Re: stmmac on Banana PI CPU stalls since Linux 6.6

I have checked out 2eb85b750512cc5dc5a93d5ff00e1f83b99651db (which is
the first bad commit that the bisect eventually identified) and tried
running:

[56/4504]mh@fan:~/linux/git/linux ((2eb85b750512...)) $ make BUILDARCH="amd64" ARCH="arm" KBUILD_DEBARCH="armhf" CROSS_COMPILE="arm-linux-gnueabihf-" drivers/net/ethernet/stmicro/stmmac/stmmac_main.lst
  SYNC    include/config/auto.conf.cmd
  SYSHDR  arch/arm/include/generated/uapi/asm/unistd-oabi.h
  SYSHDR  arch/arm/include/generated/uapi/asm/unistd-eabi.h
  HOSTCC  scripts/kallsyms
  UPD     include/config/kernel.release
  UPD     include/generated/uapi/linux/version.h
  UPD     include/generated/utsrelease.h
  SYSNR   arch/arm/include/generated/asm/unistd-nr.h
  SYSTBL  arch/arm/include/generated/calls-oabi.S
  SYSTBL  arch/arm/include/generated/calls-eabi.S
  CC      scripts/mod/empty.o
  MKELF   scripts/mod/elfconfig.h
  HOSTCC  scripts/mod/modpost.o
  CC      scripts/mod/devicetable-offsets.s
  UPD     scripts/mod/devicetable-offsets.h
  HOSTCC  scripts/mod/file2alias.o
  HOSTCC  scripts/mod/sumversion.o
  HOSTLD  scripts/mod/modpost
  CC      kernel/bounds.s
  CC      arch/arm/kernel/asm-offsets.s
  UPD     include/generated/asm-offsets.h
  CALL    scripts/checksyscalls.sh
  CHKSHA1 include/linux/atomic/atomic-arch-fallback.h
  CHKSHA1 include/linux/atomic/atomic-instrumented.h
  MKLST   drivers/net/ethernet/stmicro/stmmac/stmmac_main.lst
./scripts/makelst: 1: arithmetic expression: expecting EOF: "0x - 0x00000000"
[57/4505]mh@fan:~/linux/git/linux ((2eb85b750512...)) $

That is not what it was suppsoed to yield, right?

No. But did it actually generate
drivers/net/ethernet/stmicro/stmmac/stmmac_main.lst Sometime errors
like this are not always fatal.

My bisect eventually completed and identified
2eb85b750512cc5dc5a93d5ff00e1f83b99651db as the first bad commit.

I can make a guess.

-       memset(&priv->xstats, 0, sizeof(struct stmmac_extra_stats));

Its removed, not moved later. Deep within this structure is the
stmmac_txq_stats and stmmac_rxq_stats which this function is supposed
to return, and the two syncp variables are in it as well.

My guess is, they have an invalid state, when this memset is missing.

Try putting the memset back.

I also guess that is not the real fix, there are missing calls to
u64_stats_init().

	Andrew