Date: Thu, 27 Jun 2024 11:14:07 +0200
From: Paolo Abeni <pabeni@...hat.com>
To: yskelg@...il.com
Cc: Taehee Yoo <ap420073@...il.com>, Pedro Tammela <pctammela@...atatu.com>,
  Austin Kim <austindh.kim@...il.com>, MichelleJin <shjy180909@...il.com>,
 linux-kernel@...r.kernel.org,  linux-trace-kernel@...r.kernel.org,
 netdev@...r.kernel.org, pbuk5246@...il.com,  stable@...r.kernel.org,
 Yeoreum Yun <yeoreum.yun@....com>, Steven Rostedt <rostedt@...dmis.org>,
 Masami Hiramatsu <mhiramat@...nel.org>, Mathieu Desnoyers
 <mathieu.desnoyers@...icios.com>, Takashi Iwai <tiwai@...e.de>, "David S.
 Miller" <davem@...emloft.net>, Thomas Hellström
 <thomas.hellstrom@...ux.intel.com>, "Rafael J. Wysocki"
 <rafael@...nel.org>,  Jamal Hadi Salim <jhs@...atatu.com>, Cong Wang
 <xiyou.wangcong@...il.com>, Jiri Pirko <jiri@...nulli.us>, Eric Dumazet
 <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>
Subject: Re: [PATCH v4] tracing/net_sched: NULL pointer dereference in
 perf_trace_qdisc_reset()

On Tue, 2024-06-25 at 02:33 +0900, yskelg@...il.com wrote:
> From: Yunseong Kim <yskelg@...il.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
> 
> [ 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!
> 
> 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.
> 
> However, without our patch applied, I tested upstream 6.10.0-rc3 kernel
> using the qdisc_reset event and the ip command on my qemu virtual machine.
> 
> This 2 commands makes always kernel panic.
> 
> Linux version: 6.10.0-rc3
> 
> [    0.000000] Linux version 6.10.0-rc3-00164-g44ef20baed8e-dirty
> (paran@...ora) (gcc (GCC) 14.1.1 20240522 (Red Hat 14.1.1-4), GNU ld
> version 2.41-34.fc40) #20 SMP PREEMPT Sat Jun 15 16:51:25 KST 2024
> 
> Kernel panic message:
> 
> [  615.236484] Internal error: Oops: 0000000096000005 [#1] PREEMPT SMP
> [  615.237250] Dumping ftrace buffer:
> [  615.237679]    (ftrace buffer empty)
> [  615.238097] Modules linked in: veth crct10dif_ce virtio_gpu
> virtio_dma_buf drm_shmem_helper drm_kms_helper zynqmp_fpga xilinx_can
> xilinx_spi xilinx_selectmap xilinx_core xilinx_pr_decoupler versal_fpga
> uvcvideo uvc videobuf2_vmalloc videobuf2_memops videobuf2_v4l2 videodev
> videobuf2_common mc usbnet deflate zstd ubifs ubi rcar_canfd rcar_can
> omap_mailbox ntb_msi_test ntb_hw_epf lattice_sysconfig_spi
> lattice_sysconfig ice40_spi gpio_xilinx dwmac_altr_socfpga mdio_regmap
> stmmac_platform stmmac pcs_xpcs dfl_fme_region dfl_fme_mgr dfl_fme_br
> dfl_afu dfl fpga_region fpga_bridge can can_dev br_netfilter bridge stp
> llc atl1c ath11k_pci mhi ath11k_ahb ath11k qmi_helpers ath10k_sdio
> ath10k_pci ath10k_core ath mac80211 libarc4 cfg80211 drm fuse backlight ipv6
> Jun 22 02:36:5[3   6k152.62-4sm98k4-0k]v  kCePUr:n e1l :P IUDn:a b4le6
> 8t oC ohmma: nidpl eN oketr nteali nptaedg i6n.g1 0re.0q-urecs3t- 0at0
> 1v6i4r-tgu4a4le fa2d0dbraeeds0se-dir tyd f#f2f08
>   615.252376] Hardware name: linux,dummy-virt (DT)
> [  615.253220] pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS
> BTYPE=--)
> [  615.254433] pc : strnlen+0x6c/0xe0
> [  615.255096] lr : trace_event_get_offsets_qdisc_reset+0x94/0x3d0
> [  615.256088] sp : ffff800080b269a0
> [  615.256615] x29: ffff800080b269a0 x28: ffffc070f3f98500 x27:
> 0000000000000001
> [  615.257831] x26: 0000000000000010 x25: ffffc070f3f98540 x24:
> ffffc070f619cf60
> [  615.259020] x23: 0000000000000128 x22: 0000000000000138 x21:
> dfff800000000000
> [  615.260241] x20: ffffc070f631ad00 x19: 0000000000000128 x18:
> ffffc070f448b800
> [  615.261454] x17: 0000000000000000 x16: 0000000000000001 x15:
> ffffc070f4ba2a90
> [  615.262635] x14: ffff700010164d73 x13: 1ffff80e1e8d5eb3 x12:
> 1ffff00010164d72
> [  615.263877] x11: ffff700010164d72 x10: dfff800000000000 x9 :
> ffffc070e85d6184
> [  615.265047] x8 : ffffc070e4402070 x7 : 000000000000f1f1 x6 :
> 000000001504a6d3
> [  615.266336] x5 : ffff28ca21122140 x4 : ffffc070f5043ea8 x3 :
> 0000000000000000
> [  615.267528] x2 : 0000000000000025 x1 : 0000000000000000 x0 :
> 0000000000000000
> [  615.268747] Call trace:
> [  615.269180]  strnlen+0x6c/0xe0
> [  615.269767]  trace_event_get_offsets_qdisc_reset+0x94/0x3d0
> [  615.270716]  trace_event_raw_event_qdisc_reset+0xe8/0x4e8
> [  615.271667]  __traceiter_qdisc_reset+0xa0/0x140
> [  615.272499]  qdisc_reset+0x554/0x848
> [  615.273134]  netif_set_real_num_tx_queues+0x360/0x9a8
> [  615.274050]  veth_init_queues+0x110/0x220 [veth]
> [  615.275110]  veth_newlink+0x538/0xa50 [veth]
> [  615.276172]  __rtnl_newlink+0x11e4/0x1bc8
> [  615.276944]  rtnl_newlink+0xac/0x120
> [  615.277657]  rtnetlink_rcv_msg+0x4e4/0x1370
> [  615.278409]  netlink_rcv_skb+0x25c/0x4f0
> [  615.279122]  rtnetlink_rcv+0x48/0x70
> [  615.279769]  netlink_unicast+0x5a8/0x7b8
> [  615.280462]  netlink_sendmsg+0xa70/0x1190
> 
> 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.
> 
> 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@...r.kernel.org
> Cc: stable@...r.kernel.org # +v6.7.10, +v6.8
> Tested-by: Yunseong Kim <yskelg@...il.com>
> Signed-off-by: Yunseong Kim <yskelg@...il.com>
> Signed-off-by: Yeoreum Yun <yeoreum.yun@....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

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