In the Linux kernel, the following vulnerability has been resolved: net/sched: Fix UAF when resolving a clash KASAN reports the following UAF: BUG: KASAN: slab-use-after-free in tcf_ct_flow_table_process_conn+0x12b/0x380 [act_ct] Read of size 1 at addr ffff888c07603600 by task handler130/6469 Call Trace: <IRQ> dump_stack_lvl+0x48/0x70 print_address_description.constprop.0+0x33/0x3d0 print_report+0xc0/0x2b0 kasan_report+0xd0/0x120 __asan_load1+0x6c/0x80 tcf_ct_flow_table_process_conn+0x12b/0x380 [act_ct] tcf_ct_act+0x886/0x1350 [act_ct] tcf_action_exec+0xf8/0x1f0 fl_classify+0x355/0x360 [cls_flower] __tcf_classify+0x1fd/0x330 tcf_classify+0x21c/0x3c0 sch_handle_ingress.constprop.0+0x2c5/0x500 __netif_receive_skb_core.constprop.0+0xb25/0x1510 __netif_receive_skb_list_core+0x220/0x4c0 netif_receive_skb_list_internal+0x446/0x620 napi_complete_done+0x157/0x3d0 gro_cell_poll+0xcf/0x100 __napi_poll+0x65/0x310 net_rx_action+0x30c/0x5c0 __do_softirq+0x14f/0x491 __irq_exit_rcu+0x82/0xc0 irq_exit_rcu+0xe/0x20 common_interrupt+0xa1/0xb0 </IRQ> <TASK> asm_common_interrupt+0x27/0x40 Allocated by task 6469: kasan_save_stack+0x38/0x70 kasan_set_track+0x25/0x40 kasan_save_alloc_info+0x1e/0x40 __kasan_krealloc+0x133/0x190 krealloc+0xaa/0x130 nf_ct_ext_add+0xed/0x230 [nf_conntrack] tcf_ct_act+0x1095/0x1350 [act_ct] tcf_action_exec+0xf8/0x1f0 fl_classify+0x355/0x360 [cls_flower] __tcf_classify+0x1fd/0x330 tcf_classify+0x21c/0x3c0 sch_handle_ingress.constprop.0+0x2c5/0x500 __netif_receive_skb_core.constprop.0+0xb25/0x1510 __netif_receive_skb_list_core+0x220/0x4c0 netif_receive_skb_list_internal+0x446/0x620 napi_complete_done+0x157/0x3d0 gro_cell_poll+0xcf/0x100 __napi_poll+0x65/0x310 net_rx_action+0x30c/0x5c0 __do_softirq+0x14f/0x491 Freed by task 6469: kasan_save_stack+0x38/0x70 kasan_set_track+0x25/0x40 kasan_save_free_info+0x2b/0x60 ____kasan_slab_free+0x180/0x1f0 __kasan_slab_free+0x12/0x30 slab_free_freelist_hook+0xd2/0x1a0 __kmem_cache_free+0x1a2/0x2f0 kfree+0x78/0x120 nf_conntrack_free+0x74/0x130 [nf_conntrack] nf_ct_destroy+0xb2/0x140 [nf_conntrack] __nf_ct_resolve_clash+0x529/0x5d0 [nf_conntrack] nf_ct_resolve_clash+0xf6/0x490 [nf_conntrack] __nf_conntrack_confirm+0x2c6/0x770 [nf_conntrack] tcf_ct_act+0x12ad/0x1350 [act_ct] tcf_action_exec+0xf8/0x1f0 fl_classify+0x355/0x360 [cls_flower] __tcf_classify+0x1fd/0x330 tcf_classify+0x21c/0x3c0 sch_handle_ingress.constprop.0+0x2c5/0x500 __netif_receive_skb_core.constprop.0+0xb25/0x1510 __netif_receive_skb_list_core+0x220/0x4c0 netif_receive_skb_list_internal+0x446/0x620 napi_complete_done+0x157/0x3d0 gro_cell_poll+0xcf/0x100 __napi_poll+0x65/0x310 net_rx_action+0x30c/0x5c0 __do_softirq+0x14f/0x491 The ct may be dropped if a clash has been resolved but is still passed to the tcf_ct_flow_table_process_conn function for further usage. This issue can be fixed by retrieving ct from skb again after confirming conntrack.

In the Linux kernel, the following vulnerability has been resolved: netfilter: ipset: Fix race between namespace cleanup and gc in the list:set type Lion Ackermann reported that there is a race condition between namespace cleanup in ipset and the garbage collection of the list:set type. The namespace cleanup can destroy the list:set type of sets while the gc of the set type is waiting to run in rcu cleanup. The latter uses data from the destroyed set which thus leads use after free. The patch contains the following parts: - When destroying all sets, first remove the garbage collectors, then wait if needed and then destroy the sets. - Fix the badly ordered "wait then remove gc" for the destroy a single set case. - Fix the missing rcu locking in the list:set type in the userspace test case. - Use proper RCU list handlings in the list:set type. The patch depends on c1193d9bbbd3 (netfilter: ipset: Add list flush to cancel_gc).

In the Linux kernel, the following vulnerability has been resolved: mailbox: mtk-cmdq: Fix pm_runtime_get_sync() warning in mbox shutdown The return value of pm_runtime_get_sync() in cmdq_mbox_shutdown() will return 1 when pm runtime state is active, and we don't want to get the warning message in this case. So we change the return value < 0 for WARN_ON().

In the Linux kernel, the following vulnerability has been resolved: drm/drm_file: Fix pid refcounting race <maarten.lankhorst@linux.intel.com>, Maxime Ripard <mripard@kernel.org>, Thomas Zimmermann <tzimmermann@suse.de> filp->pid is supposed to be a refcounted pointer; however, before this patch, drm_file_update_pid() only increments the refcount of a struct pid after storing a pointer to it in filp->pid and dropping the dev->filelist_mutex, making the following race possible: process A process B ========= ========= begin drm_file_update_pid mutex_lock(&dev->filelist_mutex) rcu_replace_pointer(filp->pid, <pid B>, 1) mutex_unlock(&dev->filelist_mutex) begin drm_file_update_pid mutex_lock(&dev->filelist_mutex) rcu_replace_pointer(filp->pid, <pid A>, 1) mutex_unlock(&dev->filelist_mutex) get_pid(<pid A>) synchronize_rcu() put_pid(<pid B>) *** pid B reaches refcount 0 and is freed here *** get_pid(<pid B>) *** UAF *** synchronize_rcu() put_pid(<pid A>) As far as I know, this race can only occur with CONFIG_PREEMPT_RCU=y because it requires RCU to detect a quiescent state in code that is not explicitly calling into the scheduler. This race leads to use-after-free of a "struct pid". It is probably somewhat hard to hit because process A has to pass through a synchronize_rcu() operation while process B is between mutex_unlock() and get_pid(). Fix it by ensuring that by the time a pointer to the current task's pid is stored in the file, an extra reference to the pid has been taken. This fix also removes the condition for synchronize_rcu(); I think that optimization is unnecessary complexity, since in that case we would usually have bailed out on the lockless check above.

In the Linux kernel, the following vulnerability has been resolved: kunit: Fix kthread reference There is a race condition when a kthread finishes after the deadline and before the call to kthread_stop(), which may lead to use after free.

In the Linux kernel, the following vulnerability has been resolved: cgroup/dmem: avoid pool UAF An UAF issue was observed: BUG: KASAN: slab-use-after-free in page_counter_uncharge+0x65/0x150 Write of size 8 at addr ffff888106715440 by task insmod/527 CPU: 4 UID: 0 PID: 527 Comm: insmod 6.19.0-rc7-next-20260129+ #11 Tainted: [O]=OOT_MODULE Call Trace: <TASK> dump_stack_lvl+0x82/0xd0 kasan_report+0xca/0x100 kasan_check_range+0x39/0x1c0 page_counter_uncharge+0x65/0x150 dmem_cgroup_uncharge+0x1f/0x260 Allocated by task 527: Freed by task 0: The buggy address belongs to the object at ffff888106715400 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 64 bytes inside of freed 512-byte region [ffff888106715400, ffff888106715600) The buggy address belongs to the physical page: Memory state around the buggy address: ffff888106715300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888106715380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888106715400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888106715480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888106715500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb The issue occurs because a pool can still be held by a caller after its associated memory region is unregistered. The current implementation frees the pool even if users still hold references to it (e.g., before uncharge operations complete). This patch adds a reference counter to each pool, ensuring that a pool is only freed when its reference count drops to zero.

In the Linux kernel, the following vulnerability has been resolved: gpiolib: cdev: Fix use after free in lineinfo_changed_notify The use-after-free issue occurs as follows: when the GPIO chip device file is being closed by invoking gpio_chrdev_release(), watched_lines is freed by bitmap_free(), but the unregistration of lineinfo_changed_nb notifier chain failed due to waiting write rwsem. Additionally, one of the GPIO chip's lines is also in the release process and holds the notifier chain's read rwsem. Consequently, a race condition leads to the use-after-free of watched_lines. Here is the typical stack when issue happened: [free] gpio_chrdev_release() --> bitmap_free(cdev->watched_lines) <-- freed --> blocking_notifier_chain_unregister() --> down_write(&nh->rwsem) <-- waiting rwsem --> __down_write_common() --> rwsem_down_write_slowpath() --> schedule_preempt_disabled() --> schedule() [use] st54spi_gpio_dev_release() --> gpio_free() --> gpiod_free() --> gpiod_free_commit() --> gpiod_line_state_notify() --> blocking_notifier_call_chain() --> down_read(&nh->rwsem); <-- held rwsem --> notifier_call_chain() --> lineinfo_changed_notify() --> test_bit(xxxx, cdev->watched_lines) <-- use after free The side effect of the use-after-free issue is that a GPIO line event is being generated for userspace where it shouldn't. However, since the chrdev is being closed, userspace won't have the chance to read that event anyway. To fix the issue, call the bitmap_free() function after the unregistration of lineinfo_changed_nb notifier chain.

In the Linux kernel, the following vulnerability has been resolved: media: mediatek: vcodec: adding lock to protect encoder context list Add a lock for the ctx_list, to avoid accessing a NULL pointer within the 'vpu_enc_ipi_handler' function when the ctx_list has been deleted due to an unexpected behavior on the SCP IP block.

In the Linux kernel, the following vulnerability has been resolved: f2fs: compress: fix to cover {reserve,release}_compress_blocks() w/ cp_rwsem lock It needs to cover {reserve,release}_compress_blocks() w/ cp_rwsem lock to avoid racing with checkpoint, otherwise, filesystem metadata including blkaddr in dnode, inode fields and .total_valid_block_count may be corrupted after SPO case.

In the Linux kernel, the following vulnerability has been resolved: drm: Fix use-after-free read in drm_getunique() There is a time-of-check-to-time-of-use error in drm_getunique() due to retrieving file_priv->master prior to locking the device's master mutex. An example can be seen in the crash report of the use-after-free error found by Syzbot: https://syzkaller.appspot.com/bug?id=148d2f1dfac64af52ffd27b661981a540724f803 In the report, the master pointer was used after being freed. This is because another process had acquired the device's master mutex in drm_setmaster_ioctl(), then overwrote fpriv->master in drm_new_set_master(). The old value of fpriv->master was subsequently freed before the mutex was unlocked. To fix this, we lock the device's master mutex before retrieving the pointer from from fpriv->master. This patch passes the Syzbot reproducer test.

In the Linux kernel, the following vulnerability has been resolved: memcg: fix possible use-after-free in memcg_write_event_control() memcg_write_event_control() accesses the dentry->d_name of the specified control fd to route the write call. As a cgroup interface file can't be renamed, it's safe to access d_name as long as the specified file is a regular cgroup file. Also, as these cgroup interface files can't be removed before the directory, it's safe to access the parent too. Prior to 347c4a874710 ("memcg: remove cgroup_event->cft"), there was a call to __file_cft() which verified that the specified file is a regular cgroupfs file before further accesses. The cftype pointer returned from __file_cft() was no longer necessary and the commit inadvertently dropped the file type check with it allowing any file to slip through. With the invarients broken, the d_name and parent accesses can now race against renames and removals of arbitrary files and cause use-after-free's. Fix the bug by resurrecting the file type check in __file_cft(). Now that cgroupfs is implemented through kernfs, checking the file operations needs to go through a layer of indirection. Instead, let's check the superblock and dentry type.

In the Linux kernel, the following vulnerability has been resolved: riscv: fix race when vmap stack overflow Currently, when detecting vmap stack overflow, riscv firstly switches to the so called shadow stack, then use this shadow stack to call the get_overflow_stack() to get the overflow stack. However, there's a race here if two or more harts use the same shadow stack at the same time. To solve this race, we introduce spin_shadow_stack atomic var, which will be swap between its own address and 0 in atomic way, when the var is set, it means the shadow_stack is being used; when the var is cleared, it means the shadow_stack isn't being used. [Palmer: Add AQ to the swap, and also some comments.]

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_tables: Fix potential data-race in __nft_expr_type_get() nft_unregister_expr() can concurrent with __nft_expr_type_get(), and there is not any protection when iterate over nf_tables_expressions list in __nft_expr_type_get(). Therefore, there is potential data-race of nf_tables_expressions list entry. Use list_for_each_entry_rcu() to iterate over nf_tables_expressions list in __nft_expr_type_get(), and use rcu_read_lock() in the caller nft_expr_type_get() to protect the entire type query process.

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_tables: use timestamp to check for set element timeout Add a timestamp field at the beginning of the transaction, store it in the nftables per-netns area. Update set backend .insert, .deactivate and sync gc path to use the timestamp, this avoids that an element expires while control plane transaction is still unfinished. .lookup and .update, which are used from packet path, still use the current time to check if the element has expired. And .get path and dump also since this runs lockless under rcu read size lock. Then, there is async gc which also needs to check the current time since it runs asynchronously from a workqueue.

In the Linux kernel, the following vulnerability has been resolved: aoe: fix the potential use-after-free problem in aoecmd_cfg_pkts This patch is against CVE-2023-6270. The description of cve is: A flaw was found in the ATA over Ethernet (AoE) driver in the Linux kernel. The aoecmd_cfg_pkts() function improperly updates the refcnt on `struct net_device`, and a use-after-free can be triggered by racing between the free on the struct and the access through the `skbtxq` global queue. This could lead to a denial of service condition or potential code execution. In aoecmd_cfg_pkts(), it always calls dev_put(ifp) when skb initial code is finished. But the net_device ifp will still be used in later tx()->dev_queue_xmit() in kthread. Which means that the dev_put(ifp) should NOT be called in the success path of skb initial code in aoecmd_cfg_pkts(). Otherwise tx() may run into use-after-free because the net_device is freed. This patch removed the dev_put(ifp) in the success path in aoecmd_cfg_pkts(), and added dev_put() after skb xmit in tx().

In the Linux kernel, the following vulnerability has been resolved: crypto: qat - resolve race condition during AER recovery During the PCI AER system's error recovery process, the kernel driver may encounter a race condition with freeing the reset_data structure's memory. If the device restart will take more than 10 seconds the function scheduling that restart will exit due to a timeout, and the reset_data structure will be freed. However, this data structure is used for completion notification after the restart is completed, which leads to a UAF bug. This results in a KFENCE bug notice. BUG: KFENCE: use-after-free read in adf_device_reset_worker+0x38/0xa0 [intel_qat] Use-after-free read at 0x00000000bc56fddf (in kfence-#142): adf_device_reset_worker+0x38/0xa0 [intel_qat] process_one_work+0x173/0x340 To resolve this race condition, the memory associated to the container of the work_struct is freed on the worker if the timeout expired, otherwise on the function that schedules the worker. The timeout detection can be done by checking if the caller is still waiting for completion or not by using completion_done() function.

In the Linux kernel, the following vulnerability has been resolved: fs/proc/task_mmu: move mmu notification mechanism inside mm lock Move mmu notification mechanism inside mm lock to prevent race condition in other components which depend on it. The notifier will invalidate memory range. Depending upon the number of iterations, different memory ranges would be invalidated. The following warning would be removed by this patch: WARNING: CPU: 0 PID: 5067 at arch/x86/kvm/../../../virt/kvm/kvm_main.c:734 kvm_mmu_notifier_change_pte+0x860/0x960 arch/x86/kvm/../../../virt/kvm/kvm_main.c:734 There is no behavioural and performance change with this patch when there is no component registered with the mmu notifier. [akpm@linux-foundation.org: narrow the scope of `range', per Sean]

In the Linux kernel, the following vulnerability has been resolved: hwmon: (nct6775) Fix access to temperature configuration registers The number of temperature configuration registers does not always match the total number of temperature registers. This can result in access errors reported if KASAN is enabled. BUG: KASAN: global-out-of-bounds in nct6775_probe+0x5654/0x6fe9 nct6775_core

In the Linux kernel, the following vulnerability has been resolved: ALSA: sh: aica: reorder cleanup operations to avoid UAF bugs The dreamcastcard->timer could schedule the spu_dma_work and the spu_dma_work could also arm the dreamcastcard->timer. When the snd_pcm_substream is closing, the aica_channel will be deallocated. But it could still be dereferenced in the worker thread. The reason is that del_timer() will return directly regardless of whether the timer handler is running or not and the worker could be rescheduled in the timer handler. As a result, the UAF bug will happen. The racy situation is shown below: (Thread 1) | (Thread 2) snd_aicapcm_pcm_close() | ... | run_spu_dma() //worker | mod_timer() flush_work() | del_timer() | aica_period_elapsed() //timer kfree(dreamcastcard->channel) | schedule_work() | run_spu_dma() //worker ... | dreamcastcard->channel-> //USE In order to mitigate this bug and other possible corner cases, call mod_timer() conditionally in run_spu_dma(), then implement PCM sync_stop op to cancel both the timer and worker. The sync_stop op will be called from PCM core appropriately when needed.

In the Linux kernel, the following vulnerability has been resolved: net: phylink: add lock for serializing concurrent pl->phydev writes with resolver Currently phylink_resolve() protects itself against concurrent phylink_bringup_phy() or phylink_disconnect_phy() calls which modify pl->phydev by relying on pl->state_mutex. The problem is that in phylink_resolve(), pl->state_mutex is in a lock inversion state with pl->phydev->lock. So pl->phydev->lock needs to be acquired prior to pl->state_mutex. But that requires dereferencing pl->phydev in the first place, and without pl->state_mutex, that is racy. Hence the reason for the extra lock. Currently it is redundant, but it will serve a functional purpose once mutex_lock(&phy->lock) will be moved outside of the mutex_lock(&pl->state_mutex) section. Another alternative considered would have been to let phylink_resolve() acquire the rtnl_mutex, which is also held when phylink_bringup_phy() and phylink_disconnect_phy() are called. But since phylink_disconnect_phy() runs under rtnl_lock(), it would deadlock with phylink_resolve() when calling flush_work(&pl->resolve). Additionally, it would have been undesirable because it would have unnecessarily blocked many other call paths as well in the entire kernel, so the smaller-scoped lock was preferred.

In the Linux kernel, the following vulnerability has been resolved: ipc/mqueue, msg, sem: avoid relying on a stack reference past its expiry do_mq_timedreceive calls wq_sleep with a stack local address. The sender (do_mq_timedsend) uses this address to later call pipelined_send. This leads to a very hard to trigger race where a do_mq_timedreceive call might return and leave do_mq_timedsend to rely on an invalid address, causing the following crash: RIP: 0010:wake_q_add_safe+0x13/0x60 Call Trace: __x64_sys_mq_timedsend+0x2a9/0x490 do_syscall_64+0x80/0x680 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f5928e40343 The race occurs as: 1. do_mq_timedreceive calls wq_sleep with the address of `struct ext_wait_queue` on function stack (aliased as `ewq_addr` here) - it holds a valid `struct ext_wait_queue *` as long as the stack has not been overwritten. 2. `ewq_addr` gets added to info->e_wait_q[RECV].list in wq_add, and do_mq_timedsend receives it via wq_get_first_waiter(info, RECV) to call __pipelined_op. 3. Sender calls __pipelined_op::smp_store_release(&this->state, STATE_READY). Here is where the race window begins. (`this` is `ewq_addr`.) 4. If the receiver wakes up now in do_mq_timedreceive::wq_sleep, it will see `state == STATE_READY` and break. 5. do_mq_timedreceive returns, and `ewq_addr` is no longer guaranteed to be a `struct ext_wait_queue *` since it was on do_mq_timedreceive's stack. (Although the address may not get overwritten until another function happens to touch it, which means it can persist around for an indefinite time.) 6. do_mq_timedsend::__pipelined_op() still believes `ewq_addr` is a `struct ext_wait_queue *`, and uses it to find a task_struct to pass to the wake_q_add_safe call. In the lucky case where nothing has overwritten `ewq_addr` yet, `ewq_addr->task` is the right task_struct. In the unlucky case, __pipelined_op::wake_q_add_safe gets handed a bogus address as the receiver's task_struct causing the crash. do_mq_timedsend::__pipelined_op() should not dereference `this` after setting STATE_READY, as the receiver counterpart is now free to return. Change __pipelined_op to call wake_q_add_safe on the receiver's task_struct returned by get_task_struct, instead of dereferencing `this` which sits on the receiver's stack. As Manfred pointed out, the race potentially also exists in ipc/msg.c::expunge_all and ipc/sem.c::wake_up_sem_queue_prepare. Fix those in the same way.

In the Linux kernel, the following vulnerability has been resolved: ALSA: seq: Fix race of snd_seq_timer_open() The timer instance per queue is exclusive, and snd_seq_timer_open() should have managed the concurrent accesses. It looks as if it's checking the already existing timer instance at the beginning, but it's not right, because there is no protection, hence any later concurrent call of snd_seq_timer_open() may override the timer instance easily. This may result in UAF, as the leftover timer instance can keep running while the queue itself gets closed, as spotted by syzkaller recently. For avoiding the race, add a proper check at the assignment of tmr->timeri again, and return -EBUSY if it's been already registered.

In the Linux kernel, the following vulnerability has been resolved: VMCI: fix race between vmci_host_setup_notify and vmci_ctx_unset_notify During our test, it is found that a warning can be trigger in try_grab_folio as follow: ------------[ cut here ]------------ WARNING: CPU: 0 PID: 1678 at mm/gup.c:147 try_grab_folio+0x106/0x130 Modules linked in: CPU: 0 UID: 0 PID: 1678 Comm: syz.3.31 Not tainted 6.15.0-rc5 #163 PREEMPT(undef) RIP: 0010:try_grab_folio+0x106/0x130 Call Trace: <TASK> follow_huge_pmd+0x240/0x8e0 follow_pmd_mask.constprop.0.isra.0+0x40b/0x5c0 follow_pud_mask.constprop.0.isra.0+0x14a/0x170 follow_page_mask+0x1c2/0x1f0 __get_user_pages+0x176/0x950 __gup_longterm_locked+0x15b/0x1060 ? gup_fast+0x120/0x1f0 gup_fast_fallback+0x17e/0x230 get_user_pages_fast+0x5f/0x80 vmci_host_unlocked_ioctl+0x21c/0xf80 RIP: 0033:0x54d2cd ---[ end trace 0000000000000000 ]--- Digging into the source, context->notify_page may init by get_user_pages_fast and can be seen in vmci_ctx_unset_notify which will try to put_page. However get_user_pages_fast is not finished here and lead to following try_grab_folio warning. The race condition is shown as follow: cpu0 cpu1 vmci_host_do_set_notify vmci_host_setup_notify get_user_pages_fast(uva, 1, FOLL_WRITE, &context->notify_page); lockless_pages_from_mm gup_pgd_range gup_huge_pmd // update &context->notify_page vmci_host_do_set_notify vmci_ctx_unset_notify notify_page = context->notify_page; if (notify_page) put_page(notify_page); // page is freed __gup_longterm_locked __get_user_pages follow_trans_huge_pmd try_grab_folio // warn here To slove this, use local variable page to make notify_page can be seen after finish get_user_pages_fast.

In the Linux kernel, the following vulnerability has been resolved: rpmsg: char: Fix race between the release of rpmsg_ctrldev and cdev struct rpmsg_ctrldev contains a struct cdev. The current code frees the rpmsg_ctrldev struct in rpmsg_ctrldev_release_device(), but the cdev is a managed object, therefore its release is not predictable and the rpmsg_ctrldev could be freed before the cdev is entirely released, as in the backtrace below. [ 93.625603] ODEBUG: free active (active state 0) object type: timer_list hint: delayed_work_timer_fn+0x0/0x7c [ 93.636115] WARNING: CPU: 0 PID: 12 at lib/debugobjects.c:488 debug_print_object+0x13c/0x1b0 [ 93.644799] Modules linked in: veth xt_cgroup xt_MASQUERADE rfcomm algif_hash algif_skcipher af_alg uinput ip6table_nat fuse uvcvideo videobuf2_vmalloc venus_enc venus_dec videobuf2_dma_contig hci_uart btandroid btqca snd_soc_rt5682_i2c bluetooth qcom_spmi_temp_alarm snd_soc_rt5682v [ 93.715175] CPU: 0 PID: 12 Comm: kworker/0:1 Tainted: G B 5.4.163-lockdep #26 [ 93.723855] Hardware name: Google Lazor (rev3 - 8) with LTE (DT) [ 93.730055] Workqueue: events kobject_delayed_cleanup [ 93.735271] pstate: 60c00009 (nZCv daif +PAN +UAO) [ 93.740216] pc : debug_print_object+0x13c/0x1b0 [ 93.744890] lr : debug_print_object+0x13c/0x1b0 [ 93.749555] sp : ffffffacf5bc7940 [ 93.752978] x29: ffffffacf5bc7940 x28: dfffffd000000000 [ 93.758448] x27: ffffffacdb11a800 x26: dfffffd000000000 [ 93.763916] x25: ffffffd0734f856c x24: dfffffd000000000 [ 93.769389] x23: 0000000000000000 x22: ffffffd0733c35b0 [ 93.774860] x21: ffffffd0751994a0 x20: ffffffd075ec27c0 [ 93.780338] x19: ffffffd075199100 x18: 00000000000276e0 [ 93.785814] x17: 0000000000000000 x16: dfffffd000000000 [ 93.791291] x15: ffffffffffffffff x14: 6e6968207473696c [ 93.796768] x13: 0000000000000000 x12: ffffffd075e2b000 [ 93.802244] x11: 0000000000000001 x10: 0000000000000000 [ 93.807723] x9 : d13400dff1921900 x8 : d13400dff1921900 [ 93.813200] x7 : 0000000000000000 x6 : 0000000000000000 [ 93.818676] x5 : 0000000000000080 x4 : 0000000000000000 [ 93.824152] x3 : ffffffd0732a0fa4 x2 : 0000000000000001 [ 93.829628] x1 : ffffffacf5bc7580 x0 : 0000000000000061 [ 93.835104] Call trace: [ 93.837644] debug_print_object+0x13c/0x1b0 [ 93.841963] __debug_check_no_obj_freed+0x25c/0x3c0 [ 93.846987] debug_check_no_obj_freed+0x18/0x20 [ 93.851669] slab_free_freelist_hook+0xbc/0x1e4 [ 93.856346] kfree+0xfc/0x2f4 [ 93.859416] rpmsg_ctrldev_release_device+0x78/0xb8 [ 93.864445] device_release+0x84/0x168 [ 93.868310] kobject_cleanup+0x12c/0x298 [ 93.872356] kobject_delayed_cleanup+0x10/0x18 [ 93.876948] process_one_work+0x578/0x92c [ 93.881086] worker_thread+0x804/0xcf8 [ 93.884963] kthread+0x2a8/0x314 [ 93.888303] ret_from_fork+0x10/0x18 The cdev_device_add/del() API was created to address this issue (see commit '233ed09d7fda ("chardev: add helper function to register char devs with a struct device")'), use it instead of cdev add/del().

In the Linux kernel, the following vulnerability has been resolved: net: cpsw: Execute ndo_set_rx_mode callback in a work queue Commit 1767bb2d47b7 ("ipv6: mcast: Don't hold RTNL for IPV6_ADD_MEMBERSHIP and MCAST_JOIN_GROUP.") removed the RTNL lock for IPV6_ADD_MEMBERSHIP and MCAST_JOIN_GROUP operations. However, this change triggered the following call trace on my BeagleBone Black board: WARNING: net/8021q/vlan_core.c:236 at vlan_for_each+0x120/0x124, CPU#0: rpcbind/481 RTNL: assertion failed at net/8021q/vlan_core.c (236) Modules linked in: CPU: 0 UID: 997 PID: 481 Comm: rpcbind Not tainted 6.19.0-rc7-next-20260130-yocto-standard+ #35 PREEMPT Hardware name: Generic AM33XX (Flattened Device Tree) Call trace: unwind_backtrace from show_stack+0x28/0x2c show_stack from dump_stack_lvl+0x30/0x38 dump_stack_lvl from __warn+0xb8/0x11c __warn from warn_slowpath_fmt+0x130/0x194 warn_slowpath_fmt from vlan_for_each+0x120/0x124 vlan_for_each from cpsw_add_mc_addr+0x54/0x98 cpsw_add_mc_addr from __hw_addr_ref_sync_dev+0xc4/0xec __hw_addr_ref_sync_dev from __dev_mc_add+0x78/0x88 __dev_mc_add from igmp6_group_added+0x84/0xec igmp6_group_added from __ipv6_dev_mc_inc+0x1fc/0x2f0 __ipv6_dev_mc_inc from __ipv6_sock_mc_join+0x124/0x1b4 __ipv6_sock_mc_join from do_ipv6_setsockopt+0x84c/0x1168 do_ipv6_setsockopt from ipv6_setsockopt+0x88/0xc8 ipv6_setsockopt from do_sock_setsockopt+0xe8/0x19c do_sock_setsockopt from __sys_setsockopt+0x84/0xac __sys_setsockopt from ret_fast_syscall+0x0/0x54 This trace occurs because vlan_for_each() is called within cpsw_ndo_set_rx_mode(), which expects the RTNL lock to be held. Since modifying vlan_for_each() to operate without the RTNL lock is not straightforward, and because ndo_set_rx_mode() is invoked both with and without the RTNL lock across different code paths, simply adding rtnl_lock() in cpsw_ndo_set_rx_mode() is not a viable solution. To resolve this issue, we opt to execute the actual processing within a work queue, following the approach used by the icssg-prueth driver. Please note: To reproduce this issue, I manually reverted the changes to am335x-bone-common.dtsi from commit c477358e66a3 ("ARM: dts: am335x-bone: switch to new cpsw switch drv") in order to revert to the legacy cpsw driver.

In the Linux kernel, the following vulnerability has been resolved: ALSA: aloop: Fix racy access at PCM trigger The PCM trigger callback of aloop driver tries to check the PCM state and stop the stream of the tied substream in the corresponding cable. Since both check and stop operations are performed outside the cable lock, this may result in UAF when a program attempts to trigger frequently while opening/closing the tied stream, as spotted by fuzzers. For addressing the UAF, this patch changes two things: - It covers the most of code in loopback_check_format() with cable->lock spinlock, and add the proper NULL checks. This avoids already some racy accesses. - In addition, now we try to check the state of the capture PCM stream that may be stopped in this function, which was the major pain point leading to UAF.

In the Linux kernel, the following vulnerability has been resolved: net: octeon_ep_vf: fix free_irq dev_id mismatch in IRQ rollback octep_vf_request_irqs() requests MSI-X queue IRQs with dev_id set to ioq_vector. If request_irq() fails part-way, the rollback loop calls free_irq() with dev_id set to 'oct', which does not match the original dev_id and may leave the irqaction registered. This can keep IRQ handlers alive while ioq_vector is later freed during unwind/teardown, leading to a use-after-free or crash when an interrupt fires. Fix the error path to free IRQs with the same ioq_vector dev_id used during request_irq().

In the Linux kernel, the following vulnerability has been resolved: dpaa2-switch: add bounds check for if_id in IRQ handler The IRQ handler extracts if_id from the upper 16 bits of the hardware status register and uses it to index into ethsw->ports[] without validation. Since if_id can be any 16-bit value (0-65535) but the ports array is only allocated with sw_attr.num_ifs elements, this can lead to an out-of-bounds read potentially. Add a bounds check before accessing the array, consistent with the existing validation in dpaa2_switch_rx().

In the Linux kernel, the following vulnerability has been resolved: ext4: fix warning in ext4_iomap_begin as race between bmap and write We got issue as follows: ------------[ cut here ]------------ WARNING: CPU: 3 PID: 9310 at fs/ext4/inode.c:3441 ext4_iomap_begin+0x182/0x5d0 RIP: 0010:ext4_iomap_begin+0x182/0x5d0 RSP: 0018:ffff88812460fa08 EFLAGS: 00010293 RAX: ffff88811f168000 RBX: 0000000000000000 RCX: ffffffff97793c12 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: ffff88812c669160 R08: ffff88811f168000 R09: ffffed10258cd20f R10: ffff88812c669077 R11: ffffed10258cd20e R12: 0000000000000001 R13: 00000000000000a4 R14: 000000000000000c R15: ffff88812c6691ee FS: 00007fd0d6ff3740(0000) GS:ffff8883af180000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fd0d6dda290 CR3: 0000000104a62000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: iomap_apply+0x119/0x570 iomap_bmap+0x124/0x150 ext4_bmap+0x14f/0x250 bmap+0x55/0x80 do_vfs_ioctl+0x952/0xbd0 __x64_sys_ioctl+0xc6/0x170 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Above issue may happen as follows: bmap write bmap ext4_bmap iomap_bmap ext4_iomap_begin ext4_file_write_iter ext4_buffered_write_iter generic_perform_write ext4_da_write_begin ext4_da_write_inline_data_begin ext4_prepare_inline_data ext4_create_inline_data ext4_set_inode_flag(inode, EXT4_INODE_INLINE_DATA); if (WARN_ON_ONCE(ext4_has_inline_data(inode))) ->trigger bug_on To solved above issue hold inode lock in ext4_bamp.

A use-after-free vulnerability in the Linux Kernel io_uring system can be exploited to achieve local privilege escalation. The io_file_get_fixed function lacks the presence of ctx->uring_lock which can lead to a Use-After-Free vulnerability due a race condition with fixed files getting unregistered. We recommend upgrading past commit da24142b1ef9fd5d36b76e36bab328a5b27523e8.

A time-of-check to time-of-use issue exists in io_uring subsystem's IORING_OP_CLOSE operation in the Linux kernel's versions 5.6 - 5.11 (inclusive), which allows a local user to elevate their privileges to root. Introduced in b5dba59e0cf7e2cc4d3b3b1ac5fe81ddf21959eb, patched in 9eac1904d3364254d622bf2c771c4f85cd435fc2, backported to stable in 788d0824269bef539fe31a785b1517882eafed93.

In the Linux kernel, the following vulnerability has been resolved: KVM: Always flush async #PF workqueue when vCPU is being destroyed Always flush the per-vCPU async #PF workqueue when a vCPU is clearing its completion queue, e.g. when a VM and all its vCPUs is being destroyed. KVM must ensure that none of its workqueue callbacks is running when the last reference to the KVM _module_ is put. Gifting a reference to the associated VM prevents the workqueue callback from dereferencing freed vCPU/VM memory, but does not prevent the KVM module from being unloaded before the callback completes. Drop the misguided VM refcount gifting, as calling kvm_put_kvm() from async_pf_execute() if kvm_put_kvm() flushes the async #PF workqueue will result in deadlock. async_pf_execute() can't return until kvm_put_kvm() finishes, and kvm_put_kvm() can't return until async_pf_execute() finishes: WARNING: CPU: 8 PID: 251 at virt/kvm/kvm_main.c:1435 kvm_put_kvm+0x2d/0x320 [kvm] Modules linked in: vhost_net vhost vhost_iotlb tap kvm_intel kvm irqbypass CPU: 8 PID: 251 Comm: kworker/8:1 Tainted: G W 6.6.0-rc1-e7af8d17224a-x86/gmem-vm #119 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 Workqueue: events async_pf_execute [kvm] RIP: 0010:kvm_put_kvm+0x2d/0x320 [kvm] Call Trace: <TASK> async_pf_execute+0x198/0x260 [kvm] process_one_work+0x145/0x2d0 worker_thread+0x27e/0x3a0 kthread+0xba/0xe0 ret_from_fork+0x2d/0x50 ret_from_fork_asm+0x11/0x20 </TASK> ---[ end trace 0000000000000000 ]--- INFO: task kworker/8:1:251 blocked for more than 120 seconds. Tainted: G W 6.6.0-rc1-e7af8d17224a-x86/gmem-vm #119 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/8:1 state:D stack:0 pid:251 ppid:2 flags:0x00004000 Workqueue: events async_pf_execute [kvm] Call Trace: <TASK> __schedule+0x33f/0xa40 schedule+0x53/0xc0 schedule_timeout+0x12a/0x140 __wait_for_common+0x8d/0x1d0 __flush_work.isra.0+0x19f/0x2c0 kvm_clear_async_pf_completion_queue+0x129/0x190 [kvm] kvm_arch_destroy_vm+0x78/0x1b0 [kvm] kvm_put_kvm+0x1c1/0x320 [kvm] async_pf_execute+0x198/0x260 [kvm] process_one_work+0x145/0x2d0 worker_thread+0x27e/0x3a0 kthread+0xba/0xe0 ret_from_fork+0x2d/0x50 ret_from_fork_asm+0x11/0x20 </TASK> If kvm_clear_async_pf_completion_queue() actually flushes the workqueue, then there's no need to gift async_pf_execute() a reference because all invocations of async_pf_execute() will be forced to complete before the vCPU and its VM are destroyed/freed. And that in turn fixes the module unloading bug as __fput() won't do module_put() on the last vCPU reference until the vCPU has been freed, e.g. if closing the vCPU file also puts the last reference to the KVM module. Note that kvm_check_async_pf_completion() may also take the work item off the completion queue and so also needs to flush the work queue, as the work will not be seen by kvm_clear_async_pf_completion_queue(). Waiting on the workqueue could theoretically delay a vCPU due to waiting for the work to complete, but that's a very, very small chance, and likely a very small delay. kvm_arch_async_page_present_queued() unconditionally makes a new request, i.e. will effectively delay entering the guest, so the remaining work is really just: trace_kvm_async_pf_completed(addr, cr2_or_gpa); __kvm_vcpu_wake_up(vcpu); mmput(mm); and mmput() can't drop the last reference to the page tables if the vCPU is still alive, i.e. the vCPU won't get stuck tearing down page tables. Add a helper to do the flushing, specifically to deal with "wakeup all" work items, as they aren't actually work items, i.e. are never placed in a workqueue. Trying to flush a bogus workqueue entry rightly makes __flush_work() complain (kudos to whoever added that sanity check). Note, commit 5f6de5cbebee ("KVM: Prevent module exit until al ---truncated---

In the Linux kernel, the following vulnerability has been resolved: net: rose: fix timer races against user threads Rose timers only acquire the socket spinlock, without checking if the socket is owned by one user thread. Add a check and rearm the timers if needed. BUG: KASAN: slab-use-after-free in rose_timer_expiry+0x31d/0x360 net/rose/rose_timer.c:174 Read of size 2 at addr ffff88802f09b82a by task swapper/0/0 CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.13.0-rc5-syzkaller-00172-gd1bf27c4e176 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Call Trace: <IRQ> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0x169/0x550 mm/kasan/report.c:489 kasan_report+0x143/0x180 mm/kasan/report.c:602 rose_timer_expiry+0x31d/0x360 net/rose/rose_timer.c:174 call_timer_fn+0x187/0x650 kernel/time/timer.c:1793 expire_timers kernel/time/timer.c:1844 [inline] __run_timers kernel/time/timer.c:2418 [inline] __run_timer_base+0x66a/0x8e0 kernel/time/timer.c:2430 run_timer_base kernel/time/timer.c:2439 [inline] run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2449 handle_softirqs+0x2d4/0x9b0 kernel/softirq.c:561 __do_softirq kernel/softirq.c:595 [inline] invoke_softirq kernel/softirq.c:435 [inline] __irq_exit_rcu+0xf7/0x220 kernel/softirq.c:662 irq_exit_rcu+0x9/0x30 kernel/softirq.c:678 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1049 </IRQ>

A use after free vulnerability exists in the ALSA PCM package in the Linux Kernel. SNDRV_CTL_IOCTL_ELEM_{READ|WRITE}32 is missing locks that can be used in a use-after-free that can result in a priviledge escalation to gain ring0 access from the system user. We recommend upgrading past commit 56b88b50565cd8b946a2d00b0c83927b7ebb055e

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: avoid hci_dev_test_and_set_flag() in mgmt_init_hdev() syzbot is again reporting attempt to cancel uninitialized work at mgmt_index_removed() [1], for setting of HCI_MGMT flag from mgmt_init_hdev() from hci_mgmt_cmd() from hci_sock_sendmsg() can race with testing of HCI_MGMT flag from mgmt_index_removed() from hci_sock_bind() due to lack of serialization via hci_dev_lock(). Since mgmt_init_hdev() is called with mgmt_chan_list_lock held, we can safely split hci_dev_test_and_set_flag() into hci_dev_test_flag() and hci_dev_set_flag(). Thus, in order to close this race, set HCI_MGMT flag after INIT_DELAYED_WORK() completed. This is a local fix based on mgmt_chan_list_lock. Lack of serialization via hci_dev_lock() might be causing different race conditions somewhere else. But a global fix based on hci_dev_lock() should deserve a future patch.

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_tables: release flow rule object from commit path No need to postpone this to the commit release path, since no packets are walking over this object, this is accessed from control plane only. This helped uncovered UAF triggered by races with the netlink notifier.

In the Linux kernel, the following vulnerability has been resolved: mm/gup: fix FOLL_FORCE COW security issue and remove FOLL_COW Ever since the Dirty COW (CVE-2016-5195) security issue happened, we know that FOLL_FORCE can be possibly dangerous, especially if there are races that can be exploited by user space. Right now, it would be sufficient to have some code that sets a PTE of a R/O-mapped shared page dirty, in order for it to erroneously become writable by FOLL_FORCE. The implications of setting a write-protected PTE dirty might not be immediately obvious to everyone. And in fact ever since commit 9ae0f87d009c ("mm/shmem: unconditionally set pte dirty in mfill_atomic_install_pte"), we can use UFFDIO_CONTINUE to map a shmem page R/O while marking the pte dirty. This can be used by unprivileged user space to modify tmpfs/shmem file content even if the user does not have write permissions to the file, and to bypass memfd write sealing -- Dirty COW restricted to tmpfs/shmem (CVE-2022-2590). To fix such security issues for good, the insight is that we really only need that fancy retry logic (FOLL_COW) for COW mappings that are not writable (!VM_WRITE). And in a COW mapping, we really only broke COW if we have an exclusive anonymous page mapped. If we have something else mapped, or the mapped anonymous page might be shared (!PageAnonExclusive), we have to trigger a write fault to break COW. If we don't find an exclusive anonymous page when we retry, we have to trigger COW breaking once again because something intervened. Let's move away from this mandatory-retry + dirty handling and rely on our PageAnonExclusive() flag for making a similar decision, to use the same COW logic as in other kernel parts here as well. In case we stumble over a PTE in a COW mapping that does not map an exclusive anonymous page, COW was not properly broken and we have to trigger a fake write-fault to break COW. Just like we do in can_change_pte_writable() added via commit 64fe24a3e05e ("mm/mprotect: try avoiding write faults for exclusive anonymous pages when changing protection") and commit 76aefad628aa ("mm/mprotect: fix soft-dirty check in can_change_pte_writable()"), take care of softdirty and uffd-wp manually. For example, a write() via /proc/self/mem to a uffd-wp-protected range has to fail instead of silently granting write access and bypassing the userspace fault handler. Note that FOLL_FORCE is not only used for debug access, but also triggered by applications without debug intentions, for example, when pinning pages via RDMA. This fixes CVE-2022-2590. Note that only x86_64 and aarch64 are affected, because only those support CONFIG_HAVE_ARCH_USERFAULTFD_MINOR. Fortunately, FOLL_COW is no longer required to handle FOLL_FORCE. So let's just get rid of it. Thanks to Nadav Amit for pointing out that the pte_dirty() check in FOLL_FORCE code is problematic and might be exploitable. Note 1: We don't check for the PTE being dirty because it doesn't matter for making a "was COWed" decision anymore, and whoever modifies the page has to set the page dirty either way. Note 2: Kernels before extended uffd-wp support and before PageAnonExclusive (< 5.19) can simply revert the problematic commit instead and be safe regarding UFFDIO_CONTINUE. A backport to v5.19 requires minor adjustments due to lack of vma_soft_dirty_enabled().

In the Linux kernel, the following vulnerability has been resolved: net/mlx5: Fix a race on command flush flow Fix a refcount use after free warning due to a race on command entry. Such race occurs when one of the commands releases its last refcount and frees its index and entry while another process running command flush flow takes refcount to this command entry. The process which handles commands flush may see this command as needed to be flushed if the other process released its refcount but didn't release the index yet. Fix it by adding the needed spin lock. It fixes the following warning trace: refcount_t: addition on 0; use-after-free. WARNING: CPU: 11 PID: 540311 at lib/refcount.c:25 refcount_warn_saturate+0x80/0xe0 ... RIP: 0010:refcount_warn_saturate+0x80/0xe0 ... Call Trace: <TASK> mlx5_cmd_trigger_completions+0x293/0x340 [mlx5_core] mlx5_cmd_flush+0x3a/0xf0 [mlx5_core] enter_error_state+0x44/0x80 [mlx5_core] mlx5_fw_fatal_reporter_err_work+0x37/0xe0 [mlx5_core] process_one_work+0x1be/0x390 worker_thread+0x4d/0x3d0 ? rescuer_thread+0x350/0x350 kthread+0x141/0x160 ? set_kthread_struct+0x40/0x40 ret_from_fork+0x1f/0x30 </TASK>

In the Linux kernel, the following vulnerability has been resolved: tcp: TX zerocopy should not sense pfmemalloc status We got a recent syzbot report [1] showing a possible misuse of pfmemalloc page status in TCP zerocopy paths. Indeed, for pages coming from user space or other layers, using page_is_pfmemalloc() is moot, and possibly could give false positives. There has been attempts to make page_is_pfmemalloc() more robust, but not using it in the first place in this context is probably better, removing cpu cycles. Note to stable teams : You need to backport 84ce071e38a6 ("net: introduce __skb_fill_page_desc_noacc") as a prereq. Race is more probable after commit c07aea3ef4d4 ("mm: add a signature in struct page") because page_is_pfmemalloc() is now using low order bit from page->lru.next, which can change more often than page->index. Low order bit should never be set for lru.next (when used as an anchor in LRU list), so KCSAN report is mostly a false positive. Backporting to older kernel versions seems not necessary. [1] BUG: KCSAN: data-race in lru_add_fn / tcp_build_frag write to 0xffffea0004a1d2c8 of 8 bytes by task 18600 on cpu 0: __list_add include/linux/list.h:73 [inline] list_add include/linux/list.h:88 [inline] lruvec_add_folio include/linux/mm_inline.h:105 [inline] lru_add_fn+0x440/0x520 mm/swap.c:228 folio_batch_move_lru+0x1e1/0x2a0 mm/swap.c:246 folio_batch_add_and_move mm/swap.c:263 [inline] folio_add_lru+0xf1/0x140 mm/swap.c:490 filemap_add_folio+0xf8/0x150 mm/filemap.c:948 __filemap_get_folio+0x510/0x6d0 mm/filemap.c:1981 pagecache_get_page+0x26/0x190 mm/folio-compat.c:104 grab_cache_page_write_begin+0x2a/0x30 mm/folio-compat.c:116 ext4_da_write_begin+0x2dd/0x5f0 fs/ext4/inode.c:2988 generic_perform_write+0x1d4/0x3f0 mm/filemap.c:3738 ext4_buffered_write_iter+0x235/0x3e0 fs/ext4/file.c:270 ext4_file_write_iter+0x2e3/0x1210 call_write_iter include/linux/fs.h:2187 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x468/0x760 fs/read_write.c:578 ksys_write+0xe8/0x1a0 fs/read_write.c:631 __do_sys_write fs/read_write.c:643 [inline] __se_sys_write fs/read_write.c:640 [inline] __x64_sys_write+0x3e/0x50 fs/read_write.c:640 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd read to 0xffffea0004a1d2c8 of 8 bytes by task 18611 on cpu 1: page_is_pfmemalloc include/linux/mm.h:1740 [inline] __skb_fill_page_desc include/linux/skbuff.h:2422 [inline] skb_fill_page_desc include/linux/skbuff.h:2443 [inline] tcp_build_frag+0x613/0xb20 net/ipv4/tcp.c:1018 do_tcp_sendpages+0x3e8/0xaf0 net/ipv4/tcp.c:1075 tcp_sendpage_locked net/ipv4/tcp.c:1140 [inline] tcp_sendpage+0x89/0xb0 net/ipv4/tcp.c:1150 inet_sendpage+0x7f/0xc0 net/ipv4/af_inet.c:833 kernel_sendpage+0x184/0x300 net/socket.c:3561 sock_sendpage+0x5a/0x70 net/socket.c:1054 pipe_to_sendpage+0x128/0x160 fs/splice.c:361 splice_from_pipe_feed fs/splice.c:415 [inline] __splice_from_pipe+0x222/0x4d0 fs/splice.c:559 splice_from_pipe fs/splice.c:594 [inline] generic_splice_sendpage+0x89/0xc0 fs/splice.c:743 do_splice_from fs/splice.c:764 [inline] direct_splice_actor+0x80/0xa0 fs/splice.c:931 splice_direct_to_actor+0x305/0x620 fs/splice.c:886 do_splice_direct+0xfb/0x180 fs/splice.c:974 do_sendfile+0x3bf/0x910 fs/read_write.c:1249 __do_sys_sendfile64 fs/read_write.c:1317 [inline] __se_sys_sendfile64 fs/read_write.c:1303 [inline] __x64_sys_sendfile64+0x10c/0x150 fs/read_write.c:1303 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd value changed: 0x0000000000000000 -> 0xffffea0004a1d288 Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 18611 Comm: syz-executor.4 Not tainted 6.0.0-rc2-syzkaller-00248-ge022620b5d05-dirty #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022

In the Linux kernel, the following vulnerability has been resolved: nvme: fix a possible use-after-free in controller reset during load Unlike .queue_rq, in .submit_async_event drivers may not check the ctrl readiness for AER submission. This may lead to a use-after-free condition that was observed with nvme-tcp. The race condition may happen in the following scenario: 1. driver executes its reset_ctrl_work 2. -> nvme_stop_ctrl - flushes ctrl async_event_work 3. ctrl sends AEN which is received by the host, which in turn schedules AEN handling 4. teardown admin queue (which releases the queue socket) 5. AEN processed, submits another AER, calling the driver to submit 6. driver attempts to send the cmd ==> use-after-free In order to fix that, add ctrl state check to validate the ctrl is actually able to accept the AER submission. This addresses the above race in controller resets because the driver during teardown should: 1. change ctrl state to RESETTING 2. flush async_event_work (as well as other async work elements) So after 1,2, any other AER command will find the ctrl state to be RESETTING and bail out without submitting the AER.

In the Linux kernel, the following vulnerability has been resolved: misc: fastrpc: Fix use-after-free race condition for maps It is possible that in between calling fastrpc_map_get() until map->fl->lock is taken in fastrpc_free_map(), another thread can call fastrpc_map_lookup() and get a reference to a map that is about to be deleted. Rewrite fastrpc_map_get() to only increase the reference count of a map if it's non-zero. Propagate this to callers so they can know if a map is about to be deleted. Fixes this warning: refcount_t: addition on 0; use-after-free. WARNING: CPU: 5 PID: 10100 at lib/refcount.c:25 refcount_warn_saturate ... Call trace: refcount_warn_saturate [fastrpc_map_get inlined] [fastrpc_map_lookup inlined] fastrpc_map_create fastrpc_internal_invoke fastrpc_device_ioctl __arm64_sys_ioctl invoke_syscall

In the Linux kernel, the following vulnerability has been resolved: riscv: Sanitize syscall table indexing under speculation The syscall number is a user-controlled value used to index into the syscall table. Use array_index_nospec() to clamp this value after the bounds check to prevent speculative out-of-bounds access and subsequent data leakage via cache side channels.

In the Linux kernel, the following vulnerability has been resolved: dmaengine: mmp_pdma: Fix race condition in mmp_pdma_residue() Add proper locking in mmp_pdma_residue() to prevent use-after-free when accessing descriptor list and descriptor contents. The race occurs when multiple threads call tx_status() while the tasklet on another CPU is freeing completed descriptors: CPU 0 CPU 1 ----- ----- mmp_pdma_tx_status() mmp_pdma_residue() -> NO LOCK held list_for_each_entry(sw, ..) DMA interrupt dma_do_tasklet() -> spin_lock(&desc_lock) list_move(sw->node, ...) spin_unlock(&desc_lock) | dma_pool_free(sw) <- FREED! -> access sw->desc <- UAF! This issue can be reproduced when running dmatest on the same channel with multiple threads (threads_per_chan > 1). Fix by protecting the chain_running list iteration and descriptor access with the chan->desc_lock spinlock.

In the Linux kernel, the following vulnerability has been resolved: tee: amdtee: fix use-after-free vulnerability in amdtee_close_session There is a potential race condition in amdtee_close_session that may cause use-after-free in amdtee_open_session. For instance, if a session has refcount == 1, and one thread tries to free this session via: kref_put(&sess->refcount, destroy_session); the reference count will get decremented, and the next step would be to call destroy_session(). However, if in another thread, amdtee_open_session() is called before destroy_session() has completed execution, alloc_session() may return 'sess' that will be freed up later in destroy_session() leading to use-after-free in amdtee_open_session. To fix this issue, treat decrement of sess->refcount and removal of 'sess' from session list in destroy_session() as a critical section, so that it is executed atomically.

A vulnerability, which was classified as critical, has been found in Linux Kernel. Affected by this issue is the function tst_timer of the file drivers/atm/idt77252.c of the component IPsec. The manipulation leads to use after free. It is recommended to apply a patch to fix this issue. VDB-211934 is the identifier assigned to this vulnerability.

A vulnerability was found in Linux Kernel. It has been classified as problematic. Affected is the function nilfs_new_inode of the file fs/nilfs2/inode.c of the component BPF. The manipulation leads to use after free. It is possible to launch the attack remotely. It is recommended to apply a patch to fix this issue. The identifier of this vulnerability is VDB-211992.

A use-after-free vulnerability in the Linux kernel's netfilter: nf_tables component can be exploited to achieve local privilege escalation. Due to a race condition between nf_tables netlink control plane transaction and nft_set element garbage collection, it is possible to underflow the reference counter causing a use-after-free vulnerability. We recommend upgrading past commit 3e91b0ebd994635df2346353322ac51ce84ce6d8.

In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix use-after-free in smb_break_all_levII_oplock() There is a room in smb_break_all_levII_oplock that can cause racy issues when unlocking in the middle of the loop. This patch use read lock to protect whole loop.

In the Linux kernel, the following vulnerability has been resolved: iommufd: Fix race during abort for file descriptors fput() doesn't actually call file_operations release() synchronously, it puts the file on a work queue and it will be released eventually. This is normally fine, except for iommufd the file and the iommufd_object are tied to gether. The file has the object as it's private_data and holds a users refcount, while the object is expected to remain alive as long as the file is. When the allocation of a new object aborts before installing the file it will fput() the file and then go on to immediately kfree() the obj. This causes a UAF once the workqueue completes the fput() and tries to decrement the users refcount. Fix this by putting the core code in charge of the file lifetime, and call __fput_sync() during abort to ensure that release() is called before kfree. __fput_sync() is a bit too tricky to open code in all the object implementations. Instead the objects tell the core code where the file pointer is and the core will take care of the life cycle. If the object is successfully allocated then the file will hold a users refcount and the iommufd_object cannot be destroyed. It is worth noting that close(); ioctl(IOMMU_DESTROY); doesn't have an issue because close() is already using a synchronous version of fput(). The UAF looks like this: BUG: KASAN: slab-use-after-free in iommufd_eventq_fops_release+0x45/0xc0 drivers/iommu/iommufd/eventq.c:376 Write of size 4 at addr ffff888059c97804 by task syz.0.46/6164 CPU: 0 UID: 0 PID: 6164 Comm: syz.0.46 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xcd/0x630 mm/kasan/report.c:482 kasan_report+0xe0/0x110 mm/kasan/report.c:595 check_region_inline mm/kasan/generic.c:183 [inline] kasan_check_range+0x100/0x1b0 mm/kasan/generic.c:189 instrument_atomic_read_write include/linux/instrumented.h:96 [inline] atomic_fetch_sub_release include/linux/atomic/atomic-instrumented.h:400 [inline] __refcount_dec include/linux/refcount.h:455 [inline] refcount_dec include/linux/refcount.h:476 [inline] iommufd_eventq_fops_release+0x45/0xc0 drivers/iommu/iommufd/eventq.c:376 __fput+0x402/0xb70 fs/file_table.c:468 task_work_run+0x14d/0x240 kernel/task_work.c:227 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop+0xeb/0x110 kernel/entry/common.c:43 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x41c/0x4c0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f

In the Linux kernel, the following vulnerability has been resolved: rcu: Protect ->defer_qs_iw_pending from data race On kernels built with CONFIG_IRQ_WORK=y, when rcu_read_unlock() is invoked within an interrupts-disabled region of code [1], it will invoke rcu_read_unlock_special(), which uses an irq-work handler to force the system to notice when the RCU read-side critical section actually ends. That end won't happen until interrupts are enabled at the soonest. In some kernels, such as those booted with rcutree.use_softirq=y, the irq-work handler is used unconditionally. The per-CPU rcu_data structure's ->defer_qs_iw_pending field is updated by the irq-work handler and is both read and updated by rcu_read_unlock_special(). This resulted in the following KCSAN splat: ------------------------------------------------------------------------ BUG: KCSAN: data-race in rcu_preempt_deferred_qs_handler / rcu_read_unlock_special read to 0xffff96b95f42d8d8 of 1 bytes by task 90 on cpu 8: rcu_read_unlock_special+0x175/0x260 __rcu_read_unlock+0x92/0xa0 rt_spin_unlock+0x9b/0xc0 __local_bh_enable+0x10d/0x170 __local_bh_enable_ip+0xfb/0x150 rcu_do_batch+0x595/0xc40 rcu_cpu_kthread+0x4e9/0x830 smpboot_thread_fn+0x24d/0x3b0 kthread+0x3bd/0x410 ret_from_fork+0x35/0x40 ret_from_fork_asm+0x1a/0x30 write to 0xffff96b95f42d8d8 of 1 bytes by task 88 on cpu 8: rcu_preempt_deferred_qs_handler+0x1e/0x30 irq_work_single+0xaf/0x160 run_irq_workd+0x91/0xc0 smpboot_thread_fn+0x24d/0x3b0 kthread+0x3bd/0x410 ret_from_fork+0x35/0x40 ret_from_fork_asm+0x1a/0x30 no locks held by irq_work/8/88. irq event stamp: 200272 hardirqs last enabled at (200272): [<ffffffffb0f56121>] finish_task_switch+0x131/0x320 hardirqs last disabled at (200271): [<ffffffffb25c7859>] __schedule+0x129/0xd70 softirqs last enabled at (0): [<ffffffffb0ee093f>] copy_process+0x4df/0x1cc0 softirqs last disabled at (0): [<0000000000000000>] 0x0 ------------------------------------------------------------------------ The problem is that irq-work handlers run with interrupts enabled, which means that rcu_preempt_deferred_qs_handler() could be interrupted, and that interrupt handler might contain an RCU read-side critical section, which might invoke rcu_read_unlock_special(). In the strict KCSAN mode of operation used by RCU, this constitutes a data race on the ->defer_qs_iw_pending field. This commit therefore disables interrupts across the portion of the rcu_preempt_deferred_qs_handler() that updates the ->defer_qs_iw_pending field. This suffices because this handler is not a fast path.