Total
4499 CVE
| CVE | Vendors | Products | Updated | CVSS v3.1 |
|---|---|---|---|---|
| CVE-2025-4478 | 2 Freerdp, Redhat | 2 Freerdp, Enterprise Linux | 2025-11-06 | 7.1 High |
| A flaw was found in the FreeRDP used by Anaconda's remote install feature, where a crafted RDP packet could trigger a segmentation fault. This issue causes the service to crash and remain defunct, resulting in a denial of service. It occurs pre-boot and is likely due to a NULL pointer dereference. Rebooting is required to recover the system. | ||||
| CVE-2024-36387 | 3 Apache, Netapp, Redhat | 4 Http Server, Ontap, Enterprise Linux and 1 more | 2025-11-06 | 5.4 Medium |
| Serving WebSocket protocol upgrades over a HTTP/2 connection could result in a Null Pointer dereference, leading to a crash of the server process, degrading performance. | ||||
| CVE-2023-6536 | 3 Debian, Linux, Redhat | 20 Debian Linux, Linux Kernel, Codeready Linux Builder Eus and 17 more | 2025-11-06 | 6.5 Medium |
| A flaw was found in the Linux kernel's NVMe driver. This issue may allow an unauthenticated malicious actor to send a set of crafted TCP packages when using NVMe over TCP, leading the NVMe driver to a NULL pointer dereference in the NVMe driver, causing kernel panic and a denial of service. | ||||
| CVE-2023-6535 | 2 Linux, Redhat | 19 Linux Kernel, Codeready Linux Builder Eus, Codeready Linux Builder Eus For Power Little Endian Eus and 16 more | 2025-11-06 | 6.5 Medium |
| A flaw was found in the Linux kernel's NVMe driver. This issue may allow an unauthenticated malicious actor to send a set of crafted TCP packages when using NVMe over TCP, leading the NVMe driver to a NULL pointer dereference in the NVMe driver, causing kernel panic and a denial of service. | ||||
| CVE-2023-6356 | 3 Debian, Linux, Redhat | 20 Debian Linux, Linux Kernel, Codeready Linux Builder Eus and 17 more | 2025-11-06 | 6.5 Medium |
| A flaw was found in the Linux kernel's NVMe driver. This issue may allow an unauthenticated malicious actor to send a set of crafted TCP packages when using NVMe over TCP, leading the NVMe driver to a NULL pointer dereference in the NVMe driver and causing kernel panic and a denial of service. | ||||
| CVE-2025-37759 | 1 Linux | 1 Linux Kernel | 2025-11-06 | 5.5 Medium |
| In the Linux kernel, the following vulnerability has been resolved: ublk: fix handling recovery & reissue in ublk_abort_queue() Commit 8284066946e6 ("ublk: grab request reference when the request is handled by userspace") doesn't grab request reference in case of recovery reissue. Then the request can be requeued & re-dispatch & failed when canceling uring command. If it is one zc request, the request can be freed before io_uring returns the zc buffer back, then cause kernel panic: [ 126.773061] BUG: kernel NULL pointer dereference, address: 00000000000000c8 [ 126.773657] #PF: supervisor read access in kernel mode [ 126.774052] #PF: error_code(0x0000) - not-present page [ 126.774455] PGD 0 P4D 0 [ 126.774698] Oops: Oops: 0000 [#1] SMP NOPTI [ 126.775034] CPU: 13 UID: 0 PID: 1612 Comm: kworker/u64:55 Not tainted 6.14.0_blk+ #182 PREEMPT(full) [ 126.775676] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-1.fc39 04/01/2014 [ 126.776275] Workqueue: iou_exit io_ring_exit_work [ 126.776651] RIP: 0010:ublk_io_release+0x14/0x130 [ublk_drv] Fixes it by always grabbing request reference for aborting the request. | ||||
| CVE-2025-37774 | 1 Linux | 1 Linux Kernel | 2025-11-06 | 5.5 Medium |
| In the Linux kernel, the following vulnerability has been resolved: slab: ensure slab->obj_exts is clear in a newly allocated slab page ktest recently reported crashes while running several buffered io tests with __alloc_tagging_slab_alloc_hook() at the top of the crash call stack. The signature indicates an invalid address dereference with low bits of slab->obj_exts being set. The bits were outside of the range used by page_memcg_data_flags and objext_flags and hence were not masked out by slab_obj_exts() when obtaining the pointer stored in slab->obj_exts. The typical crash log looks like this: 00510 Unable to handle kernel NULL pointer dereference at virtual address 0000000000000010 00510 Mem abort info: 00510 ESR = 0x0000000096000045 00510 EC = 0x25: DABT (current EL), IL = 32 bits 00510 SET = 0, FnV = 0 00510 EA = 0, S1PTW = 0 00510 FSC = 0x05: level 1 translation fault 00510 Data abort info: 00510 ISV = 0, ISS = 0x00000045, ISS2 = 0x00000000 00510 CM = 0, WnR = 1, TnD = 0, TagAccess = 0 00510 GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 00510 user pgtable: 4k pages, 39-bit VAs, pgdp=0000000104175000 00510 [0000000000000010] pgd=0000000000000000, p4d=0000000000000000, pud=0000000000000000 00510 Internal error: Oops: 0000000096000045 [#1] SMP 00510 Modules linked in: 00510 CPU: 10 UID: 0 PID: 7692 Comm: cat Not tainted 6.15.0-rc1-ktest-g189e17946605 #19327 NONE 00510 Hardware name: linux,dummy-virt (DT) 00510 pstate: 20001005 (nzCv daif -PAN -UAO -TCO -DIT +SSBS BTYPE=--) 00510 pc : __alloc_tagging_slab_alloc_hook+0xe0/0x190 00510 lr : __kmalloc_noprof+0x150/0x310 00510 sp : ffffff80c87df6c0 00510 x29: ffffff80c87df6c0 x28: 000000000013d1ff x27: 000000000013d200 00510 x26: ffffff80c87df9e0 x25: 0000000000000000 x24: 0000000000000001 00510 x23: ffffffc08041953c x22: 000000000000004c x21: ffffff80c0002180 00510 x20: fffffffec3120840 x19: ffffff80c4821000 x18: 0000000000000000 00510 x17: fffffffec3d02f00 x16: fffffffec3d02e00 x15: fffffffec3d00700 00510 x14: fffffffec3d00600 x13: 0000000000000200 x12: 0000000000000006 00510 x11: ffffffc080bb86c0 x10: 0000000000000000 x9 : ffffffc080201e58 00510 x8 : ffffff80c4821060 x7 : 0000000000000000 x6 : 0000000055555556 00510 x5 : 0000000000000001 x4 : 0000000000000010 x3 : 0000000000000060 00510 x2 : 0000000000000000 x1 : ffffffc080f50cf8 x0 : ffffff80d801d000 00510 Call trace: 00510 __alloc_tagging_slab_alloc_hook+0xe0/0x190 (P) 00510 __kmalloc_noprof+0x150/0x310 00510 __bch2_folio_create+0x5c/0xf8 00510 bch2_folio_create+0x2c/0x40 00510 bch2_readahead+0xc0/0x460 00510 read_pages+0x7c/0x230 00510 page_cache_ra_order+0x244/0x3a8 00510 page_cache_async_ra+0x124/0x170 00510 filemap_readahead.isra.0+0x58/0xa0 00510 filemap_get_pages+0x454/0x7b0 00510 filemap_read+0xdc/0x418 00510 bch2_read_iter+0x100/0x1b0 00510 vfs_read+0x214/0x300 00510 ksys_read+0x6c/0x108 00510 __arm64_sys_read+0x20/0x30 00510 invoke_syscall.constprop.0+0x54/0xe8 00510 do_el0_svc+0x44/0xc8 00510 el0_svc+0x18/0x58 00510 el0t_64_sync_handler+0x104/0x130 00510 el0t_64_sync+0x154/0x158 00510 Code: d5384100 f9401c01 b9401aa3 b40002e1 (f8227881) 00510 ---[ end trace 0000000000000000 ]--- 00510 Kernel panic - not syncing: Oops: Fatal exception 00510 SMP: stopping secondary CPUs 00510 Kernel Offset: disabled 00510 CPU features: 0x0000,000000e0,00000410,8240500b 00510 Memory Limit: none Investigation indicates that these bits are already set when we allocate slab page and are not zeroed out after allocation. We are not yet sure why these crashes start happening only recently but regardless of the reason, not initializing a field that gets used later is wrong. Fix it by initializing slab->obj_exts during slab page allocation. | ||||
| CVE-2025-37755 | 1 Linux | 1 Linux Kernel | 2025-11-06 | 5.5 Medium |
| In the Linux kernel, the following vulnerability has been resolved: net: libwx: handle page_pool_dev_alloc_pages error page_pool_dev_alloc_pages could return NULL. There was a WARN_ON(!page) but it would still proceed to use the NULL pointer and then crash. This is similar to commit 001ba0902046 ("net: fec: handle page_pool_dev_alloc_pages error"). This is found by our static analysis tool KNighter. | ||||
| CVE-2025-32913 | 1 Redhat | 6 Enterprise Linux, Rhel Aus, Rhel E4s and 3 more | 2025-11-06 | 7.5 High |
| A flaw was found in libsoup, where the soup_message_headers_get_content_disposition() function is vulnerable to a NULL pointer dereference. This flaw allows a malicious HTTP peer to crash a libsoup client or server that uses this function. | ||||
| CVE-2023-6176 | 2 Linux, Redhat | 2 Linux Kernel, Enterprise Linux | 2025-11-06 | 4.7 Medium |
| A null pointer dereference flaw was found in the Linux kernel API for the cryptographic algorithm scatterwalk functionality. This issue occurs when a user constructs a malicious packet with specific socket configuration, which could allow a local user to crash the system or escalate their privileges on the system. | ||||
| CVE-2024-0841 | 2 Linux, Redhat | 2 Linux Kernel, Enterprise Linux | 2025-11-06 | 6.6 Medium |
| A null pointer dereference flaw was found in the hugetlbfs_fill_super function in the Linux kernel hugetlbfs (HugeTLB pages) functionality. This issue may allow a local user to crash the system or potentially escalate their privileges on the system. | ||||
| CVE-2023-42754 | 3 Fedoraproject, Linux, Redhat | 3 Fedora, Linux Kernel, Enterprise Linux | 2025-11-06 | 5.5 Medium |
| A NULL pointer dereference flaw was found in the Linux kernel ipv4 stack. The socket buffer (skb) was assumed to be associated with a device before calling __ip_options_compile, which is not always the case if the skb is re-routed by ipvs. This issue may allow a local user with CAP_NET_ADMIN privileges to crash the system. | ||||
| CVE-2023-6915 | 2 Linux, Redhat | 2 Linux Kernel, Enterprise Linux | 2025-11-06 | 6.2 Medium |
| A Null pointer dereference problem was found in ida_free in lib/idr.c in the Linux Kernel. This issue may allow an attacker using this library to cause a denial of service problem due to a missing check at a function return. | ||||
| CVE-2023-6622 | 3 Fedoraproject, Linux, Redhat | 3 Fedora, Linux Kernel, Enterprise Linux | 2025-11-06 | 5.5 Medium |
| A null pointer dereference vulnerability was found in nft_dynset_init() in net/netfilter/nft_dynset.c in nf_tables in the Linux kernel. This issue may allow a local attacker with CAP_NET_ADMIN user privilege to trigger a denial of service. | ||||
| CVE-2022-49796 | 1 Linux | 1 Linux Kernel | 2025-11-06 | 5.5 Medium |
| In the Linux kernel, the following vulnerability has been resolved: tracing: kprobe: Fix potential null-ptr-deref on trace_array in kprobe_event_gen_test_exit() When test_gen_kprobe_cmd() failed after kprobe_event_gen_cmd_end(), it will goto delete, which will call kprobe_event_delete() and release the corresponding resource. However, the trace_array in gen_kretprobe_test will point to the invalid resource. Set gen_kretprobe_test to NULL after called kprobe_event_delete() to prevent null-ptr-deref. BUG: kernel NULL pointer dereference, address: 0000000000000070 PGD 0 P4D 0 Oops: 0000 [#1] SMP PTI CPU: 0 PID: 246 Comm: modprobe Tainted: G W 6.1.0-rc1-00174-g9522dc5c87da-dirty #248 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014 RIP: 0010:__ftrace_set_clr_event_nolock+0x53/0x1b0 Code: e8 82 26 fc ff 49 8b 1e c7 44 24 0c ea ff ff ff 49 39 de 0f 84 3c 01 00 00 c7 44 24 18 00 00 00 00 e8 61 26 fc ff 48 8b 6b 10 <44> 8b 65 70 4c 8b 6d 18 41 f7 c4 00 02 00 00 75 2f RSP: 0018:ffffc9000159fe00 EFLAGS: 00010293 RAX: 0000000000000000 RBX: ffff88810971d268 RCX: 0000000000000000 RDX: ffff8881080be600 RSI: ffffffff811b48ff RDI: ffff88810971d058 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001 R10: ffffc9000159fe58 R11: 0000000000000001 R12: ffffffffa0001064 R13: ffffffffa000106c R14: ffff88810971d238 R15: 0000000000000000 FS: 00007f89eeff6540(0000) GS:ffff88813b600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000070 CR3: 000000010599e004 CR4: 0000000000330ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> __ftrace_set_clr_event+0x3e/0x60 trace_array_set_clr_event+0x35/0x50 ? 0xffffffffa0000000 kprobe_event_gen_test_exit+0xcd/0x10b [kprobe_event_gen_test] __x64_sys_delete_module+0x206/0x380 ? lockdep_hardirqs_on_prepare+0xd8/0x190 ? syscall_enter_from_user_mode+0x1c/0x50 do_syscall_64+0x3f/0x90 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f89eeb061b7 | ||||
| CVE-2022-49797 | 1 Linux | 1 Linux Kernel | 2025-11-06 | 5.5 Medium |
| In the Linux kernel, the following vulnerability has been resolved: tracing: kprobe: Fix potential null-ptr-deref on trace_event_file in kprobe_event_gen_test_exit() When trace_get_event_file() failed, gen_kretprobe_test will be assigned as the error code. If module kprobe_event_gen_test is removed now, the null pointer dereference will happen in kprobe_event_gen_test_exit(). Check if gen_kprobe_test or gen_kretprobe_test is error code or NULL before dereference them. BUG: kernel NULL pointer dereference, address: 0000000000000012 PGD 0 P4D 0 Oops: 0000 [#1] SMP PTI CPU: 3 PID: 2210 Comm: modprobe Not tainted 6.1.0-rc1-00171-g2159299a3b74-dirty #217 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014 RIP: 0010:kprobe_event_gen_test_exit+0x1c/0xb5 [kprobe_event_gen_test] Code: Unable to access opcode bytes at 0xffffffff9ffffff2. RSP: 0018:ffffc900015bfeb8 EFLAGS: 00010246 RAX: ffffffffffffffea RBX: ffffffffa0002080 RCX: 0000000000000000 RDX: ffffffffa0001054 RSI: ffffffffa0001064 RDI: ffffffffdfc6349c RBP: ffffffffa0000000 R08: 0000000000000004 R09: 00000000001e95c0 R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000800 R13: ffffffffa0002420 R14: 0000000000000000 R15: 0000000000000000 FS: 00007f56b75be540(0000) GS:ffff88813bc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffff9ffffff2 CR3: 000000010874a006 CR4: 0000000000330ee0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> __x64_sys_delete_module+0x206/0x380 ? lockdep_hardirqs_on_prepare+0xd8/0x190 ? syscall_enter_from_user_mode+0x1c/0x50 do_syscall_64+0x3f/0x90 entry_SYSCALL_64_after_hwframe+0x63/0xcd | ||||
| CVE-2025-37783 | 1 Linux | 1 Linux Kernel | 2025-11-06 | 5.5 Medium |
| In the Linux kernel, the following vulnerability has been resolved: drm/msm/dpu: Fix error pointers in dpu_plane_virtual_atomic_check The function dpu_plane_virtual_atomic_check was dereferencing pointers returned by drm_atomic_get_plane_state without checking for errors. This could lead to undefined behavior if the function returns an error pointer. This commit adds checks using IS_ERR to ensure that plane_state is valid before dereferencing them. Similar to commit da29abe71e16 ("drm/amd/display: Fix error pointers in amdgpu_dm_crtc_mem_type_changed"). Patchwork: https://patchwork.freedesktop.org/patch/643132/ | ||||
| CVE-2025-37781 | 2 Debian, Linux | 2 Debian Linux, Linux Kernel | 2025-11-06 | 5.5 Medium |
| In the Linux kernel, the following vulnerability has been resolved: i2c: cros-ec-tunnel: defer probe if parent EC is not present When i2c-cros-ec-tunnel and the EC driver are built-in, the EC parent device will not be found, leading to NULL pointer dereference. That can also be reproduced by unbinding the controller driver and then loading i2c-cros-ec-tunnel module (or binding the device). [ 271.991245] BUG: kernel NULL pointer dereference, address: 0000000000000058 [ 271.998215] #PF: supervisor read access in kernel mode [ 272.003351] #PF: error_code(0x0000) - not-present page [ 272.008485] PGD 0 P4D 0 [ 272.011022] Oops: Oops: 0000 [#1] SMP NOPTI [ 272.015207] CPU: 0 UID: 0 PID: 3859 Comm: insmod Tainted: G S 6.15.0-rc1-00004-g44722359ed83 #30 PREEMPT(full) 3c7fb39a552e7d949de2ad921a7d6588d3a4fdc5 [ 272.030312] Tainted: [S]=CPU_OUT_OF_SPEC [ 272.034233] Hardware name: HP Berknip/Berknip, BIOS Google_Berknip.13434.356.0 05/17/2021 [ 272.042400] RIP: 0010:ec_i2c_probe+0x2b/0x1c0 [i2c_cros_ec_tunnel] [ 272.048577] Code: 1f 44 00 00 41 57 41 56 41 55 41 54 53 48 83 ec 10 65 48 8b 05 06 a0 6c e7 48 89 44 24 08 4c 8d 7f 10 48 8b 47 50 4c 8b 60 78 <49> 83 7c 24 58 00 0f 84 2f 01 00 00 48 89 fb be 30 06 00 00 4c 9 [ 272.067317] RSP: 0018:ffffa32082a03940 EFLAGS: 00010282 [ 272.072541] RAX: ffff969580b6a810 RBX: ffff969580b68c10 RCX: 0000000000000000 [ 272.079672] RDX: 0000000000000000 RSI: 0000000000000282 RDI: ffff969580b68c00 [ 272.086804] RBP: 00000000fffffdfb R08: 0000000000000000 R09: 0000000000000000 [ 272.093936] R10: 0000000000000000 R11: ffffffffc0600000 R12: 0000000000000000 [ 272.101067] R13: ffffffffa666fbb8 R14: ffffffffc05b5528 R15: ffff969580b68c10 [ 272.108198] FS: 00007b930906fc40(0000) GS:ffff969603149000(0000) knlGS:0000000000000000 [ 272.116282] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 272.122024] CR2: 0000000000000058 CR3: 000000012631c000 CR4: 00000000003506f0 [ 272.129155] Call Trace: [ 272.131606] <TASK> [ 272.133709] ? acpi_dev_pm_attach+0xdd/0x110 [ 272.137985] platform_probe+0x69/0xa0 [ 272.141652] really_probe+0x152/0x310 [ 272.145318] __driver_probe_device+0x77/0x110 [ 272.149678] driver_probe_device+0x1e/0x190 [ 272.153864] __driver_attach+0x10b/0x1e0 [ 272.157790] ? driver_attach+0x20/0x20 [ 272.161542] bus_for_each_dev+0x107/0x150 [ 272.165553] bus_add_driver+0x15d/0x270 [ 272.169392] driver_register+0x65/0x110 [ 272.173232] ? cleanup_module+0xa80/0xa80 [i2c_cros_ec_tunnel 3a00532f3f4af4a9eade753f86b0f8dd4e4e5698] [ 272.182617] do_one_initcall+0x110/0x350 [ 272.186543] ? security_kernfs_init_security+0x49/0xd0 [ 272.191682] ? __kernfs_new_node+0x1b9/0x240 [ 272.195954] ? security_kernfs_init_security+0x49/0xd0 [ 272.201093] ? __kernfs_new_node+0x1b9/0x240 [ 272.205365] ? kernfs_link_sibling+0x105/0x130 [ 272.209810] ? kernfs_next_descendant_post+0x1c/0xa0 [ 272.214773] ? kernfs_activate+0x57/0x70 [ 272.218699] ? kernfs_add_one+0x118/0x160 [ 272.222710] ? __kernfs_create_file+0x71/0xa0 [ 272.227069] ? sysfs_add_bin_file_mode_ns+0xd6/0x110 [ 272.232033] ? internal_create_group+0x453/0x4a0 [ 272.236651] ? __vunmap_range_noflush+0x214/0x2d0 [ 272.241355] ? __free_frozen_pages+0x1dc/0x420 [ 272.245799] ? free_vmap_area_noflush+0x10a/0x1c0 [ 272.250505] ? load_module+0x1509/0x16f0 [ 272.254431] do_init_module+0x60/0x230 [ 272.258181] __se_sys_finit_module+0x27a/0x370 [ 272.262627] do_syscall_64+0x6a/0xf0 [ 272.266206] ? do_syscall_64+0x76/0xf0 [ 272.269956] ? irqentry_exit_to_user_mode+0x79/0x90 [ 272.274836] entry_SYSCALL_64_after_hwframe+0x55/0x5d [ 272.279887] RIP: 0033:0x7b9309168d39 [ 272.283466] Code: 5b 41 5c 5d c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d af 40 0c 00 f7 d8 64 89 01 8 [ 272.302210] RSP: 002b:00007fff50f1a288 EFLAGS: 00000246 ORIG_RAX: 000 ---truncated--- | ||||
| CVE-2025-38240 | 1 Linux | 1 Linux Kernel | 2025-11-06 | 5.5 Medium |
| In the Linux kernel, the following vulnerability has been resolved: drm/mediatek: dp: drm_err => dev_err in HPD path to avoid NULL ptr The function mtk_dp_wait_hpd_asserted() may be called before the `mtk_dp->drm_dev` pointer is assigned in mtk_dp_bridge_attach(). Specifically it can be called via this callpath: - mtk_edp_wait_hpd_asserted - [panel probe] - dp_aux_ep_probe Using "drm" level prints anywhere in this callpath causes a NULL pointer dereference. Change the error message directly in mtk_dp_wait_hpd_asserted() to dev_err() to avoid this. Also change the error messages in mtk_dp_parse_capabilities(), which is called by mtk_dp_wait_hpd_asserted(). While touching these prints, also add the error code to them to make future debugging easier. | ||||
| CVE-2025-23143 | 2 Debian, Linux | 2 Debian Linux, Linux Kernel | 2025-11-05 | 5.5 Medium |
| In the Linux kernel, the following vulnerability has been resolved: net: Fix null-ptr-deref by sock_lock_init_class_and_name() and rmmod. When I ran the repro [0] and waited a few seconds, I observed two LOCKDEP splats: a warning immediately followed by a null-ptr-deref. [1] Reproduction Steps: 1) Mount CIFS 2) Add an iptables rule to drop incoming FIN packets for CIFS 3) Unmount CIFS 4) Unload the CIFS module 5) Remove the iptables rule At step 3), the CIFS module calls sock_release() for the underlying TCP socket, and it returns quickly. However, the socket remains in FIN_WAIT_1 because incoming FIN packets are dropped. At this point, the module's refcnt is 0 while the socket is still alive, so the following rmmod command succeeds. # ss -tan State Recv-Q Send-Q Local Address:Port Peer Address:Port FIN-WAIT-1 0 477 10.0.2.15:51062 10.0.0.137:445 # lsmod | grep cifs cifs 1159168 0 This highlights a discrepancy between the lifetime of the CIFS module and the underlying TCP socket. Even after CIFS calls sock_release() and it returns, the TCP socket does not die immediately in order to close the connection gracefully. While this is generally fine, it causes an issue with LOCKDEP because CIFS assigns a different lock class to the TCP socket's sk->sk_lock using sock_lock_init_class_and_name(). Once an incoming packet is processed for the socket or a timer fires, sk->sk_lock is acquired. Then, LOCKDEP checks the lock context in check_wait_context(), where hlock_class() is called to retrieve the lock class. However, since the module has already been unloaded, hlock_class() logs a warning and returns NULL, triggering the null-ptr-deref. If LOCKDEP is enabled, we must ensure that a module calling sock_lock_init_class_and_name() (CIFS, NFS, etc) cannot be unloaded while such a socket is still alive to prevent this issue. Let's hold the module reference in sock_lock_init_class_and_name() and release it when the socket is freed in sk_prot_free(). Note that sock_lock_init() clears sk->sk_owner for svc_create_socket() that calls sock_lock_init_class_and_name() for a listening socket, which clones a socket by sk_clone_lock() without GFP_ZERO. [0]: CIFS_SERVER="10.0.0.137" CIFS_PATH="//${CIFS_SERVER}/Users/Administrator/Desktop/CIFS_TEST" DEV="enp0s3" CRED="/root/WindowsCredential.txt" MNT=$(mktemp -d /tmp/XXXXXX) mount -t cifs ${CIFS_PATH} ${MNT} -o vers=3.0,credentials=${CRED},cache=none,echo_interval=1 iptables -A INPUT -s ${CIFS_SERVER} -j DROP for i in $(seq 10); do umount ${MNT} rmmod cifs sleep 1 done rm -r ${MNT} iptables -D INPUT -s ${CIFS_SERVER} -j DROP [1]: DEBUG_LOCKS_WARN_ON(1) WARNING: CPU: 10 PID: 0 at kernel/locking/lockdep.c:234 hlock_class (kernel/locking/lockdep.c:234 kernel/locking/lockdep.c:223) Modules linked in: cifs_arc4 nls_ucs2_utils cifs_md4 [last unloaded: cifs] CPU: 10 UID: 0 PID: 0 Comm: swapper/10 Not tainted 6.14.0 #36 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014 RIP: 0010:hlock_class (kernel/locking/lockdep.c:234 kernel/locking/lockdep.c:223) ... Call Trace: <IRQ> __lock_acquire (kernel/locking/lockdep.c:4853 kernel/locking/lockdep.c:5178) lock_acquire (kernel/locking/lockdep.c:469 kernel/locking/lockdep.c:5853 kernel/locking/lockdep.c:5816) _raw_spin_lock_nested (kernel/locking/spinlock.c:379) tcp_v4_rcv (./include/linux/skbuff.h:1678 ./include/net/tcp.h:2547 net/ipv4/tcp_ipv4.c:2350) ... BUG: kernel NULL pointer dereference, address: 00000000000000c4 PF: supervisor read access in kernel mode PF: error_code(0x0000) - not-present page PGD 0 Oops: Oops: 0000 [#1] PREEMPT SMP NOPTI CPU: 10 UID: 0 PID: 0 Comm: swapper/10 Tainted: G W 6.14.0 #36 Tainted: [W]=WARN Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014 RIP: 0010:__lock_acquire (kernel/ ---truncated--- | ||||