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[82.37.195.13]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-4324ea1b1b1sm100250524f8f.3.2026.01.05.06.08.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 05 Jan 2026 06:08:29 -0800 (PST) Date: Mon, 5 Jan 2026 14:08:26 +0000 From: Daniel Thompson To: Marcos Paulo de Souza Cc: Richard Weinberger , Anton Ivanov , Johannes Berg , Greg Kroah-Hartman , Jason Wessel , Daniel Thompson , Douglas Anderson , Petr Mladek , Steven Rostedt , John Ogness , Sergey Senozhatsky , Jiri Slaby , Breno Leitao , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Geert Uytterhoeven , Kees Cook , Tony Luck , "Guilherme G. Piccoli" , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , Christophe Leroy , Andreas Larsson , Alexander Shishkin , Maxime Coquelin , Alexandre Torgue , Jacky Huang , Shan-Chun Hung , Laurentiu Tudor , linux-um@lists.infradead.org, linux-kernel@vger.kernel.org, kgdb-bugreport@lists.sourceforge.net, linux-serial@vger.kernel.org, netdev@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-hardening@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, sparclinux@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH 00/19] printk cleanup - part 3 Message-ID: References: <20251227-printk-cleanup-part3-v1-0-21a291bcf197@suse.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260105_060831_734181_DBDF580B X-CRM114-Status: GOOD ( 23.49 ) X-BeenThere: linux-um@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-um" Errors-To: linux-um-bounces+linux-um=archiver.kernel.org@lists.infradead.org On Mon, Jan 05, 2026 at 12:52:14PM +0000, Daniel Thompson wrote: > Hi Marcos > > On Sat, Dec 27, 2025 at 09:16:07AM -0300, Marcos Paulo de Souza wrote: > > The parts 1 and 2 can be found here [1] and here[2]. > > > > The changes proposed in this part 3 are mostly to clarify the usage of > > the interfaces for NBCON, and use the printk helpers more broadly. > > Besides it, it also introduces a new way to register consoles > > and drop thes the CON_ENABLED flag. It seems too much, but in reality > > the changes are not complex, and as the title says, it's basically a > > cleanup without changing the functional changes. > > I ran this patchset through the kgdb test suite and I'm afraid it is > reporting functional changes. > > Specifically the earlycon support for kdb has regressed (FWIW the > problem bisects down to the final patch in the series where CON_ENABLED > is removed). > > Reproduction on x86-64 KVM outside of the test suite should be easy: > > make defconfig > scripts/config \ > --enable DEBUG_INFO \ > --enable DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT \ > --enable DEBUG_FS \ > --enable KALLSYMS_ALL \ > --enable MAGIC_SYSRQ \ > --enable KGDB \ > --enable KGDB_TESTS \ > --enable KGDB_KDB \ > --enable KDB_KEYBOARD \ > --enable LKDTM \ > --enable SECURITY_LOCKDOWN_LSM > make olddefconfig > make -j$(nproc) > qemu-system-x86_64 \ > -m 1G -smp 2 -nographic \ > -kernel arch/x86/boot/bzImage \ > -append "console=ttyS0,115200 kgdboc=ttyS0 earlycon=uart8250,io,0x3f8 kgdboc_earlycon kgdbwait" Actually I realized there was a simpler reproduction (hinted at by the missing "printk: legacy bootconsole [uart8250] enabled" in the regressed case). It looks like the earlycon simply doesn't work and that means the reproduction doesn't require anything related to kgdb at all. Simply: make defconfig make -j$(nproc) qemu-system-x86_64 -m 1G -smp 2 -nographic -kernel arch/x86/boot/bzImage \ -append "earlycon=uart8250,io,0x3f8" With the part 3 patchset applied I get no output from the earlycon (without the patch set I get the early boot messages which, as expected, stop when tty0 comes up). Daniel.