3.14-rc2: RECLAIM_FS-safe -> RECLAIM_FS-unsafe lock order detected

[Hugh Dickins]

On Wed, 12 Feb 2014, Christian Kujau wrote:
> On Wed, 12 Feb 2014 at 00:11, Christian Kujau wrote:
> > After upgrading from 3.13-rc8 to 3.14-rc2 on this PowerPC G4 machine, this 
> > happened:
> > 
> > ======================================================
> > [ INFO: RECLAIM_FS-safe -> RECLAIM_FS-unsafe lock order detected ]
> > 3.14.0-rc2 #1 Not tainted
> > ------------------------------------------------------
> 
> Would this be related to the "mmotm 2014-02-05 list_lru_add lockdep splat" 
> Hugh posted[0] a few days ago?

No, that was due to a patch in mmotm or linux-next: it's not in 3.14-rc2.

Hugh

> 
> Christian.
> 
> [0] https://lkml.org/lkml/2014/2/5/878
> 
> > rm/9206 [HC0[0]:SC0[0]:HE1:SE1] is trying to acquire:
> >  (&mm->mmap_sem){++++++}, at: [<c00b3654>] might_fault+0x58/0xa0
> > 
> > and this task is already holding:
> >  (&(&ip->i_lock)->mr_lock){++++-.}, at: [<c020d3ec>] 
> > xfs_ilock_data_map_shared+0x28/0x74
> > which would create a new lock dependency:
> >  (&(&ip->i_lock)->mr_lock){++++-.} -> (&mm->mmap_sem){++++++}
> > 
> > but this new dependency connects a RECLAIM_FS-irq-safe lock:
> >  (&(&ip->i_lock)->mr_lock){++++-.}
> > ... which became RECLAIM_FS-irq-safe at:
> >   [<c0066b38>] lock_acquire+0x4c/0x68
> >   [<c00615fc>] down_write_nested+0x50/0x9c
> >   [<c01ccf50>] xfs_reclaim_inode+0x108/0x31c
> >   [<c01cd318>] xfs_reclaim_inodes_ag+0x1b4/0x35c
> >   [<c01cde40>] xfs_reclaim_inodes_nr+0x38/0x4c
> >   [<c00d4aec>] super_cache_scan+0x148/0x150
> >   [<c00a4c08>] shrink_slab_node+0x134/0x224
> >   [<c00a52fc>] shrink_slab+0x124/0x13c
> >   [<c00a7900>] kswapd+0x460/0x77c
> >   [<c004f8fc>] kthread+0xbc/0xd0
> >   [<c0010ae4>] ret_from_kernel_thread+0x5c/0x64
> > 
> > to a RECLAIM_FS-irq-unsafe lock:
> >  (&mm->mmap_sem){++++++}
> > ... which became RECLAIM_FS-irq-unsafe at:
> > ...  [<c00679fc>] lockdep_trace_alloc+0x84/0x104
> >   [<c009d86c>] __alloc_pages_nodemask+0x88/0x6b4
> >   [<c00161fc>] pte_alloc_one+0x30/0x90
> >   [<c00b3b6c>] __pte_alloc+0x20/0xf4
> >   [<c00bd1d4>] move_page_tables+0x2a0/0x2c4
> >   [<c00d7ff8>] setup_arg_pages+0x20c/0x2c8
> >   [<c0122804>] load_elf_binary+0x378/0x1234
> >   [<c00d73a0>] search_binary_handler+0x98/0x1c8
> >   [<c00d8aa4>] do_execve+0x484/0x574
> >   [<c000425c>] try_to_run_init_process+0x18/0x58
> >   [<c0004a48>] kernel_init+0xac/0x104
> >   [<c0010ae4>] ret_from_kernel_thread+0x5c/0x64
> > [...]
> > 
> > Full dmesg & .config: http://nerdbynature.de/bits/3.14-rc2/
> > 
> > Thanks,
> > Christian.
> > -- 
> > BOFH excuse #17:
> > 
> > fat electrons in the lines
> -- 
> BOFH excuse #17:
> 
> fat electrons in the lines
>