From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-Id: <20120124023929.370755245@clark.kroah.org> Date: Mon, 23 Jan 2012 18:34:42 -0800 From: Greg KH To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Gleb Natapov Subject: [062/129] Unused iocbs in a batch should not be accounted as active. In-Reply-To: <20120124024041.GA18422@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.2-stable review patch. If anyone has any objections, please let me know. ------------------ Content-Length: 1954 Lines: 64 From: Gleb Natapov commit 69e4747ee9727d660b88d7e1efe0f4afcb35db1b upstream. Since commit 080d676de095 ("aio: allocate kiocbs in batches") iocbs are allocated in a batch during processing of first iocbs. All iocbs in a batch are automatically added to ctx->active_reqs list and accounted in ctx->reqs_active. If one (not the last one) of iocbs submitted by an user fails, further iocbs are not processed, but they are still present in ctx->active_reqs and accounted in ctx->reqs_active. This causes process to stuck in a D state in wait_for_all_aios() on exit since ctx->reqs_active will never go down to zero. Furthermore since kiocb_batch_free() frees iocb without removing it from active_reqs list the list become corrupted which may cause oops. Fix this by removing iocb from ctx->active_reqs and updating ctx->reqs_active in kiocb_batch_free(). Signed-off-by: Gleb Natapov Reviewed-by: Jeff Moyer Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- fs/aio.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) --- a/fs/aio.c +++ b/fs/aio.c @@ -476,14 +476,21 @@ static void kiocb_batch_init(struct kioc batch->count = total; } -static void kiocb_batch_free(struct kiocb_batch *batch) +static void kiocb_batch_free(struct kioctx *ctx, struct kiocb_batch *batch) { struct kiocb *req, *n; + if (list_empty(&batch->head)) + return; + + spin_lock_irq(&ctx->ctx_lock); list_for_each_entry_safe(req, n, &batch->head, ki_batch) { list_del(&req->ki_batch); + list_del(&req->ki_list); kmem_cache_free(kiocb_cachep, req); + ctx->reqs_active--; } + spin_unlock_irq(&ctx->ctx_lock); } /* @@ -1742,7 +1749,7 @@ long do_io_submit(aio_context_t ctx_id, } blk_finish_plug(&plug); - kiocb_batch_free(&batch); + kiocb_batch_free(ctx, &batch); put_ioctx(ctx); return i ? i : ret; }