Bug#1116251: linux-image-6.12.48+deb13-rpi: Raspberry Pi Zero W does not boot
Hi Benjamin,
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:
> > Control: tags -1 + moreinfo
> >
> > Hi,
> >
> > On Sat, Nov 22, 2025 at 04:27:53PM +0100, Benjamin Drung wrote:
> > > Hi Uwe,
> > >
> > > On Fri, 2025-11-21 at 09:52 +0100, Uwe Kleine-König wrote:
> > > > Hello Benjamin,
> > > >
> > > > 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 (debian-kernel@lists.debian.org) (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 <oreoluwa.babatunde@oss.qualcomm.com>
> > 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 <oreoluwa.babatunde@oss.qualcomm.com>
> > Tested-by: William Zhang <william.zhang@broadcom.com>
> > Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> > Link: https://lore.kernel.org/r/20250806172421.2748302-1-oreoluwa.babatunde@oss.qualcomm.com
> > Signed-off-by: Sasha Levin <sashal@kernel.org>
> >
> > 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
Regards,
Salvatore
>From a7b62fb55c57552177ea12188c61cd501fa3e055 Mon Sep 17 00:00:00 2001
From: Salvatore Bonaccorso <carnil@debian.org>
Date: Fri, 28 Nov 2025 23:41:59 +0100
Subject: [PATCH] Revert "of: reserved_mem: Restructure call site for
dma_contiguous_early_fixup()"
This reverts commit 46efab01648a04082266115a8e917c3b26b97fa8.
---
drivers/of/of_reserved_mem.c | 16 ++++------------
include/linux/dma-map-ops.h | 3 ---
kernel/dma/contiguous.c | 2 ++
3 files changed, 6 insertions(+), 15 deletions(-)
diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
index 7b5d6562fe4a..45445a1600a9 100644
--- a/drivers/of/of_reserved_mem.c
+++ b/drivers/of/of_reserved_mem.c
@@ -24,7 +24,6 @@
#include <linux/memblock.h>
#include <linux/kmemleak.h>
#include <linux/cma.h>
-#include <linux/dma-map-ops.h>
#include "of_private.h"
@@ -129,17 +128,13 @@ static int __init __reserved_mem_reserve_reg(unsigned long node,
base = dt_mem_next_cell(dt_root_addr_cells, &prop);
size = dt_mem_next_cell(dt_root_size_cells, &prop);
- if (size && early_init_dt_reserve_memory(base, size, nomap) == 0) {
- /* Architecture specific contiguous memory fixup. */
- if (of_flat_dt_is_compatible(node, "shared-dma-pool") &&
- of_get_flat_dt_prop(node, "reusable", NULL))
- dma_contiguous_early_fixup(base, size);
+ if (size &&
+ early_init_dt_reserve_memory(base, size, nomap) == 0)
pr_debug("Reserved memory: reserved region for node '%s': base %pa, size %lu MiB\n",
uname, &base, (unsigned long)(size / SZ_1M));
- } else {
+ else
pr_err("Reserved memory: failed to reserve memory for node '%s': base %pa, size %lu MiB\n",
uname, &base, (unsigned long)(size / SZ_1M));
- }
len -= t_len;
}
@@ -422,10 +417,7 @@ static int __init __reserved_mem_alloc_size(unsigned long node, const char *unam
uname, (unsigned long)(size / SZ_1M));
return -ENOMEM;
}
- /* Architecture specific contiguous memory fixup. */
- if (of_flat_dt_is_compatible(node, "shared-dma-pool") &&
- of_get_flat_dt_prop(node, "reusable", NULL))
- dma_contiguous_early_fixup(base, size);
+
/* Save region in the reserved_mem array */
fdt_reserved_mem_save_node(node, uname, base, size);
return 0;
diff --git a/include/linux/dma-map-ops.h b/include/linux/dma-map-ops.h
index b42408a24ad1..b7773201414c 100644
--- a/include/linux/dma-map-ops.h
+++ b/include/linux/dma-map-ops.h
@@ -153,9 +153,6 @@ static inline void dma_free_contiguous(struct device *dev, struct page *page,
{
__free_pages(page, get_order(size));
}
-static inline void dma_contiguous_early_fixup(phys_addr_t base, unsigned long size)
-{
-}
#endif /* CONFIG_DMA_CMA*/
#ifdef CONFIG_DMA_DECLARE_COHERENT
diff --git a/kernel/dma/contiguous.c b/kernel/dma/contiguous.c
index 9e5d63efe7c5..8df0dfaaca18 100644
--- a/kernel/dma/contiguous.c
+++ b/kernel/dma/contiguous.c
@@ -480,6 +480,8 @@ static int __init rmem_cma_setup(struct reserved_mem *rmem)
pr_err("Reserved memory: unable to setup CMA region\n");
return err;
}
+ /* Architecture specific contiguous memory fixup. */
+ dma_contiguous_early_fixup(rmem->base, rmem->size);
if (default_cma)
dma_contiguous_default_area = cma;
--
2.51.0
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