From: Suparna Bhattacharya This patch appears to fix the hangs seen with AIO and 4G-4G for me. It ensures that the indirect versions of copy_xxx_user are used during aio retries running in worker thread context (i.e. access aio issuer's user-space instead of kernel-space). fs/aio.c | 7 ++++++- 1 files changed, 6 insertions(+), 1 deletion(-) diff -upN reference/fs/aio.c current/fs/aio.c --- reference/fs/aio.c 2004-04-29 10:39:23.000000000 -0700 +++ current/fs/aio.c 2004-04-29 10:39:23.000000000 -0700 @@ -802,18 +802,23 @@ static inline void aio_run_iocbs(struct * aio_kick_handler: * Work queue handler triggered to process pending * retries on an ioctx. Takes on the aio issuer's - * mm context before running the iocbs. + * mm context before running the iocbs, so that + * copy_xxx_user operates on the issuer's address + * space. * Run on aiod's context. */ static void aio_kick_handler(void *data) { struct kioctx *ctx = data; + mm_segment_t oldfs = get_fs(); + set_fs(USER_DS); use_mm(ctx->mm); spin_lock_irq(&ctx->ctx_lock); __aio_run_iocbs(ctx); unuse_mm(ctx->mm); spin_unlock_irq(&ctx->ctx_lock); + set_fs(oldfs); }