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Message-ID: <89643ab3-1950-4493-9993-3dd3d710be45@amd.com>
Date: Wed, 12 Jun 2024 08:36:47 -0700
From: Brett Creeley <bcreeley@....com>
To: Taehee Yoo <ap420073@...il.com>, davem@...emloft.net, kuba@...nel.org,
pabeni@...hat.com, edumazet@...gle.com, shannon.nelson@....com,
brett.creeley@....com, drivers@...sando.io, netdev@...r.kernel.org
Cc: jacob.e.keller@...el.com
Subject: Re: [PATCH net v2] ionic: fix use after netif_napi_del()
On 6/11/2024 11:04 PM, Taehee Yoo wrote:
> Caution: This message originated from an External Source. Use proper caution when opening attachments, clicking links, or responding.
>
>
> When queues are started, netif_napi_add() and napi_enable() are called.
> If there are 4 queues and only 3 queues are used for the current
> configuration, only 3 queues' napi should be registered and enabled.
> The ionic_qcq_enable() checks whether the .poll pointer is not NULL for
> enabling only the using queue' napi. Unused queues' napi will not be
> registered by netif_napi_add(), so the .poll pointer indicates NULL.
> But it couldn't distinguish whether the napi was unregistered or not
> because netif_napi_del() doesn't reset the .poll pointer to NULL.
> So, ionic_qcq_enable() calls napi_enable() for the queue, which was
> unregistered by netif_napi_del().
>
> Reproducer:
> ethtool -L <interface name> rx 1 tx 1 combined 0
> ethtool -L <interface name> rx 0 tx 0 combined 1
> ethtool -L <interface name> rx 0 tx 0 combined 4
>
> Splat looks like:
> kernel BUG at net/core/dev.c:6666!
> Oops: invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
> CPU: 3 PID: 1057 Comm: kworker/3:3 Not tainted 6.10.0-rc2+ #16
> Workqueue: events ionic_lif_deferred_work [ionic]
> RIP: 0010:napi_enable+0x3b/0x40
> Code: 48 89 c2 48 83 e2 f6 80 b9 61 09 00 00 00 74 0d 48 83 bf 60 01 00 00 00 74 03 80 ce 01 f0 4f
> RSP: 0018:ffffb6ed83227d48 EFLAGS: 00010246
> RAX: 0000000000000000 RBX: ffff97560cda0828 RCX: 0000000000000029
> RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffff97560cda0a28
> RBP: ffffb6ed83227d50 R08: 0000000000000400 R09: 0000000000000001
> R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000000
> R13: ffff97560ce3c1a0 R14: 0000000000000000 R15: ffff975613ba0a20
> FS: 0000000000000000(0000) GS:ffff975d5f780000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007f8f734ee200 CR3: 0000000103e50000 CR4: 00000000007506f0
> PKRU: 55555554
> Call Trace:
> <TASK>
> ? die+0x33/0x90
> ? do_trap+0xd9/0x100
> ? napi_enable+0x3b/0x40
> ? do_error_trap+0x83/0xb0
> ? napi_enable+0x3b/0x40
> ? napi_enable+0x3b/0x40
> ? exc_invalid_op+0x4e/0x70
> ? napi_enable+0x3b/0x40
> ? asm_exc_invalid_op+0x16/0x20
> ? napi_enable+0x3b/0x40
> ionic_qcq_enable+0xb7/0x180 [ionic 59bdfc8a035436e1c4224ff7d10789e3f14643f8]
> ionic_start_queues+0xc4/0x290 [ionic 59bdfc8a035436e1c4224ff7d10789e3f14643f8]
> ionic_link_status_check+0x11c/0x170 [ionic 59bdfc8a035436e1c4224ff7d10789e3f14643f8]
> ionic_lif_deferred_work+0x129/0x280 [ionic 59bdfc8a035436e1c4224ff7d10789e3f14643f8]
> process_one_work+0x145/0x360
> worker_thread+0x2bb/0x3d0
> ? __pfx_worker_thread+0x10/0x10
> kthread+0xcc/0x100
> ? __pfx_kthread+0x10/0x10
> ret_from_fork+0x2d/0x50
> ? __pfx_kthread+0x10/0x10
> ret_from_fork_asm+0x1a/0x30
>
> Fixes: 0f3154e6bcb3 ("ionic: Add Tx and Rx handling")
> Signed-off-by: Taehee Yoo <ap420073@...il.com>
> ---
> v2:
> - Use ionic flag instead of napi flag.
>
> drivers/net/ethernet/pensando/ionic/ionic_lif.c | 4 +---
> 1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/drivers/net/ethernet/pensando/ionic/ionic_lif.c b/drivers/net/ethernet/pensando/ionic/ionic_lif.c
> index 24870da3f484..1934e9d6d9e4 100644
> --- a/drivers/net/ethernet/pensando/ionic/ionic_lif.c
> +++ b/drivers/net/ethernet/pensando/ionic/ionic_lif.c
> @@ -304,10 +304,8 @@ static int ionic_qcq_enable(struct ionic_qcq *qcq)
> if (ret)
> return ret;
>
> - if (qcq->napi.poll)
> - napi_enable(&qcq->napi);
> -
> if (qcq->flags & IONIC_QCQ_F_INTR) {
> + napi_enable(&qcq->napi);
LGTM. Thanks for finding/fixing this!
Reviewed-by: Brett Creeley <brett.creeley@....com>
> irq_set_affinity_hint(qcq->intr.vector,
> &qcq->intr.affinity_mask);
> ionic_intr_mask(idev->intr_ctrl, qcq->intr.index,
> --
> 2.34.1
>
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