From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Subject: Re: [Bug 12945] New: SCSI Generic (sg): BUG: sleeping function called from invalid context Date: Thu, 26 Mar 2009 07:49:52 -0700 Message-ID: <20090326074952.40ffdcd9.akpm@linux-foundation.org> References: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: Received: from smtp1.linux-foundation.org ([140.211.169.13]:41515 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755844AbZCZOyg (ORCPT ); Thu, 26 Mar 2009 10:54:36 -0400 In-Reply-To: Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: bugzilla-daemon@bugzilla.kernel.org Cc: linux-scsi@vger.kernel.org, txtoxtox285@googlemail.com, FUJITA Tomonori , Jens Axboe , Douglas Gilbert , James Bottomley (switched to email. Please respond via emailed reply-to-all, not via the bugzilla web interface). On Thu, 26 Mar 2009 12:27:53 GMT bugzilla-daemon@bugzilla.kernel.org wrote: > http://bugzilla.kernel.org/show_bug.cgi?id=12945 > > Summary: SCSI Generic (sg): BUG: sleeping function called from > invalid context > Product: SCSI Drivers > Version: 2.5 > Kernel Version: 2.6.28.9 > Platform: All > OS/Version: Linux > Tree: Mainline > Status: NEW > Severity: normal > Priority: P1 > Component: Other > AssignedTo: scsi_drivers-other@kernel-bugs.osdl.org > ReportedBy: txtoxtox285@googlemail.com > Regression: No > > > Created an attachment (id=20685) > --> (http://bugzilla.kernel.org/attachment.cgi?id=20685) > Stack trace on program kill (2.6.28.9) > > I am experimenting with CD audio extraction. I use the SCSI Generic driver for > this. > > My test program uses read() and write() (instead of ioctl) to send requests to > the driver and receive responses. I use SG_FLAG_DIRECT_IO. > > When I kill my program (because I don't want to wait until it has ripped the > entire CD), I am often rewarded with messages like "BUG: sleeping function > called from invalid context at linux-2.6.28.9/include/linux/pagemap.h:347". I > have attached typical stack trace. > > Another case when I hit this BUG is when I set a time out and the CD drive > doesn't respond fast enough. A stack trace is attached. > [34215.786870] BUG: sleeping function called from invalid context at /mnt/var-pub/src/linux-2.6.28.9/include/linux/pagemap.h:347 > [34215.786880] in_atomic(): 1, irqs_disabled(): 1, pid: 0, name: swapper > [34215.786886] Pid: 0, comm: swapper Not tainted 2.6.28.9 #1 > [34215.786890] Call Trace: > [34215.786894] [] set_page_dirty_lock+0x1a/0x45 > [34215.786911] [] bio_unmap_user+0x1e/0x4a > [34215.786920] [] __blk_rq_unmap_user+0x14/0x20 > [34215.786928] [] pit_next_event+0x2e/0x49 > [34215.786934] [] blk_rq_unmap_user+0x1e/0x4b > [34215.786965] [] sg_finish_rem_req+0x6d/0x88 [sg] > [34215.786979] [] sg_rq_end_io+0x131/0x205 [sg] > [34215.786986] [] end_that_request_last+0x58/0x194 > [34215.786992] [] blk_end_io+0x48/0x7d > [34215.787019] [] scsi_next_command+0x219/0x283 [scsi_mod] > [34215.787039] [] scsi_io_completion+0x181/0x53b [scsi_mod] > [34215.787047] [] blk_done_softirq+0x5f/0x6d > [34215.787054] [] __do_softirq+0x5e/0xf8 > [34215.787061] [] call_softirq+0x1c/0x28 > [34215.787067] [] do_softirq+0x2c/0x68 > [34215.787073] [] irq_exit+0x36/0x82 > [34215.787079] [] do_IRQ+0xa6/0xb8 > [34215.787085] [] ret_from_intr+0x0/0xa > [34215.787088] [] menu_reflect+0x0/0x6d > [34215.787112] [] acpi_idle_enter_simple+0x170/0x1d6 [processor] > [34215.787127] [] acpi_idle_enter_simple+0x166/0x1d6 [processor] > [34215.787134] [] cpuidle_idle_call+0x73/0xb1 > [34215.787140] [] cpu_idle+0x3c/0x73 Argh. sg_finish_rem_req() is called from interrupt context. But blk_rq_unmap_user() can run __bio_unmap_user()->set_page_dirty_lock()->lock_page(), which can call schedule(). If it does call schedule(), the machine will crash. afacit, blk_rq_unmap_user() has always been a can-sleep function, and this is a regression caused by commit 6e5a30cba5e7c03b2cd564e968f1dd667a0f7c42 Author: FUJITA Tomonori AuthorDate: Thu Aug 28 16:17:08 2008 +0900 Commit: Jens Axboe CommitDate: Thu Oct 9 08:56:10 2008 +0200 sg: convert the direct IO path to use the block layer This patch converts the direct IO path (SG_FLAG_DIRECT_IO) to use the block layer functions (blk_get_request, blk_execute_rq_nowait, blk_rq_map_user, etc) instead of scsi_execute_async(). Signed-off-by: FUJITA Tomonori Signed-off-by: Douglas Gilbert Cc: Mike Christie Cc: James Bottomley Signed-off-by: Jens Axboe