Hi Alex, > -----Original Message----- > From: Alex Williamson <alex.williamson@xxxxxxxxxx> > Sent: Friday, April 26, 2019 11:09 AM > To: Parav Pandit <parav@xxxxxxxxxxxx> > Cc: kvm@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; > kwankhede@xxxxxxxxxx; cjia@xxxxxxxxxx > Subject: Re: [PATCHv1 7/7] vfio/mdev: Fix race conditions with mdev device > life cycle APIs [..] > > > > > > > > > Patch 6 looks ok, except I'd rather see the sanitizing loop stay > > > > > until we can otherwise fix the race above. > > > > I can put back the sanitizing look, once it looks valid. Will wait > > > > for your response. > > > > > > Yep, I think patch 6 is good w/o the removal of the sanitizing loop. > > > Will you repost it? > > > > > Just the patch-6 or 1 to 6? > > Your choice, please roll in reviews/acks if you repost the rest. > > > > > > Patch 7 needed more work, iirc. Thanks, > > > > For a moment if we assume sanitizing loop exists, than patch-7 > > > > looks good? > > > > > > Patch 7 is a bit less trivial, so I think as we're close to the > > > merge window for v5.2, I'd rather push it out to be included with > > > the later re-works. Thanks, > > > > > I agree it little less trivial, I tried to place as much comment as possible, > but it is an important fix. > > Let me repost 6-7 and decide if it can be included or not? > > Sounds good. Thanks, > I am dropping patch-7 for today and reworking the patch-6 for now. Even after keeping that that crazy loop, I am easily able to create this below [1] call trace on adding file when mdev_remove() fails with the thread sequence we discussed above. I think this is high time, we fix the sequence to match the linux bus sequence. I have some cycles this week. Post these 6 patches, I like to get total 3 patches done. 1. fix the bus sequence 2. race with parent device removal 3. do not try to add sysfs file on remove() failure Is there any possibility above 3 patches can make to 5.2, given that merge window closes in June? If yes, I will get them in 2-3 days. I will test with sample drivers and mlx5 driver. Can we get some tests also done from Kirti also done on their hw? kernel: WARNING: CPU: 2 PID: 9348 at fs/sysfs/file.c:327 sysfs_create_file_ns+0x7f/0x90 kernel: CPU: 2 PID: 9348 Comm: bash Kdump: loaded Not tainted 5.1.0-rc6-vdevbus+ #6 kernel: Hardware name: Supermicro SYS-6028U-TR4+/X10DRU-i+, BIOS 2.0b 08/09/2016 kernel: RIP: 0010:sysfs_create_file_ns+0x7f/0x90 kernel: Call Trace: kernel: remove_store+0xdc/0x100 [mdev] kernel: kernfs_fop_write+0x113/0x1a0 kernel: vfs_write+0xad/0x1b0 kernel: ksys_write+0x5a/0xe0 kernel: do_syscall_64+0x5a/0x210 kernel: entry_SYSCALL_64_after_hwframe+0x49/0xbe
