In the Linux kernel, the following vulnerability has been resolved: ALSA: hda/cs_dsp_ctl: Use private_free for control cleanup Use the control private_free callback to free the associated data block. This ensures that the memory won't leak, whatever way the control gets destroyed. The original implementation didn't actually remove the ALSA controls in hda_cs_dsp_control_remove(). It only freed the internal tracking structure. This meant it was possible to remove/unload the amp driver while leaving its ALSA controls still present in the soundcard. Obviously attempting to access them could cause segfaults or at least dereferencing stale pointers.

In the Linux kernel, the following vulnerability has been resolved: tls: fix missing memory barrier in tls_init In tls_init(), a write memory barrier is missing, and store-store reordering may cause NULL dereference in tls_{setsockopt,getsockopt}. CPU0 CPU1 ----- ----- // In tls_init() // In tls_ctx_create() ctx = kzalloc() ctx->sk_proto = READ_ONCE(sk->sk_prot) -(1) // In update_sk_prot() WRITE_ONCE(sk->sk_prot, tls_prots) -(2) // In sock_common_setsockopt() READ_ONCE(sk->sk_prot)->setsockopt() // In tls_{setsockopt,getsockopt}() ctx->sk_proto->setsockopt() -(3) In the above scenario, when (1) and (2) are reordered, (3) can observe the NULL value of ctx->sk_proto, causing NULL dereference. To fix it, we rely on rcu_assign_pointer() which implies the release barrier semantic. By moving rcu_assign_pointer() after ctx->sk_proto is initialized, we can ensure that ctx->sk_proto are visible when changing sk->sk_prot.

In the Linux kernel, the following vulnerability has been resolved: null_blk: fix null-ptr-dereference while configuring 'power' and 'submit_queues' Writing 'power' and 'submit_queues' concurrently will trigger kernel panic: Test script: modprobe null_blk nr_devices=0 mkdir -p /sys/kernel/config/nullb/nullb0 while true; do echo 1 > submit_queues; echo 4 > submit_queues; done & while true; do echo 1 > power; echo 0 > power; done Test result: BUG: kernel NULL pointer dereference, address: 0000000000000148 Oops: 0000 [#1] PREEMPT SMP RIP: 0010:__lock_acquire+0x41d/0x28f0 Call Trace: <TASK> lock_acquire+0x121/0x450 down_write+0x5f/0x1d0 simple_recursive_removal+0x12f/0x5c0 blk_mq_debugfs_unregister_hctxs+0x7c/0x100 blk_mq_update_nr_hw_queues+0x4a3/0x720 nullb_update_nr_hw_queues+0x71/0xf0 [null_blk] nullb_device_submit_queues_store+0x79/0xf0 [null_blk] configfs_write_iter+0x119/0x1e0 vfs_write+0x326/0x730 ksys_write+0x74/0x150 This is because del_gendisk() can concurrent with blk_mq_update_nr_hw_queues(): nullb_device_power_store nullb_apply_submit_queues null_del_dev del_gendisk nullb_update_nr_hw_queues if (!dev->nullb) // still set while gendisk is deleted return 0 blk_mq_update_nr_hw_queues dev->nullb = NULL Fix this problem by resuing the global mutex to protect nullb_device_power_store() and nullb_update_nr_hw_queues() from configfs.

In the Linux kernel, the following vulnerability has been resolved: netfilter: nfnetlink_queue: acquire rcu_read_lock() in instance_destroy_rcu() syzbot reported that nf_reinject() could be called without rcu_read_lock() : WARNING: suspicious RCU usage 6.9.0-rc7-syzkaller-02060-g5c1672705a1a #0 Not tainted net/netfilter/nfnetlink_queue.c:263 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 2 locks held by syz-executor.4/13427: #0: ffffffff8e334f60 (rcu_callback){....}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline] #0: ffffffff8e334f60 (rcu_callback){....}-{0:0}, at: rcu_do_batch kernel/rcu/tree.c:2190 [inline] #0: ffffffff8e334f60 (rcu_callback){....}-{0:0}, at: rcu_core+0xa86/0x1830 kernel/rcu/tree.c:2471 #1: ffff88801ca92958 (&inst->lock){+.-.}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline] #1: ffff88801ca92958 (&inst->lock){+.-.}-{2:2}, at: nfqnl_flush net/netfilter/nfnetlink_queue.c:405 [inline] #1: ffff88801ca92958 (&inst->lock){+.-.}-{2:2}, at: instance_destroy_rcu+0x30/0x220 net/netfilter/nfnetlink_queue.c:172 stack backtrace: CPU: 0 PID: 13427 Comm: syz-executor.4 Not tainted 6.9.0-rc7-syzkaller-02060-g5c1672705a1a #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024 Call Trace: <IRQ> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114 lockdep_rcu_suspicious+0x221/0x340 kernel/locking/lockdep.c:6712 nf_reinject net/netfilter/nfnetlink_queue.c:323 [inline] nfqnl_reinject+0x6ec/0x1120 net/netfilter/nfnetlink_queue.c:397 nfqnl_flush net/netfilter/nfnetlink_queue.c:410 [inline] instance_destroy_rcu+0x1ae/0x220 net/netfilter/nfnetlink_queue.c:172 rcu_do_batch kernel/rcu/tree.c:2196 [inline] rcu_core+0xafd/0x1830 kernel/rcu/tree.c:2471 handle_softirqs+0x2d6/0x990 kernel/softirq.c:554 __do_softirq kernel/softirq.c:588 [inline] invoke_softirq kernel/softirq.c:428 [inline] __irq_exit_rcu+0xf4/0x1c0 kernel/softirq.c:637 irq_exit_rcu+0x9/0x30 kernel/softirq.c:649 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1043 </IRQ> <TASK>

In the Linux kernel, the following vulnerability has been resolved: net/mlx5: Use mlx5_ipsec_rx_status_destroy to correctly delete status rules rx_create no longer allocates a modify_hdr instance that needs to be cleaned up. The mlx5_modify_header_dealloc call will lead to a NULL pointer dereference. A leak in the rules also previously occurred since there are now two rules populated related to status. BUG: kernel NULL pointer dereference, address: 0000000000000000 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 109907067 P4D 109907067 PUD 116890067 PMD 0 Oops: 0000 [#1] SMP CPU: 1 PID: 484 Comm: ip Not tainted 6.9.0-rc2-rrameshbabu+ #254 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS Arch Linux 1.16.3-1-1 04/01/2014 RIP: 0010:mlx5_modify_header_dealloc+0xd/0x70 <snip> Call Trace: <TASK> ? show_regs+0x60/0x70 ? __die+0x24/0x70 ? page_fault_oops+0x15f/0x430 ? free_to_partial_list.constprop.0+0x79/0x150 ? do_user_addr_fault+0x2c9/0x5c0 ? exc_page_fault+0x63/0x110 ? asm_exc_page_fault+0x27/0x30 ? mlx5_modify_header_dealloc+0xd/0x70 rx_create+0x374/0x590 rx_add_rule+0x3ad/0x500 ? rx_add_rule+0x3ad/0x500 ? mlx5_cmd_exec+0x2c/0x40 ? mlx5_create_ipsec_obj+0xd6/0x200 mlx5e_accel_ipsec_fs_add_rule+0x31/0xf0 mlx5e_xfrm_add_state+0x426/0xc00 <snip>

In the Linux kernel, the following vulnerability has been resolved: netfilter: tproxy: bail out if IP has been disabled on the device syzbot reports: general protection fault, probably for non-canonical address 0xdffffc0000000003: 0000 [#1] PREEMPT SMP KASAN PTI KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f] [..] RIP: 0010:nf_tproxy_laddr4+0xb7/0x340 net/ipv4/netfilter/nf_tproxy_ipv4.c:62 Call Trace: nft_tproxy_eval_v4 net/netfilter/nft_tproxy.c:56 [inline] nft_tproxy_eval+0xa9a/0x1a00 net/netfilter/nft_tproxy.c:168 __in_dev_get_rcu() can return NULL, so check for this.

In the Linux kernel, the following vulnerability has been resolved: efi: libstub: only free priv.runtime_map when allocated priv.runtime_map is only allocated when efi_novamap is not set. Otherwise, it is an uninitialized value. In the error path, it is freed unconditionally. Avoid passing an uninitialized value to free_pool. Free priv.runtime_map only when it was allocated. This bug was discovered and resolved using Coverity Static Analysis Security Testing (SAST) by Synopsys, Inc.

In the Linux kernel, the following vulnerability has been resolved: Input: cyapa - add missing input core locking to suspend/resume functions Grab input->mutex during suspend/resume functions like it is done in other input drivers. This fixes the following warning during system suspend/resume cycle on Samsung Exynos5250-based Snow Chromebook: ------------[ cut here ]------------ WARNING: CPU: 1 PID: 1680 at drivers/input/input.c:2291 input_device_enabled+0x68/0x6c Modules linked in: ... CPU: 1 PID: 1680 Comm: kworker/u4:12 Tainted: G W 6.6.0-rc5-next-20231009 #14109 Hardware name: Samsung Exynos (Flattened Device Tree) Workqueue: events_unbound async_run_entry_fn unwind_backtrace from show_stack+0x10/0x14 show_stack from dump_stack_lvl+0x58/0x70 dump_stack_lvl from __warn+0x1a8/0x1cc __warn from warn_slowpath_fmt+0x18c/0x1b4 warn_slowpath_fmt from input_device_enabled+0x68/0x6c input_device_enabled from cyapa_gen3_set_power_mode+0x13c/0x1dc cyapa_gen3_set_power_mode from cyapa_reinitialize+0x10c/0x15c cyapa_reinitialize from cyapa_resume+0x48/0x98 cyapa_resume from dpm_run_callback+0x90/0x298 dpm_run_callback from device_resume+0xb4/0x258 device_resume from async_resume+0x20/0x64 async_resume from async_run_entry_fn+0x40/0x15c async_run_entry_fn from process_scheduled_works+0xbc/0x6a8 process_scheduled_works from worker_thread+0x188/0x454 worker_thread from kthread+0x108/0x140 kthread from ret_from_fork+0x14/0x28 Exception stack(0xf1625fb0 to 0xf1625ff8) ... ---[ end trace 0000000000000000 ]--- ... ------------[ cut here ]------------ WARNING: CPU: 1 PID: 1680 at drivers/input/input.c:2291 input_device_enabled+0x68/0x6c Modules linked in: ... CPU: 1 PID: 1680 Comm: kworker/u4:12 Tainted: G W 6.6.0-rc5-next-20231009 #14109 Hardware name: Samsung Exynos (Flattened Device Tree) Workqueue: events_unbound async_run_entry_fn unwind_backtrace from show_stack+0x10/0x14 show_stack from dump_stack_lvl+0x58/0x70 dump_stack_lvl from __warn+0x1a8/0x1cc __warn from warn_slowpath_fmt+0x18c/0x1b4 warn_slowpath_fmt from input_device_enabled+0x68/0x6c input_device_enabled from cyapa_gen3_set_power_mode+0x13c/0x1dc cyapa_gen3_set_power_mode from cyapa_reinitialize+0x10c/0x15c cyapa_reinitialize from cyapa_resume+0x48/0x98 cyapa_resume from dpm_run_callback+0x90/0x298 dpm_run_callback from device_resume+0xb4/0x258 device_resume from async_resume+0x20/0x64 async_resume from async_run_entry_fn+0x40/0x15c async_run_entry_fn from process_scheduled_works+0xbc/0x6a8 process_scheduled_works from worker_thread+0x188/0x454 worker_thread from kthread+0x108/0x140 kthread from ret_from_fork+0x14/0x28 Exception stack(0xf1625fb0 to 0xf1625ff8) ... ---[ end trace 0000000000000000 ]---

In the Linux kernel, the following vulnerability has been resolved: wifi: carl9170: re-fix fortified-memset warning The carl9170_tx_release() function sometimes triggers a fortified-memset warning in my randconfig builds: In file included from include/linux/string.h:254, from drivers/net/wireless/ath/carl9170/tx.c:40: In function 'fortify_memset_chk', inlined from 'carl9170_tx_release' at drivers/net/wireless/ath/carl9170/tx.c:283:2, inlined from 'kref_put' at include/linux/kref.h:65:3, inlined from 'carl9170_tx_put_skb' at drivers/net/wireless/ath/carl9170/tx.c:342:9: include/linux/fortify-string.h:493:25: error: call to '__write_overflow_field' declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Werror=attribute-warning] 493 | __write_overflow_field(p_size_field, size); Kees previously tried to avoid this by using memset_after(), but it seems this does not fully address the problem. I noticed that the memset_after() here is done on a different part of the union (status) than the original cast was from (rate_driver_data), which may confuse the compiler. Unfortunately, the memset_after() trick does not work on driver_rates[] because that is part of an anonymous struct, and I could not get struct_group() to do this either. Using two separate memset() calls on the two members does address the warning though.

In the Linux kernel, the following vulnerability has been resolved: ipv6: sr: fix invalid unregister error path The error path of seg6_init() is wrong in case CONFIG_IPV6_SEG6_LWTUNNEL is not defined. In that case if seg6_hmac_init() fails, the genl_unregister_family() isn't called. This issue exist since commit 46738b1317e1 ("ipv6: sr: add option to control lwtunnel support"), and commit 5559cea2d5aa ("ipv6: sr: fix possible use-after-free and null-ptr-deref") replaced unregister_pernet_subsys() with genl_unregister_family() in this error path.

In the Linux kernel, the following vulnerability has been resolved: net/mlx5e: Fix netif state handling mlx5e_suspend cleans resources only if netif_device_present() returns true. However, mlx5e_resume changes the state of netif, via mlx5e_nic_enable, only if reg_state == NETREG_REGISTERED. In the below case, the above leads to NULL-ptr Oops[1] and memory leaks: mlx5e_probe _mlx5e_resume mlx5e_attach_netdev mlx5e_nic_enable <-- netdev not reg, not calling netif_device_attach() register_netdev <-- failed for some reason. ERROR_FLOW: _mlx5e_suspend <-- netif_device_present return false, resources aren't freed :( Hence, clean resources in this case as well. [1] BUG: kernel NULL pointer dereference, address: 0000000000000000 PGD 0 P4D 0 Oops: 0010 [#1] SMP CPU: 2 PID: 9345 Comm: test-ovs-ct-gen Not tainted 6.5.0_for_upstream_min_debug_2023_09_05_16_01 #1 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 RIP: 0010:0x0 Code: Unable to access opcode bytes at0xffffffffffffffd6. RSP: 0018:ffff888178aaf758 EFLAGS: 00010246 Call Trace: <TASK> ? __die+0x20/0x60 ? page_fault_oops+0x14c/0x3c0 ? exc_page_fault+0x75/0x140 ? asm_exc_page_fault+0x22/0x30 notifier_call_chain+0x35/0xb0 blocking_notifier_call_chain+0x3d/0x60 mlx5_blocking_notifier_call_chain+0x22/0x30 [mlx5_core] mlx5_core_uplink_netdev_event_replay+0x3e/0x60 [mlx5_core] mlx5_mdev_netdev_track+0x53/0x60 [mlx5_ib] mlx5_ib_roce_init+0xc3/0x340 [mlx5_ib] __mlx5_ib_add+0x34/0xd0 [mlx5_ib] mlx5r_probe+0xe1/0x210 [mlx5_ib] ? auxiliary_match_id+0x6a/0x90 auxiliary_bus_probe+0x38/0x80 ? driver_sysfs_add+0x51/0x80 really_probe+0xc9/0x3e0 ? driver_probe_device+0x90/0x90 __driver_probe_device+0x80/0x160 driver_probe_device+0x1e/0x90 __device_attach_driver+0x7d/0x100 bus_for_each_drv+0x80/0xd0 __device_attach+0xbc/0x1f0 bus_probe_device+0x86/0xa0 device_add+0x637/0x840 __auxiliary_device_add+0x3b/0xa0 add_adev+0xc9/0x140 [mlx5_core] mlx5_rescan_drivers_locked+0x22a/0x310 [mlx5_core] mlx5_register_device+0x53/0xa0 [mlx5_core] mlx5_init_one_devl_locked+0x5c4/0x9c0 [mlx5_core] mlx5_init_one+0x3b/0x60 [mlx5_core] probe_one+0x44c/0x730 [mlx5_core] local_pci_probe+0x3e/0x90 pci_device_probe+0xbf/0x210 ? kernfs_create_link+0x5d/0xa0 ? sysfs_do_create_link_sd+0x60/0xc0 really_probe+0xc9/0x3e0 ? driver_probe_device+0x90/0x90 __driver_probe_device+0x80/0x160 driver_probe_device+0x1e/0x90 __device_attach_driver+0x7d/0x100 bus_for_each_drv+0x80/0xd0 __device_attach+0xbc/0x1f0 pci_bus_add_device+0x54/0x80 pci_iov_add_virtfn+0x2e6/0x320 sriov_enable+0x208/0x420 mlx5_core_sriov_configure+0x9e/0x200 [mlx5_core] sriov_numvfs_store+0xae/0x1a0 kernfs_fop_write_iter+0x10c/0x1a0 vfs_write+0x291/0x3c0 ksys_write+0x5f/0xe0 do_syscall_64+0x3d/0x90 entry_SYSCALL_64_after_hwframe+0x46/0xb0 CR2: 0000000000000000 ---[ end trace 0000000000000000 ]---

In the Linux kernel, the following vulnerability has been resolved: ALSA: core: Fix NULL module pointer assignment at card init The commit 81033c6b584b ("ALSA: core: Warn on empty module") introduced a WARN_ON() for a NULL module pointer passed at snd_card object creation, and it also wraps the code around it with '#ifdef MODULE'. This works in most cases, but the devils are always in details. "MODULE" is defined when the target code (i.e. the sound core) is built as a module; but this doesn't mean that the caller is also built-in or not. Namely, when only the sound core is built-in (CONFIG_SND=y) while the driver is a module (CONFIG_SND_USB_AUDIO=m), the passed module pointer is ignored even if it's non-NULL, and card->module remains as NULL. This would result in the missing module reference up/down at the device open/close, leading to a race with the code execution after the module removal. For addressing the bug, move the assignment of card->module again out of ifdef. The WARN_ON() is still wrapped with ifdef because the module can be really NULL when all sound drivers are built-in. Note that we keep 'ifdef MODULE' for WARN_ON(), otherwise it would lead to a false-positive NULL module check. Admittedly it won't catch perfectly, i.e. no check is performed when CONFIG_SND=y. But, it's no real problem as it's only for debugging, and the condition is pretty rare.

In the Linux kernel, the following vulnerability has been resolved: drivers/perf: hisi: hns3: Actually use devm_add_action_or_reset() pci_alloc_irq_vectors() allocates an irq vector. When devm_add_action() fails, the irq vector is not freed, which leads to a memory leak. Replace the devm_add_action with devm_add_action_or_reset to ensure the irq vector can be destroyed when it fails.

In the Linux kernel, the following vulnerability has been resolved: ax25: Fix reference count leak issues of ax25_dev The ax25_addr_ax25dev() and ax25_dev_device_down() exist a reference count leak issue of the object "ax25_dev". Memory leak issue in ax25_addr_ax25dev(): The reference count of the object "ax25_dev" can be increased multiple times in ax25_addr_ax25dev(). This will cause a memory leak. Memory leak issues in ax25_dev_device_down(): The reference count of ax25_dev is set to 1 in ax25_dev_device_up() and then increase the reference count when ax25_dev is added to ax25_dev_list. As a result, the reference count of ax25_dev is 2. But when the device is shutting down. The ax25_dev_device_down() drops the reference count once or twice depending on if we goto unlock_put or not, which will cause memory leak. As for the issue of ax25_addr_ax25dev(), it is impossible for one pointer to be on a list twice. So add a break in ax25_addr_ax25dev(). As for the issue of ax25_dev_device_down(), increase the reference count of ax25_dev once in ax25_dev_device_up() and decrease the reference count of ax25_dev after it is removed from the ax25_dev_list.

In the Linux kernel, the following vulnerability has been resolved: ALSA: Fix deadlocks with kctl removals at disconnection In snd_card_disconnect(), we set card->shutdown flag at the beginning, call callbacks and do sync for card->power_ref_sleep waiters at the end. The callback may delete a kctl element, and this can lead to a deadlock when the device was in the suspended state. Namely: * A process waits for the power up at snd_power_ref_and_wait() in snd_ctl_info() or read/write() inside card->controls_rwsem. * The system gets disconnected meanwhile, and the driver tries to delete a kctl via snd_ctl_remove*(); it tries to take card->controls_rwsem again, but this is already locked by the above. Since the sleeper isn't woken up, this deadlocks. An easy fix is to wake up sleepers before processing the driver disconnect callbacks but right after setting the card->shutdown flag. Then all sleepers will abort immediately, and the code flows again. So, basically this patch moves the wait_event() call at the right timing. While we're at it, just to be sure, call wait_event_all() instead of wait_event(), although we don't use exclusive events on this queue for now.

In the Linux kernel, the following vulnerability has been resolved: md: fix resync softlockup when bitmap size is less than array size Is is reported that for dm-raid10, lvextend + lvchange --syncaction will trigger following softlockup: kernel:watchdog: BUG: soft lockup - CPU#3 stuck for 26s! [mdX_resync:6976] CPU: 7 PID: 3588 Comm: mdX_resync Kdump: loaded Not tainted 6.9.0-rc4-next-20240419 #1 RIP: 0010:_raw_spin_unlock_irq+0x13/0x30 Call Trace: <TASK> md_bitmap_start_sync+0x6b/0xf0 raid10_sync_request+0x25c/0x1b40 [raid10] md_do_sync+0x64b/0x1020 md_thread+0xa7/0x170 kthread+0xcf/0x100 ret_from_fork+0x30/0x50 ret_from_fork_asm+0x1a/0x30 And the detailed process is as follows: md_do_sync j = mddev->resync_min while (j < max_sectors) sectors = raid10_sync_request(mddev, j, &skipped) if (!md_bitmap_start_sync(..., &sync_blocks)) // md_bitmap_start_sync set sync_blocks to 0 return sync_blocks + sectors_skippe; // sectors = 0; j += sectors; // j never change Root cause is that commit 301867b1c168 ("md/raid10: check slab-out-of-bounds in md_bitmap_get_counter") return early from md_bitmap_get_counter(), without setting returned blocks. Fix this problem by always set returned blocks from md_bitmap_get_counter"(), as it used to be. Noted that this patch just fix the softlockup problem in kernel, the case that bitmap size doesn't match array size still need to be fixed.

In the Linux kernel, the following vulnerability has been resolved: eth: sungem: remove .ndo_poll_controller to avoid deadlocks Erhard reports netpoll warnings from sungem: netpoll_send_skb_on_dev(): eth0 enabled interrupts in poll (gem_start_xmit+0x0/0x398) WARNING: CPU: 1 PID: 1 at net/core/netpoll.c:370 netpoll_send_skb+0x1fc/0x20c gem_poll_controller() disables interrupts, which may sleep. We can't sleep in netpoll, it has interrupts disabled completely. Strangely, gem_poll_controller() doesn't even poll the completions, and instead acts as if an interrupt has fired so it just schedules NAPI and exits. None of this has been necessary for years, since netpoll invokes NAPI directly.

In the Linux kernel, the following vulnerability has been resolved: RDMA/hns: Fix deadlock on SRQ async events. xa_lock for SRQ table may be required in AEQ. Use xa_store_irq()/ xa_erase_irq() to avoid deadlock.

In the Linux kernel, the following vulnerability has been resolved: RDMA/hns: Modify the print level of CQE error Too much print may lead to a panic in kernel. Change ibdev_err() to ibdev_err_ratelimited(), and change the printing level of cqe dump to debug level.

In the Linux kernel, the following vulnerability has been resolved: netrom: fix possible dead-lock in nr_rt_ioctl() syzbot loves netrom, and found a possible deadlock in nr_rt_ioctl [1] Make sure we always acquire nr_node_list_lock before nr_node_lock(nr_node) [1] WARNING: possible circular locking dependency detected 6.9.0-rc7-syzkaller-02147-g654de42f3fc6 #0 Not tainted ------------------------------------------------------ syz-executor350/5129 is trying to acquire lock: ffff8880186e2070 (&nr_node->node_lock){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline] ffff8880186e2070 (&nr_node->node_lock){+...}-{2:2}, at: nr_node_lock include/net/netrom.h:152 [inline] ffff8880186e2070 (&nr_node->node_lock){+...}-{2:2}, at: nr_dec_obs net/netrom/nr_route.c:464 [inline] ffff8880186e2070 (&nr_node->node_lock){+...}-{2:2}, at: nr_rt_ioctl+0x1bb/0x1090 net/netrom/nr_route.c:697 but task is already holding lock: ffffffff8f7053b8 (nr_node_list_lock){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline] ffffffff8f7053b8 (nr_node_list_lock){+...}-{2:2}, at: nr_dec_obs net/netrom/nr_route.c:462 [inline] ffffffff8f7053b8 (nr_node_list_lock){+...}-{2:2}, at: nr_rt_ioctl+0x10a/0x1090 net/netrom/nr_route.c:697 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (nr_node_list_lock){+...}-{2:2}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x35/0x50 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:356 [inline] nr_remove_node net/netrom/nr_route.c:299 [inline] nr_del_node+0x4b4/0x820 net/netrom/nr_route.c:355 nr_rt_ioctl+0xa95/0x1090 net/netrom/nr_route.c:683 sock_do_ioctl+0x158/0x460 net/socket.c:1222 sock_ioctl+0x629/0x8e0 net/socket.c:1341 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:904 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:890 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+0x77/0x7f -> #0 (&nr_node->node_lock){+...}-{2:2}: check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain+0x18cb/0x58e0 kernel/locking/lockdep.c:3869 __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x35/0x50 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:356 [inline] nr_node_lock include/net/netrom.h:152 [inline] nr_dec_obs net/netrom/nr_route.c:464 [inline] nr_rt_ioctl+0x1bb/0x1090 net/netrom/nr_route.c:697 sock_do_ioctl+0x158/0x460 net/socket.c:1222 sock_ioctl+0x629/0x8e0 net/socket.c:1341 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:904 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:890 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+0x77/0x7f other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(nr_node_list_lock); lock(&nr_node->node_lock); lock(nr_node_list_lock); lock(&nr_node->node_lock); *** DEADLOCK *** 1 lock held by syz-executor350/5129: #0: ffffffff8f7053b8 (nr_node_list_lock){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline] #0: ffffffff8f7053b8 (nr_node_list_lock){+...}-{2:2}, at: nr_dec_obs net/netrom/nr_route.c:462 [inline] #0: ffffffff8f70 ---truncated---