In the Linux kernel, the following vulnerability has been resolved: smb: client: fix possible double free in smb2_set_ea() Clang static checker(scan-build) warning： fs/smb/client/smb2ops.c:1304:2: Attempt to free released memory. 1304 | kfree(ea); | ^~~~~~~~~ There is a double free in such case: 'ea is initialized to NULL' -> 'first successful memory allocation for ea' -> 'something failed, goto sea_exit' -> 'first memory release for ea' -> 'goto replay_again' -> 'second goto sea_exit before allocate memory for ea' -> 'second memory release for ea resulted in double free'. Re-initialie 'ea' to NULL near to the replay_again label, it can fix this double free problem.

In the Linux kernel, the following vulnerability has been resolved: gfs2: fix double destroy_workqueue error When gfs2_fill_super() fails, destroy_workqueue() is called within gfs2_gl_hash_clear(), and the subsequent code path calls destroy_workqueue() on the same work queue again. This issue can be fixed by setting the work queue pointer to NULL after the first destroy_workqueue() call and checking for a NULL pointer before attempting to destroy the work queue again.

In the Linux kernel, the following vulnerability has been resolved: thermal: intel: int340x: processor: Fix warning during module unload The processor_thermal driver uses pcim_device_enable() to enable a PCI device, which means the device will be automatically disabled on driver detach. Thus there is no need to call pci_disable_device() again on it. With recent PCI device resource management improvements, e.g. commit f748a07a0b64 ("PCI: Remove legacy pcim_release()"), this problem is exposed and triggers the warining below. [ 224.010735] proc_thermal_pci 0000:00:04.0: disabling already-disabled device [ 224.010747] WARNING: CPU: 8 PID: 4442 at drivers/pci/pci.c:2250 pci_disable_device+0xe5/0x100 ... [ 224.010844] Call Trace: [ 224.010845] <TASK> [ 224.010847] ? show_regs+0x6d/0x80 [ 224.010851] ? __warn+0x8c/0x140 [ 224.010854] ? pci_disable_device+0xe5/0x100 [ 224.010856] ? report_bug+0x1c9/0x1e0 [ 224.010859] ? handle_bug+0x46/0x80 [ 224.010862] ? exc_invalid_op+0x1d/0x80 [ 224.010863] ? asm_exc_invalid_op+0x1f/0x30 [ 224.010867] ? pci_disable_device+0xe5/0x100 [ 224.010869] ? pci_disable_device+0xe5/0x100 [ 224.010871] ? kfree+0x21a/0x2b0 [ 224.010873] pcim_disable_device+0x20/0x30 [ 224.010875] devm_action_release+0x16/0x20 [ 224.010878] release_nodes+0x47/0xc0 [ 224.010880] devres_release_all+0x9f/0xe0 [ 224.010883] device_unbind_cleanup+0x12/0x80 [ 224.010885] device_release_driver_internal+0x1ca/0x210 [ 224.010887] driver_detach+0x4e/0xa0 [ 224.010889] bus_remove_driver+0x6f/0xf0 [ 224.010890] driver_unregister+0x35/0x60 [ 224.010892] pci_unregister_driver+0x44/0x90 [ 224.010894] proc_thermal_pci_driver_exit+0x14/0x5f0 [processor_thermal_device_pci] ... [ 224.010921] ---[ end trace 0000000000000000 ]--- Remove the excess pci_disable_device() calls. [ rjw: Subject and changelog edits ]

In the Linux kernel, the following vulnerability has been resolved: cachefiles: fix dentry leak in cachefiles_open_file() A dentry leak may be caused when a lookup cookie and a cull are concurrent: P1 | P2 ----------------------------------------------------------- cachefiles_lookup_cookie cachefiles_look_up_object lookup_one_positive_unlocked // get dentry cachefiles_cull inode->i_flags |= S_KERNEL_FILE; cachefiles_open_file cachefiles_mark_inode_in_use __cachefiles_mark_inode_in_use can_use = false if (!(inode->i_flags & S_KERNEL_FILE)) can_use = true return false return false // Returns an error but doesn't put dentry After that the following WARNING will be triggered when the backend folder is umounted: ================================================================== BUG: Dentry 000000008ad87947{i=7a,n=Dx_1_1.img} still in use (1) [unmount of ext4 sda] WARNING: CPU: 4 PID: 359261 at fs/dcache.c:1767 umount_check+0x5d/0x70 CPU: 4 PID: 359261 Comm: umount Not tainted 6.6.0-dirty #25 RIP: 0010:umount_check+0x5d/0x70 Call Trace: <TASK> d_walk+0xda/0x2b0 do_one_tree+0x20/0x40 shrink_dcache_for_umount+0x2c/0x90 generic_shutdown_super+0x20/0x160 kill_block_super+0x1a/0x40 ext4_kill_sb+0x22/0x40 deactivate_locked_super+0x35/0x80 cleanup_mnt+0x104/0x160 ================================================================== Whether cachefiles_open_file() returns true or false, the reference count obtained by lookup_positive_unlocked() in cachefiles_look_up_object() should be released. Therefore release that reference count in cachefiles_look_up_object() to fix the above issue and simplify the code.

In the Linux kernel, the following vulnerability has been resolved: net: avoid potential underflow in qdisc_pkt_len_init() with UFO After commit 7c6d2ecbda83 ("net: be more gentle about silly gso requests coming from user") virtio_net_hdr_to_skb() had sanity check to detect malicious attempts from user space to cook a bad GSO packet. Then commit cf9acc90c80ec ("net: virtio_net_hdr_to_skb: count transport header in UFO") while fixing one issue, allowed user space to cook a GSO packet with the following characteristic : IPv4 SKB_GSO_UDP, gso_size=3, skb->len = 28. When this packet arrives in qdisc_pkt_len_init(), we end up with hdr_len = 28 (IPv4 header + UDP header), matching skb->len Then the following sets gso_segs to 0 : gso_segs = DIV_ROUND_UP(skb->len - hdr_len, shinfo->gso_size); Then later we set qdisc_skb_cb(skb)->pkt_len to back to zero :/ qdisc_skb_cb(skb)->pkt_len += (gso_segs - 1) * hdr_len; This leads to the following crash in fq_codel [1] qdisc_pkt_len_init() is best effort, we only want an estimation of the bytes sent on the wire, not crashing the kernel. This patch is fixing this particular issue, a following one adds more sanity checks for another potential bug. [1] [ 70.724101] BUG: kernel NULL pointer dereference, address: 0000000000000000 [ 70.724561] #PF: supervisor read access in kernel mode [ 70.724561] #PF: error_code(0x0000) - not-present page [ 70.724561] PGD 10ac61067 P4D 10ac61067 PUD 107ee2067 PMD 0 [ 70.724561] Oops: Oops: 0000 [#1] SMP NOPTI [ 70.724561] CPU: 11 UID: 0 PID: 2163 Comm: b358537762 Not tainted 6.11.0-virtme #991 [ 70.724561] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 70.724561] RIP: 0010:fq_codel_enqueue (net/sched/sch_fq_codel.c:120 net/sched/sch_fq_codel.c:168 net/sched/sch_fq_codel.c:230) sch_fq_codel [ 70.724561] Code: 24 08 49 c1 e1 06 44 89 7c 24 18 45 31 ed 45 31 c0 31 ff 89 44 24 14 4c 03 8b 90 01 00 00 eb 04 39 ca 73 37 4d 8b 39 83 c7 01 <49> 8b 17 49 89 11 41 8b 57 28 45 8b 5f 34 49 c7 07 00 00 00 00 49 All code ======== 0: 24 08 and $0x8,%al 2: 49 c1 e1 06 shl $0x6,%r9 6: 44 89 7c 24 18 mov %r15d,0x18(%rsp) b: 45 31 ed xor %r13d,%r13d e: 45 31 c0 xor %r8d,%r8d 11: 31 ff xor %edi,%edi 13: 89 44 24 14 mov %eax,0x14(%rsp) 17: 4c 03 8b 90 01 00 00 add 0x190(%rbx),%r9 1e: eb 04 jmp 0x24 20: 39 ca cmp %ecx,%edx 22: 73 37 jae 0x5b 24: 4d 8b 39 mov (%r9),%r15 27: 83 c7 01 add $0x1,%edi 2a:* 49 8b 17 mov (%r15),%rdx <-- trapping instruction 2d: 49 89 11 mov %rdx,(%r9) 30: 41 8b 57 28 mov 0x28(%r15),%edx 34: 45 8b 5f 34 mov 0x34(%r15),%r11d 38: 49 c7 07 00 00 00 00 movq $0x0,(%r15) 3f: 49 rex.WB Code starting with the faulting instruction =========================================== 0: 49 8b 17 mov (%r15),%rdx 3: 49 89 11 mov %rdx,(%r9) 6: 41 8b 57 28 mov 0x28(%r15),%edx a: 45 8b 5f 34 mov 0x34(%r15),%r11d e: 49 c7 07 00 00 00 00 movq $0x0,(%r15) 15: 49 rex.WB [ 70.724561] RSP: 0018:ffff95ae85e6fb90 EFLAGS: 00000202 [ 70.724561] RAX: 0000000002000000 RBX: ffff95ae841de000 RCX: 0000000000000000 [ 70.724561] RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000001 [ 70.724561] RBP: ffff95ae85e6fbf8 R08: 0000000000000000 R09: ffff95b710a30000 [ 70.724561] R10: 0000000000000000 R11: bdf289445ce31881 R12: ffff95ae85e6fc58 [ 70.724561] R13: 0000000000000000 R14: 0000000000000040 R15: 0000000000000000 [ 70.724561] FS: 000000002c5c1380(0000) GS:ffff95bd7fcc0000(0000) knlGS:0000000000000000 [ 70.724561] CS: 0010 DS: 0000 ES: 0000 C ---truncated---

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_tables: prevent nf_skb_duplicated corruption syzbot found that nf_dup_ipv4() or nf_dup_ipv6() could write per-cpu variable nf_skb_duplicated in an unsafe way [1]. Disabling preemption as hinted by the splat is not enough, we have to disable soft interrupts as well. [1] BUG: using __this_cpu_write() in preemptible [00000000] code: syz.4.282/6316 caller is nf_dup_ipv4+0x651/0x8f0 net/ipv4/netfilter/nf_dup_ipv4.c:87 CPU: 0 UID: 0 PID: 6316 Comm: syz.4.282 Not tainted 6.11.0-rc7-syzkaller-00104-g7052622fccb1 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024 Call Trace: <TASK> __dump_stack lib/dump_stack.c:93 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:119 check_preemption_disabled+0x10e/0x120 lib/smp_processor_id.c:49 nf_dup_ipv4+0x651/0x8f0 net/ipv4/netfilter/nf_dup_ipv4.c:87 nft_dup_ipv4_eval+0x1db/0x300 net/ipv4/netfilter/nft_dup_ipv4.c:30 expr_call_ops_eval net/netfilter/nf_tables_core.c:240 [inline] nft_do_chain+0x4ad/0x1da0 net/netfilter/nf_tables_core.c:288 nft_do_chain_ipv4+0x202/0x320 net/netfilter/nft_chain_filter.c:23 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline] nf_hook_slow+0xc3/0x220 net/netfilter/core.c:626 nf_hook+0x2c4/0x450 include/linux/netfilter.h:269 NF_HOOK_COND include/linux/netfilter.h:302 [inline] ip_output+0x185/0x230 net/ipv4/ip_output.c:433 ip_local_out net/ipv4/ip_output.c:129 [inline] ip_send_skb+0x74/0x100 net/ipv4/ip_output.c:1495 udp_send_skb+0xacf/0x1650 net/ipv4/udp.c:981 udp_sendmsg+0x1c21/0x2a60 net/ipv4/udp.c:1269 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg+0x1a6/0x270 net/socket.c:745 ____sys_sendmsg+0x525/0x7d0 net/socket.c:2597 ___sys_sendmsg net/socket.c:2651 [inline] __sys_sendmmsg+0x3b2/0x740 net/socket.c:2737 __do_sys_sendmmsg net/socket.c:2766 [inline] __se_sys_sendmmsg net/socket.c:2763 [inline] __x64_sys_sendmmsg+0xa0/0xb0 net/socket.c:2763 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f4ce4f7def9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f4ce5d4a038 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 00007f4ce5135f80 RCX: 00007f4ce4f7def9 RDX: 0000000000000001 RSI: 0000000020005d40 RDI: 0000000000000006 RBP: 00007f4ce4ff0b76 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f4ce5135f80 R15: 00007ffd4cbc6d68 </TASK>

In the Linux kernel, the following vulnerability has been resolved: resource: fix region_intersects() vs add_memory_driver_managed() On a system with CXL memory, the resource tree (/proc/iomem) related to CXL memory may look like something as follows. 490000000-50fffffff : CXL Window 0 490000000-50fffffff : region0 490000000-50fffffff : dax0.0 490000000-50fffffff : System RAM (kmem) Because drivers/dax/kmem.c calls add_memory_driver_managed() during onlining CXL memory, which makes "System RAM (kmem)" a descendant of "CXL Window X". This confuses region_intersects(), which expects all "System RAM" resources to be at the top level of iomem_resource. This can lead to bugs. For example, when the following command line is executed to write some memory in CXL memory range via /dev/mem, $ dd if=data of=/dev/mem bs=$((1 << 10)) seek=$((0x490000000 >> 10)) count=1 dd: error writing '/dev/mem': Bad address 1+0 records in 0+0 records out 0 bytes copied, 0.0283507 s, 0.0 kB/s the command fails as expected. However, the error code is wrong. It should be "Operation not permitted" instead of "Bad address". More seriously, the /dev/mem permission checking in devmem_is_allowed() passes incorrectly. Although the accessing is prevented later because ioremap() isn't allowed to map system RAM, it is a potential security issue. During command executing, the following warning is reported in the kernel log for calling ioremap() on system RAM. ioremap on RAM at 0x0000000490000000 - 0x0000000490000fff WARNING: CPU: 2 PID: 416 at arch/x86/mm/ioremap.c:216 __ioremap_caller.constprop.0+0x131/0x35d Call Trace: memremap+0xcb/0x184 xlate_dev_mem_ptr+0x25/0x2f write_mem+0x94/0xfb vfs_write+0x128/0x26d ksys_write+0xac/0xfe do_syscall_64+0x9a/0xfd entry_SYSCALL_64_after_hwframe+0x4b/0x53 The details of command execution process are as follows. In the above resource tree, "System RAM" is a descendant of "CXL Window 0" instead of a top level resource. So, region_intersects() will report no System RAM resources in the CXL memory region incorrectly, because it only checks the top level resources. Consequently, devmem_is_allowed() will return 1 (allow access via /dev/mem) for CXL memory region incorrectly. Fortunately, ioremap() doesn't allow to map System RAM and reject the access. So, region_intersects() needs to be fixed to work correctly with the resource tree with "System RAM" not at top level as above. To fix it, if we found a unmatched resource in the top level, we will continue to search matched resources in its descendant resources. So, we will not miss any matched resources in resource tree anymore. In the new implementation, an example resource tree |------------- "CXL Window 0" ------------| |-- "System RAM" --| will behave similar as the following fake resource tree for region_intersects(, IORESOURCE_SYSTEM_RAM, ), |-- "System RAM" --||-- "CXL Window 0a" --| Where "CXL Window 0a" is part of the original "CXL Window 0" that isn't covered by "System RAM".

In the Linux kernel, the following vulnerability has been resolved: net/mlx5e: Fix crash caused by calling __xfrm_state_delete() twice The km.state is not checked in driver's delayed work. When xfrm_state_check_expire() is called, the state can be reset to XFRM_STATE_EXPIRED, even if it is XFRM_STATE_DEAD already. This happens when xfrm state is deleted, but not freed yet. As __xfrm_state_delete() is called again in xfrm timer, the following crash occurs. To fix this issue, skip xfrm_state_check_expire() if km.state is not XFRM_STATE_VALID. Oops: general protection fault, probably for non-canonical address 0xdead000000000108: 0000 [#1] SMP CPU: 5 UID: 0 PID: 7448 Comm: kworker/u102:2 Not tainted 6.11.0-rc2+ #1 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 Workqueue: mlx5e_ipsec: eth%d mlx5e_ipsec_handle_sw_limits [mlx5_core] RIP: 0010:__xfrm_state_delete+0x3d/0x1b0 Code: 0f 84 8b 01 00 00 48 89 fd c6 87 c8 00 00 00 05 48 8d bb 40 10 00 00 e8 11 04 1a 00 48 8b 95 b8 00 00 00 48 8b 85 c0 00 00 00 <48> 89 42 08 48 89 10 48 8b 55 10 48 b8 00 01 00 00 00 00 ad de 48 RSP: 0018:ffff88885f945ec8 EFLAGS: 00010246 RAX: dead000000000122 RBX: ffffffff82afa940 RCX: 0000000000000036 RDX: dead000000000100 RSI: 0000000000000000 RDI: ffffffff82afb980 RBP: ffff888109a20340 R08: ffff88885f945ea0 R09: 0000000000000000 R10: 0000000000000000 R11: ffff88885f945ff8 R12: 0000000000000246 R13: ffff888109a20340 R14: ffff88885f95f420 R15: ffff88885f95f400 FS: 0000000000000000(0000) GS:ffff88885f940000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f2163102430 CR3: 00000001128d6001 CR4: 0000000000370eb0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <IRQ> ? die_addr+0x33/0x90 ? exc_general_protection+0x1a2/0x390 ? asm_exc_general_protection+0x22/0x30 ? __xfrm_state_delete+0x3d/0x1b0 ? __xfrm_state_delete+0x2f/0x1b0 xfrm_timer_handler+0x174/0x350 ? __xfrm_state_delete+0x1b0/0x1b0 __hrtimer_run_queues+0x121/0x270 hrtimer_run_softirq+0x88/0xd0 handle_softirqs+0xcc/0x270 do_softirq+0x3c/0x50 </IRQ> <TASK> __local_bh_enable_ip+0x47/0x50 mlx5e_ipsec_handle_sw_limits+0x7d/0x90 [mlx5_core] process_one_work+0x137/0x2d0 worker_thread+0x28d/0x3a0 ? rescuer_thread+0x480/0x480 kthread+0xb8/0xe0 ? kthread_park+0x80/0x80 ret_from_fork+0x2d/0x50 ? kthread_park+0x80/0x80 ret_from_fork_asm+0x11/0x20 </TASK>

In the Linux kernel, the following vulnerability has been resolved: uprobes: fix kernel info leak via "[uprobes]" vma xol_add_vma() maps the uninitialized page allocated by __create_xol_area() into userspace. On some architectures (x86) this memory is readable even without VM_READ, VM_EXEC results in the same pgprot_t as VM_EXEC|VM_READ, although this doesn't really matter, debugger can read this memory anyway.

In the Linux kernel, the following vulnerability has been resolved: signal: restore the override_rlimit logic Prior to commit d64696905554 ("Reimplement RLIMIT_SIGPENDING on top of ucounts") UCOUNT_RLIMIT_SIGPENDING rlimit was not enforced for a class of signals. However now it's enforced unconditionally, even if override_rlimit is set. This behavior change caused production issues. For example, if the limit is reached and a process receives a SIGSEGV signal, sigqueue_alloc fails to allocate the necessary resources for the signal delivery, preventing the signal from being delivered with siginfo. This prevents the process from correctly identifying the fault address and handling the error. From the user-space perspective, applications are unaware that the limit has been reached and that the siginfo is effectively 'corrupted'. This can lead to unpredictable behavior and crashes, as we observed with java applications. Fix this by passing override_rlimit into inc_rlimit_get_ucounts() and skip the comparison to max there if override_rlimit is set. This effectively restores the old behavior.

In the Linux kernel, the following vulnerability has been resolved: net: phy: dp83869: fix memory corruption when enabling fiber When configuring the fiber port, the DP83869 PHY driver incorrectly calls linkmode_set_bit() with a bit mask (1 << 10) rather than a bit number (10). This corrupts some other memory location -- in case of arm64 the priv pointer in the same structure. Since the advertising flags are updated from supported at the end of the function the incorrect line isn't needed at all and can be removed.

In the Linux kernel, the following vulnerability has been resolved: bpf: correctly handle malformed BPF_CORE_TYPE_ID_LOCAL relos In case of malformed relocation record of kind BPF_CORE_TYPE_ID_LOCAL referencing a non-existing BTF type, function bpf_core_calc_relo_insn would cause a null pointer deference. Fix this by adding a proper check upper in call stack, as malformed relocation records could be passed from user space. Simplest reproducer is a program: r0 = 0 exit With a single relocation record: .insn_off = 0, /* patch first instruction */ .type_id = 100500, /* this type id does not exist */ .access_str_off = 6, /* offset of string "0" */ .kind = BPF_CORE_TYPE_ID_LOCAL, See the link for original reproducer or next commit for a test case.

In the Linux kernel, the following vulnerability has been resolved: exfat: fix memory leak in exfat_load_bitmap() If the first directory entry in the root directory is not a bitmap directory entry, 'bh' will not be released and reassigned, which will cause a memory leak.

In the Linux kernel, the following vulnerability has been resolved: mptcp: handle consistently DSS corruption Bugged peer implementation can send corrupted DSS options, consistently hitting a few warning in the data path. Use DEBUG_NET assertions, to avoid the splat on some builds and handle consistently the error, dumping related MIBs and performing fallback and/or reset according to the subflow type.

In the Linux kernel, the following vulnerability has been resolved: static_call: Replace pointless WARN_ON() in static_call_module_notify() static_call_module_notify() triggers a WARN_ON(), when memory allocation fails in __static_call_add_module(). That's not really justified, because the failure case must be correctly handled by the well known call chain and the error code is passed through to the initiating userspace application. A memory allocation fail is not a fatal problem, but the WARN_ON() takes the machine out when panic_on_warn is set. Replace it with a pr_warn().

In the Linux kernel, the following vulnerability has been resolved: md/raid10: fix null ptr dereference in raid10_size() In raid10_run() if raid10_set_queue_limits() succeed, the return value is set to zero, and if following procedures failed raid10_run() will return zero while mddev->private is still NULL, causing null ptr dereference in raid10_size(). Fix the problem by only overwrite the return value if raid10_set_queue_limits() failed.

In the Linux kernel, the following vulnerability has been resolved: ALSA: hda/cs8409: Fix possible NULL dereference If snd_hda_gen_add_kctl fails to allocate memory and returns NULL, then NULL pointer dereference will occur in the next line. Since dolphin_fixups function is a hda_fixup function which is not supposed to return any errors, add simple check before dereference, ignore the fail. Found by Linux Verification Center (linuxtesting.org) with SVACE.

In the Linux kernel, the following vulnerability has been resolved: firewire: core: fix invalid port index for parent device In a commit 24b7f8e5cd65 ("firewire: core: use helper functions for self ID sequence"), the enumeration over self ID sequence was refactored with some helper functions with KUnit tests. These helper functions are guaranteed to work expectedly by the KUnit tests, however their application includes a mistake to assign invalid value to the index of port connected to parent device. This bug affects the case that any extra node devices which has three or more ports are connected to 1394 OHCI controller. In the case, the path to update the tree cache could hits WARN_ON(), and gets general protection fault due to the access to invalid address computed by the invalid value. This commit fixes the bug to assign correct port index.

In the Linux kernel, the following vulnerability has been resolved: netdevsim: Add trailing zero to terminate the string in nsim_nexthop_bucket_activity_write() This was found by a static analyzer. We should not forget the trailing zero after copy_from_user() if we will further do some string operations, sscanf() in this case. Adding a trailing zero will ensure that the function performs properly.

In the Linux kernel, the following vulnerability has been resolved: wifi: iwlwifi: mvm: set the cipher for secured NDP ranging The cipher pointer is not set, but is derefereced trying to set its content, which leads to a NULL pointer dereference. Fix it by pointing to the cipher parameter before dereferencing.

In the Linux kernel, the following vulnerability has been resolved: drm/amdgpu: add list empty check to avoid null pointer issue Add list empty check to avoid null pointer issues in some corner cases. - list_for_each_entry_safe()

In the Linux kernel, the following vulnerability has been resolved: i40e: Fix macvlan leak by synchronizing access to mac_filter_hash This patch addresses a macvlan leak issue in the i40e driver caused by concurrent access to vsi->mac_filter_hash. The leak occurs when multiple threads attempt to modify the mac_filter_hash simultaneously, leading to inconsistent state and potential memory leaks. To fix this, we now wrap the calls to i40e_del_mac_filter() and zeroing vf->default_lan_addr.addr with spin_lock/unlock_bh(&vsi->mac_filter_hash_lock), ensuring atomic operations and preventing concurrent access. Additionally, we add lockdep_assert_held(&vsi->mac_filter_hash_lock) in i40e_add_mac_filter() to help catch similar issues in the future. Reproduction steps: 1. Spawn VFs and configure port vlan on them. 2. Trigger concurrent macvlan operations (e.g., adding and deleting portvlan and/or mac filters). 3. Observe the potential memory leak and inconsistent state in the mac_filter_hash. This synchronization ensures the integrity of the mac_filter_hash and prevents the described leak.

In the Linux kernel, the following vulnerability has been resolved: bpf: Use raw_spinlock_t in ringbuf The function __bpf_ringbuf_reserve is invoked from a tracepoint, which disables preemption. Using spinlock_t in this context can lead to a "sleep in atomic" warning in the RT variant. This issue is illustrated in the example below: BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:48 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 556208, name: test_progs preempt_count: 1, expected: 0 RCU nest depth: 1, expected: 1 INFO: lockdep is turned off. Preemption disabled at: [<ffffd33a5c88ea44>] migrate_enable+0xc0/0x39c CPU: 7 PID: 556208 Comm: test_progs Tainted: G Hardware name: Qualcomm SA8775P Ride (DT) Call trace: dump_backtrace+0xac/0x130 show_stack+0x1c/0x30 dump_stack_lvl+0xac/0xe8 dump_stack+0x18/0x30 __might_resched+0x3bc/0x4fc rt_spin_lock+0x8c/0x1a4 __bpf_ringbuf_reserve+0xc4/0x254 bpf_ringbuf_reserve_dynptr+0x5c/0xdc bpf_prog_ac3d15160d62622a_test_read_write+0x104/0x238 trace_call_bpf+0x238/0x774 perf_call_bpf_enter.isra.0+0x104/0x194 perf_syscall_enter+0x2f8/0x510 trace_sys_enter+0x39c/0x564 syscall_trace_enter+0x220/0x3c0 do_el0_svc+0x138/0x1dc el0_svc+0x54/0x130 el0t_64_sync_handler+0x134/0x150 el0t_64_sync+0x17c/0x180 Switch the spinlock to raw_spinlock_t to avoid this error.

In the Linux kernel, the following vulnerability has been resolved: mm/swapfile: skip HugeTLB pages for unuse_vma I got a bad pud error and lost a 1GB HugeTLB when calling swapoff. The problem can be reproduced by the following steps: 1. Allocate an anonymous 1GB HugeTLB and some other anonymous memory. 2. Swapout the above anonymous memory. 3. run swapoff and we will get a bad pud error in kernel message: mm/pgtable-generic.c:42: bad pud 00000000743d215d(84000001400000e7) We can tell that pud_clear_bad is called by pud_none_or_clear_bad in unuse_pud_range() by ftrace. And therefore the HugeTLB pages will never be freed because we lost it from page table. We can skip HugeTLB pages for unuse_vma to fix it.

In the Linux kernel, the following vulnerability has been resolved: ocfs2: reserve space for inline xattr before attaching reflink tree One of our customers reported a crash and a corrupted ocfs2 filesystem. The crash was due to the detection of corruption. Upon troubleshooting, the fsck -fn output showed the below corruption [EXTENT_LIST_FREE] Extent list in owner 33080590 claims 230 as the next free chain record, but fsck believes the largest valid value is 227. Clamp the next record value? n The stat output from the debugfs.ocfs2 showed the following corruption where the "Next Free Rec:" had overshot the "Count:" in the root metadata block. Inode: 33080590 Mode: 0640 Generation: 2619713622 (0x9c25a856) FS Generation: 904309833 (0x35e6ac49) CRC32: 00000000 ECC: 0000 Type: Regular Attr: 0x0 Flags: Valid Dynamic Features: (0x16) HasXattr InlineXattr Refcounted Extended Attributes Block: 0 Extended Attributes Inline Size: 256 User: 0 (root) Group: 0 (root) Size: 281320357888 Links: 1 Clusters: 141738 ctime: 0x66911b56 0x316edcb8 -- Fri Jul 12 06:02:30.829349048 2024 atime: 0x66911d6b 0x7f7a28d -- Fri Jul 12 06:11:23.133669517 2024 mtime: 0x66911b56 0x12ed75d7 -- Fri Jul 12 06:02:30.317552087 2024 dtime: 0x0 -- Wed Dec 31 17:00:00 1969 Refcount Block: 2777346 Last Extblk: 2886943 Orphan Slot: 0 Sub Alloc Slot: 0 Sub Alloc Bit: 14 Tree Depth: 1 Count: 227 Next Free Rec: 230 ## Offset Clusters Block# 0 0 2310 2776351 1 2310 2139 2777375 2 4449 1221 2778399 3 5670 731 2779423 4 6401 566 2780447 ....... .... ....... ....... .... ....... The issue was in the reflink workfow while reserving space for inline xattr. The problematic function is ocfs2_reflink_xattr_inline(). By the time this function is called the reflink tree is already recreated at the destination inode from the source inode. At this point, this function reserves space for inline xattrs at the destination inode without even checking if there is space at the root metadata block. It simply reduces the l_count from 243 to 227 thereby making space of 256 bytes for inline xattr whereas the inode already has extents beyond this index (in this case up to 230), thereby causing corruption. The fix for this is to reserve space for inline metadata at the destination inode before the reflink tree gets recreated. The customer has verified the fix.

In the Linux kernel, the following vulnerability has been resolved: nilfs2: fix potential deadlock with newly created symlinks Syzbot reported that page_symlink(), called by nilfs_symlink(), triggers memory reclamation involving the filesystem layer, which can result in circular lock dependencies among the reader/writer semaphore nilfs->ns_segctor_sem, s_writers percpu_rwsem (intwrite) and the fs_reclaim pseudo lock. This is because after commit 21fc61c73c39 ("don't put symlink bodies in pagecache into highmem"), the gfp flags of the page cache for symbolic links are overwritten to GFP_KERNEL via inode_nohighmem(). This is not a problem for symlinks read from the backing device, because the __GFP_FS flag is dropped after inode_nohighmem() is called. However, when a new symlink is created with nilfs_symlink(), the gfp flags remain overwritten to GFP_KERNEL. Then, memory allocation called from page_symlink() etc. triggers memory reclamation including the FS layer, which may call nilfs_evict_inode() or nilfs_dirty_inode(). And these can cause a deadlock if they are called while nilfs->ns_segctor_sem is held: Fix this issue by dropping the __GFP_FS flag from the page cache GFP flags of newly created symlinks in the same way that nilfs_new_inode() and __nilfs_read_inode() do, as a workaround until we adopt nofs allocation scope consistently or improve the locking constraints.

In the Linux kernel, the following vulnerability has been resolved: static_call: Handle module init failure correctly in static_call_del_module() Module insertion invokes static_call_add_module() to initialize the static calls in a module. static_call_add_module() invokes __static_call_init(), which allocates a struct static_call_mod to either encapsulate the built-in static call sites of the associated key into it so further modules can be added or to append the module to the module chain. If that allocation fails the function returns with an error code and the module core invokes static_call_del_module() to clean up eventually added static_call_mod entries. This works correctly, when all keys used by the module were converted over to a module chain before the failure. If not then static_call_del_module() causes a #GP as it blindly assumes that key::mods points to a valid struct static_call_mod. The problem is that key::mods is not a individual struct member of struct static_call_key, it's part of a union to save space: union { /* bit 0: 0 = mods, 1 = sites */ unsigned long type; struct static_call_mod *mods; struct static_call_site *sites; }; key::sites is a pointer to the list of built-in usage sites of the static call. The type of the pointer is differentiated by bit 0. A mods pointer has the bit clear, the sites pointer has the bit set. As static_call_del_module() blidly assumes that the pointer is a valid static_call_mod type, it fails to check for this failure case and dereferences the pointer to the list of built-in call sites, which is obviously bogus. Cure it by checking whether the key has a sites or a mods pointer. If it's a sites pointer then the key is not to be touched. As the sites are walked in the same order as in __static_call_init() the site walk can be terminated because all subsequent sites have not been touched by the init code due to the error exit. If it was converted before the allocation fail, then the inner loop which searches for a module match will find nothing. A fail in the second allocation in __static_call_init() is harmless and does not require special treatment. The first allocation succeeded and converted the key to a module chain. That first entry has mod::mod == NULL and mod::next == NULL, so the inner loop of static_call_del_module() will neither find a module match nor a module chain. The next site in the walk was either already converted, but can't match the module, or it will exit the outer loop because it has a static_call_site pointer and not a static_call_mod pointer.

In the Linux kernel, the following vulnerability has been resolved: LoongArch: Don't crash in stack_top() for tasks without vDSO Not all tasks have a vDSO mapped, for example kthreads never do. If such a task ever ends up calling stack_top(), it will derefence the NULL vdso pointer and crash. This can for example happen when using kunit: [<9000000000203874>] stack_top+0x58/0xa8 [<90000000002956cc>] arch_pick_mmap_layout+0x164/0x220 [<90000000003c284c>] kunit_vm_mmap_init+0x108/0x12c [<90000000003c1fbc>] __kunit_add_resource+0x38/0x8c [<90000000003c2704>] kunit_vm_mmap+0x88/0xc8 [<9000000000410b14>] usercopy_test_init+0xbc/0x25c [<90000000003c1db4>] kunit_try_run_case+0x5c/0x184 [<90000000003c3d54>] kunit_generic_run_threadfn_adapter+0x24/0x48 [<900000000022e4bc>] kthread+0xc8/0xd4 [<9000000000200ce8>] ret_from_kernel_thread+0xc/0xa4

In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Add NULL check for function pointer in dcn20_set_output_transfer_func This commit adds a null check for the set_output_gamma function pointer in the dcn20_set_output_transfer_func function. Previously, set_output_gamma was being checked for null at line 1030, but then it was being dereferenced without any null check at line 1048. This could potentially lead to a null pointer dereference error if set_output_gamma is null. To fix this, we now ensure that set_output_gamma is not null before dereferencing it. We do this by adding a null check for set_output_gamma before the call to set_output_gamma at line 1048.

In the Linux kernel, the following vulnerability has been resolved: drm/connector: hdmi: Fix memory leak in drm_display_mode_from_cea_vic() modprobe drm_connector_test and then rmmod drm_connector_test, the following memory leak occurs. The `mode` allocated in drm_mode_duplicate() called by drm_display_mode_from_cea_vic() is not freed, which cause the memory leak: unreferenced object 0xffffff80cb0ee400 (size 128): comm "kunit_try_catch", pid 1948, jiffies 4294950339 hex dump (first 32 bytes): 14 44 02 00 80 07 d8 07 04 08 98 08 00 00 38 04 .D............8. 3c 04 41 04 65 04 00 00 05 00 00 00 00 00 00 00 <.A.e........... backtrace (crc 90e9585c): [<00000000ec42e3d7>] kmemleak_alloc+0x34/0x40 [<00000000d0ef055a>] __kmalloc_cache_noprof+0x26c/0x2f4 [<00000000c2062161>] drm_mode_duplicate+0x44/0x19c [<00000000f96c74aa>] drm_display_mode_from_cea_vic+0x88/0x98 [<00000000d8f2c8b4>] 0xffffffdc982a4868 [<000000005d164dbc>] kunit_try_run_case+0x13c/0x3ac [<000000006fb23398>] kunit_generic_run_threadfn_adapter+0x80/0xec [<000000006ea56ca0>] kthread+0x2e8/0x374 [<000000000676063f>] ret_from_fork+0x10/0x20 ...... Free `mode` by using drm_kunit_display_mode_from_cea_vic() to fix it.

In the Linux kernel, the following vulnerability has been resolved: phy: qcom: qmp-usbc: fix NULL-deref on runtime suspend Commit 413db06c05e7 ("phy: qcom-qmp-usb: clean up probe initialisation") removed most users of the platform device driver data from the qcom-qmp-usb driver, but mistakenly also removed the initialisation despite the data still being used in the runtime PM callbacks. This bug was later reproduced when the driver was copied to create the qmp-usbc driver. Restore the driver data initialisation at probe to avoid a NULL-pointer dereference on runtime suspend. Apparently no one uses runtime PM, which currently needs to be enabled manually through sysfs, with these drivers.

In the Linux kernel, the following vulnerability has been resolved: ice: fix memleak in ice_init_tx_topology() Fix leak of the FW blob (DDP pkg). Make ice_cfg_tx_topo() const-correct, so ice_init_tx_topology() can avoid copying whole FW blob. Copy just the topology section, and only when needed. Reuse the buffer allocated for the read of the current topology. This was found by kmemleak, with the following trace for each PF: [<ffffffff8761044d>] kmemdup_noprof+0x1d/0x50 [<ffffffffc0a0a480>] ice_init_ddp_config+0x100/0x220 [ice] [<ffffffffc0a0da7f>] ice_init_dev+0x6f/0x200 [ice] [<ffffffffc0a0dc49>] ice_init+0x29/0x560 [ice] [<ffffffffc0a10c1d>] ice_probe+0x21d/0x310 [ice] Constify ice_cfg_tx_topo() @buf parameter. This cascades further down to few more functions.

In the Linux kernel, the following vulnerability has been resolved: drm/xe: fix unbalanced rpm put() with fence_fini() Currently we can call fence_fini() twice if something goes wrong when sending the GuC CT for the tlb request, since we signal the fence and return an error, leading to the caller also calling fini() on the error path in the case of stack version of the flow, which leads to an extra rpm put() which might later cause device to enter suspend when it shouldn't. It looks like we can just drop the fini() call since the fence signaller side will already call this for us. There are known mysterious splats with device going to sleep even with an rpm ref, and this could be one candidate. v2 (Matt B): - Prefer warning if we detect double fini() (cherry picked from commit cfcbc0520d5055825f0647ab922b655688605183)

In the Linux kernel, the following vulnerability has been resolved: smb: client: Handle kstrdup failures for passwords In smb3_reconfigure(), after duplicating ctx->password and ctx->password2 with kstrdup(), we need to check for allocation failures. If ses->password allocation fails, return -ENOMEM. If ses->password2 allocation fails, free ses->password, set it to NULL, and return -ENOMEM.

In the Linux kernel, the following vulnerability has been resolved: media: cx24116: prevent overflows on SNR calculus as reported by Coverity, if reading SNR registers fail, a negative number will be returned, causing an underflow when reading SNR registers. Prevent that.

In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Add NULL check for function pointer in dcn32_set_output_transfer_func This commit adds a null check for the set_output_gamma function pointer in the dcn32_set_output_transfer_func function. Previously, set_output_gamma was being checked for null, but then it was being dereferenced without any null check. This could lead to a null pointer dereference if set_output_gamma is null. To fix this, we now ensure that set_output_gamma is not null before dereferencing it. We do this by adding a null check for set_output_gamma before the call to set_output_gamma.

In the Linux kernel, the following vulnerability has been resolved: phy: qcom: qmp-usb-legacy: fix NULL-deref on runtime suspend Commit 413db06c05e7 ("phy: qcom-qmp-usb: clean up probe initialisation") removed most users of the platform device driver data from the qcom-qmp-usb driver, but mistakenly also removed the initialisation despite the data still being used in the runtime PM callbacks. This bug was later reproduced when the driver was copied to create the qmp-usb-legacy driver. Restore the driver data initialisation at probe to avoid a NULL-pointer dereference on runtime suspend. Apparently no one uses runtime PM, which currently needs to be enabled manually through sysfs, with these drivers.

In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Check phantom_stream before it is used dcn32_enable_phantom_stream can return null, so returned value must be checked before used. This fixes 1 NULL_RETURNS issue reported by Coverity.

In the Linux kernel, the following vulnerability has been resolved: ext4: update orig_path in ext4_find_extent() In ext4_find_extent(), if the path is not big enough, we free it and set *orig_path to NULL. But after reallocating and successfully initializing the path, we don't update *orig_path, in which case the caller gets a valid path but a NULL ppath, and this may cause a NULL pointer dereference or a path memory leak. For example: ext4_split_extent path = *ppath = 2000 ext4_find_extent if (depth > path[0].p_maxdepth) kfree(path = 2000); *orig_path = path = NULL; path = kcalloc() = 3000 ext4_split_extent_at(*ppath = NULL) path = *ppath; ex = path[depth].p_ext; // NULL pointer dereference! ================================================================== BUG: kernel NULL pointer dereference, address: 0000000000000010 CPU: 6 UID: 0 PID: 576 Comm: fsstress Not tainted 6.11.0-rc2-dirty #847 RIP: 0010:ext4_split_extent_at+0x6d/0x560 Call Trace: <TASK> ext4_split_extent.isra.0+0xcb/0x1b0 ext4_ext_convert_to_initialized+0x168/0x6c0 ext4_ext_handle_unwritten_extents+0x325/0x4d0 ext4_ext_map_blocks+0x520/0xdb0 ext4_map_blocks+0x2b0/0x690 ext4_iomap_begin+0x20e/0x2c0 [...] ================================================================== Therefore, *orig_path is updated when the extent lookup succeeds, so that the caller can safely use path or *ppath.

In the Linux kernel, the following vulnerability has been resolved: x86/sgx: Fix deadlock in SGX NUMA node search When the current node doesn't have an EPC section configured by firmware and all other EPC sections are used up, CPU can get stuck inside the while loop that looks for an available EPC page from remote nodes indefinitely, leading to a soft lockup. Note how nid_of_current will never be equal to nid in that while loop because nid_of_current is not set in sgx_numa_mask. Also worth mentioning is that it's perfectly fine for the firmware not to setup an EPC section on a node. While setting up an EPC section on each node can enhance performance, it is not a requirement for functionality. Rework the loop to start and end on *a* node that has SGX memory. This avoids the deadlock looking for the current SGX-lacking node to show up in the loop when it never will.

In the Linux kernel, the following vulnerability has been resolved: xhci: tegra: fix checked USB2 port number If USB virtualizatoin is enabled, USB2 ports are shared between all Virtual Functions. The USB2 port number owned by an USB2 root hub in a Virtual Function may be less than total USB2 phy number supported by the Tegra XUSB controller. Using total USB2 phy number as port number to check all PORTSC values would cause invalid memory access. [ 116.923438] Unable to handle kernel paging request at virtual address 006c622f7665642f ... [ 117.213640] Call trace: [ 117.216783] tegra_xusb_enter_elpg+0x23c/0x658 [ 117.222021] tegra_xusb_runtime_suspend+0x40/0x68 [ 117.227260] pm_generic_runtime_suspend+0x30/0x50 [ 117.232847] __rpm_callback+0x84/0x3c0 [ 117.237038] rpm_suspend+0x2dc/0x740 [ 117.241229] pm_runtime_work+0xa0/0xb8 [ 117.245769] process_scheduled_works+0x24c/0x478 [ 117.251007] worker_thread+0x23c/0x328 [ 117.255547] kthread+0x104/0x1b0 [ 117.259389] ret_from_fork+0x10/0x20 [ 117.263582] Code: 54000222 f9461ae8 f8747908 b4ffff48 (f9400100)

In the Linux kernel, the following vulnerability has been resolved: drm: omapdrm: Add missing check for alloc_ordered_workqueue As it may return NULL pointer and cause NULL pointer dereference. Add check for the return value of alloc_ordered_workqueue.

In the Linux kernel, the following vulnerability has been resolved: drm/vc4: Stop the active perfmon before being destroyed Upon closing the file descriptor, the active performance monitor is not stopped. Although all perfmons are destroyed in `vc4_perfmon_close_file()`, the active performance monitor's pointer (`vc4->active_perfmon`) is still retained. If we open a new file descriptor and submit a few jobs with performance monitors, the driver will attempt to stop the active performance monitor using the stale pointer in `vc4->active_perfmon`. However, this pointer is no longer valid because the previous process has already terminated, and all performance monitors associated with it have been destroyed and freed. To fix this, when the active performance monitor belongs to a given process, explicitly stop it before destroying and freeing it.

In the Linux kernel, the following vulnerability has been resolved: ice: Fix improper handling of refcount in ice_sriov_set_msix_vec_count() This patch addresses an issue with improper reference count handling in the ice_sriov_set_msix_vec_count() function. First, the function calls ice_get_vf_by_id(), which increments the reference count of the vf pointer. If the subsequent call to ice_get_vf_vsi() fails, the function currently returns an error without decrementing the reference count of the vf pointer, leading to a reference count leak. The correct behavior, as implemented in this patch, is to decrement the reference count using ice_put_vf(vf) before returning an error when vsi is NULL. Second, the function calls ice_sriov_get_irqs(), which sets vf->first_vector_idx. If this call returns a negative value, indicating an error, the function returns an error without decrementing the reference count of the vf pointer, resulting in another reference count leak. The patch addresses this by adding a call to ice_put_vf(vf) before returning an error when vf->first_vector_idx < 0. This bug was identified by an experimental static analysis tool developed by our team. The tool specializes in analyzing reference count operations and identifying potential mismanagement of reference counts. In this case, the tool flagged the missing decrement operation as a potential issue, leading to this patch.

In the Linux kernel, the following vulnerability has been resolved: ASoC: qcom: Fix NULL Dereference in asoc_qcom_lpass_cpu_platform_probe() A devm_kzalloc() in asoc_qcom_lpass_cpu_platform_probe() could possibly return NULL pointer. NULL Pointer Dereference may be triggerred without addtional check. Add a NULL check for the returned pointer.

In the Linux kernel, the following vulnerability has been resolved: ACPI: battery: Fix possible crash when unregistering a battery hook When a battery hook returns an error when adding a new battery, then the battery hook is automatically unregistered. However the battery hook provider cannot know that, so it will later call battery_hook_unregister() on the already unregistered battery hook, resulting in a crash. Fix this by using the list head to mark already unregistered battery hooks as already being unregistered so that they can be ignored by battery_hook_unregister().

In the Linux kernel, the following vulnerability has been resolved: fsl/fman: Fix refcount handling of fman-related devices In mac_probe() there are multiple calls to of_find_device_by_node(), fman_bind() and fman_port_bind() which takes references to of_dev->dev. Not all references taken by these calls are released later on error path in mac_probe() and in mac_remove() which lead to reference leaks. Add references release.

In the Linux kernel, the following vulnerability has been resolved: dm vdo: don't refer to dedupe_context after releasing it Clear the dedupe_context pointer in a data_vio whenever ownership of the context is lost, so that vdo can't examine it accidentally.

In the Linux kernel, the following vulnerability has been resolved: jfs: check if leafidx greater than num leaves per dmap tree syzbot report a out of bounds in dbSplit, it because dmt_leafidx greater than num leaves per dmap tree, add a checking for dmt_leafidx in dbFindLeaf. Shaggy: Modified sanity check to apply to control pages as well as leaf pages.

In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Check null pointer before try to access it [why & how] Change the order of the pipe_ctx->plane_state check to ensure that plane_state is not null before accessing it.