Re: [PATCH 6.6 000/396] 6.6.24-rc1 review

[Greg Kroah-Hartman]

On Tue, Apr 02, 2024 at 01:37:50PM +0300, Dan Carpenter wrote:
> On Mon, Apr 01, 2024 at 09:22:52PM +0200, Alexander Wetzel wrote:
> > 
> > > Following kernel warnings have been noticed on qemu-x86_64 while running LTP
> > > cve ioctl_sg01 tests the kernel with stable-rc 6.6.24-rc1, 6.7.12-rc1 and
> > > 6.8.3-rc1.
> > > 
> > > We have started bi-secting this issue.
> > > Always reproduced.
> > > 
> > > Reported-by: Linux Kernel Functional Testing <lkft@xxxxxxxxxx>
> > > 
> > > ioctl_sg01.c:81: TINFO: Found SCSI device /dev/sg0
> > > ------------[ cut here ]------------
> > > [   36.606841] WARNING: CPU: 0 PID: 8 at drivers/scsi/sg.c:2237
> > > sg_remove_sfp_usercontext+0x145/0x150
> > > [   36.609445] Modules linked in:
> > > [   36.610793] CPU: 0 PID: 8 Comm: kworker/0:0 Not tainted 6.6.24-rc1 #1
> > > [   36.611568] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009),
> > > BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
> > > [   36.612872] Workqueue: events sg_remove_sfp_usercontext
> > > [   36.613691] RIP: 0010:sg_remove_sfp_usercontext+0x145/0x150
> > > 
> > > <trim>
> > > 
> > > [   36.621539] Call Trace:
> > > [   36.621953]  <TASK>
> > > [   36.622444]  ? show_regs+0x69/0x80
> > > [   36.622819]  ? __warn+0x8d/0x150
> > > [   36.623078]  ? sg_remove_sfp_usercontext+0x145/0x150
> > > [   36.623558]  ? report_bug+0x171/0x1a0
> > > [   36.623881]  ? handle_bug+0x42/0x80
> > > [   36.624070]  ? exc_invalid_op+0x1c/0x70
> > > [   36.624491]  ? asm_exc_invalid_op+0x1f/0x30
> > > [   36.624897]  ? sg_remove_sfp_usercontext+0x145/0x150
> > > [   36.625408]  process_one_work+0x141/0x300
> > > [   36.625769]  worker_thread+0x2f6/0x430
> > > [   36.626073]  ? __pfx_worker_thread+0x10/0x10
> > > [   36.626529]  kthread+0x105/0x140
> > > [   36.626778]  ? __pfx_kthread+0x10/0x10
> > > [   36.627059]  ret_from_fork+0x41/0x60
> > > [   36.627441]  ? __pfx_kthread+0x10/0x10
> > > [   36.627735]  ret_from_fork_asm+0x1b/0x30
> > > [   36.628293]  </TASK>
> > > [   36.628604] ---[ end trace 0000000000000000 ]---
> > > ioctl_sg01.c:122: TPASS: Output buffer is empty, no data leaked
> > > 
> > > Suspecting commit:
> > > -----
> > > scsi: sg: Avoid sg device teardown race
> > > commit 27f58c04a8f438078583041468ec60597841284d upstream.
> > > 
> > 
> > Correct. The issue is already been worked on.
> > 
> > commit 27f58c04a8f4 ("scsi: sg: Avoid sg device teardown race") fixed a real
> > issue. But also added an incorrect WARN_ON_ONCE(). Thus the scary - but
> > otherwise harmless - error message.
> 
> If you have Reboot on Oops turned on (apparently Android enables this)
> then WARN() will reboot the system so it can be pretty annoying.

Agreed, I've dropped this stable change for now because of this.

greg k-h