Linux

In the Linux kernel, the following vulnerability has been resolved: PCI/DPC: Fix use-after-free on concurrent DPC and hot-removal Keith reports a use-after-free when a DPC event occurs concurrently to hot-removal of the same portion of the hierarchy: The dpc_handler() awaits readiness of the secondary bus below the Downstream Port where the DPC event occurred. To do so, it polls the config space of the first child device on the secondary bus. If that child device is concurrently removed, accesses to its struct pci_dev cause the kernel to oops. That's because pci_bridge_wait_for_secondary_bus() neglects to hold a reference on the child device. Before v6.3, the function was only called on resume from system sleep or on runtime resume. Holding a reference wasn't necessary back then because the pciehp IRQ thread could never run concurrently. (On resume from system sleep, IRQs are not enabled until after the resume_noirq phase. And runtime resume is always awaited before a PCI device is removed.) However starting with v6.3, pci_bridge_wait_for_secondary_bus() is also called on a DPC event. Commit 53b54ad074de ("PCI/DPC: Await readiness of secondary bus after reset"), which introduced that, failed to appreciate that pci_bridge_wait_for_secondary_bus() now needs to hold a reference on the child device because dpc_handler() and pciehp may indeed run concurrently. The commit was backported to v5.10+ stable kernels, so that's the oldest one affected. Add the missing reference acquisition. Abridged stack trace: BUG: unable to handle page fault for address: 00000000091400c0 CPU: 15 PID: 2464 Comm: irq/53-pcie-dpc 6.9.0 RIP: pci_bus_read_config_dword+0x17/0x50 pci_dev_wait() pci_bridge_wait_for_secondary_bus() dpc_reset_link() pcie_do_recovery() dpc_handler()Show less

In the Linux kernel, the following vulnerability has been resolved: dev/parport: fix the array out-of-bounds risk Fixed array out-of-bounds issues caused by sprintf by replacing it with snprintf for safer data copying, ensuring the destination buffer is not overflowed. Below is the stack trace I encountered during the actual issue: [ 66.575408s] [pid:5118,cpu4,QThread,4]Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in: do_hardware_base_addr+0xcc/0xd0 [parport] [ 66.575408s] [pid:5118,cpu4,QThread,5]CPU: 4 PID: 5118 Comm: QThread Tainted: G S W O 5.10.97-arm64-desktop #7100.57021.2 [ 66.575439s] [pid:5118,cpu4,QThread,6]TGID: 5087 Comm: EFileApp [ 66.575439s] [pid:5118,cpu4,QThread,7]Hardware name: HUAWEI HUAWEI QingYun PGUX-W515x-B081/SP1PANGUXM, BIOS 1.00.07 04/29/2024 [ 66.575439s] [pid:5118,cpu4,QThread,8]Call trace: [ 66.575469s] [pid:5118,cpu4,QThread,9] dump_backtrace+0x0/0x1c0 [ 66.575469s] [pid:5118,cpu4,QThread,0] show_stack+0x14/0x20 [ 66.575469s] [pid:5118,cpu4,QThread,1] dump_stack+0xd4/0x10c [ 66.575500s] [pid:5118,cpu4,QThread,2] panic+0x1d8/0x3bc [ 66.575500s] [pid:5118,cpu4,QThread,3] __stack_chk_fail+0x2c/0x38 [ 66.575500s] [pid:5118,cpu4,QThread,4] do_hardware_base_addr+0xcc/0xd0 [parport]Show less

In the Linux kernel, the following vulnerability has been resolved: erofs: fix race in z_erofs_get_gbuf() In z_erofs_get_gbuf(), the current task may be migrated to another CPU between `z_erofs_gbuf_id()` and `spin_lock(&gbuf->lock)`. Therefore, z_erofs_put_gbuf() will trigger the following issue which was found by stress test: <2>[772156.434168] kernel BUG at fs/erofs/zutil.c:58! .. <4>[772156.435007] <4>[772156.439237] CPU: 0 PID: 3078 Comm: stress Kdump: loaded Tainted: G E 6.10.0-rc7+ #2 <4>[772156.439239] Hardware name: Alibaba Cloud Alibaba Cloud ECS, BIOS 1.0.0 01/01/2017 <4>[772156.439241] pstate: 83400005 (Nzcv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=--) <4>[772156.439243] pc : z_erofs_put_gbuf+0x64/0x70 [erofs] <4>[772156.439252] lr : z_erofs_lz4_decompress+0x600/0x6a0 [erofs] .. <6>[772156.445958] stress (3127): drop_caches: 1 <4>[772156.446120] Call trace: <4>[772156.446121] z_erofs_put_gbuf+0x64/0x70 [erofs] <4>[772156.446761] z_erofs_lz4_decompress+0x600/0x6a0 [erofs] <4>[772156.446897] z_erofs_decompress_queue+0x740/0xa10 [erofs] <4>[772156.447036] z_erofs_runqueue+0x428/0x8c0 [erofs] <4>[772156.447160] z_erofs_readahead+0x224/0x390 [erofs] ..Show less

In the Linux kernel, the following vulnerability has been resolved: fs/ntfs3: Update log->page_{mask,bits} if log->page_size changed If an NTFS file system is mounted to another system with different PAGE_SIZE from the original system, log->page_size will change in log_replay(), but log->page_{mask,bits} don't change correspondingly. This will cause a panic because "u32 bytes = log->page_size - page_off" will get a negative value in the later read_log_page().Show less

In the Linux kernel, the following vulnerability has been resolved: ASoC: fsl: fsl_qmc_audio: Check devm_kasprintf() returned value devm_kasprintf() can return a NULL pointer on failure but this returned value is not checked. Fix this lack and check the returned value.Show less

In the Linux kernel, the following vulnerability has been resolved: f2fs: fix to don't dirty inode for readonly filesystem syzbot reports f2fs bug as below: kernel BUG at fs/f2fs/inode.c:933! RIP: 0010:f2fs_evict_inode+0x1576/0x1590 fs/f2fs/inode.c:933 Call Trace: evict+0x2a4/0x620 fs/inode.c:664 dispose_list fs/inode.c:697 [inline] evict_inodes+0x5f8/0x690 fs/inode.c:747 generic_shutdown_super+0x9d/0x2c0 fs/super.c:675 kill_block_super+0x44/0x90 fs/super.c:1667 kill_f2fs_super+0x303/0x3b0 fs/f2fs/super.c:4894 deactivate_locked_super+0xc1/0x130 fs/super.c:484 cleanup_mnt+0x426/0x4c0 fs/namespace.c:1256 task_work_run+0x24a/0x300 kernel/task_work.c:180 ptrace_notify+0x2cd/0x380 kernel/signal.c:2399 ptrace_report_syscall include/linux/ptrace.h:411 [inline] ptrace_report_syscall_exit include/linux/ptrace.h:473 [inline] syscall_exit_work kernel/entry/common.c:251 [inline] syscall_exit_to_user_mode_prepare kernel/entry/common.c:278 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:283 [inline] syscall_exit_to_user_mode+0x15c/0x280 kernel/entry/common.c:296 do_syscall_64+0x50/0x110 arch/x86/entry/common.c:88 entry_SYSCALL_64_after_hwframe+0x63/0x6b The root cause is: - do_sys_open - f2fs_lookup - __f2fs_find_entry - f2fs_i_depth_write - f2fs_mark_inode_dirty_sync - f2fs_dirty_inode - set_inode_flag(inode, FI_DIRTY_INODE) - umount - kill_f2fs_super - kill_block_super - generic_shutdown_super - sync_filesystem : sb is readonly, skip sync_filesystem() - evict_inodes - iput - f2fs_evict_inode - f2fs_bug_on(sbi, is_inode_flag_set(inode, FI_DIRTY_INODE)) : trigger kernel panic When we try to repair i_current_depth in readonly filesystem, let's skip dirty inode to avoid panic in later f2fs_evict_inode().Show less

In the Linux kernel, the following vulnerability has been resolved: f2fs: fix return value of f2fs_convert_inline_inode() If device is readonly, make f2fs_convert_inline_inode() return EROFS instead of zero, otherwise it may trigger panic during writeback of inline inode's dirty page as below: f2fs_write_single_data_page+0xbb6/0x1e90 fs/f2fs/data.c:2888 f2fs_write_cache_pages fs/f2fs/data.c:3187 [inline] __f2fs_write_data_pages fs/f2fs/data.c:3342 [inline] f2fs_write_data_pages+0x1efe/0x3a90 fs/f2fs/data.c:3369 do_writepages+0x359/0x870 mm/page-writeback.c:2634 filemap_fdatawrite_wbc+0x125/0x180 mm/filemap.c:397 __filemap_fdatawrite_range mm/filemap.c:430 [inline] file_write_and_wait_range+0x1aa/0x290 mm/filemap.c:788 f2fs_do_sync_file+0x68a/0x1ae0 fs/f2fs/file.c:276 generic_write_sync include/linux/fs.h:2806 [inline] f2fs_file_write_iter+0x7bd/0x24e0 fs/f2fs/file.c:4977 call_write_iter include/linux/fs.h:2114 [inline] new_sync_write fs/read_write.c:497 [inline] vfs_write+0xa72/0xc90 fs/read_write.c:590 ksys_write+0x1a0/0x2c0 fs/read_write.c:643 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7fShow less

In the Linux kernel, the following vulnerability has been resolved: nilfs2: handle inconsistent state in nilfs_btnode_create_block() Syzbot reported that a buffer state inconsistency was detected in nilfs_btnode_create_block(), triggering a kernel bug. It is not appropriate to treat this inconsistency as a bug; it can occur if the argument block address (the buffer index of the newly created block) is a virtual block number and has been reallocated due to corruption of the bitmap used to manage its allocation state. So, modify nilfs_btnode_create_block() and its callers to treat it as a possible filesystem error, rather than triggering a kernel bug.Show less

In the Linux kernel, the following vulnerability has been resolved: block: fix deadlock between sd_remove & sd_release Our test report the following hung task: [ 2538.459400] INFO: task "kworker/0:0":7 blocked for more than 188 seconds. [ 2538.459427] Call trace: [ 2538.459430] __switch_to+0x174/0x338 [ 2538.459436] __schedule+0x628/0x9c4 [ 2538.459442] schedule+0x7c/0xe8 [ 2538.459447] schedule_preempt_disabled+0x24/0x40 [ 2538.459453] __mutex_lock+0x3ec/0xf04 [ 2538.459456] __mutex_lock_slowpath+0x14/0x24 [ 2538.459459] mutex_lock+0x30/0xd8 [ 2538.459462] del_gendisk+0xdc/0x350 [ 2538.459466] sd_remove+0x30/0x60 [ 2538.459470] device_release_driver_internal+0x1c4/0x2c4 [ 2538.459474] device_release_driver+0x18/0x28 [ 2538.459478] bus_remove_device+0x15c/0x174 [ 2538.459483] device_del+0x1d0/0x358 [ 2538.459488] __scsi_remove_device+0xa8/0x198 [ 2538.459493] scsi_forget_host+0x50/0x70 [ 2538.459497] scsi_remove_host+0x80/0x180 [ 2538.459502] usb_stor_disconnect+0x68/0xf4 [ 2538.459506] usb_unbind_interface+0xd4/0x280 [ 2538.459510] device_release_driver_internal+0x1c4/0x2c4 [ 2538.459514] device_release_driver+0x18/0x28 [ 2538.459518] bus_remove_device+0x15c/0x174 [ 2538.459523] device_del+0x1d0/0x358 [ 2538.459528] usb_disable_device+0x84/0x194 [ 2538.459532] usb_disconnect+0xec/0x300 [ 2538.459537] hub_event+0xb80/0x1870 [ 2538.459541] process_scheduled_works+0x248/0x4dc [ 2538.459545] worker_thread+0x244/0x334 [ 2538.459549] kthread+0x114/0x1bc [ 2538.461001] INFO: task "fsck.":15415 blocked for more than 188 seconds. [ 2538.461014] Call trace: [ 2538.461016] __switch_to+0x174/0x338 [ 2538.461021] __schedule+0x628/0x9c4 [ 2538.461025] schedule+0x7c/0xe8 [ 2538.461030] blk_queue_enter+0xc4/0x160 [ 2538.461034] blk_mq_alloc_request+0x120/0x1d4 [ 2538.461037] scsi_execute_cmd+0x7c/0x23c [ 2538.461040] ioctl_internal_command+0x5c/0x164 [ 2538.461046] scsi_set_medium_removal+0x5c/0xb0 [ 2538.461051] sd_release+0x50/0x94 [ 2538.461054] blkdev_put+0x190/0x28c [ 2538.461058] blkdev_release+0x28/0x40 [ 2538.461063] __fput+0xf8/0x2a8 [ 2538.461066] __fput_sync+0x28/0x5c [ 2538.461070] __arm64_sys_close+0x84/0xe8 [ 2538.461073] invoke_syscall+0x58/0x114 [ 2538.461078] el0_svc_common+0xac/0xe0 [ 2538.461082] do_el0_svc+0x1c/0x28 [ 2538.461087] el0_svc+0x38/0x68 [ 2538.461090] el0t_64_sync_handler+0x68/0xbc [ 2538.461093] el0t_64_sync+0x1a8/0x1ac T1: T2: sd_remove del_gendisk __blk_mark_disk_dead blk_freeze_queue_start ++q->mq_freeze_depth bdev_release mutex_lock(&disk->open_mutex) sd_release scsi_execute_cmd blk_queue_enter wait_event(!q->mq_freeze_depth) mutex_lock(&disk->open_mutex) SCSI does not set GD_OWNS_QUEUE, so QUEUE_FLAG_DYING is not set in this scenario. This is a classic ABBA deadlock. To fix the deadlock, make sure we don't try to acquire disk->open_mutex after freezing the queue.Show less

In the Linux kernel, the following vulnerability has been resolved: arm64: mm: Fix lockless walks with static and dynamic page-table folding Lina reports random oopsen originating from the fast GUP code when 16K pages are used with 4-level page-tables, the fourth level being folded at runtime due to lack of LPA2. In this configuration, the generic implementation of p4d_offset_lockless() will return a 'p4d_t *' corresponding to the 'pgd_t' allocated on the stack of the caller, gup_fast_pgd_range(). This is normally fine, but when the fourth level of page-table is folded at runtime, pud_offset_lockless() will offset from the address of the 'p4d_t' to calculate the address of the PUD in the same page-table page. This results in a stray stack read when the 'p4d_t' has been allocated on the stack and can send the walker into the weeds. Fix the problem by providing our own definition of p4d_offset_lockless() when CONFIG_PGTABLE_LEVELS <= 4 which returns the real page-table pointer rather than the address of the local stack variable.Show less

In the Linux kernel, the following vulnerability has been resolved: kobject_uevent: Fix OOB access within zap_modalias_env() zap_modalias_env() wrongly calculates size of memory block to move, so will cause OOB memory access issue if variable MODALIAS is not the last one within its @env parameter, fixed by correcting size to memmove.Show less

In the Linux kernel, the following vulnerability has been resolved: ice: Add a per-VF limit on number of FDIR filters While the iavf driver adds a s/w limit (128) on the number of FDIR filters that the VF can request, a malicious VF driver can request more than that and exhaust the resources for other VFs. Add a similar limit in ice.Show less

In the Linux kernel, the following vulnerability has been resolved: irqchip/imx-irqsteer: Handle runtime power management correctly The power domain is automatically activated from clk_prepare(). However, on certain platforms like i.MX8QM and i.MX8QXP, the power-on handling invokes sleeping functions, which triggers the 'scheduling while atomic' bug in the context switch path during device probing: BUG: scheduling while atomic: kworker/u13:1/48/0x00000002 Call trace: __schedule_bug+0x54/0x6c __schedule+0x7f0/0xa94 schedule+0x5c/0xc4 schedule_preempt_disabled+0x24/0x40 __mutex_lock.constprop.0+0x2c0/0x540 __mutex_lock_slowpath+0x14/0x20 mutex_lock+0x48/0x54 clk_prepare_lock+0x44/0xa0 clk_prepare+0x20/0x44 imx_irqsteer_resume+0x28/0xe0 pm_generic_runtime_resume+0x2c/0x44 __genpd_runtime_resume+0x30/0x80 genpd_runtime_resume+0xc8/0x2c0 __rpm_callback+0x48/0x1d8 rpm_callback+0x6c/0x78 rpm_resume+0x490/0x6b4 __pm_runtime_resume+0x50/0x94 irq_chip_pm_get+0x2c/0xa0 __irq_do_set_handler+0x178/0x24c irq_set_chained_handler_and_data+0x60/0xa4 mxc_gpio_probe+0x160/0x4b0 Cure this by implementing the irq_bus_lock/sync_unlock() interrupt chip callbacks and handle power management in them as they are invoked from non-atomic context. [ tglx: Rewrote change log, added Fixes tag ]Show less

In the Linux kernel, the following vulnerability has been resolved: scsi: qla2xxx: During vport delete send async logout explicitly During vport delete, it is observed that during unload we hit a crash because of stale entries in outstanding command array. For all these stale I/O entries, eh_abort was issued and aborted (fast_fail_io = 2009h) but I/Os could not complete while vport delete is in process of deleting. BUG: kernel NULL pointer dereference, address: 000000000000001c #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] PREEMPT SMP NOPTI Workqueue: qla2xxx_wq qla_do_work [qla2xxx] RIP: 0010:dma_direct_unmap_sg+0x51/0x1e0 RSP: 0018:ffffa1e1e150fc68 EFLAGS: 00010046 RAX: 0000000000000000 RBX: 0000000000000021 RCX: 0000000000000001 RDX: 0000000000000021 RSI: 0000000000000000 RDI: ffff8ce208a7a0d0 RBP: ffff8ce208a7a0d0 R08: 0000000000000000 R09: ffff8ce378aac9c8 R10: ffff8ce378aac8a0 R11: ffffa1e1e150f9d8 R12: 0000000000000000 R13: 0000000000000000 R14: ffff8ce378aac9c8 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8d217f000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000000001c CR3: 0000002089acc000 CR4: 0000000000350ee0 Call Trace: <TASK> qla2xxx_qpair_sp_free_dma+0x417/0x4e0 ? qla2xxx_qpair_sp_compl+0x10d/0x1a0 ? qla2x00_status_entry+0x768/0x2830 ? newidle_balance+0x2f0/0x430 ? dequeue_entity+0x100/0x3c0 ? qla24xx_process_response_queue+0x6a1/0x19e0 ? __schedule+0x2d5/0x1140 ? qla_do_work+0x47/0x60 ? process_one_work+0x267/0x440 ? process_one_work+0x440/0x440 ? worker_thread+0x2d/0x3d0 ? process_one_work+0x440/0x440 ? kthread+0x156/0x180 ? set_kthread_struct+0x50/0x50 ? ret_from_fork+0x22/0x30 </TASK> Send out async logout explicitly for all the ports during vport delete.Show less

In the Linux kernel, the following vulnerability has been resolved: scsi: qla2xxx: Complete command early within lock A crash was observed while performing NPIV and FW reset, BUG: kernel NULL pointer dereference, address: 000000000000001c #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 1 PREEMPT_RT SMP NOPTI RIP: 0010:dma_direct_unmap_sg+0x51/0x1e0 RSP: 0018:ffffc90026f47b88 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000021 RCX: 0000000000000002 RDX: 0000000000000021 RSI: 0000000000000000 RDI: ffff8881041130d0 RBP: ffff8881041130d0 R08: 0000000000000000 R09: 0000000000000034 R10: ffffc90026f47c48 R11: 0000000000000031 R12: 0000000000000000 R13: 0000000000000000 R14: ffff8881565e4a20 R15: 0000000000000000 FS: 00007f4c69ed3d00(0000) GS:ffff889faac80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000000001c CR3: 0000000288a50002 CR4: 00000000007706e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: <TASK> ? __die_body+0x1a/0x60 ? page_fault_oops+0x16f/0x4a0 ? do_user_addr_fault+0x174/0x7f0 ? exc_page_fault+0x69/0x1a0 ? asm_exc_page_fault+0x22/0x30 ? dma_direct_unmap_sg+0x51/0x1e0 ? preempt_count_sub+0x96/0xe0 qla2xxx_qpair_sp_free_dma+0x29f/0x3b0 [qla2xxx] qla2xxx_qpair_sp_compl+0x60/0x80 [qla2xxx] __qla2x00_abort_all_cmds+0xa2/0x450 [qla2xxx] The command completion was done early while aborting the commands in driver unload path but outside lock to avoid the WARN_ON condition of performing dma_free_attr within the lock. However this caused race condition while command completion via multiple paths causing system crash. Hence complete the command early in unload path but within the lock to avoid race condition.Show less

In the Linux kernel, the following vulnerability has been resolved: scsi: qla2xxx: validate nvme_local_port correctly The driver load failed with error message, qla2xxx [0000:04:00.0]-ffff:0: register_localport failed: ret=ffffffef and with a kernel crash, BUG: unable to handle kernel NULL pointer dereference at 0000000000000070 Workqueue: events_unbound qla_register_fcport_fn [qla2xxx] RIP: 0010:nvme_fc_register_remoteport+0x16/0x430 [nvme_fc] RSP: 0018:ffffaaa040eb3d98 EFLAGS: 00010282 RAX: 0000000000000000 RBX: ffff9dfb46b78c00 RCX: 0000000000000000 RDX: ffff9dfb46b78da8 RSI: ffffaaa040eb3e08 RDI: 0000000000000000 RBP: ffff9dfb612a0a58 R08: ffffffffaf1d6270 R09: 3a34303a30303030 R10: 34303a303030305b R11: 2078787832616c71 R12: ffff9dfb46b78dd4 R13: ffff9dfb46b78c24 R14: ffff9dfb41525300 R15: ffff9dfb46b78da8 FS: 0000000000000000(0000) GS:ffff9dfc67c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000070 CR3: 000000018da10004 CR4: 00000000000206f0 Call Trace: qla_nvme_register_remote+0xeb/0x1f0 [qla2xxx] ? qla2x00_dfs_create_rport+0x231/0x270 [qla2xxx] qla2x00_update_fcport+0x2a1/0x3c0 [qla2xxx] qla_register_fcport_fn+0x54/0xc0 [qla2xxx] Exit the qla_nvme_register_remote() function when qla_nvme_register_hba() fails and correctly validate nvme_local_port.Show less

In the Linux kernel, the following vulnerability has been resolved: RDMA/iwcm: Fix a use-after-free related to destroying CM IDs iw_conn_req_handler() associates a new struct rdma_id_private (conn_id) with an existing struct iw_cm_id (cm_id) as follows: conn_id->cm_id.iw = cm_id; cm_id->context = conn_id; cm_id->cm_handler = cma_iw_handler; rdma_destroy_id() frees both the cm_id and the struct rdma_id_private. Make sure that cm_work_handler() does not trigger a use-after-free by only freeing of the struct rdma_id_private after all pending work has finished.Show less

In the Linux kernel, the following vulnerability has been resolved: tipc: Return non-zero value from tipc_udp_addr2str() on error tipc_udp_addr2str() should return non-zero value if the UDP media address is invalid. Otherwise, a buffer overflow access can occur in tipc_media_addr_printf(). Fix this by returning 1 on an invalid UDP media address.Show less

In the Linux kernel, the following vulnerability has been resolved: net: nexthop: Initialize all fields in dumped nexthops struct nexthop_grp contains two reserved fields that are not initialized by nla_put_nh_group(), and carry garbage. This can be observed e.g. with strace (edited for clarity): # ip nexthop add id 1 dev lo # ip nexthop add id 101 group 1 # strace -e recvmsg ip nexthop get id 101 ... recvmsg(... [{nla_len=12, nla_type=NHA_GROUP}, [{id=1, weight=0, resvd1=0x69, resvd2=0x67}]] ...) = 52 The fields are reserved and therefore not currently used. But as they are, they leak kernel memory, and the fact they are not just zero complicates repurposing of the fields for new ends. Initialize the full structure.Show less