Re: [PATCH v3] mm: make expand_downwards symmetrical toexpand_upwards

From: James Bottomley
Date: Tue Apr 19 2011 - 12:07:42 EST


On Tue, 2011-04-19 at 10:46 -0500, James Bottomley wrote:
> On Tue, 2011-04-19 at 13:10 +0200, Michal Hocko wrote:
> > On Mon 18-04-11 13:56:37, Andrew Morton wrote:
> > > On Mon, 18 Apr 2011 12:01:31 +0200
> > > Michal Hocko <mhocko@xxxxxxx> wrote:
> > >
> > > > Currently we have expand_upwards exported while expand_downwards is
> > > > accessible only via expand_stack or expand_stack_downwards.
> > > >
> > > > check_stack_guard_page is a nice example of the asymmetry. It uses
> > > > expand_stack for VM_GROWSDOWN while expand_upwards is called for
> > > > VM_GROWSUP case.
> > > >
> > > > Let's clean this up by exporting both functions and make those name
> > > > consistent. Let's use expand_stack_{upwards,downwards} so that we are
> > > > explicit about stack manipulation in the name. expand_stack_downwards
> > > > has to be defined for both CONFIG_STACK_GROWS{UP,DOWN} because
> > > > get_arg_page calls the downwards version in the early process
> > > > initialization phase for growsup configuration.
> > >
> > > Has this patch been tested on any stack-grows-upwards architecture?
> >
> > The only one I can find in the tree is parisc and I do not have access
> > to any such machine. Maybe someone on the list (CCed) can help with
> > testing the patch bellow? Nevertheless, the patch doesn't change growsup
> > case. It just renames functions and exports growsdown.
>
> It compiles OK, but crashes on boot in fsck. The crash is definitely mm
> but looks to be a slab problem (it's a null deref on a spinlock in
> add_partial(), which seems unrelated to this patch).
>
> [ 15.628000] sd 1:0:2:0: [sdc] Attached SCSI disk
> done.
> [ 16.632000] EXT3-fs: barriers not enabled
> [ 16.640000] kjournald starting. Commit interval 5 seconds
> [ 16.640000] EXT3-fs (sda3): mounted filesystem with ordered data mode
> Begin: Running /scripts/local-bottom ... done.
> done.
> Begin: Running /scripts/init-bottom ... done.
> INIT: version 2.88 booting
> Setting hostname to 'ion'...done.
> Starting the hotplug events dispatcher: udevd[ 22.008000] udev[211]: starting version 164
> .
> Synthesizing the initial hotplug events...done.
> Waiting for /dev to be fully populated...done.
> Activating swap:swapon on /dev/sda2
> swapon: /dev/sda2: found swap signature: version 1, page-size 4, same byte order
> swapon: /dev/sda2: pagesize=4096, swapsize=1028157440, devsize=1028160000
> [ 28.780000] Adding 1004056k swap on /dev/sda2. Priority:-1 extents:1 across:1004056k
> .
> Will now check root file system:fsck from util-linux-ng 2.17.2
> [/sbin/fsck.ext3 (1) -- /] fsck.ext3 -a -C0 /dev/sda3
> /dev/sda3 has been mounted 37 times without being checked, check forced.
> [ 257.192000] Backtrace:=========== \ 42.8%
> [ 257.192000] [<0000000040214f78>] add_partial+0x28/0x98
> [ 257.192000] [<0000000040217ff8>] __slab_free+0x1d0/0x1d8
> [ 257.192000] [<000000004021825c>] kmem_cache_free+0xc4/0x128
> [ 257.192000] [<00000000401fd1a4>] remove_vma+0x8c/0xc0
> [ 257.192000] [<00000000401fd3a8>] exit_mmap+0x1d0/0x220
> [ 257.192000] [<0000000040156514>] mmput+0xd4/0x200
> [ 257.192000] [<000000004015c7b8>] exit_mm+0x100/0x2c0
> [ 257.192000] [<000000004015ef40>] do_exit+0x778/0x9d8
> [ 257.192000] [<000000004015f1ec>] do_group_exit+0x4c/0xe0
> [ 257.192000] [<000000004015f298>] sys_exit_group+0x18/0x28
> [ 257.192000] [<0000000040106034>] syscall_exit+0x0/0x14
> [ 257.192000]
> [ 257.192000]
> [ 257.192000] Kernel Fault: Code=26 regs=00000040bf1807d0 (Addr=0000000000000000)
> [ 257.192000]
> [ 257.192000] YZrvWESTHLNXBCVMcbcbcbcbOGFRQPDI
> [ 257.192000] PSW: 00001000000001001111000000001110 Not tainted
> [ 257.192000] r00-03 000000ff0804f00e 0000000040769e40 0000000040214f78 0000000000000000
> [ 257.192000] r04-07 0000000040746e40 0000000000000001 0000004080ded370 0000000000000001
> [ 257.192000] r08-11 0000000040654150 0000000000000000 0000000000000001 0000000000000001
> [ 257.192000] r12-15 0000000000000000 00000000ffffffff 0000000000000024 0000000000000000
> [ 257.192000] r16-19 00000000fb4ead9c 00000000fb4eac54 0000000000000000 0000000000000000
> [ 257.192000] r20-23 000000000800000e 0000000000000001 000000007bbb7180 00000000401fd1a4
> [ 257.192000] r24-27 0000000000000001 0000004080ded370 0000000000000000 0000000040746e40
> [ 257.192000] r28-31 000000007ec0a908 00000040bf1807a0 00000040bf1807d0 0000000000000016
> [ 257.192000] sr00-03 00000000002d9000 0000000000000000 0000000000000000 00000000002d9000
> [ 257.192000] sr04-07 0000000000000000 0000000000000000 0000000000000000 0000000000000000
> [ 257.192000]
> [ 257.192000] IASQ: 0000000000000000 0000000000000000 IAOQ: 000000004011bbc0 000000004011bbc4
> [ 257.192000] IIR: 0f4015dc ISR: 0000000000000000 IOR: 0000000000000000
> [ 257.192000] CPU: 0 CR30: 00000040bf180000 CR31: fffffff0f0e098e0
> [ 257.192000] ORIG_R28: 0000000040769e40
> [ 257.192000] IAOQ[0]: _raw_spin_lock+0x0/0x20
> [ 257.192000] IAOQ[1]: _raw_spin_lock+0x4/0x20
> [ 257.192000] RP(r2): add_partial+0x28/0x98
> [ 257.192000] Backtrace:
> [ 257.192000] [<0000000040214f78>] add_partial+0x28/0x98
> [ 257.192000] [<0000000040217ff8>] __slab_free+0x1d0/0x1d8
> [ 257.192000] [<000000004021825c>] kmem_cache_free+0xc4/0x128
> [ 257.192000] [<00000000401fd1a4>] remove_vma+0x8c/0xc0
> [ 257.192000] [<00000000401fd3a8>] exit_mmap+0x1d0/0x220
> [ 257.192000] [<0000000040156514>] mmput+0xd4/0x200
> [ 257.192000] [<000000004015c7b8>] exit_mm+0x100/0x2c0
> [ 257.192000] [<000000004015ef40>] do_exit+0x778/0x9d8
> [ 257.192000] [<000000004015f1ec>] do_group_exit+0x4c/0xe0
> [ 257.192000] [<000000004015f298>] sys_exit_group+0x18/0x28
> [ 257.192000] [<0000000040106034>] syscall_exit+0x0/0x14
> [ 257.192000]
> [ 257.192000] Kernel panic - not syncing: Kernel Fault
> [ 257.192000] Backtrace:
> [ 257.192000] [<000000004011f984>] show_stack+0x14/0x20
> [ 257.192000] [<000000004011f9a8>] dump_stack+0x18/0x28
> [ 257.192000] [<000000004015946c>] panic+0xd4/0x368
> [ 257.192000] [<0000000040120024>] parisc_terminate+0x14c/0x170
> [ 257.192000] [<000000004012059c>] handle_interruption+0x2ac/0x8f8
> [ 257.192000] [<000000004011bbc0>] _raw_spin_lock+0x0/0x20
> [ 257.192000]
> [ 257.192000] Rebooting in 5 seconds..
>
> It seems to be a random intermittent mm crash because the next reboot
> crashed with the same trace but after the fsck had completed and the
> third came up to the login prompt.

I should add that this crash is with CONFIG_SLUB ... do you want me to
retry with CONFIG_SLAB?

James


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/