From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (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 55FB1238C33 for ; Tue, 23 Dec 2025 06:20:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766470840; cv=none; b=IjLQxnJLkFotJYlLbjH9/f4/Z9h6nJCSLx/2ej9jCeFSPi5n1lxYT3wHfmkASWiWCk561tBcngJoHPOhTCwPLuk7E6XVAmhT335DxJUru9e7VMPwyJ7yxRI3hcngJCi8n1G3jcErL/CK8i7uv1lEPilO31rAJTuDM49oG5wD6GE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766470840; c=relaxed/simple; bh=Ei4cljcIZZwY4Zjz+c1uBY9fsxoALAtLnZCONZgpd7Y=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=EOnmzyayawLAbUS3dDC8p/xKj8b16plf+MyctvnJLh0R9TsBDeUsszQoc9Gq0Fb/3SIX4D9bcTk9PjcPwumKIDE2W+KTIRedSA8Uzcj3OQmkAgp9+1kJ5/wHYZR2qA9pRprt+eE3InRk5jURoyverG1GvVyulvLu0KfWqwNWFCI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=m0Z1ABpW; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=F0RsM6XH; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="m0Z1ABpW"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="F0RsM6XH" From: John Ogness DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1766470836; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=aH/mKIw/IcaRVIVmM+HPd+9hg4lVp7fAWzywjtGtm5E=; b=m0Z1ABpWGP+jcAE6Hz+ZvZqpPqvHPXvv1H9coQkb0DYLukfyHtqzV5S4PiVaP0rRjEjU7I BEETQrjd/pvsTkSb5X9YlYDbPIZKVYKC1YtPYHdFUPBRXB4YeE6Eps5YKmgqwqc8/nk7Nw y2j8m4ShzG3VRjQLXm5TMtPQ4XUpivkYrfhN2U6Ox540YK5eH5/fupxU6LQZ/oXXSUwjk0 eCo/dhsAFwzRm2NY9xt6D9V2v1gcZ1rx+YxMlJWZPcFWLezaLdwzsP0JJvcnaJ+D+7xPhk aM2nTpi5aBQ+ldN+HWYGhQJfyPafgjryWDLSrpX74QZ9Ck25pyFouT16nUZdFQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1766470836; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=aH/mKIw/IcaRVIVmM+HPd+9hg4lVp7fAWzywjtGtm5E=; b=F0RsM6XHfbRNcC8y25PnB1c45hHe0a7QkqworVtpmkFIbCAr2O3YAF84cxi0MyFnCbztlZ G3+VB1KvOLmZFXBA== To: ysard_git@gmx.fr, linux-kernel@vger.kernel.org Cc: pmladek@suse.com, senozhatsky@chromium.org Subject: Re: Regression: system freeze on resume from suspend introduced by printk per-console suspended state In-Reply-To: References: Date: Tue, 23 Dec 2025 07:26:35 +0106 Message-ID: <87tsxhbtxo.fsf@jogness.linutronix.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain Hi, On 2025-12-21, ysard_git@gmx.fr wrote: > I would like to report a suspend/resume regression which I bisected down > to a specific printk commit. Thanks for the report and your efforts to isolate the commit! Comments below... > Summary > ======= > > On an ASUS laptop, resuming from suspend leads to a complete system freeze: > black screen, no keyboard response. The system must be powered off forcibly. > > This regression is reproducible and was introduced by the following commit: > > 9e70a5e109a4a ("printk: Add per-console suspended state") > > Hardware / environment > ====================== > > - Laptop: G75VX ASUS > - CPU Arch: x86_64 > - BIOS Information > Version: G75VX.206 > Release Date: 02/27/2013 > - GPU: NVIDIA GeForce GTX 670MX (standalone board only, no integrated chip, no optimus) > Driver Version: 470.256.02 > - Suspend mode: suspend-to-RAM (S3) > - Distribution: Debian Testing derivative (but the regression is reproduced with mainline kernel builds) > - Last working kernel from Debian: > Linux version 6.5.0-5-amd64 (debian-kernel@lists.debian.org) > (gcc-13 (Debian 13.2.0-7) 13.2.0, GNU ld (GNU Binutils for Debian) 2.41) > #1 SMP PREEMPT_DYNAMIC Debian 6.5.13-1 (2023-11-29) > - Kernel config: based on defconfig / Debian config > - Taint flag: yes, only Nvidia proprietary drivers are loaded and compiled via DKMS > > Symptoms > ======== > > - On resume from suspend to RAM > - Screen remains black > - No visible kernel panic (no logs) > - System is completely frozen (no VT switch, no Caps lock nor Num lock responses) > - Power cycle required > > Regression details > ================== > > Suspend/resume works correctly with kernels prior to this commit. > After this commit, resume consistently results in a hard freeze. > > I performed a git bisect on the upstream kernel repository. The result is: > > 9e70a5e109a4a23367810de09be826c52d27ee2f is the first bad commit > > Commit details: > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=9e70a5e109a4a23367810de09be826c52d27ee2f > > Reverting this commit on a later kernel (v6.7 0dd3ee31125508cd67f7e7172247f05b7fd1753a) > restores correct suspend/resume behavior on this machine. Interesting. This commit removes an ugly console_lock hack to supress console flushing during the suspend/resume window. > The problem is still present on stable v6.18.2. It is great that you can reproduce it with 6.18.2. Are you also able to test 6.19-rc1 and reproduce it? It would be nice to attack the problem from the latest code first. > Additional notes > ================ > > By playing around with the tests in /sys/power/, I can say that the problem only > occurs during a real S3 and not a simulated one. > > No problem on resume: > $ echo core > /sys/power/pm_test > $ echo deep > /sys/power/mem_sleep > $ systemctl suspend > > Freeze on resume: > $ echo none > /sys/power/pm_test > $ echo deep > /sys/power/mem_sleep > $ systemctl suspend > > The issue appears hardware-dependent and may be related to the interaction > between printk console usability and resume ordering. The system likely > blocks silently during resume before the graphics stack becomes usable. > > If additional debugging, logs, or testing are needed, I am available to > provide them. It would be helpful to know if you are doing anything special (like using "no_console_suspend") or have multiple consoles. Could you send the output of: $ cat /proc/consoles and $ cat /proc/cmdline Once we have this information, we can start to dig deeper. John Ogness