In the Linux kernel, the following vulnerability has been resolved:
ice: xsk: disable txq irq before flushing hw
ice_qp_dis() intends to stop a given queue pair that is a target of xsk
pool attach/detach. One of the steps is to disable interrupts on these
queues. It currently is broken in a way that txq irq is turned off
*after* HW flush which in turn takes no effect.
ice_qp_dis():
-> ice_qvec_dis_irq()
--> disable rxq irq
--> flush hw
-> ice_vsi_stop_tx_ring()
-->disable txq irq
Below splat can be triggered by following steps:
- start xdpsock WITHOUT loading xdp prog
- run xdp_rxq_info with XDP_TX action on this interface
- start traffic
- terminate xdpsock
[ 256.312485] BUG: kernel NULL pointer dereference, address: 0000000000000018
[ 256.319560] #PF: supervisor read access in kernel mode
[ 256.324775] #PF: error_code(0x0000) - not-present page
[ 256.329994] PGD 0 P4D 0
[ 256.332574] Oops: 0000 [#1] PREEMPT SMP NOPTI
[ 256.337006] CPU: 3 PID: 32 Comm: ksoftirqd/3 Tainted: G OE 6.2.0-rc5+ #51
[ 256.345218] Hardware name: Intel Corporation S2600WFT/S2600WFT, BIOS SE5C620.86B.02.01.0008.031920191559 03/19/2019
[ 256.355807] RIP: 0010:ice_clean_rx_irq_zc+0x9c/0x7d0 [ice]
[ 256.361423] Code: b7 8f 8a 00 00 00 66 39 ca 0f 84 f1 04 00 00 49 8b 47 40 4c 8b 24 d0 41 0f b7 45 04 66 25 ff 3f 66 89 04 24 0f 84 85 02 00 00 <49> 8b 44 24 18 0f b7 14 24 48 05 00 01 00 00 49 89 04 24 49 89 44
[ 256.380463] RSP: 0018:ffffc900088bfd20 EFLAGS: 00010206
[ 256.385765] RAX: 000000000000003c RBX: 0000000000000035 RCX: 000000000000067f
[ 256.393012] RDX: 0000000000000775 RSI: 0000000000000000 RDI: ffff8881deb3ac80
[ 256.400256] RBP: 000000000000003c R08: ffff889847982710 R09: 0000000000010000
[ 256.407500] R10: ffffffff82c060c0 R11: 0000000000000004 R12: 0000000000000000
[ 256.414746] R13: ffff88811165eea0 R14: ffffc9000d255000 R15: ffff888119b37600
[ 256.421990] FS: 0000000000000000(0000) GS:ffff8897e0cc0000(0000) knlGS:0000000000000000
[ 256.430207] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 256.436036] CR2: 0000000000000018 CR3: 0000000005c0a006 CR4: 00000000007706e0
[ 256.443283] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 256.450527] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 256.457770] PKRU: 55555554
[ 256.460529] Call Trace:
[ 256.463015] <TASK>
[ 256.465157] ? ice_xmit_zc+0x6e/0x150 [ice]
[ 256.469437] ice_napi_poll+0x46d/0x680 [ice]
[ 256.473815] ? _raw_spin_unlock_irqrestore+0x1b/0x40
[ 256.478863] __napi_poll+0x29/0x160
[ 256.482409] net_rx_action+0x136/0x260
[ 256.486222] __do_softirq+0xe8/0x2e5
[ 256.489853] ? smpboot_thread_fn+0x2c/0x270
[ 256.494108] run_ksoftirqd+0x2a/0x50
[ 256.497747] smpboot_thread_fn+0x1c1/0x270
[ 256.501907] ? __pfx_smpboot_thread_fn+0x10/0x10
[ 256.506594] kthread+0xea/0x120
[ 256.509785] ? __pfx_kthread+0x10/0x10
[ 256.513597] ret_from_fork+0x29/0x50
[ 256.517238] </TASK>
In fact, irqs were not disabled and napi managed to be scheduled and run
while xsk_pool pointer was still valid, but SW ring of xdp_buff pointers
was already freed.
To fix this, call ice_qvec_dis_irq() after ice_vsi_stop_tx_ring(). Also
while at it, remove redundant ice_clean_rx_ring() call - this is handled
in ice_qp_clean_rings().
Publication date: Fri, 02 May 2025 15:55:00 +0000