Hi Michael,
On Tuesday, 2024-08-20 at 12:50:39 -04, Michael S. Tsirkin wrote:
> On Tue, Aug 20, 2024 at 03:19:13PM +0800, Xuan Zhuo wrote:
>> leads to regression on VM with the sysctl value of:
>>
>> - net.core.high_order_alloc_disable=1
>
>
>
>
>> which could see reliable crashes or scp failure (scp a file 100M in size
>> to VM):
>>
>> The issue is that the virtnet_rq_dma takes up 16 bytes at the beginning
>> of a new frag. When the frag size is larger than PAGE_SIZE,
>> everything is fine. However, if the frag is only one page and the
>> total size of the buffer and virtnet_rq_dma is larger than one page, an
>> overflow may occur. In this case, if an overflow is possible, I adjust
>> the buffer size. If net.core.high_order_alloc_disable=1, the maximum
>> buffer size is 4096 - 16. If net.core.high_order_alloc_disable=0, only
>> the first buffer of the frag is affected.
>>
>> Fixes: f9dac92ba908 ("virtio_ring: enable premapped mode whatever use_dma_api")
>> Reported-by: "Si-Wei Liu" <si-wei.liu@xxxxxxxxxx>
>> Closes: http://lore.kernel.org/all/8b20cc28-45a9-4643-8e87-ba164a540c0a@xxxxxxxxxx
>> Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
>
>
> Darren, could you pls test and confirm?
Unfortunately with this change I seem to still get a panic as soon as I start a
download using wget:
[ 144.055630] Kernel panic - not syncing: corrupted stack end detected inside scheduler
[ 144.056249] CPU: 8 PID: 37894 Comm: sleep Kdump: loaded Not tainted 6.10.0-1.el8uek.x86_64 #2
[ 144.056850] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.0-4.module+el8.9.0+90173+a3f3e83a 04/01/2014
[ 144.057585] Call Trace:
[ 144.057791] <TASK>
[ 144.057973] panic+0x347/0x370
[ 144.058223] schedule_debug.isra.0+0xfb/0x100
[ 144.058565] __schedule+0x58/0x6a0
[ 144.058838] ? refill_stock+0x26/0x50
[ 144.059120] ? srso_alias_return_thunk+0x5/0xfbef5
[ 144.059473] do_task_dead+0x42/0x50
[ 144.059752] do_exit+0x31e/0x4b0
[ 144.060011] ? __audit_syscall_entry+0xee/0x150
[ 144.060352] do_group_exit+0x30/0x80
[ 144.060633] __x64_sys_exit_group+0x18/0x20
[ 144.060946] do_syscall_64+0x8c/0x1c0
[ 144.061228] ? srso_alias_return_thunk+0x5/0xfbef5
[ 144.061570] ? __audit_filter_op+0xbe/0x140
[ 144.061873] ? srso_alias_return_thunk+0x5/0xfbef5
[ 144.062204] ? audit_reset_context+0x232/0x310
[ 144.062514] ? srso_alias_return_thunk+0x5/0xfbef5
[ 144.062851] ? syscall_exit_work+0x103/0x130
[ 144.063148] ? srso_alias_return_thunk+0x5/0xfbef5
[ 144.063473] ? syscall_exit_to_user_mode+0x77/0x220
[ 144.063813] ? srso_alias_return_thunk+0x5/0xfbef5
[ 144.064142] ? do_syscall_64+0xb9/0x1c0
[ 144.064411] ? srso_alias_return_thunk+0x5/0xfbef5
[ 144.064747] ? do_syscall_64+0xb9/0x1c0
[ 144.065018] ? srso_alias_return_thunk+0x5/0xfbef5
[ 144.065345] ? do_read_fault+0x109/0x1b0
[ 144.065628] ? srso_alias_return_thunk+0x5/0xfbef5
[ 144.065961] ? do_fault+0x1aa/0x2f0
[ 144.066212] ? handle_pte_fault+0x102/0x1a0
[ 144.066503] ? srso_alias_return_thunk+0x5/0xfbef5
[ 144.066836] ? __handle_mm_fault+0x5ed/0x710
[ 144.067137] ? srso_alias_return_thunk+0x5/0xfbef5
[ 144.067464] ? __count_memcg_events+0x72/0x110
[ 144.067779] ? srso_alias_return_thunk+0x5/0xfbef5
[ 144.068106] ? count_memcg_events.constprop.0+0x26/0x50
[ 144.068457] ? srso_alias_return_thunk+0x5/0xfbef5
[ 144.068788] ? handle_mm_fault+0xae/0x320
[ 144.069068] ? srso_alias_return_thunk+0x5/0xfbef5
[ 144.069395] ? do_user_addr_fault+0x34a/0x6b0
[ 144.069708] entry_SYSCALL_64_after_hwframe+0x76/0x7e
[ 144.070049] RIP: 0033:0x7fc5524f9c66
[ 144.070307] Code: Unable to access opcode bytes at 0x7fc5524f9c3c.
[ 144.070720] RSP: 002b:00007ffee052beb8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
[ 144.071214] RAX: ffffffffffffffda RBX: 00007fc5527bb860 RCX: 00007fc5524f9c66
[ 144.071684] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000
[ 144.072146] RBP: 0000000000000000 R08: 00000000000000e7 R09: ffffffffffffff78
[ 144.072608] R10: 00007ffee052bdef R11: 0000000000000246 R12: 00007fc5527bb860
[ 144.073076] R13: 0000000000000002 R14: 00007fc5527c4528 R15: 0000000000000000
[ 144.073543] </TASK>
[ 144.074780] Kernel Offset: 0x37c00000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff)
Thanks,
Darren.
>> ---
>> drivers/net/virtio_net.c | 12 +++++++++---
>> 1 file changed, 9 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
>> index c6af18948092..e5286a6da863 100644
>> --- a/drivers/net/virtio_net.c
>> +++ b/drivers/net/virtio_net.c
>> @@ -918,9 +918,6 @@ static void *virtnet_rq_alloc(struct receive_queue *rq, u32 size, gfp_t gfp)
>> void *buf, *head;
>> dma_addr_t addr;
>>
>> - if (unlikely(!skb_page_frag_refill(size, alloc_frag, gfp)))
>> - return NULL;
>> -
>> head = page_address(alloc_frag->page);
>>
>> dma = head;
>> @@ -2421,6 +2418,9 @@ static int add_recvbuf_small(struct virtnet_info *vi, struct receive_queue *rq,
>> len = SKB_DATA_ALIGN(len) +
>> SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
>>
>> + if (unlikely(!skb_page_frag_refill(len, &rq->alloc_frag, gfp)))
>> + return -ENOMEM;
>> +
>> buf = virtnet_rq_alloc(rq, len, gfp);
>> if (unlikely(!buf))
>> return -ENOMEM;
>> @@ -2521,6 +2521,12 @@ static int add_recvbuf_mergeable(struct virtnet_info *vi,
>> */
>> len = get_mergeable_buf_len(rq, &rq->mrg_avg_pkt_len, room);
>>
>> + if (unlikely(!skb_page_frag_refill(len + room, alloc_frag, gfp)))
>> + return -ENOMEM;
>> +
>> + if (!alloc_frag->offset && len + room + sizeof(struct virtnet_rq_dma) > alloc_frag->size)
>> + len -= sizeof(struct virtnet_rq_dma);
>> +
>> buf = virtnet_rq_alloc(rq, len + room, gfp);
>> if (unlikely(!buf))
>> return -ENOMEM;
>> --
>> 2.32.0.3.g01195cf9f
