDNA_BO_SHARE object. The import arm takes the same request but flushes the whole scatterlist, so it survives it. Nothing needs flushing for an empty range, so answer before choosing a path. Fixes: e252e3f3488a ("accel/amdxdna: Revise device bo creation and free") Cc: stable@vger.kernel.org Signed-off-by: Taimuraz Kaitmazov Reviewed-by: Lizhi Hou Signed-off-by: Lizhi Hou Link: https://patch.msgid.link/20260817230655.356785-1-taimuraz@kaitmazov.com [ moved the guard into amdxdna_drm_sync_bo_ioctl() because amdxdna_flush_bo() is absent. ] Signed-off-by: Sasha Levin --- drivers/accel/amdxdna/amdxdna_gem.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/accel/amdxdna/amdxdna_gem.c b/drivers/accel/amdxdna/amdxdna_gem.c index a719dc6aab339..ca747457cec79 100644 --- a/drivers/accel/amdxdna/amdxdna_gem.c +++ b/drivers/accel/amdxdna/amdxdna_gem.c @@ -949,6 +949,9 @@ int amdxdna_drm_sync_bo_ioctl(struct drm_device *dev, goto put_obj; } + if (!args->size) + goto unpin; + if (is_import_bo(abo)) drm_clflush_sg(abo->base.sgt); else if (abo->mem.kva) @@ -958,6 +961,7 @@ int amdxdna_drm_sync_bo_ioctl(struct drm_device *dev, else drm_WARN(&xdna->ddev, 1, "Can not get flush memory"); +unpin: amdxdna_gem_unpin(abo); XDNA_DBG(xdna, "Sync bo %d offset 0x%llx, size 0x%llx\n", -- 2.53.0