From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: WARNING in ata_qc_issue Date: Mon, 30 Oct 2017 08:23:00 -0700 Message-ID: <20171030152300.GG3252168@devbig577.frc2.facebook.com> References: <001a11425956f5f3d0055c82f08d@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <001a11425956f5f3d0055c82f08d@google.com> Sender: linux-kernel-owner@vger.kernel.org To: syzbot Cc: linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com List-Id: linux-ide@vger.kernel.org Hello, On Fri, Oct 27, 2017 at 01:19:01AM -0700, syzbot wrote: > WARNING: CPU: 1 PID: 2909 at drivers/ata/libata-core.c:5391 > ata_qc_issue+0x519/0xea0 drivers/ata/libata-core.c:5390 ... > sg_common_write.isra.17+0xf80/0x1c10 drivers/scsi/sg.c:806 > sg_write+0x7a0/0xc90 drivers/scsi/sg.c:677 > __vfs_write+0xef/0x970 fs/read_write.c:468 > vfs_write+0x189/0x510 fs/read_write.c:518 > SYSC_write fs/read_write.c:565 [inline] > SyS_write+0xef/0x220 fs/read_write.c:557 It's issuing an invalid command (data command w/o any data) via SG and libata triggered a warning before failing the command. The warning is still somewhat meaningful in that if we ever hit that during normal kernel operation, it shows the caller who's screwing up. idk, we can shut it up (nothing is really wrong in this case) or make it a bit smarter (filter out invalid sg commands earlier). Thanks. -- tejun