From: Jakub Kicinski <kuba@xxxxxxxxxx> Date: Mon, 6 May 2024 11:29:31 -0700 > On Mon, 6 May 2024 11:48:55 +0200 Alexander Lobakin wrote: >> XSk infra's been using its own DMA sync shortcut to try avoiding >> redundant function calls. Now that there is a generic one, remove >> the custom implementation and rely on the generic helpers. >> xsk_buff_dma_sync_for_cpu() doesn't need the second argument anymore, >> remove it. > > I think this is crashing xsk tests: > > [ 91.048963] BUG: kernel NULL pointer dereference, address: 0000000000000464 > [ 91.049412] #PF: supervisor read access in kernel mode > [ 91.049739] #PF: error_code(0x0000) - not-present page > [ 91.050057] PGD 0 P4D 0 > [ 91.050221] Oops: 0000 [#1] PREEMPT SMP NOPTI > [ 91.050500] CPU: 1 PID: 114 Comm: new_name Tainted: G OE 6.9.0-rc6-gad3c108348fd-dirty #372 > [ 91.051088] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014 > [ 91.051649] RIP: 0010:xp_alloc+0x76/0x240 Ah okay. Didn't account generic (non-ZC) XSk. Will fix in v6. Thanks for the report! > [ 91.051903] Code: 48 89 0a 48 89 00 48 89 40 08 41 c7 44 24 34 00 00 00 00 49 8b 44 24 18 48 05 00 01 00 00 49 89 04 24 49 89 44 24 10 48 8b 3b <f6> 87 64 04 00 00 20 0f 85 16 01 00 00 48 8b 44 24 08 65 48 33 04 > [ 91.053055] RSP: 0018:ffff99e7c00f0b00 EFLAGS: 00010286 > [ 91.053400] RAX: ffff99e7c0c9d100 RBX: ffff89a400901c00 RCX: 0000000000010000 > [ 91.053838] RDX: 0000000000000000 RSI: 0000000000000010 RDI: 0000000000000000 > [ 91.054277] RBP: ffff89a4026e30e0 R08: 0000000000000001 R09: 0000000000009000 > [ 91.054716] R10: 779660ad50f0d4e6 R11: 79b5ce88640fb4f7 R12: ffff89a40c31d870 > [ 91.055156] R13: 0000000000000020 R14: 0000000000000000 R15: ffff89a4068c6000 > [ 91.055596] FS: 00007f87685bef80(0000) GS:ffff89a43bd00000(0000) knlGS:0000000000000000 > [ 91.056090] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 91.056458] CR2: 0000000000000464 CR3: 000000010229c001 CR4: 0000000000770ef0 > [ 91.056904] PKRU: 55555554 > [ 91.057079] Call Trace: > [ 91.057237] <IRQ> > [ 91.057371] ? __die_body+0x1f/0x70 > [ 91.057595] ? page_fault_oops+0x15a/0x460 > [ 91.057852] ? find_held_lock+0x2b/0x80 > [ 91.058093] ? __skb_flow_dissect+0x30f/0x1f10 > [ 91.058374] ? lock_release+0xbd/0x280 > [ 91.058610] ? exc_page_fault+0x67/0x1e0 > [ 91.058859] ? asm_exc_page_fault+0x26/0x30 > [ 91.059126] ? xp_alloc+0x76/0x240 > [ 91.059341] __xsk_rcv+0x1f0/0x360 > [ 91.059558] ? __skb_get_hash+0x5b/0x1f0 > [ 91.059804] ? __skb_get_hash+0x5b/0x1f0 > [ 91.060050] __xsk_map_redirect+0x7c/0x2c0 > [ 91.060315] ? rcu_read_lock_held_common+0x2e/0x50 > [ 91.060622] xdp_do_redirect+0x28f/0x4b0 > [ 91.060871] veth_xdp_rcv_skb+0x29e/0x930 > [ 91.061126] veth_xdp_rcv+0x184/0x290 > [ 91.061358] ? update_load_avg+0x8c/0x8c0 > [ 91.061609] ? select_task_rq_fair+0x1ff/0x15a0 > [ 91.061894] ? place_entity+0x19/0x100 > [ 91.062131] veth_poll+0x6c/0x2f0 > [ 91.062343] ? _raw_spin_unlock_irqrestore+0x27/0x50 > [ 91.062653] ? try_to_wake_up+0x261/0x8d0 > [ 91.062905] ? find_held_lock+0x2b/0x80 > [ 91.063147] __napi_poll+0x27/0x200 > [ 91.063376] net_rx_action+0x172/0x320 > [ 91.063617] __do_softirq+0xb6/0x3a3 > [ 91.063843] ? __dev_direct_xmit+0x167/0x1b0 > [ 91.064114] do_softirq.part.0+0x3b/0x70 > [ 91.064373] </IRQ> > [ 91.064511] <TASK> > [ 91.064650] __local_bh_enable_ip+0xbd/0xe0 > [ 91.064913] __dev_direct_xmit+0x16c/0x1b0 > [ 91.065171] xsk_generic_xmit+0x703/0xb10 > [ 91.065425] xsk_sendmsg+0x21f/0x2f0 Olek
