Re: [GIT PULL] SLAB changes for v3.10

[Tony Lindgren <tony@atomide.com>]

[-- Attachment #1: Type: text/plain, Size: 1694 bytes --]

* Christoph Lameter <cl@linux.com> [130508 07:01]:
> On Tue, 7 May 2013, Tony Lindgren wrote:
> 
> > OK got it narrowed down to CONFIG_DEBUG_SPINLOCK=y causing the problem
> > with commit 8a965b3b. Ain't nothing like bisecting and booting and then
> > diffing .config files on top of that.
> >
> > > Without reverting 8a965b3b I'm getting:
> 
> The patch (commit 8a965b3baa89ffedc73c0fbc750006c631012ced) merely changed the sequence of
> slab creation to address an issue in SLAB.
> 
> Hmmm.. But if KMALLOC_SHIFT_LOW is higher than 6 or 7 then the creation of
> the non-power of two slab could be skipped as a result of the patch. But
> we should not need them in those cases.
> 
> Can I see the kernel config?

Attached are minimal defconfig-bad and defconfig-good with pretty
much everything disabled. These boot vexpress in qemu using earlyprintk
for the output.
 
> What is the value of KMALLOC_SHIFT_LOW?

It's 6.
 
> Can you figure out which kernel slab the function is trying to access?

I can certainly debug it further, but it's also pretty easy to reproduce:

1. Download and build qemu-linaro from:

   https://git.linaro.org/gitweb?p=qemu/qemu-linaro.git

   The last time I tried the stock qemu I could not get vexpress to
   boot with it, don't know if that's still the case. But the above
   works for me.

2. Cross compile kernel with the attached defconfig-bad

   $ ARCH=arm CROSS_COMPILE=... make zImage

3. Try to boot the kernel in qemu

   $ qemu-system-arm -machine vexpress-a9 -m 1024 -curses -net nic \
	-net user -serial stdio -append "console=ttyAMA0,115200n8 \
	root=/dev/mmcblk0p2 ro rootwait physmap.enabled=0 \
	debug earlyprintk" -kernel zImage

Regards,

Tony

[-- Attachment #2: defconfig-bad --]
[-- Type: text/plain, Size: 1922 bytes --]

CONFIG_SYSVIPC=y
CONFIG_NO_HZ=y
CONFIG_HIGH_RES_TIMERS=y
CONFIG_BSD_PROCESS_ACCT=y
CONFIG_IKCONFIG=y
CONFIG_IKCONFIG_PROC=y
CONFIG_LOG_BUF_SHIFT=16
CONFIG_BLK_DEV_INITRD=y
CONFIG_EXPERT=y
CONFIG_SLAB=y
CONFIG_PROFILING=y
CONFIG_OPROFILE=y
# CONFIG_BLOCK is not set
CONFIG_ARCH_VEXPRESS_CA9X4=y
CONFIG_ARM_THUMBEE=y
CONFIG_SMP=y
CONFIG_NR_CPUS=2
CONFIG_ZBOOT_ROM_TEXT=0x0
CONFIG_ZBOOT_ROM_BSS=0x0
CONFIG_CMDLINE="root=/dev/mmcblk0p2 rootwait console=ttyO2,115200"
CONFIG_KEXEC=y
CONFIG_FPE_NWFPE=y
CONFIG_BINFMT_MISC=y
CONFIG_UEVENT_HELPER_PATH="/sbin/hotplug"
CONFIG_DEVTMPFS=y
CONFIG_DEVTMPFS_MOUNT=y
CONFIG_CMA=y
CONFIG_INPUT_JOYDEV=y
CONFIG_INPUT_EVDEV=y
CONFIG_KEYBOARD_GPIO=y
CONFIG_KEYBOARD_MATRIX=y
CONFIG_INPUT_TOUCHSCREEN=y
CONFIG_INPUT_MISC=y
CONFIG_VT_HW_CONSOLE_BINDING=y
# CONFIG_LEGACY_PTYS is not set
CONFIG_SERIAL_8250=y
CONFIG_SERIAL_8250_CONSOLE=y
CONFIG_SERIAL_8250_NR_UARTS=32
CONFIG_SERIAL_8250_EXTENDED=y
CONFIG_SERIAL_8250_MANY_PORTS=y
CONFIG_SERIAL_8250_SHARE_IRQ=y
CONFIG_SERIAL_8250_DETECT_IRQ=y
CONFIG_SERIAL_8250_RSA=y
CONFIG_SERIAL_AMBA_PL011=y
CONFIG_SERIAL_AMBA_PL011_CONSOLE=y
CONFIG_DEBUG_GPIO=y
CONFIG_GPIO_SYSFS=y
# CONFIG_HWMON is not set
CONFIG_FB=y
CONFIG_FIRMWARE_EDID=y
CONFIG_FB_MODE_HELPERS=y
CONFIG_FB_TILEBLITTING=y
CONFIG_BACKLIGHT_LCD_SUPPORT=y
CONFIG_LCD_PLATFORM=y
CONFIG_FRAMEBUFFER_CONSOLE=y
CONFIG_FRAMEBUFFER_CONSOLE_ROTATION=y
CONFIG_FONTS=y
CONFIG_FONT_8x8=y
CONFIG_FONT_8x16=y
CONFIG_LOGO=y
# CONFIG_USB_SUPPORT is not set
# CONFIG_IOMMU_SUPPORT is not set
# CONFIG_FILE_LOCKING is not set
# CONFIG_DNOTIFY is not set
# CONFIG_INOTIFY_USER is not set
CONFIG_TMPFS=y
# CONFIG_MISC_FILESYSTEMS is not set
CONFIG_PRINTK_TIME=y
CONFIG_MAGIC_SYSRQ=y
CONFIG_SCHEDSTATS=y
CONFIG_TIMER_STATS=y
CONFIG_PROVE_LOCKING=y
# CONFIG_DEBUG_BUGVERBOSE is not set
CONFIG_DEBUG_INFO=y
# CONFIG_FTRACE is not set
CONFIG_DEBUG_LL=y
CONFIG_DEBUG_VEXPRESS_UART0_CA9=y
CONFIG_EARLY_PRINTK=y

[-- Attachment #3: defconfig-good --]
[-- Type: text/plain, Size: 1921 bytes --]

CONFIG_SYSVIPC=y
CONFIG_NO_HZ=y
CONFIG_HIGH_RES_TIMERS=y
CONFIG_BSD_PROCESS_ACCT=y
CONFIG_IKCONFIG=y
CONFIG_IKCONFIG_PROC=y
CONFIG_LOG_BUF_SHIFT=16
CONFIG_BLK_DEV_INITRD=y
CONFIG_EXPERT=y
CONFIG_KALLSYMS_ALL=y
CONFIG_SLAB=y
CONFIG_PROFILING=y
CONFIG_OPROFILE=y
# CONFIG_BLOCK is not set
CONFIG_ARCH_VEXPRESS_CA9X4=y
CONFIG_ARM_THUMBEE=y
CONFIG_SMP=y
CONFIG_NR_CPUS=2
CONFIG_ZBOOT_ROM_TEXT=0x0
CONFIG_ZBOOT_ROM_BSS=0x0
CONFIG_CMDLINE="root=/dev/mmcblk0p2 rootwait console=ttyO2,115200"
CONFIG_KEXEC=y
CONFIG_FPE_NWFPE=y
CONFIG_BINFMT_MISC=y
CONFIG_UEVENT_HELPER_PATH="/sbin/hotplug"
CONFIG_DEVTMPFS=y
CONFIG_DEVTMPFS_MOUNT=y
CONFIG_CMA=y
CONFIG_INPUT_JOYDEV=y
CONFIG_INPUT_EVDEV=y
CONFIG_KEYBOARD_GPIO=y
CONFIG_KEYBOARD_MATRIX=y
CONFIG_INPUT_TOUCHSCREEN=y
CONFIG_INPUT_MISC=y
CONFIG_VT_HW_CONSOLE_BINDING=y
# CONFIG_LEGACY_PTYS is not set
CONFIG_SERIAL_8250=y
CONFIG_SERIAL_8250_CONSOLE=y
CONFIG_SERIAL_8250_NR_UARTS=32
CONFIG_SERIAL_8250_EXTENDED=y
CONFIG_SERIAL_8250_MANY_PORTS=y
CONFIG_SERIAL_8250_SHARE_IRQ=y
CONFIG_SERIAL_8250_DETECT_IRQ=y
CONFIG_SERIAL_8250_RSA=y
CONFIG_SERIAL_AMBA_PL011=y
CONFIG_SERIAL_AMBA_PL011_CONSOLE=y
CONFIG_DEBUG_GPIO=y
CONFIG_GPIO_SYSFS=y
# CONFIG_HWMON is not set
CONFIG_FB=y
CONFIG_FIRMWARE_EDID=y
CONFIG_FB_MODE_HELPERS=y
CONFIG_FB_TILEBLITTING=y
CONFIG_BACKLIGHT_LCD_SUPPORT=y
CONFIG_LCD_PLATFORM=y
CONFIG_FRAMEBUFFER_CONSOLE=y
CONFIG_FRAMEBUFFER_CONSOLE_ROTATION=y
CONFIG_FONTS=y
CONFIG_FONT_8x8=y
CONFIG_FONT_8x16=y
CONFIG_LOGO=y
# CONFIG_USB_SUPPORT is not set
# CONFIG_IOMMU_SUPPORT is not set
# CONFIG_FILE_LOCKING is not set
# CONFIG_DNOTIFY is not set
# CONFIG_INOTIFY_USER is not set
CONFIG_TMPFS=y
# CONFIG_MISC_FILESYSTEMS is not set
CONFIG_PRINTK_TIME=y
CONFIG_MAGIC_SYSRQ=y
CONFIG_SCHEDSTATS=y
CONFIG_TIMER_STATS=y
# CONFIG_DEBUG_BUGVERBOSE is not set
CONFIG_DEBUG_INFO=y
# CONFIG_FTRACE is not set
CONFIG_DEBUG_LL=y
CONFIG_DEBUG_VEXPRESS_UART0_CA9=y
CONFIG_EARLY_PRINTK=y