On Sat, Jun 22, 2024 at 1:58 PM <yskelg@xxxxxxxxx> wrote: > > From: Yunseong Kim <yskelg@xxxxxxxxx> > Hi Yunseong, Thanks a lot for this work! > In the TRACE_EVENT(qdisc_reset) NULL dereference occurred from > > qdisc->dev_queue->dev <NULL> ->name > > This situation simulated from bunch of veths and Bluetooth dis/reconnection. > > During qdisc initialization, qdisc was being set to noop_queue. > In veth_init_queue, the initial tx_num was reduced back to one, > causing the qdisc reset to be called with noop, which led to the kernel panic. > > I've attached the GitHub gist link that C converted syz-execprogram > source code and 3 log of reproduced vmcore-dmesg. > > https://gist.github.com/yskelg/cc64562873ce249cdd0d5a358b77d740 > > Yeoreum and I use two fuzzing tool simultaneously. > > One process with syz-executor : https://github.com/google/syzkaller > > $ ./syz-execprog -executor=./syz-executor -repeat=1 -sandbox=setuid \ > -enable=none -collide=false log1 > > The other process with perf fuzzer: > https://github.com/deater/perf_event_tests/tree/master/fuzzer > > $ perf_event_tests/fuzzer/perf_fuzzer > > I think this will happen on the kernel version. > > Linux kernel version +v6.7.10, +v6.8, +v6.9 and it could happen in v6.10. > > This occurred from 51270d573a8d. I think this patch is absolutely > necessary. Previously, It was showing not intended string value of name. > > I've reproduced 3 time from my fedora 40 Debug Kernel with any other module > or patched. > > version: 6.10.0-0.rc2.20240608gitdc772f8237f9.29.fc41.aarch64+debug > > [ 5287.164555] veth0_vlan: left promiscuous mode > [ 5287.164929] veth1_macvtap: left promiscuous mode > [ 5287.164950] veth0_macvtap: left promiscuous mode > [ 5287.164983] veth1_vlan: left promiscuous mode > [ 5287.165008] veth0_vlan: left promiscuous mode > [ 5287.165450] veth1_macvtap: left promiscuous mode > [ 5287.165472] veth0_macvtap: left promiscuous mode > [ 5287.165502] veth1_vlan: left promiscuous mode > … > [ 5297.598240] bridge0: port 2(bridge_slave_1) entered blocking state > [ 5297.598262] bridge0: port 2(bridge_slave_1) entered forwarding state > [ 5297.598296] bridge0: port 1(bridge_slave_0) entered blocking state > [ 5297.598313] bridge0: port 1(bridge_slave_0) entered forwarding state > [ 5297.616090] 8021q: adding VLAN 0 to HW filter on device bond0 > [ 5297.620405] bridge0: port 1(bridge_slave_0) entered disabled state > [ 5297.620730] bridge0: port 2(bridge_slave_1) entered disabled state > [ 5297.627247] 8021q: adding VLAN 0 to HW filter on device team0 > [ 5297.629636] bridge0: port 1(bridge_slave_0) entered blocking state > … > [ 5298.002798] bridge_slave_0: left promiscuous mode > [ 5298.002869] bridge0: port 1(bridge_slave_0) entered disabled state > [ 5298.309444] bond0 (unregistering): (slave bond_slave_0): Releasing backup interface > [ 5298.315206] bond0 (unregistering): (slave bond_slave_1): Releasing backup interface > [ 5298.320207] bond0 (unregistering): Released all slaves > [ 5298.354296] hsr_slave_0: left promiscuous mode > [ 5298.360750] hsr_slave_1: left promiscuous mode > [ 5298.374889] veth1_macvtap: left promiscuous mode > [ 5298.374931] veth0_macvtap: left promiscuous mode > [ 5298.374988] veth1_vlan: left promiscuous mode > [ 5298.375024] veth0_vlan: left promiscuous mode > [ 5299.109741] team0 (unregistering): Port device team_slave_1 removed > [ 5299.185870] team0 (unregistering): Port device team_slave_0 removed > … > [ 5300.155443] Bluetooth: hci3: unexpected cc 0x0c03 length: 249 > 1 > [ 5300.155724] Bluetooth: hci3: unexpected cc 0x1003 length: 249 > 9 > [ 5300.155988] Bluetooth: hci3: unexpected cc 0x1001 length: 249 > 9 > …. > [ 5301.075531] team0: Port device team_slave_1 added > [ 5301.085515] bridge0: port 1(bridge_slave_0) entered blocking state > [ 5301.085531] bridge0: port 1(bridge_slave_0) entered disabled state > [ 5301.085588] bridge_slave_0: entered allmulticast mode > [ 5301.085800] bridge_slave_0: entered promiscuous mode > [ 5301.095617] bridge0: port 1(bridge_slave_0) entered blocking state > [ 5301.095633] bridge0: port 1(bridge_slave_0) entered disabled state > … > [ 5301.149734] bond0: (slave bond_slave_0): Enslaving as an active interface with an up link > [ 5301.173234] bond0: (slave bond_slave_0): Enslaving as an active interface with an up link > [ 5301.180517] bond0: (slave bond_slave_1): Enslaving as an active interface with an up link > [ 5301.193481] hsr_slave_0: entered promiscuous mode > [ 5301.204425] hsr_slave_1: entered promiscuous mode > [ 5301.210172] debugfs: Directory 'hsr0' with parent 'hsr' already present! > [ 5301.210185] Cannot create hsr debugfs directory > [ 5301.224061] bond0: (slave bond_slave_1): Enslaving as an active interface with an up link > [ 5301.246901] bond0: (slave bond_slave_0): Enslaving as an active interface with an up link > [ 5301.255934] team0: Port device team_slave_0 added > [ 5301.256480] team0: Port device team_slave_1 added > [ 5301.256948] team0: Port device team_slave_0 added > … > [ 5301.435928] hsr_slave_0: entered promiscuous mode > [ 5301.446029] hsr_slave_1: entered promiscuous mode > [ 5301.455872] debugfs: Directory 'hsr0' with parent 'hsr' already present! > [ 5301.455884] Cannot create hsr debugfs directory > [ 5301.502664] hsr_slave_0: entered promiscuous mode > [ 5301.513675] hsr_slave_1: entered promiscuous mode > [ 5301.526155] debugfs: Directory 'hsr0' with parent 'hsr' already present! > [ 5301.526164] Cannot create hsr debugfs directory > [ 5301.563662] hsr_slave_0: entered promiscuous mode > [ 5301.576129] hsr_slave_1: entered promiscuous mode > [ 5301.580259] debugfs: Directory 'hsr0' with parent 'hsr' already present! > [ 5301.580270] Cannot create hsr debugfs directory > [ 5301.590269] 8021q: adding VLAN 0 to HW filter on device bond0 > > [ 5301.595872] KASAN: null-ptr-deref in range [0x0000000000000130-0x0000000000000137] > [ 5301.595877] Mem abort info: > [ 5301.595881] ESR = 0x0000000096000006 > [ 5301.595885] EC = 0x25: DABT (current EL), IL = 32 bits > [ 5301.595889] SET = 0, FnV = 0 > [ 5301.595893] EA = 0, S1PTW = 0 > [ 5301.595896] FSC = 0x06: level 2 translation fault > [ 5301.595900] Data abort info: > [ 5301.595903] ISV = 0, ISS = 0x00000006, ISS2 = 0x00000000 > [ 5301.595907] CM = 0, WnR = 0, TnD = 0, TagAccess = 0 > [ 5301.595911] GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 > [ 5301.595915] [dfff800000000026] address between user and kernel address ranges > [ 5301.595971] Internal error: Oops: 0000000096000006 [#1] SMP > … > [ 5301.596076] CPU: 2 PID: 102769 Comm: > syz-executor.3 Kdump: loaded Tainted: > G W ------- --- 6.10.0-0.rc2.20240608gitdc772f8237f9.29.fc41.aarch64+debug #1 > [ 5301.596080] Hardware name: VMware, Inc. VMware20,1/VBSA, > BIOS VMW201.00V.21805430.BA64.2305221830 05/22/2023 > [ 5301.596082] pstate: 01400005 (nzcv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--) > [ 5301.596085] pc : strnlen+0x40/0x88 > [ 5301.596114] lr : trace_event_get_offsets_qdisc_reset+0x6c/0x2b0 > [ 5301.596124] sp : ffff8000beef6b40 > [ 5301.596126] x29: ffff8000beef6b40 x28: dfff800000000000 x27: 0000000000000001 > [ 5301.596131] x26: 6de1800082c62bd0 x25: 1ffff000110aa9e0 x24: ffff800088554f00 > [ 5301.596136] x23: ffff800088554ec0 x22: 0000000000000130 x21: 0000000000000140 > [ 5301.596140] x20: dfff800000000000 x19: ffff8000beef6c60 x18: ffff7000115106d8 > [ 5301.596143] x17: ffff800121bad000 x16: ffff800080020000 x15: 0000000000000006 > [ 5301.596147] x14: 0000000000000002 x13: ffff0001f3ed8d14 x12: ffff700017ddeda5 > [ 5301.596151] x11: 1ffff00017ddeda4 x10: ffff700017ddeda4 x9 : ffff800082cc5eec > [ 5301.596155] x8 : 0000000000000004 x7 : 00000000f1f1f1f1 x6 : 00000000f2f2f200 > [ 5301.596158] x5 : 00000000f3f3f3f3 x4 : ffff700017dded80 x3 : 00000000f204f1f1 > [ 5301.596162] x2 : 0000000000000026 x1 : 0000000000000000 x0 : 0000000000000130 > [ 5301.596166] Call trace: > [ 5301.596175] strnlen+0x40/0x88 > [ 5301.596179] trace_event_get_offsets_qdisc_reset+0x6c/0x2b0 > [ 5301.596182] perf_trace_qdisc_reset+0xb0/0x538 > [ 5301.596184] __traceiter_qdisc_reset+0x68/0xc0 > [ 5301.596188] qdisc_reset+0x43c/0x5e8 > [ 5301.596190] netif_set_real_num_tx_queues+0x288/0x770 > [ 5301.596194] veth_init_queues+0xfc/0x130 [veth] > [ 5301.596198] veth_newlink+0x45c/0x850 [veth] > [ 5301.596202] rtnl_newlink_create+0x2c8/0x798 > [ 5301.596205] __rtnl_newlink+0x92c/0xb60 > [ 5301.596208] rtnl_newlink+0xd8/0x130 > [ 5301.596211] rtnetlink_rcv_msg+0x2e0/0x890 > [ 5301.596214] netlink_rcv_skb+0x1c4/0x380 > [ 5301.596225] rtnetlink_rcv+0x20/0x38 > [ 5301.596227] netlink_unicast+0x3c8/0x640 > [ 5301.596231] netlink_sendmsg+0x658/0xa60 > [ 5301.596234] __sock_sendmsg+0xd0/0x180 > [ 5301.596243] __sys_sendto+0x1c0/0x280 > [ 5301.596246] __arm64_sys_sendto+0xc8/0x150 > [ 5301.596249] invoke_syscall+0xdc/0x268 > [ 5301.596256] el0_svc_common.constprop.0+0x16c/0x240 > [ 5301.596259] do_el0_svc+0x48/0x68 > [ 5301.596261] el0_svc+0x50/0x188 > [ 5301.596265] el0t_64_sync_handler+0x120/0x130 > [ 5301.596268] el0t_64_sync+0x194/0x198 > [ 5301.596272] Code: eb15001f 54000120 d343fc02 12000801 (38f46842) > [ 5301.596285] SMP: stopping secondary CPUs > [ 5301.597053] Starting crashdump kernel... > [ 5301.597057] Bye! > > Yeoreum and I don't know if the patch we wrote will fix the underlying cause, > but we think that priority is to prevent kernel panic happening. > So, we're sending this patch. > > Link: https://lore.kernel.org/lkml/20240229143432.273b4871@xxxxxxxxxxxxxxxxxx/t/ > Fixes: 51270d573a8d ("tracing/net_sched: Fix tracepoints that save qdisc_dev() as a string") > Cc: netdev@xxxxxxxxxxxxxxx > Cc: stable@xxxxxxxxxxxxxxx # +v6.7.10, +v6.8 > Signed-off-by: Yunseong Kim <yskelg@xxxxxxxxx> > Signed-off-by: Yeoreum Yun <yeoreum.yun@xxxxxxx> > --- > include/trace/events/qdisc.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/include/trace/events/qdisc.h b/include/trace/events/qdisc.h > index f1b5e816e7e5..170b51fbe47a 100644 > --- a/include/trace/events/qdisc.h > +++ b/include/trace/events/qdisc.h > @@ -81,7 +81,7 @@ TRACE_EVENT(qdisc_reset, > TP_ARGS(q), > > TP_STRUCT__entry( > - __string( dev, qdisc_dev(q)->name ) > + __string(dev, qdisc_dev(q) ? qdisc_dev(q)->name : "noop_queue") > __string( kind, q->ops->id ) > __field( u32, parent ) > __field( u32, handle ) > -- > 2.45.2 > I found a simple reproducer, please use the below command to test this patch. echo 1 > /sys/kernel/debug/tracing/events/enable ip link add veth0 type veth peer name veth1 In my machine, the splat looks like: BUG: kernel NULL pointer dereference, address: 0000000000000130 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: Oops: 0000 [#1] PREEMPT SMP NOPTI CPU: 1 PID: 1207 Comm: ip Not tainted 6.10.0-rc4+ #25 362ec22a686962a9936425abea9a73f03b445c0c Hardware name: ASUS System Product Name/PRIME Z690-P D4, BIOS 0603 11/01/2021 RIP: 0010:strlen+0x0/0x20 Code: f7 75 ec 31 c0 c3 cc cc cc cc 48 89 f8 c3 cc cc cc cc 0f 1f 84 00 00 00 00 00 90 90 90 90 9c RSP: 0018:ffffbed8435c7630 EFLAGS: 00010206 RAX: ffffffff92d629c0 RBX: ffffa14100185c60 RCX: 0000000000000000 RDX: 0000000000000001 RSI: ffffffff92d62840 RDI: 0000000000000130 RBP: ffffffff92dc4600 R08: 0000000000000fd0 R09: 0000000000000010 R10: ffffffff92c66c98 R11: 0000000000000001 R12: 0000000000000001 R13: 0000000000000000 R14: 0000000000000130 R15: ffffffff92d62840 FS: 00007f6a94e50b80(0000) GS:ffffa1485f680000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000130 CR3: 0000000103414000 CR4: 00000000007506f0 PKRU: 55555554 Call Trace: <TASK> ? __die+0x20/0x70 ? page_fault_oops+0x15a/0x460 ? trace_event_raw_event_x86_exceptions+0x5f/0xa0 ? exc_page_fault+0x6e/0x180 ? asm_exc_page_fault+0x22/0x30 ? __pfx_strlen+0x10/0x10 trace_event_raw_event_qdisc_reset+0x4d/0x180 ? synchronize_rcu_expedited+0x215/0x240 ? __pfx_autoremove_wake_function+0x10/0x10 qdisc_reset+0x130/0x150 netif_set_real_num_tx_queues+0xe3/0x1e0 veth_init_queues+0x44/0x70 [veth 24a9dd1cd1b1b279e1b467ad46d47a753799b428] veth_newlink+0x22b/0x440 [veth 24a9dd1cd1b1b279e1b467ad46d47a753799b428] __rtnl_newlink+0x718/0x990 rtnl_newlink+0x44/0x70 rtnetlink_rcv_msg+0x159/0x410 ? kmalloc_reserve+0x90/0xf0 ? trace_event_raw_event_kmem_cache_alloc+0x87/0xe0 ? __pfx_rtnetlink_rcv_msg+0x10/0x10 netlink_rcv_skb+0x54/0x100 netlink_unicast+0x243/0x370 netlink_sendmsg+0x1bb/0x3e0 ____sys_sendmsg+0x2bb/0x320 ? copy_msghdr_from_user+0x6d/0xa0 ___sys_sendmsg+0x88/0xd0 Thanks a lot! Taehee Yoo
