Dear Song,
Am 28.03.22 um 08:37 schrieb Song Liu:
Thanks Paul for highlighting the issue.
Thank you for getting back to me so quickly.
+ Rick, who highlighted some potential issues with this. (also attached
the stack trace).
I already had added him, but forgot to document it in the message. Sorry
for that.
On Mar 27, 2022, at 3:36 AM, Paul Menzel <pmenzel@xxxxxxxxxxxxx> wrote:
Am 26.03.22 um 19:46 schrieb Paul Menzel:
#regzbot introduced: fac54e2bfb5be2b0bbf115fe80d45f59fd773048
#regzbot title: BUG: Bad page state in process systemd-udevd
Am 04.02.22 um 19:57 schrieb Song Liu:
From: Song Liu <songliubraving@xxxxxx>
This enables module_alloc() to allocate huge page for 2MB+ requests.
To check the difference of this change, we need enable config
CONFIG_PTDUMP_DEBUGFS, and call module_alloc(2MB). Before the change,
/sys/kernel/debug/page_tables/kernel shows pte for this map. With the
change, /sys/kernel/debug/page_tables/ show pmd for thie map.
Signed-off-by: Song Liu <songliubraving@xxxxxx>
---
arch/x86/Kconfig | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 6fddb63271d9..e0e0d00cf103 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -159,6 +159,7 @@ config X86
select HAVE_ALIGNED_STRUCT_PAGE if SLUB
select HAVE_ARCH_AUDITSYSCALL
select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE
+ select HAVE_ARCH_HUGE_VMALLOC if HAVE_ARCH_HUGE_VMAP
select HAVE_ARCH_JUMP_LABEL
select HAVE_ARCH_JUMP_LABEL_RELATIVE
select HAVE_ARCH_KASAN if X86_64
Testing Linus’ current master branch, Linux logs critical messages like below:
BUG: Bad page state in process systemd-udevd pfn:102e03
I bisected to your commit fac54e2bfb5 (x86/Kconfig: select
HAVE_ARCH_HUGE_VMALLOC with HAVE_ARCH_HUGE_VMAP).
Sorry, I forget to mention, that this is a 32-bit (i686) userspace,
but a 64-bit Linux kernel, so it might be the same issue as
mentioned in commit eed1fcee556f (x86: Disable
HAVE_ARCH_HUGE_VMALLOC on 32-bit x86), but didn’t fix the issue for
64-bit Linux kernel and 32-bit userspace.
I will look more into this tomorrow. To clarify, what is the 32-bit
user space that triggers this? Is it systemd-udevd? Is the systemd
also i686?
Yes, everything – also systemd – is i686. You can build a 32-bit VM
image with grml-debootstrap [1]:
sudo DEBOOTSTRAP=mmdebstrap ~/src/grml-debootstrap/grml-debootstrap
--vm --vmfile --vmsize 3G --target /dev/shm/debian-32.img -r sid --arch
i686 --filesystem ext4
Then run that with QEMU, but pass the 64-bit Linux kernel to QEMU
directly with the switches `-kernel` and `-append`, or install the amd64
Linux kernel into the Debian VM image or the package created with `make
bindeb-pkg` with `dpkg -i …`.
Kind regards,
Paul
[1]: https://github.com/grml/grml-debootstrap/
