Hi Paolo,
On 6/27/24 6:14 오후, Paolo Abeni wrote:
On Tue, 2024-06-25 at 02:33 +0900, yskelg@gmail.com wrote:
From: Yunseong Kim yskelg@gmail.com
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 disconnection and 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
[ 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!
After applying our patch, I didn't find any kernel panic errors.
We've found a simple reproducer
# echo 1 > /sys/kernel/debug/tracing/events/qdisc/qdisc_reset/enable
# ip link add veth0 type veth peer name veth1
Error: Unknown device type.
Fixes: 51270d573a8d ("tracing/net_sched: Fix tracepoints that save qdisc_dev() as a string") Link: https://lore.kernel.org/lkml/20240229143432.273b4871@gandalf.local.home/t/ Cc: netdev@vger.kernel.org Cc: stable@vger.kernel.org # +v6.7.10, +v6.8 Tested-by: Yunseong Kim yskelg@gmail.com Signed-off-by: Yunseong Kim yskelg@gmail.com Signed-off-by: Yeoreum Yun yeoreum.yun@arm.com
I took the liberty of dropping the stable tag when applying, because as noted from Petro this patch will not address the issue on v6.7.10 nor on +v6.8, as they lack the upstream commit 2c92ca849fcc ("tracing/treewide: Remove second parameter of __assign_str()") and a we need slightly different fix on such trees, including the TP_fast_assign() chunk.
Could you please take care of such backport?
Thanks,
Paolo
Thank you Paolo for your hard work.
Yes, I'll try Pedro's review for +v6.7.10, test it and submit a backport patch.
Link: https://lore.kernel.org/all/06d0ea61-47ee-4e54-9dfa-a711c5bc07d0@mojatatu.co...
Warm regards, Yunseong Kim