From 7e972fe242240973536d3db55301f0c33ca2fa6b Mon Sep 17 00:00:00 2001 From: Robert Marko Date: Mon, 30 Sep 2024 12:13:42 +0200 Subject: [PATCH] generic: backport ("net: free_netdev: exit earlier if dummy") Currently, when removing ath11k or any other driver that uses dummy netdev kernel will crash with: [ 365.004961] ------------[ cut here ]------------ [ 365.004992] kernel BUG at net/core/dev.c:10979! [ 365.008642] Internal error: Oops - BUG: 00000000f2000800 [#1] SMP [ 365.012898] Modules linked in: pppoe ppp_async nft_fib_inet nf_flow_table_inet ath11k_ahb(O) ath11k(O) pppox ppp_generic nft_reject_ipv6 nft_reject_ipv4 nft_reject_inet nft_reject nft_redir nft_quota nft_numgen nft_nat nft_masq nft_log nft_limit nft_hash nft_flow_offload nft_fib_c [ 365.064794] CPU: 3 PID: 3896 Comm: procd Tainted: G O 6.6.52 #0 [ 365.087031] Hardware name: QNAP 301w (DT) [ 365.094058] pstate: 20400005 (nzCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 365.098229] pc : free_netdev+0x164/0x1a0 [ 365.104994] lr : free_netdev+0xec/0x1a0 [ 365.109159] sp : ffffffc081d33b90 [ 365.112718] x29: ffffffc081d33b90 x28: ffffff80039d3c00 x27: ffffff800307f000 [ 365.116199] x26: ffffff800538a000 x25: ffffff8005388000 x24: ffffff800538a4c0 [ 365.123317] x23: 00000000000023a4 x22: ffffff8005388f68 x21: ffffff8004e37050 [ 365.130434] x20: ffffff8004e37000 x19: ffffff8004e36ee8 x18: 0000000000000152 [ 365.137552] x17: 63775f357636712e x16: 3030303030646320 x15: ffffffc081436e20 [ 365.144670] x14: ffffff80033f261c x13: 00000000000000d9 x12: 0000000000000002 [ 365.151789] x11: 0000000000000000 x10: 00000000000008a0 x9 : ffffffc081d33980 [ 365.158906] x8 : ffffff80039d4500 x7 : ffffff803fdda6c0 x6 : 0000000000000007 [ 365.166025] x5 : 0000000000000000 x4 : 00000000000000c1 x3 : 00000000000001f4 [ 365.173143] x2 : ffffff803fdd4b78 x1 : ffffff8004e37050 x0 : 0000000000000005 [ 365.180261] Call trace: [ 365.187370] free_netdev+0x164/0x1a0 [ 365.189630] 0xffffffc079b373f0 [ 365.193447] 0xffffffc079b374c0 [ 365.196311] platform_shutdown+0x24/0x34 [ 365.199438] device_shutdown+0x160/0x268 [ 365.203605] kernel_restart+0x40/0xc0 [ 365.207510] __do_sys_reboot+0x104/0x220 [ 365.211070] __arm64_sys_reboot+0x24/0x30 [ 365.215063] invoke_syscall.constprop.0+0x5c/0x108 [ 365.218971] do_el0_svc+0x40/0xc8 [ 365.223655] el0_svc+0x30/0xb8 [ 365.227041] el0t_64_sync_handler+0x120/0x12c [ 365.229995] el0t_64_sync+0x178/0x17c [ 365.234424] Code: f94013f5 a8c37bfd d50323bf d65f03c0 (d4210000) [ 365.238072] ---[ end trace 0000000000000000 ]--- Wireless backports include alloc_netdev_dummy() backport but they dont have the required free_netdev change first, so backport it. Fixes: #16531 Fixes: 384d079fd876 ("mac80211: update to version 6.11") Link: https://github.com/openwrt/openwrt/pull/16549 Signed-off-by: Robert Marko --- ...et-free_netdev-exit-earlier-if-dummy.patch | 35 +++++++++++++++++++ 1 file changed, 35 insertions(+) create mode 100644 target/linux/generic/backport-6.6/900-v6.11-net-free_netdev-exit-earlier-if-dummy.patch diff --git a/target/linux/generic/backport-6.6/900-v6.11-net-free_netdev-exit-earlier-if-dummy.patch b/target/linux/generic/backport-6.6/900-v6.11-net-free_netdev-exit-earlier-if-dummy.patch new file mode 100644 index 0000000000..31beb11d54 --- /dev/null +++ b/target/linux/generic/backport-6.6/900-v6.11-net-free_netdev-exit-earlier-if-dummy.patch @@ -0,0 +1,35 @@ +From f8d05679fb3faae478d604177b0c188b340371cd Mon Sep 17 00:00:00 2001 +From: Breno Leitao +Date: Mon, 22 Apr 2024 05:38:55 -0700 +Subject: [PATCH] net: free_netdev: exit earlier if dummy + +For dummy devices, exit earlier at free_netdev() instead of executing +the whole function. This is necessary, because dummy devices are +special, and shouldn't have the second part of the function executed. + +Otherwise reg_state, which is NETREG_DUMMY, will be overwritten and +there will be no way to identify that this is a dummy device. Also, this +device do not need the final put_device(), since dummy devices are not +registered (through register_netdevice()), where the device reference is +increased (at netdev_register_kobject()/device_add()). + +Suggested-by: Jakub Kicinski +Signed-off-by: Breno Leitao +Reviewed-by: Ido Schimmel +Signed-off-by: David S. Miller +--- + net/core/dev.c | 3 ++- + 1 file changed, 2 insertions(+), 1 deletion(-) + +--- a/net/core/dev.c ++++ b/net/core/dev.c +@@ -10966,7 +10966,8 @@ void free_netdev(struct net_device *dev) + dev->xdp_bulkq = NULL; + + /* Compatibility with error handling in drivers */ +- if (dev->reg_state == NETREG_UNINITIALIZED) { ++ if (dev->reg_state == NETREG_UNINITIALIZED || ++ dev->reg_state == NETREG_DUMMY) { + netdev_freemem(dev); + return; + } -- 2.30.2