Control: forwarded -1 https://lore.kernel.org/linux-iommu/hnwgn7glub4klmkzabzcm76eldaa3xm5ua72eldwzesblveo2a@4xq2bxhmbsyq Hello,
I extended the audience to people involved in the creation of 2c223f7239f376a90d71903ec474ba887cf21d94. On Wed, Dec 17, 2025 at 11:07:00PM +0100, Benjamin Drung wrote: > On Wed, 2025-12-17 at 22:20 +0100, Benjamin Drung wrote: > > On Sun, 2025-11-30 at 10:27 +0100, Salvatore Bonaccorso wrote: > > > On Sat, Nov 29, 2025 at 12:02:00AM +0100, Salvatore Bonaccorso wrote: > > > > On Fri, Nov 28, 2025 at 10:53:17PM +0100, Benjamin Drung wrote: > > > > > On Wed, 2025-11-26 at 08:52 +0100, Salvatore Bonaccorso wrote: > > > > > > On Sat, Nov 22, 2025 at 04:27:53PM +0100, Benjamin Drung wrote: > > > > > > > On Fri, 2025-11-21 at 09:52 +0100, Uwe Kleine-König wrote: > > > > > > > > On Thu, Nov 20, 2025 at 11:11:07AM +0100, Benjamin Drung wrote: > > > > > > > > > On Thu, 2025-11-20 at 08:58 +0100, Uwe Kleine-König wrote: > > > > > > > > > > On Mon, Nov 17, 2025 at 02:05:41AM +0100, Benjamin Drung > > > > > > > > > > wrote: > > > > > > > > > > > On Wed, 2025-11-05 at 20:14 +0100, Uwe Kleine-König wrote: > > > > > > > > > > > > Can you try adding > > > > > > > > > > > > > > > > > > > > > > > > earlyprintk=serial,0x7e215040 > > > > > > > > > > > > > > > > > > > > > > > > to the kernel commandline. Not sure this activates the > > > > > > > > > > > > right procedures, > > > > > > > > > > > > maybe try it with the working kernel first. > > > > > > > > > > > > > > > > > > > > > > I tried with the working kernel 6.12.43+deb13-rpi but > > > > > > > > > > > these were the > > > > > > > > > > > earliest lines: > > > > > > > > > > > > > > > > > > > > > > [ 4.116565] printk: legacy console [ttyS1] enabled > > > > > > > > > > > [ 4.129635] printk: legacy bootconsole [earlycon0] > > > > > > > > > > > disabled > > > > > > > > > > > [ 4.147050] bcm2835-power bcm2835-power: Broadcom > > > > > > > > > > > BCM2835 power domains driver > > > > > > > > > > > [ 4.160972] mousedev: PS/2 mouse device common for all > > > > > > > > > > > mice > > > > > > > > > > > [ 4.172622] i2c-bcm2835 20805000.i2c: Could not read > > > > > > > > > > > clock-frequency property > > > > > > > > > > > [ 4.186585] bcm2835-wdt bcm2835-wdt: Broadcom BCM2835 > > > > > > > > > > > watchdog timer > > > > > > > > > > > > > > > > > > > > > > I tried with 6.12.57+deb13-rpi but that failed to boot > > > > > > > > > > > and the > > > > > > > > > > > earlyprintk line did not give any additional logs. > > > > > > > > > > > > > > > > > > > > Can you please provide a full kernel log of the working > > > > > > > > > > kernel? > > > > > > > > > > > > > > > > > > dmesg log is attached. > > > > > > > > > > > > > > > > > > > Also please provide the output of: > > > > > > > > > > > > > > > > > > > > for f in /proc/tty/driver/*; do echo $f; sed 's/^/ /' > > > > > > > > > > < $f; done > > > > > > > > > > > > > > > > > > /proc/tty/driver/serial > > > > > > > > > serinfo:1.0 driver revision: > > > > > > > > > 0: uart:unknown port:00000000 irq:0 > > > > > > > > > 1: uart:16550 mmio:0x20215040 irq:53 tx:15629 rx:0 > > > > > > > > > RTS|CTS|DTR > > > > > > > > > 2: uart:unknown port:00000000 irq:0 > > > > > > > > > 3: uart:unknown port:00000000 irq:0 > > > > > > > > > /proc/tty/driver/ttyAMA > > > > > > > > > serinfo:1.0 driver revision: > > > > > > > > > 0: uart:PL011 rev2 mmio:0x20201000 irq:81 tx:452 rx:980 > > > > > > > > > RTS|CTS|DTR > > > > > > > > > > > > > > > > OK, is > > > > > > > > > > > > > > > > earlyprintk=serial,0x20215040 > > > > > > > > > > > > > > > > more communicative then? > > > > > > > > > > > > > > Nope, but I found > > > > > > > https://www.raspberrypi.com/documentation/computers/configuration.html#enabling-early-console-for-linux > > > > > > > and setting earlycon=uart8250,mmio32,0x20215040 worked. The kernel > > > > > > > 6.12.43+deb13-rpi booted with printing the early lines as well > > > > > > > (see > > > > > > > dmesg of previous mail). > > > > > > > > > > > > > > With all other experiments cleaned, I tried the latest kernel: > > > > > > > > > > > > > > ``` > > > > > > > $ cat /etc/default/raspi-extra-cmdline > > > > > > > earlycon=uart8250,mmio32,0x20215040 > > > > > > > $ update-initramfs -u > > > > > > > ``` > > > > > > > > > > > > > > I got following logs before it got stuck: > > > > > > > > > > > > > > ``` > > > > > > > [ 0.000000] Booting Linux on physical CPU 0x0 > > > > > > > [ 0.000000] Linux version 6.12.57+deb13-rpi > > > > > > > ([email protected]) (arm-linux-gnueabi-gcc-14 > > > > > > > (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44) > > > > > > > #1 Debian 6.12.57-1 (2025-11-05) > > > > > > > [ 0.000000] CPU: ARMv6-compatible processor [410fb767] > > > > > > > revision 7 (ARMv7), cr=00c5387d > > > > > > > [ 0.000000] CPU: PIPT / VIPT nonaliasing data cache, VIPT > > > > > > > nonaliasing instruction cache > > > > > > > [ 0.000000] OF: fdt: Machine model: Raspberry Pi Zero W Rev 1.1 > > > > > > > [ 0.000000] random: crng init done > > > > > > > [ 0.000000] earlycon: uart8250 at MMIO32 0x20215040 (options > > > > > > > '') > > > > > > > [ 0.000000] printk: legacy bootconsole [uart8250] enabled > > > > > > > [ 0.000000] Memory policy: Data cache writeback > > > > > > > [ 0.000000] Reserved memory: bypass linux,cma node, using > > > > > > > cmdline CMA params instead > > > > > > > [ 0.000000] OF: reserved mem: node linux,cma compatible > > > > > > > matching fail > > > > > > > [ 0.000000] cma: Reserved 64 MiB at 0x17000000 on node -1 > > > > > > > ``` > > > > > > > > > > > > > > It looks like being cma related and I found a cma boot option in > > > > > > > /etc/default/raspi-firmware. So I modified > > > > > > > /boot/firmware/cmdline.txt > > > > > > > and changed cma=64M to cma=0. Then the system booted without > > > > > > > problems: > > > > > > > > > > > > > > ``` > > > > > > > [...] > > > > > > > [ 0.000000] Reserved memory: bypass linux,cma node, using > > > > > > > cmdline CMA params instead > > > > > > > [ 0.000000] OF: reserved mem: node linux,cma compatible > > > > > > > matching fail > > > > > > > [ 0.000000] Zone ranges: > > > > > > > [ 0.000000] Normal [mem > > > > > > > 0x0000000000000000-0x000000001bffffff] > > > > > > > [ 0.000000] Movable zone start for each node > > > > > > > [ 0.000000] Early memory node ranges > > > > > > > [ 0.000000] node 0: [mem > > > > > > > 0x0000000000000000-0x000000001bffffff] > > > > > > > [ 0.000000] Initmem setup node 0 [mem > > > > > > > 0x0000000000000000-0x000000001bffffff] > > > > > > > [ 0.000000] Kernel command line: dma.dmachans=0x7ff5 > > > > > > > bcm2708.boardrev=0x9000c1 bcm2708.serial=0x8bb1238 > > > > > > > bcm2708.uart_clock=48000000 bcm2708.disk_led_gpio=47 > > > > > > > smsc95xx.macaddr=B8:27:EB:BB:12:38 vc_mem.mem_base=0x1ec00000 > > > > > > > vc_mem.mem_size=0x20000000 console=tty0 console=ttyS1,115200 > > > > > > > root=/dev/mmcblk0p2 rw fsck.repair=yes net.ifnames=0 cma=0 > > > > > > > rootwait earlycon=uart8250,mmio32,0x20215040 > > > > > > > [...] > > > > > > > ``` > > > > > > > > > > > > > > Then I persisted this change by setting CMA=0 in > > > > > > > /etc/default/raspi-firmware: > > > > > > > > > > > > > > ``` > > > > > > > $ grep -Ev '^(#|$)' /etc/default/raspi-firmware > > > > > > > CMA=0 > > > > > > > $ update-initramfs -u > > > > > > > ``` > > > > > > > > > > > > > > This config removes the cma cmdline option completely. The system > > > > > > > still > > > > > > > boots: > > > > > > > > > > > > > > ``` > > > > > > > [...] > > > > > > > [ 0.000000] Memory policy: Data cache writeback > > > > > > > [ 0.000000] Reserved memory: created CMA memory pool at > > > > > > > 0x17000000, size 64 MiB > > > > > > > [ 0.000000] OF: reserved mem: initialized node linux,cma, > > > > > > > compatible id shared-dma-pool > > > > > > > [ 0.000000] OF: reserved mem: 0x17000000..0x1affffff (65536 > > > > > > > KiB) map reusable linux,cma > > > > > > > [ 0.000000] Zone ranges: > > > > > > > [ 0.000000] Normal [mem > > > > > > > 0x0000000000000000-0x000000001bffffff] > > > > > > > [ 0.000000] Movable zone start for each node > > > > > > > [ 0.000000] Early memory node ranges > > > > > > > [ 0.000000] node 0: [mem > > > > > > > 0x0000000000000000-0x000000001bffffff] > > > > > > > [ 0.000000] Initmem setup node 0 [mem > > > > > > > 0x0000000000000000-0x000000001bffffff] > > > > > > > [ 0.000000] Kernel command line: dma.dmachans=0x7ff5 > > > > > > > bcm2708.boardrev=0x9000c1 bcm2708.serial=0x8bb1238 > > > > > > > bcm2708.uart_clock=48000000 bcm2708.disk_led_gpio=47 > > > > > > > smsc95xx.macaddr=B8:27:EB:BB:12:38 vc_mem.mem_base=0x1ec00000 > > > > > > > vc_mem.mem_size=0x20000000 console=tty0 console=ttyS1,115200 > > > > > > > root=/dev/mmcblk0p2 rw fsck.repair=yes net.ifnames=0 rootwait > > > > > > > earlycon=uart8250,mmio32,0x20215040 > > > > > > > [...] > > > > > > > ``` > > > > > > > > > > > > > > That should hopefully narrow down the issue space. > > > > > > > > > > > > If I'm not wrong the only cma related change between 6.12.43 and > > > > > > 6.12.48 was the backport of 2c223f7239f3 ("of: reserved_mem: > > > > > > Restructure call site for dma_contiguous_early_fixup()"): > > > > > > > > > > > > commit 46efab01648a04082266115a8e917c3b26b97fa8 > > > > > > Author: Oreoluwa Babatunde <[email protected]> > > > > > > Date: Wed Aug 6 10:24:21 2025 -0700 > > > > > > > > > > > > of: reserved_mem: Restructure call site for > > > > > > dma_contiguous_early_fixup() > > > > > > > > > > > > [ Upstream commit 2c223f7239f376a90d71903ec474ba887cf21d94 ] > > > > > > > > > > > > Restructure the call site for dma_contiguous_early_fixup() > > > > > > to > > > > > > where the reserved_mem nodes are being parsed from the DT > > > > > > so that > > > > > > dma_mmu_remap[] is populated before dma_contiguous_remap() > > > > > > is called. > > > > > > > > > > > > Fixes: 8a6e02d0c00e ("of: reserved_mem: Restructure how the > > > > > > reserved memory regions are processed") > > > > > > Signed-off-by: Oreoluwa Babatunde > > > > > > <[email protected]> > > > > > > Tested-by: William Zhang <[email protected]> > > > > > > Signed-off-by: Marek Szyprowski <[email protected]> > > > > > > Link: > > > > > > https://lore.kernel.org/r/[email protected] > > > > > > Signed-off-by: Sasha Levin <[email protected]> > > > > > > > > > > > > Uwe, would that make sense? Benjamin can you try to make a build > > > > > > with > > > > > > that commit reverted, does it fix the problem? > > > > > > > > > > Building the kernel on the Pi Zero would probably take ages. I have a > > > > > Raspberry Pi 5 running arm64. That should be able to build the kernel > > > > > in > > > > > a armel schroot, shouldn't it? Is there documentation for building the > > > > > kernel? > > > > > > > > I hope it is fine for Uwe that i respond here, he might have another > > > > more efficient way to reach our goal. > > > > > > > > But we have the simple-patching guideline here: > > > > https://kernel-team.pages.debian.net/kernel-handbook/ch-common-tasks.html#id-1.6.6.4 > > > > > > > > That should work within an armel schroot work well, e.g. on a > > > > porterbox amdahl.d.o i would first setup a schroot via: > > > > > > > > schroot -b -c chroot:trixie_armel-dchroot -n linux > > > > dd-schroot-cmd -c linux apt-get update > > > > dd-schroot-cmd -c linux apt-get dist-upgrade > > > > dd-schroot-cmd -c linux apt-get build-dep linux > > > > schroot -r -c linux > > > > (see https://dsa.debian.org/doc/schroot/) > > > > > > > > Then download the linux/6.12.57-1 source and make the revert patch > > > > available. > > > > > > > > apt-get source linux > > > > cd linux-* > > > > ./debian/bin/test-patches -f rpi > > > > ../0001-Revert-of-reserved_mem-Restructure-call-site-for-dma.patch > > > > > > In case you can/want trust unsigned packages (but I have put a > > > sha256sum along signed with my key in the DD keyring), you can test > > > the patch revert via the packages on: > > > https://people.debian.org/~carnil/tmp/linux/1116251/ > > > > Thanks for providing the kernel. I downloaded linux-image- > > 6.12+unreleased-rpi_6.12.57-1a~test_armel.deb and installed it. This > > kernel hangs on boot (see attached boot.log). It hangs there > > reproducible. > > The "Linux version 4.14.98+" in the log puzzled me and > /etc/kernel/postinst.d/z50-raspi-firmware did not copy kernel > 6.12.57-1a~test to /boot/firmware. > > I found the old kernel.img and kernel7.img that I deleted. I copied the > 6.12.57-1a~test kernel manually: > > ``` > update-initramfs -u -k 6.12+unreleased-rpi > cd /boot/firmware/ > cp ../vmlinuz-6.12+unreleased-rpi . > cp ../initrd.img-6.12+unreleased-rpi . > vim config.txt > reboot > ``` > > Then the Pi booted the correct kernel (6.12+unreleased-rpi) successfully > with following cmdline configurations: > > * no cma set > * cma=0 > * cma=64M If I understood right that means that 46efab01648a04082266115a8e917c3b26b97fa8 aka 2c223f7239f376a90d71903ec474ba887cf21d94 broke booting on the Raspberry Pi Zero W when CMA is used. #regzbot introduced: 2c223f7239f376a90d71903ec474ba887cf21d94 Does this ring a bell for someone, or do you have some debugging instructions? Complete context is available at https://bugs.debian.org/1116251. Best regards Uwe
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