On 2019/2/17 2:18, Eric Dumazet wrote: > On Fri, Feb 15, 2019 at 9:36 PM Kefeng Wang <wangkefeng.w...@huawei.com> > wrote: >> >> >> On 2019/2/15 21:57, Eric Dumazet wrote: >>> On Fri, Feb 15, 2019 at 5:37 AM Kefeng Wang <wangkefeng.w...@huawei.com> >>> wrote: >>>> With CONFIG_DEBUG_SPINLOCK=y, we find following stack, >>>> >>>> BUG: spinlock wrong CPU on CPU#0, ip/16047 >>>> lock: 0xffff803f5febc998, .magic: dead4ead, .owner: ip/16047, >>>> .owner_cpu: 0 >>>> CPU: 1 PID: 16047 Comm: ip Kdump: loaded Tainted: G E >>>> 4.19.12.aarch64 #1 >>>> Hardware name: Huawei TaiShan 2280 V2/BC82AMDA, BIOS TA BIOS TaiShan 2280 >>>> V2 - B900 01/29/2019 >>>> Call trace: >>>> dump_backtrace+0x0/0x1c0 >>>> show_stack+0x24/0x30 >>>> dump_stack+0x90/0xbc >>>> spin_dump+0x84/0xa8 >>>> do_raw_spin_unlock+0xf8/0x100 >>>> _raw_spin_unlock+0x20/0x30 >>>> bond_get_stats+0x110/0x140 [bonding] >>>> rtnl_fill_stats+0x50/0x150 >>>> rtnl_fill_ifinfo+0x4d4/0xd18 >>>> rtnl_dump_ifinfo+0x200/0x3a8 >>>> netlink_dump+0x100/0x2b0 >>>> netlink_recvmsg+0x310/0x3e8 >>>> sock_recvmsg+0x58/0x68 >>>> ___sys_recvmsg+0xd0/0x278 >>>> __sys_recvmsg+0x74/0xd0 >>>> __arm64_sys_recvmsg+0x2c/0x38 >>>> el0_svc_common+0x7c/0x118 >>>> el0_svc_handler+0x30/0x40 >>>> el0_svc+0x8/0xc >>>> >>>> and then lead to softlockup issue, fix this by using mutex lock instead >>>> of spin lock. >>>> >>>> Signed-off-by: Kefeng Wang <wangkefeng.w...@huawei.com> >>>> --- >>>> >>>> Not sure if this is right fix, please correct me if I'm wrong. >>>> >>> Make sure to also try : >>> >>> cat /proc/net/dev >> Yes, no regression with this patch in our test or 'cat /proc/net/dev' >> > You really should have a warning showing up. > > Make sure you have : DEBUG_ATOMIC_SLEEP=y (I thought this was > automatically selected with LOCKDEP on, maybe not...) > > Please take a look at net/core/net-procfs.c , functions > dev_seq_start(), dev_seq_printf_stats(), dev_seq_show() > > We can not use a mutex in a section protected by rcu_read_lock()
ok, thanks for your direction, we will do more research and test. > . >
