On Thu, Feb 13, 2020 at 10:28:18AM -0400, Jason Gunthorpe wrote:
> On Wed, Feb 12, 2020 at 09:26:34AM +0200, Leon Romanovsky wrote:
> > From: Yonatan Cohen <yonatanc@xxxxxxxxxxxx>
> >
> > When unloading ib_umad, remove ibdev sys file 1st before
> > port removal to prevent kernel oops.
> >
> > ib_mad's method ibdev_show() might access a umad port
> > whoes ibdev field has already been NULLed when rmmod ib_umad
> > was issued from another shell.
> >
> > Consider this scenario
> > shell-1 shell-2
> > rmmod ib_mod cat /sys/devices/../ibdev
> > | |
> > ib_umad_kill_port() ibdev_show()
> > port->ib_dev = NULL dev_name(port->ib_dev)
> >
> > kernel stack
> > PF: error_code(0x0000) - not-present page
> > Oops: 0000 [#1] SMP DEBUG_PAGEALLOC PTI
> > RIP: 0010:ibdev_show+0x18/0x50 [ib_umad]
> > RSP: 0018:ffffc9000097fe40 EFLAGS: 00010282
> > RAX: 0000000000000000 RBX: ffffffffa0441120 RCX: ffff8881df514000
> > RDX: ffff8881df514000 RSI: ffffffffa0441120 RDI: ffff8881df1e8870
> > RBP: ffffffff81caf000 R08: ffff8881df1e8870 R09: 0000000000000000
> > R10: 0000000000001000 R11: 0000000000000003 R12: ffff88822f550b40
> > R13: 0000000000000001 R14: ffffc9000097ff08 R15: ffff8882238bad58
> > FS: 00007f1437ff3740(0000) GS:ffff888236940000(0000) knlGS:0000000000000000
> > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > CR2: 00000000000004e8 CR3: 00000001e0dfc001 CR4: 00000000001606e0
> > Call Trace:
> > dev_attr_show+0x15/0x50
> > sysfs_kf_seq_show+0xb8/0x1a0
> > seq_read+0x12d/0x350
> > vfs_read+0x89/0x140
> > ksys_read+0x55/0xd0
> > do_syscall_64+0x55/0x1b0
> > entry_SYSCALL_64_after_hwframe+0x44/0xa9:
> >
> > Fixes: e9dd5daf884c ("IB/umad: Refactor code to use cdev_device_add()")
>
> This is the wrong fixes line, this ordering change was actually
> deliberately done:
>
Can you please fix the fixes line, so I will resend unaccepted patches only?
Thanks
