Re: 3.14-rc2 XFS backtrace because irqs_disabled.

[Al Viro <viro@xxxxxxxxxxxxxxxxxx>]

On Tue, Feb 11, 2014 at 11:03:58PM -0500, Dave Jones wrote:
> [ 3111.414202]  [<ffffffff8d1f9036>] bio_alloc_bioset+0x156/0x210
> [ 3111.414855]  [<ffffffffc0314231>] _xfs_buf_ioapply+0x1c1/0x3c0 [xfs]
> [ 3111.415517]  [<ffffffffc03858f2>] ? xlog_bdstrat+0x22/0x60 [xfs]
> [ 3111.416175]  [<ffffffffc031449b>] xfs_buf_iorequest+0x6b/0xf0 [xfs]
> [ 3111.416843]  [<ffffffffc03858f2>] xlog_bdstrat+0x22/0x60 [xfs]
> [ 3111.417509]  [<ffffffffc0387a87>] xlog_sync+0x3a7/0x5b0 [xfs]
> [ 3111.418175]  [<ffffffffc0387d9f>] xlog_state_release_iclog+0x10f/0x120 
> [xfs]
> [ 3111.418846]  [<ffffffffc0388840>] xlog_write+0x6f0/0x800 [xfs]
> [ 3111.419518]  [<ffffffffc038a061>] xlog_cil_push+0x2f1/0x410 [xfs]

Very interesting.  The first thing xlog_cil_push() is doing is blocking
kmalloc().  So at that point it still hadn't been atomic.  I'd probably
slap may_sleep() in the beginning of xlog_sync() and see if that triggers...