From: Greg Kroah-Hartman Date: Sat, 5 Mar 2022 14:51:58 +0000 (+0100) Subject: 4.19-stable patches X-Git-Tag: v4.9.305~59 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=0728e5c9c5c781b64574fb1936843ea401f117b4;p=thirdparty%2Fkernel%2Fstable-queue.git 4.19-stable patches added patches: xen-netfront-destroy-queues-before-real_num_tx_queues-is-zeroed.patch --- diff --git a/queue-4.19/series b/queue-4.19/series index 23bf700bcde..cb8f0ac8d7f 100644 --- a/queue-4.19/series +++ b/queue-4.19/series @@ -28,3 +28,4 @@ net-smc-fix-unexpected-smc_clc_decl_err_regrmb-error-generated-by-client.patch net-smc-fix-unexpected-smc_clc_decl_err_regrmb-error-cause-by-server.patch block-fix-fsync-always-failed-if-once-failed.patch pci-pciehp-fix-infinite-loop-in-irq-handler-upon-power-fault.patch +xen-netfront-destroy-queues-before-real_num_tx_queues-is-zeroed.patch diff --git a/queue-4.19/xen-netfront-destroy-queues-before-real_num_tx_queues-is-zeroed.patch b/queue-4.19/xen-netfront-destroy-queues-before-real_num_tx_queues-is-zeroed.patch new file mode 100644 index 00000000000..35c227e2113 --- /dev/null +++ b/queue-4.19/xen-netfront-destroy-queues-before-real_num_tx_queues-is-zeroed.patch @@ -0,0 +1,138 @@ +From dcf4ff7a48e7598e6b10126cc02177abb8ae4f3f Mon Sep 17 00:00:00 2001 +From: =?UTF-8?q?Marek=20Marczykowski-G=C3=B3recki?= + +Date: Wed, 23 Feb 2022 22:19:54 +0100 +Subject: xen/netfront: destroy queues before real_num_tx_queues is zeroed +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +From: Marek Marczykowski-Górecki + +commit dcf4ff7a48e7598e6b10126cc02177abb8ae4f3f upstream. + +xennet_destroy_queues() relies on info->netdev->real_num_tx_queues to +delete queues. Since d7dac083414eb5bb99a6d2ed53dc2c1b405224e5 +("net-sysfs: update the queue counts in the unregistration path"), +unregister_netdev() indirectly sets real_num_tx_queues to 0. Those two +facts together means, that xennet_destroy_queues() called from +xennet_remove() cannot do its job, because it's called after +unregister_netdev(). This results in kfree-ing queues that are still +linked in napi, which ultimately crashes: + + BUG: kernel NULL pointer dereference, address: 0000000000000000 + #PF: supervisor read access in kernel mode + #PF: error_code(0x0000) - not-present page + PGD 0 P4D 0 + Oops: 0000 [#1] PREEMPT SMP PTI + CPU: 1 PID: 52 Comm: xenwatch Tainted: G W 5.16.10-1.32.fc32.qubes.x86_64+ #226 + RIP: 0010:free_netdev+0xa3/0x1a0 + Code: ff 48 89 df e8 2e e9 00 00 48 8b 43 50 48 8b 08 48 8d b8 a0 fe ff ff 48 8d a9 a0 fe ff ff 49 39 c4 75 26 eb 47 e8 ed c1 66 ff <48> 8b 85 60 01 00 00 48 8d 95 60 01 00 00 48 89 ef 48 2d 60 01 00 + RSP: 0000:ffffc90000bcfd00 EFLAGS: 00010286 + RAX: 0000000000000000 RBX: ffff88800edad000 RCX: 0000000000000000 + RDX: 0000000000000001 RSI: ffffc90000bcfc30 RDI: 00000000ffffffff + RBP: fffffffffffffea0 R08: 0000000000000000 R09: 0000000000000000 + R10: 0000000000000000 R11: 0000000000000001 R12: ffff88800edad050 + R13: ffff8880065f8f88 R14: 0000000000000000 R15: ffff8880066c6680 + FS: 0000000000000000(0000) GS:ffff8880f3300000(0000) knlGS:0000000000000000 + CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 + CR2: 0000000000000000 CR3: 00000000e998c006 CR4: 00000000003706e0 + Call Trace: + + xennet_remove+0x13d/0x300 [xen_netfront] + xenbus_dev_remove+0x6d/0xf0 + __device_release_driver+0x17a/0x240 + device_release_driver+0x24/0x30 + bus_remove_device+0xd8/0x140 + device_del+0x18b/0x410 + ? _raw_spin_unlock+0x16/0x30 + ? klist_iter_exit+0x14/0x20 + ? xenbus_dev_request_and_reply+0x80/0x80 + device_unregister+0x13/0x60 + xenbus_dev_changed+0x18e/0x1f0 + xenwatch_thread+0xc0/0x1a0 + ? do_wait_intr_irq+0xa0/0xa0 + kthread+0x16b/0x190 + ? set_kthread_struct+0x40/0x40 + ret_from_fork+0x22/0x30 + + +Fix this by calling xennet_destroy_queues() from xennet_uninit(), +when real_num_tx_queues is still available. This ensures that queues are +destroyed when real_num_tx_queues is set to 0, regardless of how +unregister_netdev() was called. + +Originally reported at +https://github.com/QubesOS/qubes-issues/issues/7257 + +Fixes: d7dac083414eb5bb9 ("net-sysfs: update the queue counts in the unregistration path") +Cc: stable@vger.kernel.org +Signed-off-by: Marek Marczykowski-Górecki +Signed-off-by: David S. Miller +Signed-off-by: Greg Kroah-Hartman +--- + drivers/net/xen-netfront.c | 39 +++++++++++++++++++++++---------------- + 1 file changed, 23 insertions(+), 16 deletions(-) + +--- a/drivers/net/xen-netfront.c ++++ b/drivers/net/xen-netfront.c +@@ -764,6 +764,28 @@ static int xennet_close(struct net_devic + return 0; + } + ++static void xennet_destroy_queues(struct netfront_info *info) ++{ ++ unsigned int i; ++ ++ for (i = 0; i < info->netdev->real_num_tx_queues; i++) { ++ struct netfront_queue *queue = &info->queues[i]; ++ ++ if (netif_running(info->netdev)) ++ napi_disable(&queue->napi); ++ netif_napi_del(&queue->napi); ++ } ++ ++ kfree(info->queues); ++ info->queues = NULL; ++} ++ ++static void xennet_uninit(struct net_device *dev) ++{ ++ struct netfront_info *np = netdev_priv(dev); ++ xennet_destroy_queues(np); ++} ++ + static void xennet_set_rx_rsp_cons(struct netfront_queue *queue, RING_IDX val) + { + unsigned long flags; +@@ -1376,6 +1398,7 @@ static void xennet_poll_controller(struc + #endif + + static const struct net_device_ops xennet_netdev_ops = { ++ .ndo_uninit = xennet_uninit, + .ndo_open = xennet_open, + .ndo_stop = xennet_close, + .ndo_start_xmit = xennet_start_xmit, +@@ -1863,22 +1886,6 @@ error: + return err; + } + +-static void xennet_destroy_queues(struct netfront_info *info) +-{ +- unsigned int i; +- +- for (i = 0; i < info->netdev->real_num_tx_queues; i++) { +- struct netfront_queue *queue = &info->queues[i]; +- +- if (netif_running(info->netdev)) +- napi_disable(&queue->napi); +- netif_napi_del(&queue->napi); +- } +- +- kfree(info->queues); +- info->queues = NULL; +-} +- + static int xennet_create_queues(struct netfront_info *info, + unsigned int *num_queues) + {