Commits
Chuck Lever committed 839f7ad6932
NFS: Fix "kernel BUG at fs/aio.c:554!" Nick Piggin reports: > I'm getting use after frees in aio code in NFS > > [ 2703.396766] Call Trace: > [ 2703.396858] [<ffffffff8100b057>] ? native_sched_clock+0x27/0x80 > [ 2703.396959] [<ffffffff8108509e>] ? put_lock_stats+0xe/0x40 > [ 2703.397058] [<ffffffff81088348>] ? lock_release_holdtime+0xa8/0x140 > [ 2703.397159] [<ffffffff8108a2a5>] lock_acquire+0x95/0x1b0 > [ 2703.397260] [<ffffffff811627db>] ? aio_put_req+0x2b/0x60 > [ 2703.397361] [<ffffffff81039701>] ? get_parent_ip+0x11/0x50 > [ 2703.397464] [<ffffffff81612a31>] _raw_spin_lock_irq+0x41/0x80 > [ 2703.397564] [<ffffffff811627db>] ? aio_put_req+0x2b/0x60 > [ 2703.397662] [<ffffffff811627db>] aio_put_req+0x2b/0x60 > [ 2703.397761] [<ffffffff811647fe>] do_io_submit+0x2be/0x7c0 > [ 2703.397895] [<ffffffff81164d0b>] sys_io_submit+0xb/0x10 > [ 2703.397995] [<ffffffff8100307b>] system_call_fastpath+0x16/0x1b > > Adding some tracing, it is due to nfs completing the request then > returning something other than -EIOCBQUEUED, so aio.c > also completes the request. To address this, prevent the NFS direct I/O engine from completing async iocbs when the forward path returns an error without starting any I/O. This fix appears to survive ^C during both "xfstest no. 208" and "fsx -Z." It's likely this bug has existed for a very long while, as we are seeing very similar symptoms in OEL 5. Copying stable. Cc: Stable <stable@kernel.org> Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>