ocfs2: don't use iocb when EIOCBQUEUED returns
When -EIOCBQUEUED returns, it means that aio_complete() will be called
from dio_complete(), which is an asynchronous progress against
write_iter. Generally, IO is a very slow progress than executing
instruction, but we still can't take the risk to access a freed iocb.
And we do face a BUG crash issue. Using the crash tool, iocb is
obviously freed already.
crash> struct -x kiocb
ffff881a350f5900
struct kiocb {
ki_filp = 0xffff881a350f5a80,
ki_pos = 0x0,
ki_complete = 0x0,
private = 0x0,
ki_flags = 0x0
}
And the backtrace shows:
ocfs2_file_write_iter+0xcaa/0xd00 [ocfs2]
aio_run_iocb+0x229/0x2f0
do_io_submit+0x291/0x540
SyS_io_submit+0x10/0x20
system_call_fastpath+0x16/0x75
Link: http://lkml.kernel.org/r/1523361653-14439-1-git-send-email-ge.changwei@h3c.com
Signed-off-by: Changwei Ge <ge.changwei@h3c.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Joseph Qi <jiangqi903@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>