On Thu, Mar 26, 2009 at 3:49 PM, Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote: > > (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@xxxxxxxxxxxxxxxxxxx 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@xxxxxxxxxxxxxxxxxxxx >> ReportedBy: txtoxtox285@xxxxxxxxxxxxxx >> 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] <IRQ> [<ffffffff8026c4cc>] set_page_dirty_lock+0x1a/0x45 >> [34215.786911] [<ffffffff802ae17d>] bio_unmap_user+0x1e/0x4a >> [34215.786920] [<ffffffff802e876b>] __blk_rq_unmap_user+0x14/0x20 >> [34215.786928] [<ffffffff80210852>] pit_next_event+0x2e/0x49 >> [34215.786934] [<ffffffff802e8795>] blk_rq_unmap_user+0x1e/0x4b >> [34215.786965] [<ffffffffa0163475>] sg_finish_rem_req+0x6d/0x88 [sg] >> [34215.786979] [<ffffffffa0164ef3>] sg_rq_end_io+0x131/0x205 [sg] >> [34215.786986] [<ffffffff802e5c1f>] end_that_request_last+0x58/0x194 >> [34215.786992] [<ffffffff802e5e00>] blk_end_io+0x48/0x7d >> [34215.787019] [<ffffffffa0026bef>] scsi_next_command+0x219/0x283 [scsi_mod] >> [34215.787039] [<ffffffffa00279b1>] scsi_io_completion+0x181/0x53b [scsi_mod] >> [34215.787047] [<ffffffff802e9737>] blk_done_softirq+0x5f/0x6d >> [34215.787054] [<ffffffff80230787>] __do_softirq+0x5e/0xf8 >> [34215.787061] [<ffffffff8020ca8c>] call_softirq+0x1c/0x28 >> [34215.787067] [<ffffffff8020d6bc>] do_softirq+0x2c/0x68 >> [34215.787073] [<ffffffff80230696>] irq_exit+0x36/0x82 >> [34215.787079] [<ffffffff8020d79e>] do_IRQ+0xa6/0xb8 >> [34215.787085] [<ffffffff8020c256>] ret_from_intr+0x0/0xa >> [34215.787088] <EOI> [<ffffffff8034f648>] menu_reflect+0x0/0x6d >> [34215.787112] [<ffffffffa0147d51>] acpi_idle_enter_simple+0x170/0x1d6 [processor] >> [34215.787127] [<ffffffffa0147d47>] acpi_idle_enter_simple+0x166/0x1d6 [processor] >> [34215.787134] [<ffffffff8034eb32>] cpuidle_idle_call+0x73/0xb1 >> [34215.787140] [<ffffffff8020ac2a>] 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 <fujita.tomonori@xxxxxxxxxxxxx> > AuthorDate: Thu Aug 28 16:17:08 2008 +0900 > Commit: Jens Axboe <jens.axboe@xxxxxxxxxx> > 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 <fujita.tomonori@xxxxxxxxxxxxx> > Signed-off-by: Douglas Gilbert <dougg@xxxxxxxxxx> > Cc: Mike Christie <michaelc@xxxxxxxxxxx> > Cc: James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx> > Signed-off-by: Jens Axboe <jens.axboe@xxxxxxxxxx> > > Andrew, thank you for your quick response. So as a temporary workaround I will not use direct I/O and wait for a patch. -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
