kernel/linux.git/drivers/net/xen-netback, branch v5.19

xen/netback: avoid entering xenvif_rx_next_skb() with an empty rx queue

2022-07-14T17:12:12+00:00

xenvif_rx_next_skb() is expecting the rx queue not being empty, but in case the loop in xenvif_rx_action() is doing multiple iterations, the availability of another skb in the rx queue is not being checked. This can lead to crashes: [40072.537261] BUG: unable to handle kernel NULL pointer dereference at 0000000000000080 [40072.537407] IP: xenvif_rx_skb+0x23/0x590 [xen_netback] [40072.537534] PGD 0 P4D 0 [40072.537644] Oops: 0000 [#1] SMP NOPTI [40072.537749] CPU: 0 PID: 12505 Comm: v1-c40247-q2-gu Not tainted 4.12.14-122.121-default #1 SLE12-SP5 [40072.537867] Hardware name: HP ProLiant DL580 Gen9/ProLiant DL580 Gen9, BIOS U17 11/23/2021 [40072.537999] task: ffff880433b38100 task.stack: ffffc90043d40000 [40072.538112] RIP: e030:xenvif_rx_skb+0x23/0x590 [xen_netback] [40072.538217] RSP: e02b:ffffc90043d43de0 EFLAGS: 00010246 [40072.538319] RAX: 0000000000000000 RBX: ffffc90043cd7cd0 RCX: 00000000000000f7 [40072.538430] RDX: 0000000000000000 RSI: 0000000000000006 RDI: ffffc90043d43df8 [40072.538531] RBP: 000000000000003f R08: 000077ff80000000 R09: 0000000000000008 [40072.538644] R10: 0000000000007ff0 R11: 00000000000008f6 R12: ffffc90043ce2708 [40072.538745] R13: 0000000000000000 R14: ffffc90043d43ed0 R15: ffff88043ea748c0 [40072.538861] FS: 0000000000000000(0000) GS:ffff880484600000(0000) knlGS:0000000000000000 [40072.538988] CS: e033 DS: 0000 ES: 0000 CR0: 0000000080050033 [40072.539088] CR2: 0000000000000080 CR3: 0000000407ac8000 CR4: 0000000000040660 [40072.539211] Call Trace: [40072.539319] xenvif_rx_action+0x71/0x90 [xen_netback] [40072.539429] xenvif_kthread_guest_rx+0x14a/0x29c [xen_netback] Fix that by stopping the loop in case the rx queue becomes empty. Cc: stable@vger.kernel.org Fixes: 98f6d57ced73 ("xen-netback: process guest rx packets in batches") Signed-off-by: Juergen Gross Reviewed-by: Jan Beulich Reviewed-by: Paul Durrant Link: https://lore.kernel.org/r/20220713135322.19616-1-jgross@suse.com Signed-off-by: Jakub Kicinski

xen/netback: fix incorrect usage of RING_HAS_UNCONSUMED_REQUESTS()

2022-05-31T10:22:22+00:00

Commit 6fac592cca60 ("xen: update ring.h") missed to fix one use case of RING_HAS_UNCONSUMED_REQUESTS(). Reported-by: Jan Beulich Fixes: 6fac592cca60 ("xen: update ring.h") Signed-off-by: Juergen Gross Reviewed-by: Jan Beulich Acked-by: Wei Liu Link: https://lore.kernel.org/r/20220530113459.20124-1-jgross@suse.com Signed-off-by: Paolo Abeni

eth: remove copies of the NAPI_POLL_WEIGHT define

2022-04-29T10:56:41+00:00

Defining local versions of NAPI_POLL_WEIGHT with the same values in the drivers just makes refactoring harder. Drop the special defines in a bunch of drivers where the removal is relatively simple so grouping into one patch does not impact reviewability. Signed-off-by: Jakub Kicinski Reviewed-by: Paul Durrant Signed-off-by: David S. Miller

Revert "xen-netback: Check for hotplug-status existence before watching"

2022-02-24T16:58:37+00:00

This reverts commit 2afeec08ab5c86ae21952151f726bfe184f6b23d. The reasoning in the commit was wrong - the code expected to setup the watch even if 'hotplug-status' didn't exist. In fact, it relied on the watch being fired the first time - to check if maybe 'hotplug-status' is already set to 'connected'. Not registering a watch for non-existing path (which is the case if hotplug script hasn't been executed yet), made the backend not waiting for the hotplug script to execute. This in turns, made the netfront think the interface is fully operational, while in fact it was not (the vif interface on xen-netback side might not be configured yet). This was a workaround for 'hotplug-status' erroneously being removed. But since that is reverted now, the workaround is not necessary either. More discussion at https://lore.kernel.org/xen-devel/afedd7cb-a291-e773-8b0d-4db9b291fa98@ipxe.org/T/#u Signed-off-by: Marek Marczykowski-Górecki Reviewed-by: Paul Durrant Reviewed-by: Michael Brown Link: https://lore.kernel.org/r/20220222001817.2264967-2-marmarek@invisiblethingslab.com Signed-off-by: Jakub Kicinski

Revert "xen-netback: remove 'hotplug-status' once it has served its purpose"

2022-02-24T16:58:37+00:00

This reverts commit 1f2565780e9b7218cf92c7630130e82dcc0fe9c2. The 'hotplug-status' node should not be removed as long as the vif device remains configured. Otherwise the xen-netback would wait for re-running the network script even if it was already called (in case of the frontent re-connecting). But also, it _should_ be removed when the vif device is destroyed (for example when unbinding the driver) - otherwise hotplug script would not configure the device whenever it re-appear. Moving removal of the 'hotplug-status' node was a workaround for nothing calling network script after xen-netback module is reloaded. But when vif interface is re-created (on xen-netback unbind/bind for example), the script should be called, regardless of who does that - currently this case is not handled by the toolstack, and requires manual script call. Keeping hotplug-status=connected to skip the call is wrong and leads to not configured interface. More discussion at https://lore.kernel.org/xen-devel/afedd7cb-a291-e773-8b0d-4db9b291fa98@ipxe.org/T/#u Signed-off-by: Marek Marczykowski-Górecki Reviewed-by: Paul Durrant Link: https://lore.kernel.org/r/20220222001817.2264967-1-marmarek@invisiblethingslab.com Signed-off-by: Jakub Kicinski

xen/netback: don't queue unlimited number of packages

2021-12-16T07:43:12+00:00

In case a guest isn't consuming incoming network traffic as fast as it is coming in, xen-netback is buffering network packages in unlimited numbers today. This can result in host OOM situations. Commit f48da8b14d04ca8 ("xen-netback: fix unlimited guest Rx internal queue and carrier flapping") meant to introduce a mechanism to limit the amount of buffered data by stopping the Tx queue when reaching the data limit, but this doesn't work for cases like UDP. When hitting the limit don't queue further SKBs, but drop them instead. In order to be able to tell Rx packages have been dropped increment the rx_dropped statistics counter in this case. It should be noted that the old solution to continue queueing SKBs had the additional problem of an overflow of the 32-bit rx_queue_len value would result in intermittent Tx queue enabling. This is part of XSA-392 Fixes: f48da8b14d04ca8 ("xen-netback: fix unlimited guest Rx internal queue and carrier flapping") Signed-off-by: Juergen Gross Reviewed-by: Jan Beulich

xen/netback: fix rx queue stall detection

2021-12-16T07:42:56+00:00

Commit 1d5d48523900a4b ("xen-netback: require fewer guest Rx slots when not using GSO") introduced a security problem in netback, as an interface would only be regarded to be stalled if no slot is available in the rx queue ring page. In case the SKB at the head of the queued requests will need more than one rx slot and only one slot is free the stall detection logic will never trigger, as the test for that is only looking for at least one slot to be free. Fix that by testing for the needed number of slots instead of only one slot being available. In order to not have to take the rx queue lock that often, store the number of needed slots in the queue data. As all SKB dequeue operations happen in the rx queue kernel thread this is safe, as long as the number of needed slots is accessed via READ/WRITE_ONCE() only and updates are always done with the rx queue lock held. Add a small helper for obtaining the number of free slots. This is part of XSA-392 Fixes: 1d5d48523900a4b ("xen-netback: require fewer guest Rx slots when not using GSO") Signed-off-by: Juergen Gross Reviewed-by: Jan Beulich

net: xen: use eth_hw_addr_set()

2021-10-22T17:15:54+00:00

Commit 406f42fa0d3c ("net-next: When a bond have a massive amount of VLANs...") introduced a rbtree for faster Ethernet address look up. To maintain netdev->dev_addr in this tree we need to make all the writes to it got through appropriate helpers. Signed-off-by: Jakub Kicinski

xen-netback: Remove redundant initialization of variable err

2021-10-15T10:02:36+00:00

The variable err is being initialized with a value that is never read, it is being updated immediately afterwards. The assignment is redundant and can be removed. Addresses-Coverity: ("Unused value") Signed-off-by: Colin Ian King Signed-off-by: David S. Miller

xen-netback: correct success/error reporting for the SKB-with-fraglist case

2021-09-19T11:10:26+00:00

When re-entering the main loop of xenvif_tx_check_gop() a 2nd time, the special considerations for the head of the SKB no longer apply. Don't mistakenly report ERROR to the frontend for the first entry in the list, even if - from all I can tell - this shouldn't matter much as the overall transmit will need to be considered failed anyway. Signed-off-by: Jan Beulich Reviewed-by: Paul Durrant Signed-off-by: David S. Miller