Hi, Leon Thanks. From the patch https://lore.kernel.org/netdev/20200306134518.84416-1-kgraul@xxxxxxxxxxxxx, @@ -240,6 +240,9 @@ static void smc_ib_port_event_work(struct work_struct *work) work, struct smc_ib_device, port_event_work); u8 port_idx; + if (list_empty(&smcibdev->list)) + return; + for_each_set_bit(port_idx, &smcibdev->port_event_mask, SMC_MAX_PORTS) { smc_ib_remember_port_attr(smcibdev, port_idx + 1); clear_bit(port_idx, &smcibdev->port_event_mask); This block is try to check smcibdev->list to avoid ib_query_port after the NIC is down. But smcibdev->list is used by spinlock when add and del. " ... 549 spin_lock(&smc_ib_devices.lock); 550 list_add_tail(&smcibdev->list, &smc_ib_devices.list); 551 spin_unlock(&smc_ib_devices.lock); ... 579 spin_lock(&smc_ib_devices.lock); 580 list_del_init(&smcibdev->list); /* remove from smc_ib_devices */ 581 spin_unlock(&smc_ib_devices.lock); ... " So in the above block, is it necessary to protect smcibdev->list when it is accessed? Please comment on it. Thanks a lot. Zhu Yanjun -----Original Message----- From: Leon Romanovsky <leon@xxxxxxxxxx> Sent: Tuesday, March 10, 2020 3:40 PM To: Jason Gunthorpe <jgg@xxxxxxxxxxxx> Cc: syzbot <syzbot+e11efb687f5ab7f01f3d@xxxxxxxxxxxxxxxxxxxxxxxxx>; dledford@xxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; linux-rdma@xxxxxxxxxxxxxxx; Moni Shoua <monis@xxxxxxxxxxxx>; syzkaller-bugs@xxxxxxxxxxxxxxxx; Yanjun Zhu <yanjunz@xxxxxxxxxxxx> Subject: Re: KASAN: use-after-free Read in rxe_query_port On Mon, Mar 09, 2020 at 02:34:51PM -0300, Jason Gunthorpe wrote: > On Sun, Mar 01, 2020 at 03:20:12AM -0800, syzbot wrote: > > Hello, > > > > syzbot found the following crash on: > > > > HEAD commit: f8788d86 Linux 5.6-rc3 > > git tree: upstream > > console output: https://syzkaller.appspot.com/x/log.txt?x=132d3645e00000 > > kernel config: https://syzkaller.appspot.com/x/.config?x=9833e26bab355358 > > dashboard link: https://syzkaller.appspot.com/bug?extid=e11efb687f5ab7f01f3d > > compiler: gcc (GCC) 9.0.0 20181231 (experimental) > > > > Unfortunately, I don't have any reproducer for this crash yet. > > > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > > Reported-by: syzbot+e11efb687f5ab7f01f3d@xxxxxxxxxxxxxxxxxxxxxxxxx > > Yanjun, do you have some idea what this could be? See this fix in the net mailing list. https://lore.kernel.org/netdev/20200306134518.84416-1-kgraul@xxxxxxxxxxxxx Thanks > > Thanks, > Jason
