On 08.02.2019 21:55, Sander Eikelenboom wrote: > On 08/02/2019 19:52, Heiner Kallweit wrote: >> On 08.02.2019 19:29, Sander Eikelenboom wrote: >>> L.S., >>> >>> While testing a linux 5.0-rc5 kernel (with some patches on top but they >>> don't seem related) under Xen i the nasty splat below, >>> that I haven encountered with Linux 4.20.x. >>> >>> Unfortunately I haven't got a clear reproducer for this and bisecting could >>> be nasty due to another (networking related) kernel bug. >>> >>> If you need more info, want me to run a debug patch etc., please feel free >>> to ask. >>> >> Thanks for the report. However I see no change in the r8169 driver between >> 4.20 and 5.0 with regard to BQL code. Having said that the root cause could >> be somewhere else. Therefore I'm afraid a bisect will be needed. > > Hmm i did some diging and i think: > bd7153bd83b806bfcc2e79b7a6f43aa653d06ef3 r8169: remove unneeded mmiowb > barriers > 2e6eedb4813e34d8d84ac0eb3afb668966f3f356 r8169: make use of xmit_more and > __netdev_sent_queue > 620344c43edfa020bbadfd81a144ebe5181fc94f net: core: add __netdev_sent_queue > as variant of __netdev_tx_sent_queue > You're right. Thought this was added in 4.20 already. The BQL code pattern I copied from the mlx4 driver and so far I haven't heard about this issue from any user of physical hw. And due to the fact that a lot of mainboards have onboard Realtek network I have quite a few testers out there. Does the issue occur under specific circumstances like very high load?
If indeed the xmit_more patch causes the issue, I think we have to involve Eric Dumazet as author of the underlying changes. > would be candidates, which were merged in 5.0. > > I have reverted the first two, see how that works out. > > -- > Sander > Heiner > >>> -- >>> Sander >>> >> Heiner >> >>> >>> [ 6466.554866] kernel BUG at lib/dynamic_queue_limits.c:27! >>> [ 6466.571425] invalid opcode: 0000 [#1] SMP NOPTI >>> [ 6466.585890] CPU: 3 PID: 7057 Comm: as Not tainted >>> 5.0.0-rc5-20190208-thp-net-florian-doflr+ #1 >>> [ 6466.598693] Hardware name: MSI MS-7640/890FXA-GD70 (MS-7640) , BIOS >>> V1.8B1 09/13/2010 >>> [ 6466.611579] RIP: e030:dql_completed+0x126/0x140 >>> [ 6466.624339] Code: 2b 47 54 ba 00 00 00 00 c7 47 54 ff ff ff ff 0f 48 c2 >>> 48 8b 15 7b 39 4a 01 48 89 57 58 e9 48 ff ff ff 44 89 c0 e9 40 ff ff ff >>> <0f> 0b 8b 47 50 29 e8 41 0f 48 c3 eb 9f 90 90 90 90 90 90 90 90 90 >>> [ 6466.648130] RSP: e02b:ffff88807d4c3e78 EFLAGS: 00010297 >>> [ 6466.659616] RAX: 0000000000000042 RBX: ffff8880049cf800 RCX: >>> 0000000000000000 >>> [ 6466.672835] RDX: 0000000000000001 RSI: 0000000000000042 RDI: >>> ffff8880049cf8c0 >>> [ 6466.684521] RBP: ffff888077df7260 R08: 0000000000000001 R09: >>> 0000000000000000 >>> [ 6466.696824] R10: 00000000387c2336 R11: 00000000387c2336 R12: >>> 0000000010000000 >>> [ 6466.709953] R13: ffff888077df6898 R14: ffff888077df75c0 R15: >>> 0000000000454677 >>> [ 6466.722165] FS: 00007fd869147200(0000) GS:ffff88807d4c0000(0000) >>> knlGS:0000000000000000 >>> [ 6466.733228] CS: e030 DS: 0000 ES: 0000 CR0: 0000000080050033 >>> [ 6466.746581] CR2: 00007fd867dfd000 CR3: 0000000074884000 CR4: >>> 0000000000000660 >>> [ 6466.758366] Call Trace: >>> [ 6466.768118] <IRQ> >>> [ 6466.778214] rtl8169_poll+0x4f4/0x640 >>> [ 6466.789198] net_rx_action+0x23d/0x370 >>> [ 6466.798467] __do_softirq+0xed/0x229 >>> [ 6466.807039] irq_exit+0xb7/0xc0 >>> [ 6466.815471] xen_evtchn_do_upcall+0x27/0x40 >>> [ 6466.826647] xen_do_hypervisor_callback+0x29/0x40 >>> [ 6466.835902] </IRQ> >>> [ 6466.845361] RIP: e030:xen_hypercall_mmu_update+0xa/0x20 >>> [ 6466.853390] Code: 51 41 53 b8 00 00 00 00 0f 05 41 5b 59 c3 cc cc cc cc >>> cc cc cc cc cc cc cc cc cc cc cc cc cc cc 51 41 53 b8 01 00 00 00 0f 05 >>> <41> 5b 59 c3 cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc >>> [ 6466.874031] RSP: e02b:ffffc90003c0bdd0 EFLAGS: 00000246 >>> [ 6466.883452] RAX: 0000000000000000 RBX: 000000041f83bfe8 RCX: >>> ffffffff8100102a >>> [ 6466.891986] RDX: deadbeefdeadf00d RSI: deadbeefdeadf00d RDI: >>> deadbeefdeadf00d >>> [ 6466.903402] RBP: 0000000000000fe8 R08: 000000000000000b R09: >>> 0000000000000000 >>> [ 6466.911201] R10: deadbeefdeadf00d R11: 0000000000000246 R12: >>> 800000050c346067 >>> [ 6466.918491] R13: ffff8880607c4fe8 R14: ffff888005082800 R15: >>> 0000000000000000 >>> [ 6466.926647] ? xen_hypercall_mmu_update+0xa/0x20 >>> [ 6466.938195] ? xen_set_pte_at+0x78/0xe0 >>> [ 6466.947046] ? __handle_mm_fault+0xc43/0x1060 >>> [ 6466.955772] ? do_mmap+0x44b/0x5b0 >>> [ 6466.964410] ? handle_mm_fault+0xf8/0x200 >>> [ 6466.973290] ? __do_page_fault+0x231/0x4a0 >>> [ 6466.981973] ? page_fault+0x8/0x30 >>> [ 6466.990904] ? page_fault+0x1e/0x30 >>> [ 6466.999585] Modules linked in: >>> [ 6467.007533] ---[ end trace 94bec01608fe4061 ]--- >>> [ 6467.016751] RIP: e030:dql_completed+0x126/0x140 >>> [ 6467.024271] Code: 2b 47 54 ba 00 00 00 00 c7 47 54 ff ff ff ff 0f 48 c2 >>> 48 8b 15 7b 39 4a 01 48 89 57 58 e9 48 ff ff ff 44 89 c0 e9 40 ff ff ff >>> <0f> 0b 8b 47 50 29 e8 41 0f 48 c3 eb 9f 90 90 90 90 90 90 90 90 90 >>> [ 6467.039726] RSP: e02b:ffff88807d4c3e78 EFLAGS: 00010297 >>> [ 6467.047243] RAX: 0000000000000042 RBX: ffff8880049cf800 RCX: >>> 0000000000000000 >>> [ 6467.054202] RDX: 0000000000000001 RSI: 0000000000000042 RDI: >>> ffff8880049cf8c0 >>> [ 6467.062000] RBP: ffff888077df7260 R08: 0000000000000001 R09: >>> 0000000000000000 >>> [ 6467.069664] R10: 00000000387c2336 R11: 00000000387c2336 R12: >>> 0000000010000000 >>> [ 6467.077715] R13: ffff888077df6898 R14: ffff888077df75c0 R15: >>> 0000000000454677 >>> [ 6467.084916] FS: 00007fd869147200(0000) GS:ffff88807d4c0000(0000) >>> knlGS:0000000000000000 >>> [ 6467.093352] CS: e030 DS: 0000 ES: 0000 CR0: 0000000080050033 >>> [ 6467.101492] CR2: 00007fd867dfd000 CR3: 0000000074884000 CR4: >>> 0000000000000660 >>> [ 6467.110542] Kernel panic - not syncing: Fatal exception in interrupt >>> [ 6467.118166] Kernel Offset: disabled >>> (XEN) [2019-02-08 18:04:48.854] Hardware Dom0 crashed: rebooting machine in >>> 5 seconds. >>> >> > >
