Il giorno 08 dic 2017, alle ore 01:34, Holger Hoffst=C3=A4tte =

[off-list ref] ha scritto:

=20
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So plugging in a device on USB with BFQ as scheduler now works without
hiccup (probably thanks to Ming Lei's last patch), but of course I =

found

another problem. Unmounting the device after use, changing the =

scheduler

back to deadline or kyber and rmmod'ing the BFQ module reproducibly =

gives me:

=20

Hi Holger,
this is just to tell you that we have not overlooked your report, and
we are already working on it.  We are proceeding slowly, because we
are also working on a large backlog that I hope we will clear soon.

Thanks,
Paolo

kernel: =

=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D

kernel: BUG bfq_queue (Tainted: G    B          ): Objects remaining =

in bfq_queue on __kmem_cache_shutdown()

kernel: =

--------------------------------------------------------------------------=
---

kernel:=20
kernel: INFO: Slab 0xffffea001601fc00 objects=3D37 used=3D3 =

fp=3D0xffff8805807f0360 flags=3D0x8000000000008100

kernel: CPU: 0 PID: 9967 Comm: rmmod Tainted: G    B           4.14.5 =

#1

kernel: Hardware name: Gigabyte Technology Co., Ltd. =

P67-DS3-B3/P67-DS3-B3, BIOS F1 05/06/2011

kernel: Call Trace:
kernel:  dump_stack+0x46/0x5e
kernel:  slab_err+0x9e/0xb0
kernel:  ? on_each_cpu_mask+0x35/0x40
kernel:  ? ksm_migrate_page+0x60/0x60
kernel:  ? __kmalloc+0x1c9/0x1d0
kernel:  __kmem_cache_shutdown+0x177/0x350
kernel:  shutdown_cache+0xf/0x130
kernel:  kmem_cache_destroy+0x19e/0x1b0
kernel:  SyS_delete_module+0x168/0x230
kernel:  ? exit_to_usermode_loop+0x39/0x80
kernel:  entry_SYSCALL_64_fastpath+0x13/0x94
kernel: RIP: 0033:0x7f53e4136b97
kernel: RSP: 002b:00007ffd660061d8 EFLAGS: 00000206 ORIG_RAX: =

00000000000000b0

kernel: RAX: ffffffffffffffda RBX: 0000000000000003 RCX: =

00007f53e4136b97

kernel: RDX: 000000000000000a RSI: 0000000000000800 RDI: =

00000000006247f8

kernel: RBP: 0000000000000000 R08: 00007ffd66005171 R09: =

0000000000000000

kernel: R10: 00007f53e41acbc0 R11: 0000000000000206 R12: =

0000000000624790

kernel: R13: 00007ffd660051d0 R14: 0000000000624790 R15: =

0000000000623260

kernel: INFO: Object 0xffff8805807f0000 @offset=3D0
kernel: INFO: Object 0xffff8805807f01b0 @offset=3D432
kernel: INFO: Object 0xffff8805807f3cc0 @offset=3D15552
kernel: kmem_cache_destroy bfq_queue: Slab cache still has objects
kernel: CPU: 0 PID: 9967 Comm: rmmod Tainted: G    B           4.14.5 =

#1

kernel: Hardware name: Gigabyte Technology Co., Ltd. =

P67-DS3-B3/P67-DS3-B3, BIOS F1 05/06/2011

kernel: Call Trace:
kernel:  dump_stack+0x46/0x5e
kernel:  kmem_cache_destroy+0x191/0x1b0
kernel:  SyS_delete_module+0x168/0x230
kernel:  ? exit_to_usermode_loop+0x39/0x80
kernel:  entry_SYSCALL_64_fastpath+0x13/0x94
kernel: RIP: 0033:0x7f53e4136b97
kernel: RSP: 002b:00007ffd660061d8 EFLAGS: 00000206 ORIG_RAX: =

00000000000000b0

kernel: RAX: ffffffffffffffda RBX: 0000000000000003 RCX: =

00007f53e4136b97

kernel: RDX: 000000000000000a RSI: 0000000000000800 RDI: =

00000000006247f8

kernel: RBP: 0000000000000000 R08: 00007ffd66005171 R09: =

0000000000000000

kernel: R10: 00007f53e41acbc0 R11: 0000000000000206 R12: =

0000000000624790

kernel: R13: 00007ffd660051d0 R14: 0000000000624790 R15: =

0000000000623260

=20
Unloading e.g. kyber repeatably works fine, so I assume this is a bug. =

:)

I'm running 4.14.5 (currently in -rc1) + block/scsi picked from =

4.15-git and

the list. Would be good to know if someone can reproduce it.
=20
thanks,
Holger