Search Results (19586 CVEs found)

CVE Vendors Products Updated CVSS v3.1
CVE-2023-54316 1 Linux 1 Linux Kernel 2026-04-15 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: refscale: Fix uninitalized use of wait_queue_head_t Running the refscale test occasionally crashes the kernel with the following error: [ 8569.952896] BUG: unable to handle page fault for address: ffffffffffffffe8 [ 8569.952900] #PF: supervisor read access in kernel mode [ 8569.952902] #PF: error_code(0x0000) - not-present page [ 8569.952904] PGD c4b048067 P4D c4b049067 PUD c4b04b067 PMD 0 [ 8569.952910] Oops: 0000 [#1] PREEMPT_RT SMP NOPTI [ 8569.952916] Hardware name: Dell Inc. PowerEdge R750/0WMWCR, BIOS 1.2.4 05/28/2021 [ 8569.952917] RIP: 0010:prepare_to_wait_event+0x101/0x190 : [ 8569.952940] Call Trace: [ 8569.952941] <TASK> [ 8569.952944] ref_scale_reader+0x380/0x4a0 [refscale] [ 8569.952959] kthread+0x10e/0x130 [ 8569.952966] ret_from_fork+0x1f/0x30 [ 8569.952973] </TASK> The likely cause is that init_waitqueue_head() is called after the call to the torture_create_kthread() function that creates the ref_scale_reader kthread. Although this init_waitqueue_head() call will very likely complete before this kthread is created and starts running, it is possible that the calling kthread will be delayed between the calls to torture_create_kthread() and init_waitqueue_head(). In this case, the new kthread will use the waitqueue head before it is properly initialized, which is not good for the kernel's health and well-being. The above crash happened here: static inline void __add_wait_queue(...) { : if (!(wq->flags & WQ_FLAG_PRIORITY)) <=== Crash here The offset of flags from list_head entry in wait_queue_entry is -0x18. If reader_tasks[i].wq.head.next is NULL as allocated reader_task structure is zero initialized, the instruction will try to access address 0xffffffffffffffe8, which is exactly the fault address listed above. This commit therefore invokes init_waitqueue_head() before creating the kthread.
CVE-2023-54317 1 Linux 1 Linux Kernel 2026-04-15 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: dm flakey: don't corrupt the zero page When we need to zero some range on a block device, the function __blkdev_issue_zero_pages submits a write bio with the bio vector pointing to the zero page. If we use dm-flakey with corrupt bio writes option, it will corrupt the content of the zero page which results in crashes of various userspace programs. Glibc assumes that memory returned by mmap is zeroed and it uses it for calloc implementation; if the newly mapped memory is not zeroed, calloc will return non-zeroed memory. Fix this bug by testing if the page is equal to ZERO_PAGE(0) and avoiding the corruption in this case.
CVE-2023-54318 1 Linux 1 Linux Kernel 2026-04-15 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: net/smc: use smc_lgr_list.lock to protect smc_lgr_list.list iterate in smcr_port_add While doing smcr_port_add, there maybe linkgroup add into or delete from smc_lgr_list.list at the same time, which may result kernel crash. So, use smc_lgr_list.lock to protect smc_lgr_list.list iterate in smcr_port_add. The crash calltrace show below: BUG: kernel NULL pointer dereference, address: 0000000000000000 PGD 0 P4D 0 Oops: 0000 [#1] SMP NOPTI CPU: 0 PID: 559726 Comm: kworker/0:92 Kdump: loaded Tainted: G Hardware name: Alibaba Cloud Alibaba Cloud ECS, BIOS 449e491 04/01/2014 Workqueue: events smc_ib_port_event_work [smc] RIP: 0010:smcr_port_add+0xa6/0xf0 [smc] RSP: 0000:ffffa5a2c8f67de0 EFLAGS: 00010297 RAX: 0000000000000001 RBX: ffff9935e0650000 RCX: 0000000000000000 RDX: 0000000000000010 RSI: ffff9935e0654290 RDI: ffff9935c8560000 RBP: 0000000000000000 R08: 0000000000000000 R09: ffff9934c0401918 R10: 0000000000000000 R11: ffffffffb4a5c278 R12: ffff99364029aae4 R13: ffff99364029aa00 R14: 00000000ffffffed R15: ffff99364029ab08 FS: 0000000000000000(0000) GS:ffff994380600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 0000000f06a10003 CR4: 0000000002770ef0 PKRU: 55555554 Call Trace: smc_ib_port_event_work+0x18f/0x380 [smc] process_one_work+0x19b/0x340 worker_thread+0x30/0x370 ? process_one_work+0x340/0x340 kthread+0x114/0x130 ? __kthread_cancel_work+0x50/0x50 ret_from_fork+0x1f/0x30
CVE-2023-54319 1 Linux 1 Linux Kernel 2026-04-15 N/A
In the Linux kernel, the following vulnerability has been resolved: pinctrl: at91-pio4: check return value of devm_kasprintf() devm_kasprintf() returns a pointer to dynamically allocated memory. Pointer could be NULL in case allocation fails. Check pointer validity. Identified with coccinelle (kmerr.cocci script). Depends-on: 1c4e5c470a56 ("pinctrl: at91: use devm_kasprintf() to avoid potential leaks") Depends-on: 5a8f9cf269e8 ("pinctrl: at91-pio4: use proper format specifier for unsigned int")
CVE-2023-54323 1 Linux 1 Linux Kernel 2026-04-15 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: cxl/pmem: Fix nvdimm registration races A loop of the form: while true; do modprobe cxl_pci; modprobe -r cxl_pci; done ...fails with the following crash signature: BUG: kernel NULL pointer dereference, address: 0000000000000040 [..] RIP: 0010:cxl_internal_send_cmd+0x5/0xb0 [cxl_core] [..] Call Trace: <TASK> cxl_pmem_ctl+0x121/0x240 [cxl_pmem] nvdimm_get_config_data+0xd6/0x1a0 [libnvdimm] nd_label_data_init+0x135/0x7e0 [libnvdimm] nvdimm_probe+0xd6/0x1c0 [libnvdimm] nvdimm_bus_probe+0x7a/0x1e0 [libnvdimm] really_probe+0xde/0x380 __driver_probe_device+0x78/0x170 driver_probe_device+0x1f/0x90 __device_attach_driver+0x85/0x110 bus_for_each_drv+0x7d/0xc0 __device_attach+0xb4/0x1e0 bus_probe_device+0x9f/0xc0 device_add+0x445/0x9c0 nd_async_device_register+0xe/0x40 [libnvdimm] async_run_entry_fn+0x30/0x130 ...namely that the bottom half of async nvdimm device registration runs after the CXL has already torn down the context that cxl_pmem_ctl() needs. Unlike the ACPI NFIT case that benefits from launching multiple nvdimm device registrations in parallel from those listed in the table, CXL is already marked PROBE_PREFER_ASYNCHRONOUS. So provide for a synchronous registration path to preclude this scenario.
CVE-2023-54326 1 Linux 1 Linux Kernel 2026-04-15 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: misc: pci_endpoint_test: Free IRQs before removing the device In pci_endpoint_test_remove(), freeing the IRQs after removing the device creates a small race window for IRQs to be received with the test device memory already released, causing the IRQ handler to access invalid memory, resulting in an oops. Free the device IRQs before removing the device to avoid this issue.
CVE-2023-7324 1 Linux 1 Linux Kernel 2026-04-15 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: scsi: ses: Fix possible addl_desc_ptr out-of-bounds accesses Sanitize possible addl_desc_ptr out-of-bounds accesses in ses_enclosure_data_process().
CVE-2022-50752 1 Linux 1 Linux Kernel 2026-04-15 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: md/raid5: Remove unnecessary bio_put() in raid5_read_one_chunk() When running chunk-sized reads on disks with badblocks duplicate bio free/puts are observed: ============================================================================= BUG bio-200 (Not tainted): Object already free ----------------------------------------------------------------------------- Allocated in mempool_alloc_slab+0x17/0x20 age=3 cpu=2 pid=7504 __slab_alloc.constprop.0+0x5a/0xb0 kmem_cache_alloc+0x31e/0x330 mempool_alloc_slab+0x17/0x20 mempool_alloc+0x100/0x2b0 bio_alloc_bioset+0x181/0x460 do_mpage_readpage+0x776/0xd00 mpage_readahead+0x166/0x320 blkdev_readahead+0x15/0x20 read_pages+0x13f/0x5f0 page_cache_ra_unbounded+0x18d/0x220 force_page_cache_ra+0x181/0x1c0 page_cache_sync_ra+0x65/0xb0 filemap_get_pages+0x1df/0xaf0 filemap_read+0x1e1/0x700 blkdev_read_iter+0x1e5/0x330 vfs_read+0x42a/0x570 Freed in mempool_free_slab+0x17/0x20 age=3 cpu=2 pid=7504 kmem_cache_free+0x46d/0x490 mempool_free_slab+0x17/0x20 mempool_free+0x66/0x190 bio_free+0x78/0x90 bio_put+0x100/0x1a0 raid5_make_request+0x2259/0x2450 md_handle_request+0x402/0x600 md_submit_bio+0xd9/0x120 __submit_bio+0x11f/0x1b0 submit_bio_noacct_nocheck+0x204/0x480 submit_bio_noacct+0x32e/0xc70 submit_bio+0x98/0x1a0 mpage_readahead+0x250/0x320 blkdev_readahead+0x15/0x20 read_pages+0x13f/0x5f0 page_cache_ra_unbounded+0x18d/0x220 Slab 0xffffea000481b600 objects=21 used=0 fp=0xffff8881206d8940 flags=0x17ffffc0010201(locked|slab|head|node=0|zone=2|lastcpupid=0x1fffff) CPU: 0 PID: 34525 Comm: kworker/u24:2 Not tainted 6.0.0-rc2-localyes-265166-gf11c5343fa3f #143 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-1ubuntu1.1 04/01/2014 Workqueue: raid5wq raid5_do_work Call Trace: <TASK> dump_stack_lvl+0x5a/0x78 dump_stack+0x10/0x16 print_trailer+0x158/0x165 object_err+0x35/0x50 free_debug_processing.cold+0xb7/0xbe __slab_free+0x1ae/0x330 kmem_cache_free+0x46d/0x490 mempool_free_slab+0x17/0x20 mempool_free+0x66/0x190 bio_free+0x78/0x90 bio_put+0x100/0x1a0 mpage_end_io+0x36/0x150 bio_endio+0x2fd/0x360 md_end_io_acct+0x7e/0x90 bio_endio+0x2fd/0x360 handle_failed_stripe+0x960/0xb80 handle_stripe+0x1348/0x3760 handle_active_stripes.constprop.0+0x72a/0xaf0 raid5_do_work+0x177/0x330 process_one_work+0x616/0xb20 worker_thread+0x2bd/0x6f0 kthread+0x179/0x1b0 ret_from_fork+0x22/0x30 </TASK> The double free is caused by an unnecessary bio_put() in the if(is_badblock(...)) error path in raid5_read_one_chunk(). The error path was moved ahead of bio_alloc_clone() in c82aa1b76787c ("md/raid5: move checking badblock before clone bio in raid5_read_one_chunk"). The previous code checked and freed align_bio which required a bio_put. After the move that is no longer needed as raid_bio is returned to the control of the common io path which performs its own endio resulting in a double free on bad device blocks.
CVE-2022-50634 1 Linux 1 Linux Kernel 2026-04-15 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: power: supply: cw2015: Fix potential null-ptr-deref in cw_bat_probe() cw_bat_probe() calls create_singlethread_workqueue() and not checked the ret value, which may return NULL. And a null-ptr-deref may happen: cw_bat_probe() create_singlethread_workqueue() # failed, cw_bat->wq is NULL queue_delayed_work() queue_delayed_work_on() __queue_delayed_work() # warning here, but continue __queue_work() # access wq->flags, null-ptr-deref Check the ret value and return -ENOMEM if it is NULL.
CVE-2022-50641 1 Linux 1 Linux Kernel 2026-04-15 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: HSI: omap_ssi: Fix refcount leak in ssi_probe When returning or breaking early from a for_each_available_child_of_node() loop, we need to explicitly call of_node_put() on the child node to possibly release the node.
CVE-2022-50642 1 Linux 1 Linux Kernel 2026-04-15 7.0 High
In the Linux kernel, the following vulnerability has been resolved: platform/chrome: cros_ec_typec: zero out stale pointers `cros_typec_get_switch_handles` allocates four pointers when obtaining type-c switch handles. These pointers are all freed if failing to obtain any of them; therefore, pointers in `port` become stale. The stale pointers eventually cause use-after-free or double free in later code paths. Zeroing out all pointer fields after freeing to eliminate these stale pointers.
CVE-2022-50643 1 Linux 1 Linux Kernel 2026-04-15 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: cifs: Fix xid leak in cifs_copy_file_range() If the file is used by swap, before return -EOPNOTSUPP, should free the xid, otherwise, the xid will be leaked.
CVE-2022-50644 1 Linux 1 Linux Kernel 2026-04-15 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: clk: ti: dra7-atl: Fix reference leak in of_dra7_atl_clk_probe pm_runtime_get_sync() will increment pm usage counter. Forgetting to putting operation will result in reference leak. Add missing pm_runtime_put_sync in some error paths.
CVE-2022-50646 1 Linux 1 Linux Kernel 2026-04-15 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: scsi: hpsa: Fix possible memory leak in hpsa_init_one() The hpda_alloc_ctlr_info() allocates h and its field reply_map. However, in hpsa_init_one(), if alloc_percpu() failed, the hpsa_init_one() jumps to clean1 directly, which frees h and leaks the h->reply_map. Fix by calling hpda_free_ctlr_info() to release h->replay_map and h instead free h directly.
CVE-2022-50647 1 Linux 1 Linux Kernel 2026-04-15 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: RISC-V: Make port I/O string accessors actually work Fix port I/O string accessors such as `insb', `outsb', etc. which use the physical PCI port I/O address rather than the corresponding memory mapping to get at the requested location, which in turn breaks at least accesses made by our parport driver to a PCIe parallel port such as: PCI parallel port detected: 1415:c118, I/O at 0x1000(0x1008), IRQ 20 parport0: PC-style at 0x1000 (0x1008), irq 20, using FIFO [PCSPP,TRISTATE,COMPAT,EPP,ECP] causing a memory access fault: Unable to handle kernel access to user memory without uaccess routines at virtual address 0000000000001008 Oops [#1] Modules linked in: CPU: 1 PID: 350 Comm: cat Not tainted 6.0.0-rc2-00283-g10d4879f9ef0-dirty #23 Hardware name: SiFive HiFive Unmatched A00 (DT) epc : parport_pc_fifo_write_block_pio+0x266/0x416 ra : parport_pc_fifo_write_block_pio+0xb4/0x416 epc : ffffffff80542c3e ra : ffffffff80542a8c sp : ffffffd88899fc60 gp : ffffffff80fa2700 tp : ffffffd882b1e900 t0 : ffffffd883d0b000 t1 : ffffffffff000002 t2 : 4646393043330a38 s0 : ffffffd88899fcf0 s1 : 0000000000001000 a0 : 0000000000000010 a1 : 0000000000000000 a2 : ffffffd883d0a010 a3 : 0000000000000023 a4 : 00000000ffff8fbb a5 : ffffffd883d0a001 a6 : 0000000100000000 a7 : ffffffc800000000 s2 : ffffffffff000002 s3 : ffffffff80d28880 s4 : ffffffff80fa1f50 s5 : 0000000000001008 s6 : 0000000000000008 s7 : ffffffd883d0a000 s8 : 0004000000000000 s9 : ffffffff80dc1d80 s10: ffffffd8807e4000 s11: 0000000000000000 t3 : 00000000000000ff t4 : 393044410a303930 t5 : 0000000000001000 t6 : 0000000000040000 status: 0000000200000120 badaddr: 0000000000001008 cause: 000000000000000f [<ffffffff80543212>] parport_pc_compat_write_block_pio+0xfe/0x200 [<ffffffff8053bbc0>] parport_write+0x46/0xf8 [<ffffffff8050530e>] lp_write+0x158/0x2d2 [<ffffffff80185716>] vfs_write+0x8e/0x2c2 [<ffffffff80185a74>] ksys_write+0x52/0xc2 [<ffffffff80185af2>] sys_write+0xe/0x16 [<ffffffff80003770>] ret_from_syscall+0x0/0x2 ---[ end trace 0000000000000000 ]--- For simplicity address the problem by adding PCI_IOBASE to the physical address requested in the respective wrapper macros only, observing that the raw accessors such as `__insb', `__outsb', etc. are not supposed to be used other than by said macros. Remove the cast to `long' that is no longer needed on `addr' now that it is used as an offset from PCI_IOBASE and add parentheses around `addr' needed for predictable evaluation in macro expansion. No need to make said adjustments in separate changes given that current code is gravely broken and does not ever work.
CVE-2022-50648 1 Linux 1 Linux Kernel 2026-04-15 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: ftrace: Fix recursive locking direct_mutex in ftrace_modify_direct_caller Naveen reported recursive locking of direct_mutex with sample ftrace-direct-modify.ko: [ 74.762406] WARNING: possible recursive locking detected [ 74.762887] 6.0.0-rc6+ #33 Not tainted [ 74.763216] -------------------------------------------- [ 74.763672] event-sample-fn/1084 is trying to acquire lock: [ 74.764152] ffffffff86c9d6b0 (direct_mutex){+.+.}-{3:3}, at: \ register_ftrace_function+0x1f/0x180 [ 74.764922] [ 74.764922] but task is already holding lock: [ 74.765421] ffffffff86c9d6b0 (direct_mutex){+.+.}-{3:3}, at: \ modify_ftrace_direct+0x34/0x1f0 [ 74.766142] [ 74.766142] other info that might help us debug this: [ 74.766701] Possible unsafe locking scenario: [ 74.766701] [ 74.767216] CPU0 [ 74.767437] ---- [ 74.767656] lock(direct_mutex); [ 74.767952] lock(direct_mutex); [ 74.768245] [ 74.768245] *** DEADLOCK *** [ 74.768245] [ 74.768750] May be due to missing lock nesting notation [ 74.768750] [ 74.769332] 1 lock held by event-sample-fn/1084: [ 74.769731] #0: ffffffff86c9d6b0 (direct_mutex){+.+.}-{3:3}, at: \ modify_ftrace_direct+0x34/0x1f0 [ 74.770496] [ 74.770496] stack backtrace: [ 74.770884] CPU: 4 PID: 1084 Comm: event-sample-fn Not tainted ... [ 74.771498] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), ... [ 74.772474] Call Trace: [ 74.772696] <TASK> [ 74.772896] dump_stack_lvl+0x44/0x5b [ 74.773223] __lock_acquire.cold.74+0xac/0x2b7 [ 74.773616] lock_acquire+0xd2/0x310 [ 74.773936] ? register_ftrace_function+0x1f/0x180 [ 74.774357] ? lock_is_held_type+0xd8/0x130 [ 74.774744] ? my_tramp2+0x11/0x11 [ftrace_direct_modify] [ 74.775213] __mutex_lock+0x99/0x1010 [ 74.775536] ? register_ftrace_function+0x1f/0x180 [ 74.775954] ? slab_free_freelist_hook.isra.43+0x115/0x160 [ 74.776424] ? ftrace_set_hash+0x195/0x220 [ 74.776779] ? register_ftrace_function+0x1f/0x180 [ 74.777194] ? kfree+0x3e1/0x440 [ 74.777482] ? my_tramp2+0x11/0x11 [ftrace_direct_modify] [ 74.777941] ? __schedule+0xb40/0xb40 [ 74.778258] ? register_ftrace_function+0x1f/0x180 [ 74.778672] ? my_tramp1+0xf/0xf [ftrace_direct_modify] [ 74.779128] register_ftrace_function+0x1f/0x180 [ 74.779527] ? ftrace_set_filter_ip+0x33/0x70 [ 74.779910] ? __schedule+0xb40/0xb40 [ 74.780231] ? my_tramp1+0xf/0xf [ftrace_direct_modify] [ 74.780678] ? my_tramp2+0x11/0x11 [ftrace_direct_modify] [ 74.781147] ftrace_modify_direct_caller+0x5b/0x90 [ 74.781563] ? 0xffffffffa0201000 [ 74.781859] ? my_tramp1+0xf/0xf [ftrace_direct_modify] [ 74.782309] modify_ftrace_direct+0x1b2/0x1f0 [ 74.782690] ? __schedule+0xb40/0xb40 [ 74.783014] ? simple_thread+0x2a/0xb0 [ftrace_direct_modify] [ 74.783508] ? __schedule+0xb40/0xb40 [ 74.783832] ? my_tramp2+0x11/0x11 [ftrace_direct_modify] [ 74.784294] simple_thread+0x76/0xb0 [ftrace_direct_modify] [ 74.784766] kthread+0xf5/0x120 [ 74.785052] ? kthread_complete_and_exit+0x20/0x20 [ 74.785464] ret_from_fork+0x22/0x30 [ 74.785781] </TASK> Fix this by using register_ftrace_function_nolock in ftrace_modify_direct_caller.
CVE-2022-50649 1 Linux 1 Linux Kernel 2026-04-15 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: power: supply: adp5061: fix out-of-bounds read in adp5061_get_chg_type() ADP5061_CHG_STATUS_1_CHG_STATUS is masked with 0x07, which means a length of 8, but adp5061_chg_type array size is 4, may end up reading 4 elements beyond the end of the adp5061_chg_type[] array.
CVE-2022-50633 1 Linux 1 Linux Kernel 2026-04-15 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: usb: dwc3: qcom: Fix memory leak in dwc3_qcom_interconnect_init of_icc_get() alloc resources for path handle, we should release it when not need anymore. Like the release in dwc3_qcom_interconnect_exit() function. Add icc_put() in error handling to fix this.
CVE-2022-50632 1 Linux 1 Linux Kernel 2026-04-15 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: drivers: perf: marvell_cn10k: Fix hotplug callback leak in tad_pmu_init() tad_pmu_init() won't remove the callback added by cpuhp_setup_state_multi() when platform_driver_register() failed. Remove the callback by cpuhp_remove_multi_state() in fail path. Similar to the handling of arm_ccn_init() in commit 26242b330093 ("bus: arm-ccn: Prevent hotplug callback leak")
CVE-2022-50650 1 Linux 1 Linux Kernel 2026-04-15 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: bpf: Fix reference state management for synchronous callbacks Currently, verifier verifies callback functions (sync and async) as if they will be executed once, (i.e. it explores execution state as if the function was being called once). The next insn to explore is set to start of subprog and the exit from nested frame is handled using curframe > 0 and prepare_func_exit. In case of async callback it uses a customized variant of push_stack simulating a kind of branch to set up custom state and execution context for the async callback. While this approach is simple and works when callback really will be executed only once, it is unsafe for all of our current helpers which are for_each style, i.e. they execute the callback multiple times. A callback releasing acquired references of the caller may do so multiple times, but currently verifier sees it as one call inside the frame, which then returns to caller. Hence, it thinks it released some reference that the cb e.g. got access through callback_ctx (register filled inside cb from spilled typed register on stack). Similarly, it may see that an acquire call is unpaired inside the callback, so the caller will copy the reference state of callback and then will have to release the register with new ref_obj_ids. But again, the callback may execute multiple times, but the verifier will only account for acquired references for a single symbolic execution of the callback, which will cause leaks. Note that for async callback case, things are different. While currently we have bpf_timer_set_callback which only executes it once, even for multiple executions it would be safe, as reference state is NULL and check_reference_leak would force program to release state before BPF_EXIT. The state is also unaffected by analysis for the caller frame. Hence async callback is safe. Since we want the reference state to be accessible, e.g. for pointers loaded from stack through callback_ctx's PTR_TO_STACK, we still have to copy caller's reference_state to callback's bpf_func_state, but we enforce that whatever references it adds to that reference_state has been released before it hits BPF_EXIT. This requires introducing a new callback_ref member in the reference state to distinguish between caller vs callee references. Hence, check_reference_leak now errors out if it sees we are in callback_fn and we have not released callback_ref refs. Since there can be multiple nested callbacks, like frame 0 -> cb1 -> cb2 etc. we need to also distinguish between whether this particular ref belongs to this callback frame or parent, and only error for our own, so we store state->frameno (which is always non-zero for callbacks). In short, callbacks can read parent reference_state, but cannot mutate it, to be able to use pointers acquired by the caller. They must only undo their changes (by releasing their own acquired_refs before BPF_EXIT) on top of caller reference_state before returning (at which point the caller and callback state will match anyway, so no need to copy it back to caller).