Re: [PATCH 00/19] printk cleanup - part 3
From: Marcos Paulo de Souza <hidden>
Date: 2026-01-13 12:41:54
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linux-arm-kernel, linux-fsdevel, linux-hardening, linux-m68k, linux-serial, linux-um, lkml, netdev, sparclinux
On Mon, 2026-01-05 at 14:08 +0000, Daniel Thompson wrote:
On Mon, Jan 05, 2026 at 12:52:14PM +0000, Daniel Thompson wrote:quoted
Hi Marcos On Sat, Dec 27, 2025 at 09:16:07AM -0300, Marcos Paulo de Souza wrote:quoted
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).
Hi Daniel, sorry for the late reply! Lots of things to check lately :) Ok, I reproduced here, thanks a lot for testing kgdboc, it's a quick way to check that the new register_console_force is not working. Let me take a look to find what's wrong. Thanks a lot for finding this issue!
Daniel.