A NULL pointer dereference flaw was found in the Linux kernel’s IEEE 802.15.4 wireless networking subsystem in the way the user closes the LR-WPAN connection. This flaw allows a local user to crash the system. The highest threat from this vulnerability is to system availability.

In the Linux kernel, the following vulnerability has been resolved: driver core: Fix a potential null-ptr-deref in module_add_driver() Inject fault while probing of-fpga-region, if kasprintf() fails in module_add_driver(), the second sysfs_remove_link() in exit path will cause null-ptr-deref as below because kernfs_name_hash() will call strlen() with NULL driver_name. Fix it by releasing resources based on the exit path sequence. KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] Mem abort info: ESR = 0x0000000096000005 EC = 0x25: DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 FSC = 0x05: level 1 translation fault Data abort info: ISV = 0, ISS = 0x00000005, ISS2 = 0x00000000 CM = 0, WnR = 0, TnD = 0, TagAccess = 0 GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 [dfffffc000000000] address between user and kernel address ranges Internal error: Oops: 0000000096000005 [#1] PREEMPT SMP Dumping ftrace buffer: (ftrace buffer empty) Modules linked in: of_fpga_region(+) fpga_region fpga_bridge cfg80211 rfkill 8021q garp mrp stp llc ipv6 [last unloaded: of_fpga_region] CPU: 2 UID: 0 PID: 2036 Comm: modprobe Not tainted 6.11.0-rc2-g6a0e38264012 #295 Hardware name: linux,dummy-virt (DT) pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : strlen+0x24/0xb0 lr : kernfs_name_hash+0x1c/0xc4 sp : ffffffc081f97380 x29: ffffffc081f97380 x28: ffffffc081f97b90 x27: ffffff80c821c2a0 x26: ffffffedac0be418 x25: 0000000000000000 x24: ffffff80c09d2000 x23: 0000000000000000 x22: 0000000000000000 x21: 0000000000000000 x20: 0000000000000000 x19: 0000000000000000 x18: 0000000000001840 x17: 0000000000000000 x16: 0000000000000000 x15: 1ffffff8103f2e42 x14: 00000000f1f1f1f1 x13: 0000000000000004 x12: ffffffb01812d61d x11: 1ffffff01812d61c x10: ffffffb01812d61c x9 : dfffffc000000000 x8 : 0000004fe7ed29e4 x7 : ffffff80c096b0e7 x6 : 0000000000000001 x5 : ffffff80c096b0e0 x4 : 1ffffffdb990efa2 x3 : 0000000000000000 x2 : 0000000000000000 x1 : dfffffc000000000 x0 : 0000000000000000 Call trace: strlen+0x24/0xb0 kernfs_name_hash+0x1c/0xc4 kernfs_find_ns+0x118/0x2e8 kernfs_remove_by_name_ns+0x80/0x100 sysfs_remove_link+0x74/0xa8 module_add_driver+0x278/0x394 bus_add_driver+0x1f0/0x43c driver_register+0xf4/0x3c0 __platform_driver_register+0x60/0x88 of_fpga_region_init+0x20/0x1000 [of_fpga_region] do_one_initcall+0x110/0x788 do_init_module+0x1dc/0x5c8 load_module+0x3c38/0x4cac init_module_from_file+0xd4/0x128 idempotent_init_module+0x2cc/0x528 __arm64_sys_finit_module+0xac/0x100 invoke_syscall+0x6c/0x258 el0_svc_common.constprop.0+0x160/0x22c do_el0_svc+0x44/0x5c el0_svc+0x48/0xb8 el0t_64_sync_handler+0x13c/0x158 el0t_64_sync+0x190/0x194 Code: f2fbffe1 a90157f4 12000802 aa0003f5 (38e16861) ---[ end trace 0000000000000000 ]--- Kernel panic - not syncing: Oops: Fatal exception

In the Linux kernel, the following vulnerability has been resolved: lib/group_cpus: fix NULL pointer dereference from group_cpus_evenly() While testing null_blk with configfs, echo 0 > poll_queues will trigger following panic: BUG: kernel NULL pointer dereference, address: 0000000000000010 Oops: Oops: 0000 [#1] SMP NOPTI CPU: 27 UID: 0 PID: 920 Comm: bash Not tainted 6.15.0-02023-gadbdb95c8696-dirty #1238 PREEMPT(undef) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.1-2.fc37 04/01/2014 RIP: 0010:__bitmap_or+0x48/0x70 Call Trace: <TASK> __group_cpus_evenly+0x822/0x8c0 group_cpus_evenly+0x2d9/0x490 blk_mq_map_queues+0x1e/0x110 null_map_queues+0xc9/0x170 [null_blk] blk_mq_update_queue_map+0xdb/0x160 blk_mq_update_nr_hw_queues+0x22b/0x560 nullb_update_nr_hw_queues+0x71/0xf0 [null_blk] nullb_device_poll_queues_store+0xa4/0x130 [null_blk] configfs_write_iter+0x109/0x1d0 vfs_write+0x26e/0x6f0 ksys_write+0x79/0x180 __x64_sys_write+0x1d/0x30 x64_sys_call+0x45c4/0x45f0 do_syscall_64+0xa5/0x240 entry_SYSCALL_64_after_hwframe+0x76/0x7e Root cause is that numgrps is set to 0, and ZERO_SIZE_PTR is returned from kcalloc(), and later ZERO_SIZE_PTR will be deferenced. Fix the problem by checking numgrps first in group_cpus_evenly(), and return NULL directly if numgrps is zero. [yukuai3@huawei.com: also fix the non-SMP version]

In the Linux kernel, the following vulnerability has been resolved: vme: Fix error not catched in fake_init() In fake_init(), __root_device_register() is possible to fail but it's ignored, which can cause unregistering vme_root fail when exit. general protection fault, probably for non-canonical address 0xdffffc000000008c KASAN: null-ptr-deref in range [0x0000000000000460-0x0000000000000467] RIP: 0010:root_device_unregister+0x26/0x60 Call Trace: <TASK> __x64_sys_delete_module+0x34f/0x540 do_syscall_64+0x38/0x90 entry_SYSCALL_64_after_hwframe+0x63/0xcd Return error when __root_device_register() fails.

In the Linux kernel, the following vulnerability has been resolved: media: coda: Add check for dcoda_iram_alloc As the coda_iram_alloc may return NULL pointer, it should be better to check the return value in order to avoid NULL poineter dereference, same as the others.

In the Linux kernel, the following vulnerability has been resolved: net: dsa: felix: suppress non-changes to the tagging protocol The way in which dsa_tree_change_tag_proto() works is that when dsa_tree_notify() fails, it doesn't know whether the operation failed mid way in a multi-switch tree, or it failed for a single-switch tree. So even though drivers need to fail cleanly in ds->ops->change_tag_protocol(), DSA will still call dsa_tree_notify() again, to restore the old tag protocol for potential switches in the tree where the change did succeeed (before failing for others). This means for the felix driver that if we report an error in felix_change_tag_protocol(), we'll get another call where proto_ops == old_proto_ops. If we proceed to act upon that, we may do unexpected things. For example, we will call dsa_tag_8021q_register() twice in a row, without any dsa_tag_8021q_unregister() in between. Then we will actually call dsa_tag_8021q_unregister() via old_proto_ops->teardown, which (if it manages to run at all, after walking through corrupted data structures) will leave the ports inoperational anyway. The bug can be readily reproduced if we force an error while in tag_8021q mode; this crashes the kernel. echo ocelot-8021q > /sys/class/net/eno2/dsa/tagging echo edsa > /sys/class/net/eno2/dsa/tagging # -EPROTONOSUPPORT Unable to handle kernel NULL pointer dereference at virtual address 0000000000000014 Call trace: vcap_entry_get+0x24/0x124 ocelot_vcap_filter_del+0x198/0x270 felix_tag_8021q_vlan_del+0xd4/0x21c dsa_switch_tag_8021q_vlan_del+0x168/0x2cc dsa_switch_event+0x68/0x1170 dsa_tree_notify+0x14/0x34 dsa_port_tag_8021q_vlan_del+0x84/0x110 dsa_tag_8021q_unregister+0x15c/0x1c0 felix_tag_8021q_teardown+0x16c/0x180 felix_change_tag_protocol+0x1bc/0x230 dsa_switch_event+0x14c/0x1170 dsa_tree_change_tag_proto+0x118/0x1c0

In the Linux kernel, the following vulnerability has been resolved: net: If sock is dead don't access sock's sk_wq in sk_stream_wait_memory Fixes the below NULL pointer dereference: [...] [ 14.471200] Call Trace: [ 14.471562] <TASK> [ 14.471882] lock_acquire+0x245/0x2e0 [ 14.472416] ? remove_wait_queue+0x12/0x50 [ 14.473014] ? _raw_spin_lock_irqsave+0x17/0x50 [ 14.473681] _raw_spin_lock_irqsave+0x3d/0x50 [ 14.474318] ? remove_wait_queue+0x12/0x50 [ 14.474907] remove_wait_queue+0x12/0x50 [ 14.475480] sk_stream_wait_memory+0x20d/0x340 [ 14.476127] ? do_wait_intr_irq+0x80/0x80 [ 14.476704] do_tcp_sendpages+0x287/0x600 [ 14.477283] tcp_bpf_push+0xab/0x260 [ 14.477817] tcp_bpf_sendmsg_redir+0x297/0x500 [ 14.478461] ? __local_bh_enable_ip+0x77/0xe0 [ 14.479096] tcp_bpf_send_verdict+0x105/0x470 [ 14.479729] tcp_bpf_sendmsg+0x318/0x4f0 [ 14.480311] sock_sendmsg+0x2d/0x40 [ 14.480822] ____sys_sendmsg+0x1b4/0x1c0 [ 14.481390] ? copy_msghdr_from_user+0x62/0x80 [ 14.482048] ___sys_sendmsg+0x78/0xb0 [ 14.482580] ? vmf_insert_pfn_prot+0x91/0x150 [ 14.483215] ? __do_fault+0x2a/0x1a0 [ 14.483738] ? do_fault+0x15e/0x5d0 [ 14.484246] ? __handle_mm_fault+0x56b/0x1040 [ 14.484874] ? lock_is_held_type+0xdf/0x130 [ 14.485474] ? find_held_lock+0x2d/0x90 [ 14.486046] ? __sys_sendmsg+0x41/0x70 [ 14.486587] __sys_sendmsg+0x41/0x70 [ 14.487105] ? intel_pmu_drain_pebs_core+0x350/0x350 [ 14.487822] do_syscall_64+0x34/0x80 [ 14.488345] entry_SYSCALL_64_after_hwframe+0x63/0xcd [...] The test scenario has the following flow: thread1 thread2 ----------- --------------- tcp_bpf_sendmsg tcp_bpf_send_verdict tcp_bpf_sendmsg_redir sock_close tcp_bpf_push_locked __sock_release tcp_bpf_push //inet_release do_tcp_sendpages sock->ops->release sk_stream_wait_memory // tcp_close sk_wait_event sk->sk_prot->close release_sock(__sk); *** lock_sock(sk); __tcp_close sock_orphan(sk) sk->sk_wq = NULL release_sock **** lock_sock(__sk); remove_wait_queue(sk_sleep(sk), &wait); sk_sleep(sk) //NULL pointer dereference &rcu_dereference_raw(sk->sk_wq)->wait While waiting for memory in thread1, the socket is released with its wait queue because thread2 has closed it. This caused by tcp_bpf_send_verdict didn't increase the f_count of psock->sk_redir->sk_socket->file in thread1. We should check if SOCK_DEAD flag is set on wakeup in sk_stream_wait_memory before accessing the wait queue.

In the Linux kernel, the following vulnerability has been resolved: net: tap: NULL pointer derefence in dev_parse_header_protocol when skb->dev is null Fixes a NULL pointer derefence bug triggered from tap driver. When tap_get_user calls virtio_net_hdr_to_skb the skb->dev is null (in tap.c skb->dev is set after the call to virtio_net_hdr_to_skb) virtio_net_hdr_to_skb calls dev_parse_header_protocol which needs skb->dev field to be valid. The line that trigers the bug is in dev_parse_header_protocol (dev is at offset 0x10 from skb and is stored in RAX register) if (!dev->header_ops || !dev->header_ops->parse_protocol) 22e1: mov 0x10(%rbx),%rax 22e5: mov 0x230(%rax),%rax Setting skb->dev before the call in tap.c fixes the issue. BUG: kernel NULL pointer dereference, address: 0000000000000230 RIP: 0010:virtio_net_hdr_to_skb.constprop.0+0x335/0x410 [tap] Code: c0 0f 85 b7 fd ff ff eb d4 41 39 c6 77 cf 29 c6 48 89 df 44 01 f6 e8 7a 79 83 c1 48 85 c0 0f 85 d9 fd ff ff eb b7 48 8b 43 10 <48> 8b 80 30 02 00 00 48 85 c0 74 55 48 8b 40 28 48 85 c0 74 4c 48 RSP: 0018:ffffc90005c27c38 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff888298f25300 RCX: 0000000000000010 RDX: 0000000000000005 RSI: ffffc90005c27cb6 RDI: ffff888298f25300 RBP: ffffc90005c27c80 R08: 00000000ffffffea R09: 00000000000007e8 R10: ffff88858ec77458 R11: 0000000000000000 R12: 0000000000000001 R13: 0000000000000014 R14: ffffc90005c27e08 R15: ffffc90005c27cb6 FS: 0000000000000000(0000) GS:ffff88858ec40000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000230 CR3: 0000000281408006 CR4: 00000000003706e0 Call Trace: tap_get_user+0x3f1/0x540 [tap] tap_sendmsg+0x56/0x362 [tap] ? get_tx_bufs+0xc2/0x1e0 [vhost_net] handle_tx_copy+0x114/0x670 [vhost_net] handle_tx+0xb0/0xe0 [vhost_net] handle_tx_kick+0x15/0x20 [vhost_net] vhost_worker+0x7b/0xc0 [vhost] ? vhost_vring_call_reset+0x40/0x40 [vhost] kthread+0xfa/0x120 ? kthread_complete_and_exit+0x20/0x20 ret_from_fork+0x1f/0x30

In the Linux kernel, the following vulnerability has been resolved: drm/msm/disp/dpu1: avoid clearing hw interrupts if hw_intr is null during drm uninit If edp modeset init is failed due to panel being not ready and probe defers during drm bind, avoid clearing irqs and dereference hw_intr when hw_intr is null. BUG: Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 Call trace: dpu_core_irq_uninstall+0x50/0xb0 dpu_irq_uninstall+0x18/0x24 msm_drm_uninit+0xd8/0x16c msm_drm_bind+0x580/0x5fc try_to_bring_up_master+0x168/0x1c0 __component_add+0xb4/0x178 component_add+0x1c/0x28 dp_display_probe+0x38c/0x400 platform_probe+0xb0/0xd0 really_probe+0xcc/0x2c8 __driver_probe_device+0xbc/0xe8 driver_probe_device+0x48/0xf0 __device_attach_driver+0xa0/0xc8 bus_for_each_drv+0x8c/0xd8 __device_attach+0xc4/0x150 device_initial_probe+0x1c/0x28 Changes in V2: - Update commit message and coreect fixes tag. Patchwork: https://patchwork.freedesktop.org/patch/484430/

In the Linux kernel, the following vulnerability has been resolved: media: cx88: Fix a null-ptr-deref bug in buffer_prepare() When the driver calls cx88_risc_buffer() to prepare the buffer, the function call may fail, resulting in a empty buffer and null-ptr-deref later in buffer_queue(). The following log can reveal it: [ 41.822762] general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN PTI [ 41.824488] KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] [ 41.828027] RIP: 0010:buffer_queue+0xc2/0x500 [ 41.836311] Call Trace: [ 41.836945] __enqueue_in_driver+0x141/0x360 [ 41.837262] vb2_start_streaming+0x62/0x4a0 [ 41.838216] vb2_core_streamon+0x1da/0x2c0 [ 41.838516] __vb2_init_fileio+0x981/0xbc0 [ 41.839141] __vb2_perform_fileio+0xbf9/0x1120 [ 41.840072] vb2_fop_read+0x20e/0x400 [ 41.840346] v4l2_read+0x215/0x290 [ 41.840603] vfs_read+0x162/0x4c0 Fix this by checking the return value of cx88_risc_buffer() [hverkuil: fix coding style issues]

In the Linux kernel, the following vulnerability has been resolved: ASoC: rt7*-sdw: harden jack_detect_handler Realtek headset codec drivers typically check if the card is instantiated before proceeding with the jack detection. The rt700, rt711 and rt711-sdca are however missing a check on the card pointer, which can lead to NULL dereferences encountered in driver bind/unbind tests.

In the Linux kernel, the following vulnerability has been resolved: x86/fpu: Fix copy_xstate_to_uabi() to copy init states correctly When an extended state component is not present in fpstate, but in init state, the function copies from init_fpstate via copy_feature(). But, dynamic states are not present in init_fpstate because of all-zeros init states. Then retrieving them from init_fpstate will explode like this: BUG: kernel NULL pointer dereference, address: 0000000000000000 ... RIP: 0010:memcpy_erms+0x6/0x10 ? __copy_xstate_to_uabi_buf+0x381/0x870 fpu_copy_guest_fpstate_to_uabi+0x28/0x80 kvm_arch_vcpu_ioctl+0x14c/0x1460 [kvm] ? __this_cpu_preempt_check+0x13/0x20 ? vmx_vcpu_put+0x2e/0x260 [kvm_intel] kvm_vcpu_ioctl+0xea/0x6b0 [kvm] ? kvm_vcpu_ioctl+0xea/0x6b0 [kvm] ? __fget_light+0xd4/0x130 __x64_sys_ioctl+0xe3/0x910 ? debug_smp_processor_id+0x17/0x20 ? fpregs_assert_state_consistent+0x27/0x50 do_syscall_64+0x3f/0x90 entry_SYSCALL_64_after_hwframe+0x63/0xcd Adjust the 'mask' to zero out the userspace buffer for the features that are not available both from fpstate and from init_fpstate. The dynamic features depend on the compacted XSAVE format. Ensure it is enabled before reading XCOMP_BV in init_fpstate.

In the Linux kernel, the following vulnerability has been resolved: tipc: fix NULL deref in cleanup_bearer() syzbot found [1] that after blamed commit, ub->ubsock->sk was NULL when attempting the atomic_dec() : atomic_dec(&tipc_net(sock_net(ub->ubsock->sk))->wq_count); Fix this by caching the tipc_net pointer. [1] Oops: general protection fault, probably for non-canonical address 0xdffffc0000000006: 0000 [#1] PREEMPT SMP KASAN PTI KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037] CPU: 0 UID: 0 PID: 5896 Comm: kworker/0:3 Not tainted 6.13.0-rc1-next-20241203-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Workqueue: events cleanup_bearer RIP: 0010:read_pnet include/net/net_namespace.h:387 [inline] RIP: 0010:sock_net include/net/sock.h:655 [inline] RIP: 0010:cleanup_bearer+0x1f7/0x280 net/tipc/udp_media.c:820 Code: 18 48 89 d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 3c f7 99 f6 48 8b 1b 48 83 c3 30 e8 f0 e4 60 00 48 89 d8 48 c1 e8 03 <42> 80 3c 28 00 74 08 48 89 df e8 1a f7 99 f6 49 83 c7 e8 48 8b 1b RSP: 0018:ffffc9000410fb70 EFLAGS: 00010206 RAX: 0000000000000006 RBX: 0000000000000030 RCX: ffff88802fe45a00 RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffffc9000410f900 RBP: ffff88807e1f0908 R08: ffffc9000410f907 R09: 1ffff92000821f20 R10: dffffc0000000000 R11: fffff52000821f21 R12: ffff888031d19980 R13: dffffc0000000000 R14: dffffc0000000000 R15: ffff88807e1f0918 FS: 0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000556ca050b000 CR3: 0000000031c0c000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

In the Linux kernel, the following vulnerability has been resolved: drm/msm/mdp5: Return error code in mdp5_mixer_release when deadlock is detected There is a possibility for mdp5_get_global_state to return -EDEADLK when acquiring the modeset lock, but currently global_state in mdp5_mixer_release doesn't check for if an error is returned. To avoid a NULL dereference error, let's have mdp5_mixer_release check if an error is returned and propagate that error. Patchwork: https://patchwork.freedesktop.org/patch/485181/

In the Linux kernel, the following vulnerability has been resolved: HID: nintendo: fix rumble worker null pointer deref We can dereference a null pointer trying to queue work to a destroyed workqueue. If the device is disconnected, nintendo_hid_remove is called, in which the rumble_queue is destroyed. Avoid using that queue to defer rumble work once the controller state is set to JOYCON_CTLR_STATE_REMOVED. This eliminates the null pointer dereference.

In the Linux kernel, the following vulnerability has been resolved: phy: qcom-qmp-combo: fix NULL-deref on runtime resume Commit fc64623637da ("phy: qcom-qmp-combo,usb: add support for separate PCS_USB region") started treating the PCS_USB registers as potentially separate from the PCS registers but used the wrong base when no PCS_USB offset has been provided. Fix the PCS_USB base used at runtime resume to prevent dereferencing a NULL pointer on platforms that do not provide a PCS_USB offset (e.g. SC7180).

In the Linux kernel, the following vulnerability has been resolved: wifi: mac80211: fix general-protection-fault in ieee80211_subif_start_xmit() When device is running and the interface status is changed, the gpf issue is triggered. The problem triggering process is as follows: Thread A: Thread B ieee80211_runtime_change_iftype() process_one_work() ... ... ieee80211_do_stop() ... ... ... sdata->bss = NULL ... ... ieee80211_subif_start_xmit() ieee80211_multicast_to_unicast //!sdata->bss->multicast_to_unicast cause gpf issue When the interface status is changed, the sending queue continues to send packets. After the bss is set to NULL, the bss is accessed. As a result, this causes a general-protection-fault issue. The following is the stack information: general protection fault, probably for non-canonical address 0xdffffc000000002f: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000178-0x000000000000017f] Workqueue: mld mld_ifc_work RIP: 0010:ieee80211_subif_start_xmit+0x25b/0x1310 Call Trace: <TASK> dev_hard_start_xmit+0x1be/0x990 __dev_queue_xmit+0x2c9a/0x3b60 ip6_finish_output2+0xf92/0x1520 ip6_finish_output+0x6af/0x11e0 ip6_output+0x1ed/0x540 mld_sendpack+0xa09/0xe70 mld_ifc_work+0x71c/0xdb0 process_one_work+0x9bf/0x1710 worker_thread+0x665/0x1080 kthread+0x2e4/0x3a0 ret_from_fork+0x1f/0x30 </TASK>

In the Linux kernel, the following vulnerability has been resolved: drivers/md/md-bitmap: check the return value of md_bitmap_get_counter() Check the return value of md_bitmap_get_counter() in case it returns NULL pointer, which will result in a null pointer dereference. v2: update the check to include other dereference

In the Linux kernel, the following vulnerability has been resolved: vdpa_sim_blk: set number of address spaces and virtqueue groups Commit bda324fd037a ("vdpasim: control virtqueue support") added two new fields (nas, ngroups) to vdpasim_dev_attr, but we forgot to initialize them for vdpa_sim_blk. When creating a new vdpa_sim_blk device this causes the kernel to panic in this way:    $ vdpa dev add mgmtdev vdpasim_blk name blk0    BUG: kernel NULL pointer dereference, address: 0000000000000030    ...    RIP: 0010:vhost_iotlb_add_range_ctx+0x41/0x220 [vhost_iotlb]    ...    Call Trace:     <TASK>     vhost_iotlb_add_range+0x11/0x800 [vhost_iotlb]     vdpasim_map_range+0x91/0xd0 [vdpa_sim]     vdpasim_alloc_coherent+0x56/0x90 [vdpa_sim]     ... This happens because vdpasim->iommu[0] is not initialized when dev_attr.nas is 0. Let's fix this issue by initializing both (nas, ngroups) to 1 for vdpa_sim_blk.

In the Linux kernel, the following vulnerability has been resolved: powerpc/rtas: Fix RTAS MSR[HV] handling for Cell The semi-recent changes to MSR handling when entering RTAS (firmware) cause crashes on IBM Cell machines. An example trace: kernel tried to execute user page (2fff01a8) - exploit attempt? (uid: 0) BUG: Unable to handle kernel instruction fetch Faulting instruction address: 0x2fff01a8 Oops: Kernel access of bad area, sig: 11 [#1] BE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=4 NUMA Cell Modules linked in: CPU: 0 PID: 0 Comm: swapper/0 Tainted: G W 6.0.0-rc2-00433-gede0a8d3307a #207 NIP: 000000002fff01a8 LR: 0000000000032608 CTR: 0000000000000000 REGS: c0000000015236b0 TRAP: 0400 Tainted: G W (6.0.0-rc2-00433-gede0a8d3307a) MSR: 0000000008001002 <ME,RI> CR: 00000000 XER: 20000000 ... NIP 0x2fff01a8 LR 0x32608 Call Trace: 0xc00000000143c5f8 (unreliable) .rtas_call+0x224/0x320 .rtas_get_boot_time+0x70/0x150 .read_persistent_clock64+0x114/0x140 .read_persistent_wall_and_boot_offset+0x24/0x80 .timekeeping_init+0x40/0x29c .start_kernel+0x674/0x8f0 start_here_common+0x1c/0x50 Unlike PAPR platforms where RTAS is only used in guests, on the IBM Cell machines Linux runs with MSR[HV] set but also uses RTAS, provided by SLOF. Fix it by copying the MSR[HV] bit from the MSR value we've just read using mfmsr into the value used for RTAS. It seems like we could also fix it using an #ifdef CELL to set MSR[HV], but that doesn't work because it's possible to build a single kernel image that runs on both Cell native and pseries.

In the Linux kernel, the following vulnerability has been resolved: md/bitmap: don't set sb values if can't pass sanity check If bitmap area contains invalid data, kernel will crash then mdadm triggers "Segmentation fault". This is cluster-md speical bug. In non-clustered env, mdadm will handle broken metadata case. In clustered array, only kernel space handles bitmap slot info. But even this bug only happened in clustered env, current sanity check is wrong, the code should be changed. How to trigger: (faulty injection) dd if=/dev/zero bs=1M count=1 oflag=direct of=/dev/sda dd if=/dev/zero bs=1M count=1 oflag=direct of=/dev/sdb mdadm -C /dev/md0 -b clustered -e 1.2 -n 2 -l mirror /dev/sda /dev/sdb mdadm -Ss echo aaa > magic.txt == below modifying slot 2 bitmap data == dd if=magic.txt of=/dev/sda seek=16384 bs=1 count=3 <== destroy magic dd if=/dev/zero of=/dev/sda seek=16436 bs=1 count=4 <== ZERO chunksize mdadm -A /dev/md0 /dev/sda /dev/sdb == kernel crashes. mdadm outputs "Segmentation fault" == Reason of kernel crash: In md_bitmap_read_sb (called by md_bitmap_create), bad bitmap magic didn't block chunksize assignment, and zero value made DIV_ROUND_UP_SECTOR_T() trigger "divide error". Crash log: kernel: md: md0 stopped. kernel: md/raid1:md0: not clean -- starting background reconstruction kernel: md/raid1:md0: active with 2 out of 2 mirrors kernel: dlm: ... ... kernel: md-cluster: Joined cluster 44810aba-38bb-e6b8-daca-bc97a0b254aa slot 1 kernel: md0: invalid bitmap file superblock: bad magic kernel: md_bitmap_copy_from_slot can't get bitmap from slot 2 kernel: md-cluster: Could not gather bitmaps from slot 2 kernel: divide error: 0000 [#1] SMP NOPTI kernel: CPU: 0 PID: 1603 Comm: mdadm Not tainted 5.14.6-1-default kernel: Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) kernel: RIP: 0010:md_bitmap_create+0x1d1/0x850 [md_mod] kernel: RSP: 0018:ffffc22ac0843ba0 EFLAGS: 00010246 kernel: ... ... kernel: Call Trace: kernel: ? dlm_lock_sync+0xd0/0xd0 [md_cluster 77fe..7a0] kernel: md_bitmap_copy_from_slot+0x2c/0x290 [md_mod 24ea..d3a] kernel: load_bitmaps+0xec/0x210 [md_cluster 77fe..7a0] kernel: md_bitmap_load+0x81/0x1e0 [md_mod 24ea..d3a] kernel: do_md_run+0x30/0x100 [md_mod 24ea..d3a] kernel: md_ioctl+0x1290/0x15a0 [md_mod 24ea....d3a] kernel: ? mddev_unlock+0xaa/0x130 [md_mod 24ea..d3a] kernel: ? blkdev_ioctl+0xb1/0x2b0 kernel: block_ioctl+0x3b/0x40 kernel: __x64_sys_ioctl+0x7f/0xb0 kernel: do_syscall_64+0x59/0x80 kernel: ? exit_to_user_mode_prepare+0x1ab/0x230 kernel: ? syscall_exit_to_user_mode+0x18/0x40 kernel: ? do_syscall_64+0x69/0x80 kernel: entry_SYSCALL_64_after_hwframe+0x44/0xae kernel: RIP: 0033:0x7f4a15fa722b kernel: ... ... kernel: ---[ end trace 8afa7612f559c868 ]--- kernel: RIP: 0010:md_bitmap_create+0x1d1/0x850 [md_mod]

In the Linux kernel, the following vulnerability has been resolved: wifi: wilc1000: add missing unregister_netdev() in wilc_netdev_ifc_init() Fault injection test reports this issue: kernel BUG at net/core/dev.c:10731! invalid opcode: 0000 [#1] PREEMPT SMP KASAN PTI Call Trace: <TASK> wilc_netdev_ifc_init+0x19f/0x220 [wilc1000 884bf126e9e98af6a708f266a8dffd53f99e4bf5] wilc_cfg80211_init+0x30c/0x380 [wilc1000 884bf126e9e98af6a708f266a8dffd53f99e4bf5] wilc_bus_probe+0xad/0x2b0 [wilc1000_spi 1520a7539b6589cc6cde2ae826a523a33f8bacff] spi_probe+0xe4/0x140 really_probe+0x17e/0x3f0 __driver_probe_device+0xe3/0x170 driver_probe_device+0x49/0x120 The root case here is alloc_ordered_workqueue() fails, but cfg80211_unregister_netdevice() or unregister_netdev() not be called in error handling path. To fix add unregister_netdev goto lable to add the unregister operation in error handling path.

In the Linux kernel, the following vulnerability has been resolved: ice: xsk: prohibit usage of non-balanced queue id Fix the following scenario: 1. ethtool -L $IFACE rx 8 tx 96 2. xdpsock -q 10 -t -z Above refers to a case where user would like to attach XSK socket in txonly mode at a queue id that does not have a corresponding Rx queue. At this moment ice's XSK logic is tightly bound to act on a "queue pair", e.g. both Tx and Rx queues at a given queue id are disabled/enabled and both of them will get XSK pool assigned, which is broken for the presented queue configuration. This results in the splat included at the bottom, which is basically an OOB access to Rx ring array. To fix this, allow using the ids only in scope of "combined" queues reported by ethtool. However, logic should be rewritten to allow such configurations later on, which would end up as a complete rewrite of the control path, so let us go with this temporary fix. [420160.558008] BUG: kernel NULL pointer dereference, address: 0000000000000082 [420160.566359] #PF: supervisor read access in kernel mode [420160.572657] #PF: error_code(0x0000) - not-present page [420160.579002] PGD 0 P4D 0 [420160.582756] Oops: 0000 [#1] PREEMPT SMP NOPTI [420160.588396] CPU: 10 PID: 21232 Comm: xdpsock Tainted: G OE 5.19.0-rc7+ #10 [420160.597893] Hardware name: Intel Corporation S2600WFT/S2600WFT, BIOS SE5C620.86B.02.01.0008.031920191559 03/19/2019 [420160.609894] RIP: 0010:ice_xsk_pool_setup+0x44/0x7d0 [ice] [420160.616968] Code: f3 48 83 ec 40 48 8b 4f 20 48 8b 3f 65 48 8b 04 25 28 00 00 00 48 89 44 24 38 31 c0 48 8d 04 ed 00 00 00 00 48 01 c1 48 8b 11 <0f> b7 92 82 00 00 00 48 85 d2 0f 84 2d 75 00 00 48 8d 72 ff 48 85 [420160.639421] RSP: 0018:ffffc9002d2afd48 EFLAGS: 00010282 [420160.646650] RAX: 0000000000000050 RBX: ffff88811d8bdd00 RCX: ffff888112c14ff8 [420160.655893] RDX: 0000000000000000 RSI: ffff88811d8bdd00 RDI: ffff888109861000 [420160.665166] RBP: 000000000000000a R08: 000000000000000a R09: 0000000000000000 [420160.674493] R10: 000000000000889f R11: 0000000000000000 R12: 000000000000000a [420160.683833] R13: 000000000000000a R14: 0000000000000000 R15: ffff888117611828 [420160.693211] FS: 00007fa869fc1f80(0000) GS:ffff8897e0880000(0000) knlGS:0000000000000000 [420160.703645] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [420160.711783] CR2: 0000000000000082 CR3: 00000001d076c001 CR4: 00000000007706e0 [420160.721399] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [420160.731045] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [420160.740707] PKRU: 55555554 [420160.745960] Call Trace: [420160.750962] <TASK> [420160.755597] ? kmalloc_large_node+0x79/0x90 [420160.762703] ? __kmalloc_node+0x3f5/0x4b0 [420160.769341] xp_assign_dev+0xfd/0x210 [420160.775661] ? shmem_file_read_iter+0x29a/0x420 [420160.782896] xsk_bind+0x152/0x490 [420160.788943] __sys_bind+0xd0/0x100 [420160.795097] ? exit_to_user_mode_prepare+0x20/0x120 [420160.802801] __x64_sys_bind+0x16/0x20 [420160.809298] do_syscall_64+0x38/0x90 [420160.815741] entry_SYSCALL_64_after_hwframe+0x63/0xcd [420160.823731] RIP: 0033:0x7fa86a0dd2fb [420160.830264] Code: c3 66 0f 1f 44 00 00 48 8b 15 69 8b 0c 00 f7 d8 64 89 02 b8 ff ff ff ff eb bc 0f 1f 44 00 00 f3 0f 1e fa b8 31 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 3d 8b 0c 00 f7 d8 64 89 01 48 [420160.855410] RSP: 002b:00007ffc1146f618 EFLAGS: 00000246 ORIG_RAX: 0000000000000031 [420160.866366] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fa86a0dd2fb [420160.876957] RDX: 0000000000000010 RSI: 00007ffc1146f680 RDI: 0000000000000003 [420160.887604] RBP: 000055d7113a0520 R08: 00007fa868fb8000 R09: 0000000080000000 [420160.898293] R10: 0000000000008001 R11: 0000000000000246 R12: 000055d7113a04e0 [420160.909038] R13: 000055d7113a0320 R14: 000000000000000a R15: 0000000000000000 [420160.919817] </TASK> [420160.925659] Modules linked in: ice(OE) af_packet binfmt_misc ---truncated---

In the Linux kernel, the following vulnerability has been resolved: tee: add overflow check in register_shm_helper() With special lengths supplied by user space, register_shm_helper() has an integer overflow when calculating the number of pages covered by a supplied user space memory region. This causes internal_get_user_pages_fast() a helper function of pin_user_pages_fast() to do a NULL pointer dereference: Unable to handle kernel NULL pointer dereference at virtual address 0000000000000010 Modules linked in: CPU: 1 PID: 173 Comm: optee_example_a Not tainted 5.19.0 #11 Hardware name: QEMU QEMU Virtual Machine, BIOS 0.0.0 02/06/2015 pc : internal_get_user_pages_fast+0x474/0xa80 Call trace: internal_get_user_pages_fast+0x474/0xa80 pin_user_pages_fast+0x24/0x4c register_shm_helper+0x194/0x330 tee_shm_register_user_buf+0x78/0x120 tee_ioctl+0xd0/0x11a0 __arm64_sys_ioctl+0xa8/0xec invoke_syscall+0x48/0x114 Fix this by adding an an explicit call to access_ok() in tee_shm_register_user_buf() to catch an invalid user space address early.

In the Linux kernel, the following vulnerability has been resolved: net/mlx5: Fix bridge mode operations when there are no VFs Currently, trying to set the bridge mode attribute when numvfs=0 leads to a crash: bridge link set dev eth2 hwmode vepa [ 168.967392] BUG: kernel NULL pointer dereference, address: 0000000000000030 [...] [ 168.969989] RIP: 0010:mlx5_add_flow_rules+0x1f/0x300 [mlx5_core] [...] [ 168.976037] Call Trace: [ 168.976188] <TASK> [ 168.978620] _mlx5_eswitch_set_vepa_locked+0x113/0x230 [mlx5_core] [ 168.979074] mlx5_eswitch_set_vepa+0x7f/0xa0 [mlx5_core] [ 168.979471] rtnl_bridge_setlink+0xe9/0x1f0 [ 168.979714] rtnetlink_rcv_msg+0x159/0x400 [ 168.980451] netlink_rcv_skb+0x54/0x100 [ 168.980675] netlink_unicast+0x241/0x360 [ 168.980918] netlink_sendmsg+0x1f6/0x430 [ 168.981162] ____sys_sendmsg+0x3bb/0x3f0 [ 168.982155] ___sys_sendmsg+0x88/0xd0 [ 168.985036] __sys_sendmsg+0x59/0xa0 [ 168.985477] do_syscall_64+0x79/0x150 [ 168.987273] entry_SYSCALL_64_after_hwframe+0x76/0x7e [ 168.987773] RIP: 0033:0x7f8f7950f917 (esw->fdb_table.legacy.vepa_fdb is null) The bridge mode is only relevant when there are multiple functions per port. Therefore, prevent setting and getting this setting when there are no VFs. Note that after this change, there are no settings to change on the PF interface using `bridge link` when there are no VFs, so the interface no longer appears in the `bridge link` output.

In the Linux kernel, the following vulnerability has been resolved: iommu/mediatek: Fix NULL pointer dereference when printing dev_name When larbdev is NULL (in the case I hit, the node is incorrectly set iommus = <&iommu NUM>), it will cause device_link_add() fail and kernel crashes when we try to print dev_name(larbdev). Let's fail the probe if a larbdev is NULL to avoid invalid inputs from dts. It should work for normal correct setting and avoid the crash caused by my incorrect setting. Error log: [ 18.189042][ T301] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000050 ... [ 18.344519][ T301] pstate: a0400005 (NzCv daif +PAN -UAO) [ 18.345213][ T301] pc : mtk_iommu_probe_device+0xf8/0x118 [mtk_iommu] [ 18.346050][ T301] lr : mtk_iommu_probe_device+0xd0/0x118 [mtk_iommu] [ 18.346884][ T301] sp : ffffffc00a5635e0 [ 18.347392][ T301] x29: ffffffc00a5635e0 x28: ffffffd44a46c1d8 [ 18.348156][ T301] x27: ffffff80c39a8000 x26: ffffffd44a80cc38 [ 18.348917][ T301] x25: 0000000000000000 x24: ffffffd44a80cc38 [ 18.349677][ T301] x23: ffffffd44e4da4c6 x22: ffffffd44a80cc38 [ 18.350438][ T301] x21: ffffff80cecd1880 x20: 0000000000000000 [ 18.351198][ T301] x19: ffffff80c439f010 x18: ffffffc00a50d0c0 [ 18.351959][ T301] x17: ffffffffffffffff x16: 0000000000000004 [ 18.352719][ T301] x15: 0000000000000004 x14: ffffffd44eb5d420 [ 18.353480][ T301] x13: 0000000000000ad2 x12: 0000000000000003 [ 18.354241][ T301] x11: 00000000fffffad2 x10: c0000000fffffad2 [ 18.355003][ T301] x9 : a0d288d8d7142d00 x8 : a0d288d8d7142d00 [ 18.355763][ T301] x7 : ffffffd44c2bc640 x6 : 0000000000000000 [ 18.356524][ T301] x5 : 0000000000000080 x4 : 0000000000000001 [ 18.357284][ T301] x3 : 0000000000000000 x2 : 0000000000000005 [ 18.358045][ T301] x1 : 0000000000000000 x0 : 0000000000000000 [ 18.360208][ T301] Hardware name: MT6873 (DT) [ 18.360771][ T301] Call trace: [ 18.361168][ T301] dump_backtrace+0xf8/0x1f0 [ 18.361737][ T301] dump_stack_lvl+0xa8/0x11c [ 18.362305][ T301] dump_stack+0x1c/0x2c [ 18.362816][ T301] mrdump_common_die+0x184/0x40c [mrdump] [ 18.363575][ T301] ipanic_die+0x24/0x38 [mrdump] [ 18.364230][ T301] atomic_notifier_call_chain+0x128/0x2b8 [ 18.364937][ T301] die+0x16c/0x568 [ 18.365394][ T301] __do_kernel_fault+0x1e8/0x214 [ 18.365402][ T301] do_page_fault+0xb8/0x678 [ 18.366934][ T301] do_translation_fault+0x48/0x64 [ 18.368645][ T301] do_mem_abort+0x68/0x148 [ 18.368652][ T301] el1_abort+0x40/0x64 [ 18.368660][ T301] el1h_64_sync_handler+0x54/0x88 [ 18.368668][ T301] el1h_64_sync+0x68/0x6c [ 18.368673][ T301] mtk_iommu_probe_device+0xf8/0x118 [mtk_iommu] ...

In the Linux kernel, the following vulnerability has been resolved: drm/amdgpu: fix the waring dereferencing hive Check the amdgpu_hive_info *hive that maybe is NULL.

In the Linux kernel, the following vulnerability has been resolved: mac802154: fix missing INIT_LIST_HEAD in ieee802154_if_add() Kernel fault injection test reports null-ptr-deref as follows: BUG: kernel NULL pointer dereference, address: 0000000000000008 RIP: 0010:cfg802154_netdev_notifier_call+0x120/0x310 include/linux/list.h:114 Call Trace: <TASK> raw_notifier_call_chain+0x6d/0xa0 kernel/notifier.c:87 call_netdevice_notifiers_info+0x6e/0xc0 net/core/dev.c:1944 unregister_netdevice_many_notify+0x60d/0xcb0 net/core/dev.c:1982 unregister_netdevice_queue+0x154/0x1a0 net/core/dev.c:10879 register_netdevice+0x9a8/0xb90 net/core/dev.c:10083 ieee802154_if_add+0x6ed/0x7e0 net/mac802154/iface.c:659 ieee802154_register_hw+0x29c/0x330 net/mac802154/main.c:229 mcr20a_probe+0xaaa/0xcb1 drivers/net/ieee802154/mcr20a.c:1316 ieee802154_if_add() allocates wpan_dev as netdev's private data, but not init the list in struct wpan_dev. cfg802154_netdev_notifier_call() manage the list when device register/unregister, and may lead to null-ptr-deref. Use INIT_LIST_HEAD() on it to initialize it correctly.

In the Linux kernel, the following vulnerability has been resolved: drm/amdgpu: Change AMDGPU_VA_RESERVED_TRAP_SIZE to 64KB Currently, AMDGPU_VA_RESERVED_TRAP_SIZE is hardcoded to 8KB, while KFD_CWSR_TBA_TMA_SIZE is defined as 2 * PAGE_SIZE. On systems with 4K pages, both values match (8KB), so allocation and reserved space are consistent. However, on 64K page-size systems, KFD_CWSR_TBA_TMA_SIZE becomes 128KB, while the reserved trap area remains 8KB. This mismatch causes the kernel to crash when running rocminfo or rccl unit tests. Kernel attempted to read user page (2) - exploit attempt? (uid: 1001) BUG: Kernel NULL pointer dereference on read at 0x00000002 Faulting instruction address: 0xc0000000002c8a64 Oops: Kernel access of bad area, sig: 11 [#1] LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA pSeries CPU: 34 UID: 1001 PID: 9379 Comm: rocminfo Tainted: G E 6.19.0-rc4-amdgpu-00320-gf23176405700 #56 VOLUNTARY Tainted: [E]=UNSIGNED_MODULE Hardware name: IBM,9105-42A POWER10 (architected) 0x800200 0xf000006 of:IBM,FW1060.30 (ML1060_896) hv:phyp pSeries NIP: c0000000002c8a64 LR: c00000000125dbc8 CTR: c00000000125e730 REGS: c0000001e0957580 TRAP: 0300 Tainted: G E MSR: 8000000000009033 <SF,EE,ME,IR,DR,RI,LE> CR: 24008268 XER: 00000036 CFAR: c00000000125dbc4 DAR: 0000000000000002 DSISR: 40000000 IRQMASK: 1 GPR00: c00000000125d908 c0000001e0957820 c0000000016e8100 c00000013d814540 GPR04: 0000000000000002 c00000013d814550 0000000000000045 0000000000000000 GPR08: c00000013444d000 c00000013d814538 c00000013d814538 0000000084002268 GPR12: c00000000125e730 c000007e2ffd5f00 ffffffffffffffff 0000000000020000 GPR16: 0000000000000000 0000000000000002 c00000015f653000 0000000000000000 GPR20: c000000138662400 c00000013d814540 0000000000000000 c00000013d814500 GPR24: 0000000000000000 0000000000000002 c0000001e0957888 c0000001e0957878 GPR28: c00000013d814548 0000000000000000 c00000013d814540 c0000001e0957888 NIP [c0000000002c8a64] __mutex_add_waiter+0x24/0xc0 LR [c00000000125dbc8] __mutex_lock.constprop.0+0x318/0xd00 Call Trace: 0xc0000001e0957890 (unreliable) __mutex_lock.constprop.0+0x58/0xd00 amdgpu_amdkfd_gpuvm_alloc_memory_of_gpu+0x6fc/0xb60 [amdgpu] kfd_process_alloc_gpuvm+0x54/0x1f0 [amdgpu] kfd_process_device_init_cwsr_dgpu+0xa4/0x1a0 [amdgpu] kfd_process_device_init_vm+0xd8/0x2e0 [amdgpu] kfd_ioctl_acquire_vm+0xd0/0x130 [amdgpu] kfd_ioctl+0x514/0x670 [amdgpu] sys_ioctl+0x134/0x180 system_call_exception+0x114/0x300 system_call_vectored_common+0x15c/0x2ec This patch changes AMDGPU_VA_RESERVED_TRAP_SIZE to 64 KB and KFD_CWSR_TBA_TMA_SIZE to the AMD GPU page size. This means we reserve 64 KB for the trap in the address space, but only allocate 8 KB within it. With this approach, the allocation size never exceeds the reserved area. (cherry picked from commit 31b8de5e55666f26ea7ece5f412b83eab3f56dbb)

In the Linux kernel, the following vulnerability has been resolved: auxdisplay: line-display: fix NULL dereference in linedisp_release linedisp_release() currently retrieves the enclosing struct linedisp via to_linedisp(). That lookup depends on the attachment list, but the attachment may already have been removed before put_device() invokes the release callback. This can happen in linedisp_unregister(), and can also be reached from some linedisp_register() error paths. In that case, to_linedisp() returns NULL and linedisp_release() dereferences it while freeing the display resources. The struct device released here is the embedded linedisp->dev used by linedisp_register(), so retrieve the enclosing object directly with container_of() instead.

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: fix null ptr deref on hci_sync_conn_complete_evt This event is just specified for SCO and eSCO link types. On the reception of a HCI_Synchronous_Connection_Complete for a BDADDR of an existing LE connection, LE link type and a status that triggers the second case of the packet processing a NULL pointer dereference happens, as conn->link is NULL.

In the Linux kernel, the following vulnerability has been resolved: i2c: dev: check return value when calling dev_set_name() If dev_set_name() fails, the dev_name() is null, check the return value of dev_set_name() to avoid the null-ptr-deref.

In the Linux kernel, the following vulnerability has been resolved: eventfs: Use list_del_rcu() for SRCU protected list variable Chi Zhiling reported: We found a null pointer accessing in tracefs[1], the reason is that the variable 'ei_child' is set to LIST_POISON1, that means the list was removed in eventfs_remove_rec. so when access the ei_child->is_freed, the panic triggered. by the way, the following script can reproduce this panic loop1 (){ while true do echo "p:kp submit_bio" > /sys/kernel/debug/tracing/kprobe_events echo "" > /sys/kernel/debug/tracing/kprobe_events done } loop2 (){ while true do tree /sys/kernel/debug/tracing/events/kprobes/ done } loop1 & loop2 [1]: [ 1147.959632][T17331] Unable to handle kernel paging request at virtual address dead000000000150 [ 1147.968239][T17331] Mem abort info: [ 1147.971739][T17331] ESR = 0x0000000096000004 [ 1147.976172][T17331] EC = 0x25: DABT (current EL), IL = 32 bits [ 1147.982171][T17331] SET = 0, FnV = 0 [ 1147.985906][T17331] EA = 0, S1PTW = 0 [ 1147.989734][T17331] FSC = 0x04: level 0 translation fault [ 1147.995292][T17331] Data abort info: [ 1147.998858][T17331] ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000 [ 1148.005023][T17331] CM = 0, WnR = 0, TnD = 0, TagAccess = 0 [ 1148.010759][T17331] GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 [ 1148.016752][T17331] [dead000000000150] address between user and kernel address ranges [ 1148.024571][T17331] Internal error: Oops: 0000000096000004 [#1] SMP [ 1148.030825][T17331] Modules linked in: team_mode_loadbalance team nlmon act_gact cls_flower sch_ingress bonding tls macvlan dummy ib_core bridge stp llc veth amdgpu amdxcp mfd_core gpu_sched drm_exec drm_buddy radeon crct10dif_ce video drm_suballoc_helper ghash_ce drm_ttm_helper sha2_ce ttm sha256_arm64 i2c_algo_bit sha1_ce sbsa_gwdt cp210x drm_display_helper cec sr_mod cdrom drm_kms_helper binfmt_misc sg loop fuse drm dm_mod nfnetlink ip_tables autofs4 [last unloaded: tls] [ 1148.072808][T17331] CPU: 3 PID: 17331 Comm: ls Tainted: G W ------- ---- 6.6.43 #2 [ 1148.081751][T17331] Source Version: 21b3b386e948bedd29369af66f3e98ab01b1c650 [ 1148.088783][T17331] Hardware name: Greatwall GW-001M1A-FTF/GW-001M1A-FTF, BIOS KunLun BIOS V4.0 07/16/2020 [ 1148.098419][T17331] pstate: 20000005 (nzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 1148.106060][T17331] pc : eventfs_iterate+0x2c0/0x398 [ 1148.111017][T17331] lr : eventfs_iterate+0x2fc/0x398 [ 1148.115969][T17331] sp : ffff80008d56bbd0 [ 1148.119964][T17331] x29: ffff80008d56bbf0 x28: ffff001ff5be2600 x27: 0000000000000000 [ 1148.127781][T17331] x26: ffff001ff52ca4e0 x25: 0000000000009977 x24: dead000000000100 [ 1148.135598][T17331] x23: 0000000000000000 x22: 000000000000000b x21: ffff800082645f10 [ 1148.143415][T17331] x20: ffff001fddf87c70 x19: ffff80008d56bc90 x18: 0000000000000000 [ 1148.151231][T17331] x17: 0000000000000000 x16: 0000000000000000 x15: ffff001ff52ca4e0 [ 1148.159048][T17331] x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000 [ 1148.166864][T17331] x11: 0000000000000000 x10: 0000000000000000 x9 : ffff8000804391d0 [ 1148.174680][T17331] x8 : 0000000180000000 x7 : 0000000000000018 x6 : 0000aaab04b92862 [ 1148.182498][T17331] x5 : 0000aaab04b92862 x4 : 0000000080000000 x3 : 0000000000000068 [ 1148.190314][T17331] x2 : 000000000000000f x1 : 0000000000007ea8 x0 : 0000000000000001 [ 1148.198131][T17331] Call trace: [ 1148.201259][T17331] eventfs_iterate+0x2c0/0x398 [ 1148.205864][T17331] iterate_dir+0x98/0x188 [ 1148.210036][T17331] __arm64_sys_getdents64+0x78/0x160 [ 1148.215161][T17331] invoke_syscall+0x78/0x108 [ 1148.219593][T17331] el0_svc_common.constprop.0+0x48/0xf0 [ 1148.224977][T17331] do_el0_svc+0x24/0x38 [ 1148.228974][T17331] el0_svc+0x40/0x168 [ 1148.232798][T17 ---truncated---

In the Linux kernel, the following vulnerability has been resolved: scsi: sd: Fix potential NULL pointer dereference If sd_probe() sees an early error before sdkp->device is initialized, sd_zbc_release_disk() is called. This causes a NULL pointer dereference when sd_is_zoned() is called inside that function. Avoid this by removing the call to sd_zbc_release_disk() in sd_probe() error path. This change is safe and does not result in zone information memory leakage because the zone information for a zoned disk is allocated only when sd_revalidate_disk() is called, at which point sdkp->disk_dev is fully set, resulting in sd_disk_release() being called when needed to cleanup a disk zone information using sd_zbc_release_disk().

In the Linux kernel, the following vulnerability has been resolved: spi: spi-fsl-qspi: check return value after calling platform_get_resource_byname() It will cause null-ptr-deref if platform_get_resource_byname() returns NULL, we need check the return value.

In the Linux kernel, the following vulnerability has been resolved: usb: gadget: renesas_usb3: validate endpoint index in standard request handlers The GET_STATUS and SET/CLEAR_FEATURE handlers extract the endpoint number from the host-supplied wIndex without any sort of validation. Fix this up by validating the number of endpoints actually match up with the number the device has before attempting to dereference a pointer based on this math. This is just like what was done in commit ee0d382feb44 ("usb: gadget: aspeed_udc: validate endpoint index for ast udc") for the aspeed driver.

In the Linux kernel, the following vulnerability has been resolved: apparmor: avoid crash when parsed profile name is empty When processing a packed profile in unpack_profile() described like "profile :ns::samba-dcerpcd /usr/lib*/samba/{,samba/}samba-dcerpcd {...}" a string ":samba-dcerpcd" is unpacked as a fully-qualified name and then passed to aa_splitn_fqname(). aa_splitn_fqname() treats ":samba-dcerpcd" as only containing a namespace. Thus it returns NULL for tmpname, meanwhile tmpns is non-NULL. Later aa_alloc_profile() crashes as the new profile name is NULL now. general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] CPU: 6 PID: 1657 Comm: apparmor_parser Not tainted 6.7.0-rc2-dirty #16 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.2-3-gd478f380-rebuilt.opensuse.org 04/01/2014 RIP: 0010:strlen+0x1e/0xa0 Call Trace: <TASK> ? strlen+0x1e/0xa0 aa_policy_init+0x1bb/0x230 aa_alloc_profile+0xb1/0x480 unpack_profile+0x3bc/0x4960 aa_unpack+0x309/0x15e0 aa_replace_profiles+0x213/0x33c0 policy_update+0x261/0x370 profile_replace+0x20e/0x2a0 vfs_write+0x2af/0xe00 ksys_write+0x126/0x250 do_syscall_64+0x46/0xf0 entry_SYSCALL_64_after_hwframe+0x6e/0x76 </TASK> ---[ end trace 0000000000000000 ]--- RIP: 0010:strlen+0x1e/0xa0 It seems such behaviour of aa_splitn_fqname() is expected and checked in other places where it is called (e.g. aa_remove_profiles). Well, there is an explicit comment "a ns name without a following profile is allowed" inside. AFAICS, nothing can prevent unpacked "name" to be in form like ":samba-dcerpcd" - it is passed from userspace. Deny the whole profile set replacement in such case and inform user with EPROTO and an explaining message. Found by Linux Verification Center (linuxtesting.org).

In the Linux kernel, the following vulnerability has been resolved: media: vidtv: fix NULL pointer dereference in vidtv_channel_pmt_match_sections syzbot reported a general protection fault in vidtv_psi_desc_assign [1]. vidtv_psi_pmt_stream_init() can return NULL on memory allocation failure, but vidtv_channel_pmt_match_sections() does not check for this. When tail is NULL, the subsequent call to vidtv_psi_desc_assign(&tail->descriptor, desc) dereferences a NULL pointer offset, causing a general protection fault. Add a NULL check after vidtv_psi_pmt_stream_init(). On failure, clean up the already-allocated stream chain and return. [1] Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN PTI KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] RIP: 0010:vidtv_psi_desc_assign+0x24/0x90 drivers/media/test-drivers/vidtv/vidtv_psi.c:629 Call Trace: <TASK> vidtv_channel_pmt_match_sections drivers/media/test-drivers/vidtv/vidtv_channel.c:349 [inline] vidtv_channel_si_init+0x1445/0x1a50 drivers/media/test-drivers/vidtv/vidtv_channel.c:479 vidtv_mux_init+0x526/0xbe0 drivers/media/test-drivers/vidtv/vidtv_mux.c:519 vidtv_start_streaming drivers/media/test-drivers/vidtv/vidtv_bridge.c:194 [inline] vidtv_start_feed+0x33e/0x4d0 drivers/media/test-drivers/vidtv/vidtv_bridge.c:239

In the Linux kernel, the following vulnerability has been resolved: usb: gadget: uvc: fix NULL pointer dereference during unbind race Commit b81ac4395bbe ("usb: gadget: uvc: allow for application to cleanly shutdown") introduced two stages of synchronization waits totaling 1500ms in uvc_function_unbind() to prevent several types of kernel panics. However, this timing-based approach is insufficient during power management (PM) transitions. When the PM subsystem starts freezing user space processes, the wait_event_interruptible_timeout() is aborted early, which allows the unbind thread to proceed and nullify the gadget pointer (cdev->gadget = NULL): [ 814.123447][ T947] configfs-gadget.g1 gadget.0: uvc: uvc_function_unbind() [ 814.178583][ T3173] PM: suspend entry (deep) [ 814.192487][ T3173] Freezing user space processes [ 814.197668][ T947] configfs-gadget.g1 gadget.0: uvc: uvc_function_unbind no clean disconnect, wait for release When the PM subsystem resumes or aborts the suspend and tasks are restarted, the V4L2 release path is executed and attempts to access the already nullified gadget pointer, triggering a kernel panic: [ 814.292597][ C0] PM: pm_system_irq_wakeup: 479 triggered dhdpcie_host_wake [ 814.386727][ T3173] Restarting tasks ... [ 814.403522][ T4558] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000030 [ 814.404021][ T4558] pc : usb_gadget_deactivate+0x14/0xf4 [ 814.404031][ T4558] lr : usb_function_deactivate+0x54/0x94 [ 814.404078][ T4558] Call trace: [ 814.404080][ T4558] usb_gadget_deactivate+0x14/0xf4 [ 814.404083][ T4558] usb_function_deactivate+0x54/0x94 [ 814.404087][ T4558] uvc_function_disconnect+0x1c/0x5c [ 814.404092][ T4558] uvc_v4l2_release+0x44/0xac [ 814.404095][ T4558] v4l2_release+0xcc/0x130 Address the race condition and NULL pointer dereference by: 1. State Synchronization (flag + mutex) Introduce a 'func_unbound' flag in struct uvc_device. This allows uvc_function_disconnect() to safely skip accessing the nullified cdev->gadget pointer. As suggested by Alan Stern, this flag is protected by a new mutex (uvc->lock) to ensure proper memory ordering and prevent instruction reordering or speculative loads. This mutex is also used to protect 'func_connected' for consistent state management. 2. Explicit Synchronization (completion) Use a completion to synchronize uvc_function_unbind() with the uvc_vdev_release() callback. This prevents Use-After-Free (UAF) by ensuring struct uvc_device is freed after all video device resources are released.

In the Linux kernel, the following vulnerability has been resolved: HID: alps: fix NULL pointer dereference in alps_raw_event() Commit ecfa6f34492c ("HID: Add HID_CLAIMED_INPUT guards in raw_event callbacks missing them") attempted to fix up the HID drivers that had missed the previous fix that was done in 2ff5baa9b527 ("HID: appleir: Fix potential NULL dereference at raw event handle"), but the alps driver was missed. Fix this up by properly checking in the hid-alps driver that it had been claimed correctly before attempting to process the raw event.

In the Linux kernel, the following vulnerability has been resolved: net: sparx5: switchdev: fix possible NULL pointer dereference As the possible failure of the allocation, devm_kzalloc() may return NULL pointer. Therefore, it should be better to check the 'db' in order to prevent the dereference of NULL pointer.

In the Linux kernel, the following vulnerability has been resolved: comedi: ni_atmio16d: Fix invalid clean-up after failed attach If the driver's COMEDI "attach" handler function (`atmio16d_attach()`) returns an error, the COMEDI core will call the driver's "detach" handler function (`atmio16d_detach()`) to clean up. This calls `reset_atmio16d()` unconditionally, but depending on where the error occurred in the attach handler, the device may not have been sufficiently initialized to call `reset_atmio16d()`. It uses `dev->iobase` as the I/O port base address and `dev->private` as the pointer to the COMEDI device's private data structure. `dev->iobase` may still be set to its initial value of 0, which would result in undesired writes to low I/O port addresses. `dev->private` may still be `NULL`, which would result in null pointer dereferences. Fix `atmio16d_detach()` by checking that `dev->private` is valid (non-null) before calling `reset_atmio16d()`. This implies that `dev->iobase` was set correctly since that is set up before `dev->private`.

In the Linux kernel, the following vulnerability has been resolved: usb: cdns3: gadget: fix NULL pointer dereference in ep_queue When the gadget endpoint is disabled or not yet configured, the ep->desc pointer can be NULL. This leads to a NULL pointer dereference when __cdns3_gadget_ep_queue() is called, causing a kernel crash. Add a check to return -ESHUTDOWN if ep->desc is NULL, which is the standard return code for unconfigured endpoints. This prevents potential crashes when ep_queue is called on endpoints that are not ready.

In the Linux kernel, the following vulnerability has been resolved: net: ethernet: mtk_ppe: avoid NULL deref when gmac0 is disabled If the gmac0 is disabled, the precheck for a valid ingress device will cause a NULL pointer deref and crash the system. This happens because eth->netdev[0] will be NULL but the code will directly try to access netdev_ops. Instead of just checking for the first net_device, it must be checked if any of the mtk_eth net_devices is matching the netdev_ops of the ingress device.

In the Linux kernel, the following vulnerability has been resolved: net: lan966x: fix page_pool error handling in lan966x_fdma_rx_alloc_page_pool() page_pool_create() can return an ERR_PTR on failure. The return value is used unconditionally in the loop that follows, passing the error pointer through xdp_rxq_info_reg_mem_model() into page_pool_use_xdp_mem(), which dereferences it, causing a kernel oops. Add an IS_ERR check after page_pool_create() to return early on failure.

In the Linux kernel, the following vulnerability has been resolved: EDAC/mc: Fix error path ordering in edac_mc_alloc() When the mci->pvt_info allocation in edac_mc_alloc() fails, the error path will call put_device() which will end up calling the device's release function. However, the init ordering is wrong such that device_initialize() happens *after* the failed allocation and thus the device itself and the release function pointer are not initialized yet when they're called: MCE: In-kernel MCE decoding enabled. ------------[ cut here ]------------ kobject: '(null)': is not initialized, yet kobject_put() is being called. WARNING: lib/kobject.c:734 at kobject_put, CPU#22: systemd-udevd CPU: 22 UID: 0 PID: 538 Comm: systemd-udevd Not tainted 7.0.0-rc1+ #2 PREEMPT(full) RIP: 0010:kobject_put Call Trace: <TASK> edac_mc_alloc+0xbe/0xe0 [edac_core] amd64_edac_init+0x7a4/0xff0 [amd64_edac] ? __pfx_amd64_edac_init+0x10/0x10 [amd64_edac] do_one_initcall ... Reorder the calling sequence so that the device is initialized and thus the release function pointer is properly set before it can be used. This was found by Claude while reviewing another EDAC patch.

In the Linux kernel, the following vulnerability has been resolved: mmc: vub300: fix NULL-deref on disconnect Make sure to deregister the controller before dropping the reference to the driver data on disconnect to avoid NULL-pointer dereferences or use-after-free.

In the Linux kernel, the following vulnerability has been resolved: net/mlx5e: Fix peer flow lists handling The cited change refactored mlx5e_tc_del_fdb_peer_flow() to only clear DUP flag when list of peer flows has become empty. However, if any concurrent user holds a reference to a peer flow (for example, the neighbor update workqueue task is updating peer flow's parent encap entry concurrently), then the flow will not be removed from the peer list and, consecutively, DUP flag will remain set. Since mlx5e_tc_del_fdb_peers_flow() calls mlx5e_tc_del_fdb_peer_flow() for every possible peer index the algorithm will try to remove the flow from eswitch instances that it has never peered with causing either NULL pointer dereference when trying to remove the flow peer list head of peer_index that was never initialized or a warning if the list debug config is enabled[0]. Fix the issue by always removing the peer flow from the list even when not releasing the last reference to it. [0]: [ 3102.985806] ------------[ cut here ]------------ [ 3102.986223] list_del corruption, ffff888139110698->next is NULL [ 3102.986757] WARNING: CPU: 2 PID: 22109 at lib/list_debug.c:53 __list_del_entry_valid_or_report+0x4f/0xc0 [ 3102.987561] Modules linked in: act_ct nf_flow_table bonding act_tunnel_key act_mirred act_skbedit vxlan cls_matchall nfnetlink_cttimeout act_gact cls_flower sch_ingress mlx5_vdpa vringh vhost_iotlb vdpa openvswitch nsh xt_MASQUERADE nf_conntrack_netlink nfnetlink iptable_nat xt_addrtype xt_conntrack nf_nat br_netfilter rpcsec_gss_krb5 auth_rpcg ss oid_registry overlay rpcrdma rdma_ucm ib_iser libiscsi scsi_transport_iscsi ib_umad rdma_cm ib_ipoib iw_cm ib_cm mlx5_ib ib_uverbs ib_core mlx5_core [last unloaded: bonding] [ 3102.991113] CPU: 2 PID: 22109 Comm: revalidator28 Not tainted 6.6.0-rc6+ #3 [ 3102.991695] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 [ 3102.992605] RIP: 0010:__list_del_entry_valid_or_report+0x4f/0xc0 [ 3102.993122] Code: 39 c2 74 56 48 8b 32 48 39 fe 75 62 48 8b 51 08 48 39 f2 75 73 b8 01 00 00 00 c3 48 89 fe 48 c7 c7 48 fd 0a 82 e8 41 0b ad ff <0f> 0b 31 c0 c3 48 89 fe 48 c7 c7 70 fd 0a 82 e8 2d 0b ad ff 0f 0b [ 3102.994615] RSP: 0018:ffff8881383e7710 EFLAGS: 00010286 [ 3102.995078] RAX: 0000000000000000 RBX: 0000000000000002 RCX: 0000000000000000 [ 3102.995670] RDX: 0000000000000001 RSI: ffff88885f89b640 RDI: ffff88885f89b640 [ 3102.997188] DEL flow 00000000be367878 on port 0 [ 3102.998594] RBP: dead000000000122 R08: 0000000000000000 R09: c0000000ffffdfff [ 3102.999604] R10: 0000000000000008 R11: ffff8881383e7598 R12: dead000000000100 [ 3103.000198] R13: 0000000000000002 R14: ffff888139110000 R15: ffff888101901240 [ 3103.000790] FS: 00007f424cde4700(0000) GS:ffff88885f880000(0000) knlGS:0000000000000000 [ 3103.001486] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 3103.001986] CR2: 00007fd42e8dcb70 CR3: 000000011e68a003 CR4: 0000000000370ea0 [ 3103.002596] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 3103.003190] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 3103.003787] Call Trace: [ 3103.004055] <TASK> [ 3103.004297] ? __warn+0x7d/0x130 [ 3103.004623] ? __list_del_entry_valid_or_report+0x4f/0xc0 [ 3103.005094] ? report_bug+0xf1/0x1c0 [ 3103.005439] ? console_unlock+0x4a/0xd0 [ 3103.005806] ? handle_bug+0x3f/0x70 [ 3103.006149] ? exc_invalid_op+0x13/0x60 [ 3103.006531] ? asm_exc_invalid_op+0x16/0x20 [ 3103.007430] ? __list_del_entry_valid_or_report+0x4f/0xc0 [ 3103.007910] mlx5e_tc_del_fdb_peers_flow+0xcf/0x240 [mlx5_core] [ 3103.008463] mlx5e_tc_del_flow+0x46/0x270 [mlx5_core] [ 3103.008944] mlx5e_flow_put+0x26/0x50 [mlx5_core] [ 3103.009401] mlx5e_delete_flower+0x25f/0x380 [mlx5_core] [ 3103.009901] tc_setup_cb_destroy+0xab/0x180 [ 3103.010292] fl_hw_destroy_filter+0x99/0xc0 [cls_flower] [ 3103.010779] __fl_delete+0x2d4/0x2f0 [cls_flower] [ 3103.0 ---truncated---

In the Linux kernel, the following vulnerability has been resolved: btrfs: set BTRFS_ROOT_ORPHAN_CLEANUP during subvol create We have recently observed a number of subvolumes with broken dentries. ls-ing the parent dir looks like: drwxrwxrwt 1 root root 16 Jan 23 16:49 . drwxr-xr-x 1 root root 24 Jan 23 16:48 .. d????????? ? ? ? ? ? broken_subvol and similarly stat-ing the file fails. In this state, deleting the subvol fails with ENOENT, but attempting to create a new file or subvol over it errors out with EEXIST and even aborts the fs. Which leaves us a bit stuck. dmesg contains a single notable error message reading: "could not do orphan cleanup -2" 2 is ENOENT and the error comes from the failure handling path of btrfs_orphan_cleanup(), with the stack leading back up to btrfs_lookup(). btrfs_lookup btrfs_lookup_dentry btrfs_orphan_cleanup // prints that message and returns -ENOENT After some detailed inspection of the internal state, it became clear that: - there are no orphan items for the subvol - the subvol is otherwise healthy looking, it is not half-deleted or anything, there is no drop progress, etc. - the subvol was created a while ago and does the meaningful first btrfs_orphan_cleanup() call that sets BTRFS_ROOT_ORPHAN_CLEANUP much later. - after btrfs_orphan_cleanup() fails, btrfs_lookup_dentry() returns -ENOENT, which results in a negative dentry for the subvolume via d_splice_alias(NULL, dentry), leading to the observed behavior. The bug can be mitigated by dropping the dentry cache, at which point we can successfully delete the subvolume if we want. i.e., btrfs_lookup() btrfs_lookup_dentry() if (!sb_rdonly(inode->vfs_inode)->vfs_inode) btrfs_orphan_cleanup(sub_root) test_and_set_bit(BTRFS_ROOT_ORPHAN_CLEANUP) btrfs_search_slot() // finds orphan item for inode N ... prints "could not do orphan cleanup -2" if (inode == ERR_PTR(-ENOENT)) inode = NULL; return d_splice_alias(NULL, dentry) // NEGATIVE DENTRY for valid subvolume btrfs_orphan_cleanup() does test_and_set_bit(BTRFS_ROOT_ORPHAN_CLEANUP) on the root when it runs, so it cannot run more than once on a given root, so something else must run concurrently. However, the obvious routes to deleting an orphan when nlinks goes to 0 should not be able to run without first doing a lookup into the subvolume, which should run btrfs_orphan_cleanup() and set the bit. The final important observation is that create_subvol() calls d_instantiate_new() but does not set BTRFS_ROOT_ORPHAN_CLEANUP, so if the dentry cache gets dropped, the next lookup into the subvolume will make a real call into btrfs_orphan_cleanup() for the first time. This opens up the possibility of concurrently deleting the inode/orphan items but most typical evict() paths will be holding a reference on the parent dentry (child dentry holds parent->d_lockref.count via dget in d_alloc(), released in __dentry_kill()) and prevent the parent from being removed from the dentry cache. The one exception is delayed iputs. Ordered extent creation calls igrab() on the inode. If the file is unlinked and closed while those refs are held, iput() in __dentry_kill() decrements i_count but does not trigger eviction (i_count > 0). The child dentry is freed and the subvol dentry's d_lockref.count drops to 0, making it evictable while the inode is still alive. Since there are two races (the race between writeback and unlink and the race between lookup and delayed iputs), and there are too many moving parts, the following three diagrams show the complete picture. (Only the second and third are races) Phase 1: Create Subvol in dentry cache without BTRFS_ROOT_ORPHAN_CLEANUP set btrfs_mksubvol() lookup_one_len() __lookup_slow() d_alloc_parallel() __d_alloc() // d_lockref.count = 1 create_subvol(dentry) // doesn't touch the bit.. d_instantiate_new(dentry, inode) // dentry in cache with d_lockref.c ---truncated---

In the Linux kernel, the following vulnerability has been resolved: mm/damon/sysfs: check contexts->nr before accessing contexts_arr[0] Multiple sysfs command paths dereference contexts_arr[0] without first verifying that kdamond->contexts->nr == 1. A user can set nr_contexts to 0 via sysfs while DAMON is running, causing NULL pointer dereferences. In more detail, the issue can be triggered by privileged users like below. First, start DAMON and make contexts directory empty (kdamond->contexts->nr == 0). # damo start # cd /sys/kernel/mm/damon/admin/kdamonds/0 # echo 0 > contexts/nr_contexts Then, each of below commands will cause the NULL pointer dereference. # echo update_schemes_stats > state # echo update_schemes_tried_regions > state # echo update_schemes_tried_bytes > state # echo update_schemes_effective_quotas > state # echo update_tuned_intervals > state Guard all commands (except OFF) at the entry point of damon_sysfs_handle_cmd().