Filtered by vendor Linux Subscriptions
Filtered by product Linux Kernel Subscriptions
Total 15214 CVE
CVE Vendors Products Updated CVSS v3.1
CVE-2024-58055 1 Linux 1 Linux Kernel 2025-11-03 7.8 High
In the Linux kernel, the following vulnerability has been resolved: usb: gadget: f_tcm: Don't free command immediately Don't prematurely free the command. Wait for the status completion of the sense status. It can be freed then. Otherwise we will double-free the command.
CVE-2024-58054 1 Linux 1 Linux Kernel 2025-11-03 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: staging: media: max96712: fix kernel oops when removing module The following kernel oops is thrown when trying to remove the max96712 module: Unable to handle kernel paging request at virtual address 00007375746174db Mem abort info: ESR = 0x0000000096000004 EC = 0x25: DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 FSC = 0x04: level 0 translation fault Data abort info: ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000 CM = 0, WnR = 0, TnD = 0, TagAccess = 0 GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 user pgtable: 4k pages, 48-bit VAs, pgdp=000000010af89000 [00007375746174db] pgd=0000000000000000, p4d=0000000000000000 Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP Modules linked in: crct10dif_ce polyval_ce mxc_jpeg_encdec flexcan snd_soc_fsl_sai snd_soc_fsl_asoc_card snd_soc_fsl_micfil dwc_mipi_csi2 imx_csi_formatter polyval_generic v4l2_jpeg imx_pcm_dma can_dev snd_soc_imx_audmux snd_soc_wm8962 snd_soc_imx_card snd_soc_fsl_utils max96712(C-) rpmsg_ctrl rpmsg_char pwm_fan fuse [last unloaded: imx8_isi] CPU: 0 UID: 0 PID: 754 Comm: rmmod Tainted: G C 6.12.0-rc6-06364-g327fec852c31 #17 Tainted: [C]=CRAP Hardware name: NXP i.MX95 19X19 board (DT) pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : led_put+0x1c/0x40 lr : v4l2_subdev_put_privacy_led+0x48/0x58 sp : ffff80008699bbb0 x29: ffff80008699bbb0 x28: ffff00008ac233c0 x27: 0000000000000000 x26: 0000000000000000 x25: 0000000000000000 x24: 0000000000000000 x23: ffff000080cf1170 x22: ffff00008b53bd00 x21: ffff8000822ad1c8 x20: ffff000080ff5c00 x19: ffff00008b53be40 x18: 0000000000000000 x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000 x14: 0000000000000004 x13: ffff0000800f8010 x12: 0000000000000000 x11: ffff000082acf5c0 x10: ffff000082acf478 x9 : ffff0000800f8010 x8 : 0101010101010101 x7 : 7f7f7f7f7f7f7f7f x6 : fefefeff6364626d x5 : 8080808000000000 x4 : 0000000000000020 x3 : 00000000553a3dc1 x2 : ffff00008ac233c0 x1 : ffff00008ac233c0 x0 : ff00737574617473 Call trace: led_put+0x1c/0x40 v4l2_subdev_put_privacy_led+0x48/0x58 v4l2_async_unregister_subdev+0x2c/0x1a4 max96712_remove+0x1c/0x38 [max96712] i2c_device_remove+0x2c/0x9c device_remove+0x4c/0x80 device_release_driver_internal+0x1cc/0x228 driver_detach+0x4c/0x98 bus_remove_driver+0x6c/0xbc driver_unregister+0x30/0x60 i2c_del_driver+0x54/0x64 max96712_i2c_driver_exit+0x18/0x1d0 [max96712] __arm64_sys_delete_module+0x1a4/0x290 invoke_syscall+0x48/0x10c el0_svc_common.constprop.0+0xc0/0xe0 do_el0_svc+0x1c/0x28 el0_svc+0x34/0xd8 el0t_64_sync_handler+0x120/0x12c el0t_64_sync+0x190/0x194 Code: f9000bf3 aa0003f3 f9402800 f9402000 (f9403400) ---[ end trace 0000000000000000 ]--- This happens because in v4l2_i2c_subdev_init(), the i2c_set_cliendata() is called again and the data is overwritten to point to sd, instead of priv. So, in remove(), the wrong pointer is passed to v4l2_async_unregister_subdev(), leading to a crash.
CVE-2024-58052 1 Linux 1 Linux Kernel 2025-11-03 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: drm/amdgpu: Fix potential NULL pointer dereference in atomctrl_get_smc_sclk_range_table The function atomctrl_get_smc_sclk_range_table() does not check the return value of smu_atom_get_data_table(). If smu_atom_get_data_table() fails to retrieve SMU_Info table, it returns NULL which is later dereferenced. Found by Linux Verification Center (linuxtesting.org) with SVACE. In practice this should never happen as this code only gets called on polaris chips and the vbios data table will always be present on those chips.
CVE-2024-58051 1 Linux 1 Linux Kernel 2025-11-03 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: ipmi: ipmb: Add check devm_kasprintf() returned value devm_kasprintf() can return a NULL pointer on failure but this returned value is not checked.
CVE-2024-58034 1 Linux 1 Linux Kernel 2025-11-03 7.8 High
In the Linux kernel, the following vulnerability has been resolved: memory: tegra20-emc: fix an OF node reference bug in tegra_emc_find_node_by_ram_code() As of_find_node_by_name() release the reference of the argument device node, tegra_emc_find_node_by_ram_code() releases some device nodes while still in use, resulting in possible UAFs. According to the bindings and the in-tree DTS files, the "emc-tables" node is always device's child node with the property "nvidia,use-ram-code", and the "lpddr2" node is a child of the "emc-tables" node. Thus utilize the for_each_child_of_node() macro and of_get_child_by_name() instead of of_find_node_by_name() to simplify the code. This bug was found by an experimental verification tool that I am developing. [krzysztof: applied v1, adjust the commit msg to incorporate v2 parts]
CVE-2024-58020 1 Linux 1 Linux Kernel 2025-11-03 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: HID: multitouch: Add NULL check in mt_input_configured devm_kasprintf() can return a NULL pointer on failure,but this returned value in mt_input_configured() is not checked. Add NULL check in mt_input_configured(), to handle kernel NULL pointer dereference error.
CVE-2024-58017 1 Linux 1 Linux Kernel 2025-11-03 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: printk: Fix signed integer overflow when defining LOG_BUF_LEN_MAX Shifting 1 << 31 on a 32-bit int causes signed integer overflow, which leads to undefined behavior. To prevent this, cast 1 to u32 before performing the shift, ensuring well-defined behavior. This change explicitly avoids any potential overflow by ensuring that the shift occurs on an unsigned 32-bit integer.
CVE-2024-58016 1 Linux 1 Linux Kernel 2025-11-03 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: safesetid: check size of policy writes syzbot attempts to write a buffer with a large size to a sysfs entry with writes handled by handle_policy_update(), triggering a warning in kmalloc. Check the size specified for write buffers before allocating. [PM: subject tweak]
CVE-2024-58014 1 Linux 1 Linux Kernel 2025-11-03 7.1 High
In the Linux kernel, the following vulnerability has been resolved: wifi: brcmsmac: add gain range check to wlc_phy_iqcal_gainparams_nphy() In 'wlc_phy_iqcal_gainparams_nphy()', add gain range check to WARN() instead of possible out-of-bounds 'tbl_iqcal_gainparams_nphy' access. Compile tested only. Found by Linux Verification Center (linuxtesting.org) with SVACE.
CVE-2024-58013 1 Linux 1 Linux Kernel 2025-11-03 7.8 High
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: MGMT: Fix slab-use-after-free Read in mgmt_remove_adv_monitor_sync This fixes the following crash: ================================================================== BUG: KASAN: slab-use-after-free in mgmt_remove_adv_monitor_sync+0x3a/0xd0 net/bluetooth/mgmt.c:5543 Read of size 8 at addr ffff88814128f898 by task kworker/u9:4/5961 CPU: 1 UID: 0 PID: 5961 Comm: kworker/u9:4 Not tainted 6.12.0-syzkaller-10684-gf1cd565ce577 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Workqueue: hci0 hci_cmd_sync_work Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0x169/0x550 mm/kasan/report.c:489 kasan_report+0x143/0x180 mm/kasan/report.c:602 mgmt_remove_adv_monitor_sync+0x3a/0xd0 net/bluetooth/mgmt.c:5543 hci_cmd_sync_work+0x22b/0x400 net/bluetooth/hci_sync.c:332 process_one_work kernel/workqueue.c:3229 [inline] process_scheduled_works+0xa63/0x1850 kernel/workqueue.c:3310 worker_thread+0x870/0xd30 kernel/workqueue.c:3391 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 </TASK> Allocated by task 16026: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:377 [inline] __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:394 kasan_kmalloc include/linux/kasan.h:260 [inline] __kmalloc_cache_noprof+0x243/0x390 mm/slub.c:4314 kmalloc_noprof include/linux/slab.h:901 [inline] kzalloc_noprof include/linux/slab.h:1037 [inline] mgmt_pending_new+0x65/0x250 net/bluetooth/mgmt_util.c:269 mgmt_pending_add+0x36/0x120 net/bluetooth/mgmt_util.c:296 remove_adv_monitor+0x102/0x1b0 net/bluetooth/mgmt.c:5568 hci_mgmt_cmd+0xc47/0x11d0 net/bluetooth/hci_sock.c:1712 hci_sock_sendmsg+0x7b8/0x11c0 net/bluetooth/hci_sock.c:1832 sock_sendmsg_nosec net/socket.c:711 [inline] __sock_sendmsg+0x221/0x270 net/socket.c:726 sock_write_iter+0x2d7/0x3f0 net/socket.c:1147 new_sync_write fs/read_write.c:586 [inline] vfs_write+0xaeb/0xd30 fs/read_write.c:679 ksys_write+0x18f/0x2b0 fs/read_write.c:731 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 16022: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:582 poison_slab_object mm/kasan/common.c:247 [inline] __kasan_slab_free+0x59/0x70 mm/kasan/common.c:264 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2338 [inline] slab_free mm/slub.c:4598 [inline] kfree+0x196/0x420 mm/slub.c:4746 mgmt_pending_foreach+0xd1/0x130 net/bluetooth/mgmt_util.c:259 __mgmt_power_off+0x183/0x430 net/bluetooth/mgmt.c:9550 hci_dev_close_sync+0x6c4/0x11c0 net/bluetooth/hci_sync.c:5208 hci_dev_do_close net/bluetooth/hci_core.c:483 [inline] hci_dev_close+0x112/0x210 net/bluetooth/hci_core.c:508 sock_do_ioctl+0x158/0x460 net/socket.c:1209 sock_ioctl+0x626/0x8e0 net/socket.c:1328 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f
CVE-2024-58011 1 Linux 1 Linux Kernel 2025-11-03 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: platform/x86: int3472: Check for adev == NULL Not all devices have an ACPI companion fwnode, so adev might be NULL. This can e.g. (theoretically) happen when a user manually binds one of the int3472 drivers to another i2c/platform device through sysfs. Add a check for adev not being set and return -ENODEV in that case to avoid a possible NULL pointer deref in skl_int3472_get_acpi_buffer().
CVE-2024-58010 1 Linux 1 Linux Kernel 2025-11-03 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: binfmt_flat: Fix integer overflow bug on 32 bit systems Most of these sizes and counts are capped at 256MB so the math doesn't result in an integer overflow. The "relocs" count needs to be checked as well. Otherwise on 32bit systems the calculation of "full_data" could be wrong. full_data = data_len + relocs * sizeof(unsigned long);
CVE-2024-58009 2 Linux, Redhat 2 Linux Kernel, Enterprise Linux 2025-11-03 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: handle NULL sock pointer in l2cap_sock_alloc A NULL sock pointer is passed into l2cap_sock_alloc() when it is called from l2cap_sock_new_connection_cb() and the error handling paths should also be aware of it. Seemingly a more elegant solution would be to swap bt_sock_alloc() and l2cap_chan_create() calls since they are not interdependent to that moment but then l2cap_chan_create() adds the soon to be deallocated and still dummy-initialized channel to the global list accessible by many L2CAP paths. The channel would be removed from the list in short period of time but be a bit more straight-forward here and just check for NULL instead of changing the order of function calls. Found by Linux Verification Center (linuxtesting.org) with SVACE static analysis tool.
CVE-2024-58007 2 Linux, Redhat 2 Linux Kernel, Enterprise Linux 2025-11-03 7.1 High
In the Linux kernel, the following vulnerability has been resolved: soc: qcom: socinfo: Avoid out of bounds read of serial number On MSM8916 devices, the serial number exposed in sysfs is constant and does not change across individual devices. It's always: db410c:/sys/devices/soc0$ cat serial_number 2644893864 The firmware used on MSM8916 exposes SOCINFO_VERSION(0, 8), which does not have support for the serial_num field in the socinfo struct. There is an existing check to avoid exposing the serial number in that case, but it's not correct: When checking the item_size returned by SMEM, we need to make sure the *end* of the serial_num is within bounds, instead of comparing with the *start* offset. The serial_number currently exposed on MSM8916 devices is just an out of bounds read of whatever comes after the socinfo struct in SMEM. Fix this by changing offsetof() to offsetofend(), so that the size of the field is also taken into account.
CVE-2024-58005 2 Linux, Redhat 2 Linux Kernel, Enterprise Linux 2025-11-03 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: tpm: Change to kvalloc() in eventlog/acpi.c The following failure was reported on HPE ProLiant D320: [ 10.693310][ T1] tpm_tis STM0925:00: 2.0 TPM (device-id 0x3, rev-id 0) [ 10.848132][ T1] ------------[ cut here ]------------ [ 10.853559][ T1] WARNING: CPU: 59 PID: 1 at mm/page_alloc.c:4727 __alloc_pages_noprof+0x2ca/0x330 [ 10.862827][ T1] Modules linked in: [ 10.866671][ T1] CPU: 59 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.12.0-lp155.2.g52785e2-default #1 openSUSE Tumbleweed (unreleased) 588cd98293a7c9eba9013378d807364c088c9375 [ 10.882741][ T1] Hardware name: HPE ProLiant DL320 Gen12/ProLiant DL320 Gen12, BIOS 1.20 10/28/2024 [ 10.892170][ T1] RIP: 0010:__alloc_pages_noprof+0x2ca/0x330 [ 10.898103][ T1] Code: 24 08 e9 4a fe ff ff e8 34 36 fa ff e9 88 fe ff ff 83 fe 0a 0f 86 b3 fd ff ff 80 3d 01 e7 ce 01 00 75 09 c6 05 f8 e6 ce 01 01 <0f> 0b 45 31 ff e9 e5 fe ff ff f7 c2 00 00 08 00 75 42 89 d9 80 e1 [ 10.917750][ T1] RSP: 0000:ffffb7cf40077980 EFLAGS: 00010246 [ 10.923777][ T1] RAX: 0000000000000000 RBX: 0000000000040cc0 RCX: 0000000000000000 [ 10.931727][ T1] RDX: 0000000000000000 RSI: 000000000000000c RDI: 0000000000040cc0 The above transcript shows that ACPI pointed a 16 MiB buffer for the log events because RSI maps to the 'order' parameter of __alloc_pages_noprof(). Address the bug by moving from devm_kmalloc() to devm_add_action() and kvmalloc() and devm_add_action().
CVE-2024-58002 1 Linux 1 Linux Kernel 2025-11-03 7.8 High
In the Linux kernel, the following vulnerability has been resolved: media: uvcvideo: Remove dangling pointers When an async control is written, we copy a pointer to the file handle that started the operation. That pointer will be used when the device is done. Which could be anytime in the future. If the user closes that file descriptor, its structure will be freed, and there will be one dangling pointer per pending async control, that the driver will try to use. Clean all the dangling pointers during release(). To avoid adding a performance penalty in the most common case (no async operation), a counter has been introduced with some logic to make sure that it is properly handled.
CVE-2024-58001 1 Linux 1 Linux Kernel 2025-11-03 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: ocfs2: handle a symlink read error correctly Patch series "Convert ocfs2 to use folios". Mark did a conversion of ocfs2 to use folios and sent it to me as a giant patch for review ;-) So I've redone it as individual patches, and credited Mark for the patches where his code is substantially the same. It's not a bad way to do it; his patch had some bugs and my patches had some bugs. Hopefully all our bugs were different from each other. And hopefully Mark likes all the changes I made to his code! This patch (of 23): If we can't read the buffer, be sure to unlock the page before returning.
CVE-2024-57998 1 Linux 1 Linux Kernel 2025-11-03 7.8 High
In the Linux kernel, the following vulnerability has been resolved: OPP: add index check to assert to avoid buffer overflow in _read_freq() Pass the freq index to the assert function to make sure we do not read a freq out of the opp->rates[] table when called from the indexed variants: dev_pm_opp_find_freq_exact_indexed() or dev_pm_opp_find_freq_ceil/floor_indexed(). Add a secondary parameter to the assert function, unused for assert_single_clk() then add assert_clk_index() which will check for the clock index when called from the _indexed() find functions.
CVE-2024-57997 1 Linux 1 Linux Kernel 2025-11-03 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: wifi: wcn36xx: fix channel survey memory allocation size KASAN reported a memory allocation issue in wcn->chan_survey due to incorrect size calculation. This commit uses kcalloc to allocate memory for wcn->chan_survey, ensuring proper initialization and preventing the use of uninitialized values when there are no frames on the channel.
CVE-2024-57996 1 Linux 1 Linux Kernel 2025-11-03 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: net_sched: sch_sfq: don't allow 1 packet limit The current implementation does not work correctly with a limit of 1. iproute2 actually checks for this and this patch adds the check in kernel as well. This fixes the following syzkaller reported crash: UBSAN: array-index-out-of-bounds in net/sched/sch_sfq.c:210:6 index 65535 is out of range for type 'struct sfq_head[128]' CPU: 0 PID: 2569 Comm: syz-executor101 Not tainted 5.10.0-smp-DEV #1 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x125/0x19f lib/dump_stack.c:120 ubsan_epilogue lib/ubsan.c:148 [inline] __ubsan_handle_out_of_bounds+0xed/0x120 lib/ubsan.c:347 sfq_link net/sched/sch_sfq.c:210 [inline] sfq_dec+0x528/0x600 net/sched/sch_sfq.c:238 sfq_dequeue+0x39b/0x9d0 net/sched/sch_sfq.c:500 sfq_reset+0x13/0x50 net/sched/sch_sfq.c:525 qdisc_reset+0xfe/0x510 net/sched/sch_generic.c:1026 tbf_reset+0x3d/0x100 net/sched/sch_tbf.c:319 qdisc_reset+0xfe/0x510 net/sched/sch_generic.c:1026 dev_reset_queue+0x8c/0x140 net/sched/sch_generic.c:1296 netdev_for_each_tx_queue include/linux/netdevice.h:2350 [inline] dev_deactivate_many+0x6dc/0xc20 net/sched/sch_generic.c:1362 __dev_close_many+0x214/0x350 net/core/dev.c:1468 dev_close_many+0x207/0x510 net/core/dev.c:1506 unregister_netdevice_many+0x40f/0x16b0 net/core/dev.c:10738 unregister_netdevice_queue+0x2be/0x310 net/core/dev.c:10695 unregister_netdevice include/linux/netdevice.h:2893 [inline] __tun_detach+0x6b6/0x1600 drivers/net/tun.c:689 tun_detach drivers/net/tun.c:705 [inline] tun_chr_close+0x104/0x1b0 drivers/net/tun.c:3640 __fput+0x203/0x840 fs/file_table.c:280 task_work_run+0x129/0x1b0 kernel/task_work.c:185 exit_task_work include/linux/task_work.h:33 [inline] do_exit+0x5ce/0x2200 kernel/exit.c:931 do_group_exit+0x144/0x310 kernel/exit.c:1046 __do_sys_exit_group kernel/exit.c:1057 [inline] __se_sys_exit_group kernel/exit.c:1055 [inline] __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1055 do_syscall_64+0x6c/0xd0 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7fe5e7b52479 Code: Unable to access opcode bytes at RIP 0x7fe5e7b5244f. RSP: 002b:00007ffd3c800398 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fe5e7b52479 RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000000 RBP: 00007fe5e7bcd2d0 R08: ffffffffffffffb8 R09: 0000000000000014 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fe5e7bcd2d0 R13: 0000000000000000 R14: 00007fe5e7bcdd20 R15: 00007fe5e7b24270 The crash can be also be reproduced with the following (with a tc recompiled to allow for sfq limits of 1): tc qdisc add dev dummy0 handle 1: root tbf rate 1Kbit burst 100b lat 1s ../iproute2-6.9.0/tc/tc qdisc add dev dummy0 handle 2: parent 1:10 sfq limit 1 ifconfig dummy0 up ping -I dummy0 -f -c2 -W0.1 8.8.8.8 sleep 1 Scenario that triggers the crash: * the first packet is sent and queued in TBF and SFQ; qdisc qlen is 1 * TBF dequeues: it peeks from SFQ which moves the packet to the gso_skb list and keeps qdisc qlen set to 1. TBF is out of tokens so it schedules itself for later. * the second packet is sent and TBF tries to queues it to SFQ. qdisc qlen is now 2 and because the SFQ limit is 1 the packet is dropped by SFQ. At this point qlen is 1, and all of the SFQ slots are empty, however q->tail is not NULL. At this point, assuming no more packets are queued, when sch_dequeue runs again it will decrement the qlen for the current empty slot causing an underflow and the subsequent out of bounds access.