Linux Kernel Vulnerabilities

In the Linux kernel, the following vulnerability has been resolved: iommu/arm-smmu-v3: Manage teardown with devm arm_smmu_device_remove() manually frees the IOPF queue, destroys the vmid_map and disables the device, while the IRQs and queues are devm managed. devm unwinds only after remove() returns, so the cleanup runs in the wrong order. The IOPF queue is freed before the event-queue IRQ whose handler uses it. Manage all of it with devm so the unwind order is correct. Free the IOPF queue and vmid_map via devm actions, and disable the device from one registered after arm_smmu_device_reset(). This is also a prerequisite for fixing a Tegra241 CMDQV CMD_SYNC use-after-free in the subsequent patch.

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In the Linux kernel, the following vulnerability has been resolved: PCI/proc: Use file_ns_capable() when checking config space read access proc_bus_pci_read() decides how much of the config space is readable based on capable(CAP_SYS_ADMIN), which checks the credentials of the task calling read(), not the credentials of the process that opened the file. The sysfs equivalent, pci_read_config(), has checked the credentials of the opening process since commit de139a339395 ("pci: check caps from sysfs file open to read device dependent config space"), so a privileged process can open the config space file and pass the file descriptor to an unprivileged process (for example, a process running a KVM guest with an assigned device), which can then read the entire config space. The check was subsequently routed through the LSM framework in commit 47970b1b2aa6 ("pci: use security_capable() when checking capablities during config space read") and converted to the dedicated helper in commit ab0fa82b2df9 ("pci-sysfs: use proper file capability helper function"). Thus, the two interfaces check the same capability against different credentials. Checking the credentials of the task calling read() makes the outcome depend on who reads rather than who opened, so the restriction is bypassed whenever a more privileged process reads through the descriptor. Checking the credentials recorded in file->f_cred settles the decision at open() time and ties it to the file, where it cannot change with the caller. Use file_ns_capable() to check CAP_SYS_ADMIN against the credentials in effect when the file was opened, bringing the procfs interface in line with the sysfs behaviour. As a result, a file descriptor opened by a privileged process and passed to an unprivileged one now allows the entire config space to be read through procfs, matching sysfs.

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In the Linux kernel, the following vulnerability has been resolved: kasan: fix cache shrink race with CPU hotplug kasan_quarantine_remove_cache() first invokes per_cpu_remove_cache() on all online CPUs. Each callback moves objects belonging to the cache from cpu_quarantine to the CPU's shrink_qlist, where they can later be freed from task context. kmem_cache_destroy() invokes the quarantine removal path while holding cpus_read_lock(), but kmem_cache_shrink() does not. The latter can therefore race with CPU offlining as follows: kmem_cache_shrink() CPU hotplug ------------------- ----------- on_each_cpu() CPU1 moves objects to CPU1's shrink_qlist on_each_cpu() returns CPU1 goes offline kasan_cpu_offline() drains cpu_quarantine leaves shrink_qlist untouched for_each_online_cpu() skips CPU1 The objects left on CPU1's shrink_qlist are not returned to the slab allocator. This may prevent kmem_cache_shrink() from releasing slabs that would otherwise become empty. If CPU1 remains offline, a later kmem_cache_destroy() also skips the list and can report that the cache still contains objects. An intermittent occurrence was observed with a virtio-9p filesystem. The mount and umount commands both returned 0, but the kernel logged the following during the userspace-triggered teardown: [ 2994.380134][ T111] BUG 9p-fcall-cache-1 (Tainted: G B ): Objects remaining on __kmem_cache_shutdown() [ 2994.381140][ T111] Object 0xff11000004361118 @offset=4376 [ 2994.381607][ T111] Allocated in p9_fcall_init+0x201/0x400 age=19564 cpu=1 pid=104 [ 2994.382591][ T111] p9_fcall_init+0x201/0x400 [ 2994.382810][ T111] p9_tag_alloc+0x12f/0x700 [ 2994.382982][ T111] p9_client_prepare_req+0x102/0x3e0 [ 2994.383165][ T111] p9_client_rpc+0x1ab/0xa50 [ 2994.383334][ T111] p9_client_getattr_dotl+0xb0/0x1a0 [ 2994.383515][ T111] v9fs_vfs_getattr_dotl+0x115/0x360 [ 2994.383719][ T111] vfs_getattr_nosec+0x22c/0x3a0 [ 2994.383910][ T111] vfs_statx+0xd7/0x170 [ 2994.384062][ T111] vfs_fstatat+0x45/0x80 [ 2994.384215][ T111] __do_sys_newfstatat+0x84/0xe0 [ 2994.384386][ T111] do_syscall_64+0x115/0x6a0 [ 2994.384566][ T111] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 2994.399720][ T111] WARNING: mm/slub.c:1244 at __kmem_cache_shutdown+0x363/0x500, CPU#0: busybox/111 [ 2994.405655][ T111] Call Trace: [ 2994.406325][ T111] kmem_cache_destroy+0x73/0x1b0 [ 2994.406630][ T111] p9_client_destroy+0x271/0x3c0 [ 2994.407210][ T111] v9fs_session_close+0x3c/0x260 [ 2994.407409][ T111] v9fs_kill_super+0x48/0x90 [ 2994.407584][ T111] deactivate_locked_super+0xa3/0x160 [ 2994.407778][ T111] cleanup_mnt+0x1dd/0x3e0 Thus, a successful umount left objects in the 9p fcall cache and prevented the cache from being destroyed cleanly. Per-CPU shrink_qlist storage exists for every possible CPU, and each list is protected by its own raw spinlock. Iterate over possible CPUs so that a list populated before its CPU went offline is drained as well. for_each_possible_cpu() can do more work than for_each_online_cpu(), but this change only affects CONFIG_KASAN_GENERIC kernels. The extra work is limited to cache shrink and cache destruction paths and does not affect the normal allocation/free fast path. It adds one raw-spinlock-protected scan of each possible CPU's shrink list. These lists are normally empty; a non-empty list is traversed to remove objects belonging to the cache being shrunk or destroyed.

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In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_core: use skb_get() instead of skb_clone() for req_skb BT enable fails intermittently with -ETIMEDOUT (-110). The kernel log shows the HCI Read Local Version command was sent and the firmware replied with status 0x00 (logged by hci_req_cmd_complete() BT_DBG), but the waiter in __hci_cmd_sync_sk() never woke up and timed out after 10 s: bluetooth hci0: Opcode 0xfc00 // __hci_cmd_sync_sk bluetooth hci0: opcode 0xfc00 plen 1 // hci_cmd_sync_add bluetooth hci0: skb len 4 // hci_cmd_sync_alloc bluetooth hci0: length 1 // hci_req_sync_run Bluetooth: hci0 cmd_cnt 1 cmd queued 1 // hci_cmd_work Bluetooth: hci0 type 1 len 4 // hci_send_frame Bluetooth: opcode 0xfc00 status 0x00 // hci_req_cmd_complete <-- req_skb NULL: req_complete_skb not set, hci_cmd_sync_complete() never called, req_status stays HCI_REQ_PEND --> <-- 10 s later: wait_event_interruptible_timeout expires --> bluetooth hci0: end: err -110 // __hci_cmd_sync_sk The root cause is that hci_send_cmd_sync() clones the sent command into hdev->req_skb so that hci_req_cmd_complete() can locate the registered completion callback. Under memory pressure this skb_clone() fails, leaving hdev->req_skb NULL. The firmware reply is received and processed, but hci_req_cmd_complete() finds NULL req_skb, so hci_cmd_sync_complete() is never called, req_status stays HCI_REQ_PEND, and the waiter times out with -ETIMEDOUT. req_skb is only used to read bt_cb(skb)->hci callbacks and opcode -- it is never modified. Replace skb_clone() with skb_get(), which simply increments the reference count of hdev->sent_cmd without allocating new memory and therefore cannot fail. This issue was first observed as a use-after-free in ttyport_close() when ttyport_open() failed, which was investigated in an earlier patch series [1]. That investigation led to the discovery of the true root cause described above. [1] https://lore.kernel.org/all/[email protected]/

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In the Linux kernel, the following vulnerability has been resolved: smb: client: harden DFS cache against invalid target hints Currently, get_tgt_name() returns ERR_PTR(-ENOENT) when ce->tgthint is NULL, and dfs_cache_noreq_update_tgthint() assumes ce->tgthint is always valid. In preparation for clearing ce->tgthint in free_tgts(), harden callers of get_tgt_name() against ERR_PTR results and harden dfs_cache_noreq_update_tgthint() against NULL pointer dereferences.

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In the Linux kernel, the following vulnerability has been resolved: nfsd: initialize DRC hash table before registering shrinker shrinker_register() precedes the INIT_LIST_HEAD loop and the drc_hashsize store. On weakly-ordered architectures (arm64, ppc), a shrinker scan can observe drc_hashsize before the bucket list heads are initialized, causing a NULL deref in the DRC shrinker callback. Move bucket initialization and the drc_hashsize store before shrinker_register() so the hash table is fully initialized before it becomes visible to the shrinker.

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In the Linux kernel, the following vulnerability has been resolved: nfsd: guard nfsd_serv deref in nfsd_file_net_dispose nfsd_file_net_dispose() is the consumer side of l->freeme: the nfsd service thread loop calls it to drain entries that the filecache garbage collector and shrinker append via nfsd_file_dispose_list_delayed(). During per-net teardown, nn->nfsd_serv is cleared before the filecache laundrette is shut down, so the service thread can still run a dispose pass that finds more than eight entries on l->freeme and dereferences a NULL svc_serv: nfsd service thread loop nfsd_file_net_dispose(nn) if (!list_empty(&l->freeme)) { ... svc_wake_up(nn->nfsd_serv); /* nn->nfsd_serv == NULL */ } The sibling helper nfsd_file_dispose_list_delayed() already documents this ordering and caches nn->nfsd_serv into a local before testing it for NULL. nfsd_file_net_dispose() was introduced with the same raw svc_wake_up(nn->nfsd_serv) call and never picked up the guard. Fix by loading nn->nfsd_serv into a local svc_serv pointer and only calling svc_wake_up() when it is non-NULL, matching the pattern in nfsd_file_dispose_list_delayed().

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In the Linux kernel, the following vulnerability has been resolved: of: fix out-of-bounds read in of_alias_scan() stem parser The stem parser tests isdigit(*(end - 1)) before checking end > start and so reads one byte before the property name when the name is empty or all digits. Check the bound first.

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In the Linux kernel, the following vulnerability has been resolved: usb: gadget: f_tcm: fix deadlock in usbg_make_tpg() usbg_make_tpg() held dep_lock while calling configfs_depend_item_unlocked(), which acquires the configfs root inode lock when operating across subsystems. This creates a circular lock dependency with configfs_rmdir(): dep_lock -> configfs root inode lock -> su_mutex -> dep_lock In usbg_make_tpg(), dep_lock only serialized the read of opts->ready, which is a monotonic flag that transitions from false to true exactly once (in tcm_set_name()) and never reverts. Remove dep_lock from usbg_make_tpg() entirely and use READ_ONCE/WRITE_ONCE to access opts->ready locklessly instead.

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In the Linux kernel, the following vulnerability has been resolved: cdx: Fix double free when sysfs file creation fails In cdx_create_res_attr(), if sysfs_create_bin_file() fails, the code frees res_attr but doesn't set cdx_dev->res_attr[num] to NULL. This leaves a dangling pointer in the array. Then cdx_destroy_res_attr() frees the already-freed memory. Fix the double free by initializing cdx_dev->res_attr[num] after sysfs_create_bin_file() completes.

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In the Linux kernel, the following vulnerability has been resolved: mm/page_owner: use memcg_data snapshot to avoid TOCTOU in print_page_owner_memcg() print_page_owner_memcg() reads page->memcg_data via READ_ONCE() at the start to guard against tail pages and NULL data. However, it later re-reads page->memcg_data locklessly in two places: 1: page_memcg_check(page) 2: PageMemcgKmem(page) (via folio_memcg_kmem(), which includes VM_BUG_ON assertions for tail pages and MEMCG_DATA_OBJEXTS) If the page is concurrently freed and reallocated as a THP tail page or slab page between these calls, the VM_BUG_ON assertions can trigger on CONFIG_DEBUG_VM=y builds, crashing the kernel. Fix both TOCTOU issues by using the memcg_data snapshot throughout.

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In the Linux kernel, the following vulnerability has been resolved: mm/madvise: skip device-private PMDs in cold and pageout walks madvise_cold_or_pageout_pte_range() takes pmd_trans_huge_lock(), whose pmd_is_huge() check returns true for a device-private PMD. The subsequent !pmd_present() branch has a VM_BUG_ON() asserting migration is the only allowed non-present case; a device-private PMD trips it. Skip device-private PMDs in that non-present branch and continue to huge_unlock before calling pmd_folio(). Downgrade the check to VM_WARN_ON_ONCE() so an unexpected PMD softleaf logs a warning rather than panicking. Drop the thp_migration_supported() guard: it expands to IS_ENABLED(CONFIG_ARCH_SUPPORTS_PMD_SOFTLEAF), and both pmd_is_migration_entry() and pmd_is_device_private_entry() already return false when that config is not selected, so the guard suppresses only the case where the warning would already be silent. Potential trigger: an HMM-based GPU driver races with madvise(MADV_COLD)/MADV_PAGEOUT: pmd_trans_huge(*pmd) reads true, then migrate_vma_pages() flips the PMD to a device-private entry before the PMD lock is acquired.

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In the Linux kernel, the following vulnerability has been resolved: mm/huge_memory: skip device-private PMDs in madvise_free_huge_pmd madvise_free_pte_range() checks pmd_trans_huge(*pmd) unlocked, then madvise_free_huge_pmd() takes pmd_trans_huge_lock(). pmd_is_huge() returns true for a device-private PMD, so orig_pmd can be device-private and enter the !pmd_present() branch. Skip device-private PMDs in that non-present branch and continue to out before calling pmd_folio(). Downgrade the check to VM_WARN_ON_ONCE() so an unexpected PMD softleaf logs a warning rather than panicking. Drop the thp_migration_supported() guard: it expands to IS_ENABLED(CONFIG_ARCH_SUPPORTS_PMD_SOFTLEAF), and both pmd_is_migration_entry() and pmd_is_device_private_entry() already return false when that config is not selected, so the guard suppresses only the case where the warning would already be silent. Potential trigger: an HMM-based GPU driver races with madvise(MADV_FREE): migrate_vma_pages() flips the PMD to a device-private entry between the caller's pmd_trans_huge() check and the callee's pmd_trans_huge_lock().

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In the Linux kernel, the following vulnerability has been resolved: clocksource/drivers/timer-sun4i: Advertise a real minimum delta sun4i_clkevt_next_event() compensates for the timer stop/start synchronization delay by programming evt - TIMER_SYNC_TICKS into the hardware interval register. The clockevent device currently advertises TIMER_SYNC_TICKS as min_delta_ticks, so the clockevents core is allowed to call set_next_event() with evt == TIMER_SYNC_TICKS. That programs a zero-tick interval. With oneshot/highres/nohz timer operation this can leave the next event stuck, which was observed as a boot hang on Allwinner D1 after the clockevents core started reusing forced minimum-delta events. Advertise one extra tick instead, so the smallest event accepted by the core still programs at least one hardware tick after the synchronization compensation.

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In the Linux kernel, the following vulnerability has been resolved: sched_ext: Keep kick_sync waiting on the rq's own CPU kick_sync_wait_bal_cb() assumes it runs on the rq's CPU from the __schedule() tail: the snapshots it compares against live in that CPU's percpu area and the busy-wait runs with the rq lock dropped and IRQs enabled. However, dispatch can now drop the rq lock while the callback sits queued, and rq lock takers in that window (the sched class change paths, the scx task iterator) flush pending balance callbacks on release, running the callback on a foreign CPU. Such a run compares against unrelated snapshots and can deadlock when the executing CPU is itself a wait target. Bail on a foreign CPU and leave the wait state alone. The wait only observes progress that the resched kicks already guarantee and the rq's next wait picks up the stale cpus_to_sync bits.

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In the Linux kernel, the following vulnerability has been resolved: signal: avoid shared siginfo namespace rewrites send_signal_locked() rewrites sender ids for the target namespace. Group sends reuse the same siginfo, so one recipient can affect the next. Copy the siginfo before changing it.

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In the Linux kernel, the following vulnerability has been resolved: staging: media: tegra-video: fix of_node_put() on VIP parse errors tegra_vip_channel_of_parse() initializes np from dev->of_node without taking a reference, but its error paths drop one through the err_node_put label. This underflows the refcount of the VIP device's OF node when endpoint parsing fails on a malformed device tree. The only reference the function takes on np is the success-path of_node_get() stored in vip->chan.of_node, and that one is already released by the tegra_vip_init() error path and by tegra_vip_exit(). Return errors directly instead of jumping to the bogus cleanup label.

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In the Linux kernel, the following vulnerability has been resolved: ipv6: use RCU iterator to dump route exceptions rt6_nh_dump_exceptions() uses hlist_for_each_entry() to iterate over RCU-protected exception lists. The caller holds rcu_read_lock(), but does not hold rt6_exception_lock, so rt6_insert_exception() can concurrently add an entry with hlist_add_head_rcu(). KCSAN reports this race (irrelevant details omitted): ================================================================== BUG: KCSAN: data-race in rt6_insert_exception / rt6_nh_dump_exceptions write (marked) to 0xffff8a7c44c59620 of 8 bytes by interrupt on cpu 5: rt6_insert_exception+0x3bb/0x760 __ip6_rt_update_pmtu+0x4fe/0x750 ip6_sk_update_pmtu+0x19a/0x3b0 udpv6_err+0x3ff/0x800 icmpv6_notify+0x1e1/0x440 icmpv6_rcv+0x8c0/0xab0 ip6_protocol_deliver_rcu+0x616/0x840 ip6_input_finish+0xb9/0x160 ... entry_SYSCALL_64_after_hwframe+0x77/0x7f read to 0xffff8a7c44c59620 of 8 bytes by task 549 on cpu 14: rt6_nh_dump_exceptions+0xb3/0x260 rt6_dump_route+0x53e/0x5f0 fib6_dump_node+0x6d/0xf0 fib6_walk_continue+0x290/0x2d0 fib6_dump_table+0x28d/0x360 inet6_dump_fib+0x37d/0x620 rtnl_dumpit+0x7b/0xd0 netlink_dump+0x3ae/0x7e0 ... entry_SYSCALL_64_after_hwframe+0x77/0x7f 4 locks held by dumper/549: ... #1: (rcu_read_lock){....}-{1:3}, at: inet6_dump_fib+0x88/0x620 #2: (&tb->tb6_lock){+.-.}-{3:3}, at: fib6_dump_table+0x1e9/0x360 #3: (rcu_read_lock){....}-{1:3}, at: rt6_dump_route+0x483/0x5f0 value changed: 0xffff8a7c44e05700 -> 0xffff8a7c45d60100 Reported by Kernel Concurrency Sanitizer on: CPU: 14 UID: 0 PID: 549 Comm: dumper Not tainted 7.2.0-rc7-virtme #38 PREEMPT(lazy) ... Use hlist_for_each_entry_rcu() to safely iterate over the exception list.

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In the Linux kernel, the following vulnerability has been resolved: mm/mm_init: deferred_grow_zone(): fix out-of-range first_deferred_pfn With CONFIG_DEFERRED_STRUCT_PAGE_INIT enabled, deferred_grow_zone() initializes struct pages early in boot to satisfy an allocation. With a large CMA reservation in place, the ranges deferred_init_memmap() finds may not add up to the allocation it was asked for, and the function ends up initializing the memory map of the entire zone and still falls short. That is fine in itself: the function accounts for it and leaves the caller to decide whether it now has enough memory. However, the update of pgdat->first_deferred_pfn that tracks where uninitialized memory map starts could overflow. If the node's RAM end is not aligned on PAGES_PER_SECTION boundaries and some deferred struct pages were initialized, pgdat->first_deferred_pfn would point past the end of the node's memory. deferred_init_memmap() later picks up from pgdat->first_deferred_pfn and hits a BUG_ON(), because it expects a pfn within its node. For example, when running a kernel with CONFIG_DEFERRED_STRUCT_PAGE_INIT=y and CONFIG_CMA=y using the following qemu command line qemu-system-x86_64 -enable-kvm -m 8032M -kernel bzImage \ -append "nokaslr cma=4768M@0x100000000" the kernel panics: kernel BUG at mm/mm_init.c:2131! CPU: 3 UID: 0 PID: 36 Comm: pgdatinit0 Not tainted 7.2.0-rc6 #1 RIP: 0010:deferred_init_memmap+0x1b8/0x1c0 RAX: 0000000000236000 R13: 0000000000238000 Call Trace: kthread+0xdf/0x120 ret_from_fork+0x187/0x250 Make sure that the update of pgdta->first_deferred_pfn does not overflow when the entire zone's (and therefore node's) memory map is initialized. [rppt: massaged the changelog]

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In the Linux kernel, the following vulnerability has been resolved: mm/hugetlb: initialize gigantic bootmem hugepage struct pages earlier Gigantic bootmem HugeTLB pages are currently initialized from hugetlb_init(), but page_alloc_init_late() runs earlier and walks pageblocks to determine zone contiguity. If a bootmem HugeTLB region is marked noinit, set_zone_contiguous() can observe still-uninitialized struct pages through __pageblock_pfn_to_page(). This may not trigger an immediate failure, but it can make set_zone_contiguous() compute the wrong zone contiguity state. If extra poisoned-page checks are added in this path, such as PF_POISONED_CHECK() in page_zone_id(), it can also trigger an early boot panic. Initialize gigantic bootmem HugeTLB struct pages from page_alloc_init_late(), before zone contiguity is evaluated, so later page allocator setup only sees valid struct page state. This also makes the initialization order more natural, as struct pages should be initialized before later code inspects them.

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In the Linux kernel, the following vulnerability has been resolved: lockd: fix swapped arguments in nlmsvc_match_ip() When releasing locks by server IP address via /proc/fs/nfsd/unlock_ip, nlmsvc_unlock_all_by_ip() calls nlm_traverse_files() with the server sockaddr as the opaque @data argument: nlm_traverse_files(server_addr, nlmsvc_match_ip, NULL); The match callback is later invoked from nlm_traverse_locks() as: match(lockhost, host); where the first argument is the nlm_host that owns the lock, and the second argument is the @data that was originally passed down (here the server sockaddr). This is the convention every other match callback relies on (nlmsvc_mark_host(), nlmsvc_same_host(), nlmsvc_is_client()): arg1 is the real nlm_host, arg2 is the caller-supplied reference value. nlmsvc_match_ip() has had these two arguments reversed ever since the unlock-by-IP feature was introduced in commit 4373ea84c84d ("lockd: unlock lockd locks associated with a given server ip"): return rpc_cmp_addr(nlm_srcaddr(host), datap); Here @host is actually the server sockaddr, so nlm_srcaddr(host) dereferences a struct sockaddr as a struct nlm_host and reads garbage at the offset of h_srcaddr; meanwhile @datap is actually the lock owner's nlm_host but is compared as a sockaddr. As a result the comparison practically never matches and locks are not released for the requested IP. Swap the arguments so the lock owner's source address is compared against the requested server address: return rpc_cmp_addr(nlm_srcaddr(datap), (struct sockaddr *)host); [ cel: fix the misleading typedef parameter names too ]

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In the Linux kernel, the following vulnerability has been resolved: mm/hugetlb: fix boot panic with CONFIG_DEBUG_VM and HVO bootmem pages Patch series "mm: Refactor bootmem gigantic hugepage allocation", v4. This series is split out from the earlier larger series "mm: Generalize HVO for HugeTLB and device DAX" [1]. It collects the first 19 patches of that series as a standalone set of fixes and preparatory cleanups around bootmem HugeTLB handling, sparse initialization ordering, and related vmemmap setup. The first patches fix a few bugs found while reviewing the existing code, including incorrect bootmem HVO handling, wrong vmemmap registration arguments, a powerpc compound-vmemmap tracking bug, and too-late initialization of gigantic bootmem HugeTLB struct pages. The rest of the series reorders early memory initialization so the relevant zone state is available before sparse and HugeTLB boot-time setup runs, then simplifies the remaining bootmem gigantic hugepage allocation path and removes code made obsolete by that rework. At a high level: - patches [1-4] fix boot-time and arch-specific bugs - patches [5-12] reorder and simplify sparse/mm/hugetlb early init - patches [13-19] refactor bootmem gigantic hugepage allocation and remove obsolete helpers and state This patch (of 19): Commit 622026e87c40 ("mm/hugetlb: remove fake head pages") switched HVO to reuse per-zone shared tail pages from zone->vmemmap_tails[]. Those shared tail pages were initialized in hugetlb_vmemmap_init(), but bootmem HugeTLB folios are prepared earlier from gather_bootmem_prealloc(). With hugetlb_free_vmemmap=on, prep_and_add_bootmem_folios() can access pageblock flags on bootmem HugeTLB pages whose mirrored tail struct pages already point to the shared tail page. On CONFIG_DEBUG_VM kernels, get_pfnblock_bitmap_bitidx() then dereferences the still-uninitialized shared tail page and can panic during boot. Initialize zone->vmemmap_tails[] from gather_bootmem_prealloc(), before bootmem HugeTLB folios are processed, and drop the later initialization from hugetlb_vmemmap_init(). This bug only affects CONFIG_DEBUG_VM kernels, where the relevant assertion is evaluated.

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In the Linux kernel, the following vulnerability has been resolved: drm/nouveau/dmem: fix callocated underflow on large folio split nouveau_dmem_folio_free() drops chunk->callocated once per freed folio, while a large (compound) device-private folio is only counted once when it is allocated. When such a folio is split, the mm core invokes ->folio_split() (nouveau_dmem_folio_split()) once for each new sub-folio, but the hook only fixes up the sub-folio metadata and leaves chunk->callocated unchanged. Each resulting sub-folio is later freed separately, so after a split the single allocation (+1) is met by N frees (-N), leaving chunk->callocated short by N-1. On the first split/free cycle it underflows: WARN_ON(!chunk->callocated) fires, the unsigned counter wraps and never returns to zero, so the chunk can no longer be reclaimed (nouveau_dmem_fini() also warns on the leaked count). Account for the new sub-folio in the split hook, under the same lock as nouveau_dmem_folio_free(), so the count stays balanced.

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In the Linux kernel, the following vulnerability has been resolved: drm/gud: validate TV mode names before creating enum property The GUD protocol returns TV mode names as fixed-size GUD_CONNECTOR_TV_MODE_NAME_LEN entries and requires each name to be NUL-terminated. gud_connector_add_tv_mode() currently passes each fixed-size entry directly to drm_mode_create_tv_properties_legacy(), which eventually reaches drm_property_add_enum() and strlen(). If a device returns an entry without a terminating NUL byte, strlen() reads past the end of the slot and can run beyond the allocated buffer, triggering an out-of-bounds read. Validate that each returned TV mode name contains a NUL terminator within its fixed-size slot before passing it to the DRM property code. If a malformed entry is found, reject the device response with -EIO. This fixes the out-of-bounds read without changing the handling of valid devices, and avoids silently truncating malformed protocol data.

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In the Linux kernel, the following vulnerability has been resolved: f2fs: fix to zero post-EOF data when extending file size generic/794 4s ... - output mismatch (see /share/git/fstests/results//generic/794.out.bad) --- tests/generic/794.out 2026-06-12 08:46:32.766426241 +0800 +++ /share/git/fstests/results//generic/794.out.bad 2026-07-05 18:32:55.000000000 +0800 @@ -1,4 +1,16 @@ QA output created by 794 append_write +FAIL: non-zero data in gap [4080,4096) after shutdown+remount +000000 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a >ZZZZZZZZZZZZZZZZ< +* +001000 truncate_up ... (Run 'diff -u /share/git/fstests/tests/generic/794.out /share/git/fstests/results//generic/794.out.bad' to see the entire diff) Ran: generic/794 Failures: generic/794 Failed 1 of 1 tests Steps of generic/794: 1. write 4096 bytes to file w/ 0x5a 2. use fiemap to get PBA of first block in file 3. truncate file to 4080 4. umount; write 4096 bytes to file w/ 0x5a directly via PBA; mount 5. extend filesize via a) append 4096 from offset 4096, or b) truncate 8192, or c) fallocate 4096 from offset 4096 6. verify the gap is zeroed in memory [4080,4096) 7. sync range 4096 from offset 4096; shutdown -f (flush meta before shutdown) 8. umount; mount; verify [4080,4096) is zeroed or not. When extending file size (e.g. via truncate, fallocate, or write) across an unaligned EOF boundary, we need to ensure that post-EOF data in the partial page is zeroed out in pagecache and marked dirty, then writeback the cache to persist zeroed data before committing inode w/ updated i_size. This help to prevent stale disk data beyond the previous EOF from being exposed after remounting or crash recovery. Since f2fs is a LFS filesystem, we only support direct write via PBA in pinfile, and pinfile has section-aligned filesize, so in Android, there should no problem, but for other usage in different environment, let's fix this w/ fsync_mode=strict mount option.

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In the Linux kernel, the following vulnerability has been resolved: media: meson: vdec: fix NULL pointer deref in vdec_try_fmt_common When VIDIOC_TRY_FMT is called with an unsupported pixel format on the OUTPUT queue, vdec_try_fmt_common() falls back to V4L2_PIX_FMT_MPEG2. However, if a distro has locally patched MPEG2 support out (as it has been broken for some time) the platform format table does not contain MPEG2 so find_format() returns NULL and the subsequent dereference of fmt_out->max_width triggers a NULL pointer dereference. Fix this by falling back to the first format in the platform's format array instead of hardcoding V4L2_PIX_FMT_MPEG2. This is always valid since every platform defines at least one format.

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In the Linux kernel, the following vulnerability has been resolved: s390/vfio-ap: fix potential use of uninitialized apm_filtered bitmap The DECLARE_BITMAP(apm_filtered, AP_DEVICES) macro allocates the bitmap on the stack without zero-initializing it. In vfio_ap_mdev_hot_plug_cfg(), the vfio_ap_mdev_filter_matrix() function is only called to initialize and populate apm_filtered if either filter_adapters or filter_domains is true. If the hot plug configuration change only adds control domains (meaning filter_cdoms is true, but filter_adapters and filter_domains are both false), vfio_ap_mdev_filter_matrix() is bypassed. Consequently, apm_filtered is passed to reset_queues_for_apids() with uninitialized stack garbage. This can cause reset_queues_for_apids() to interpret arbitrary stack garbage bits as valid APIDs to reset, potentially performing unintended guest hardware queue resets. Fix this by zero-initializing the apm_filtered bitmap at the beginning of vfio_ap_mdev_hot_plug_cfg() using bitmap_zero().

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In the Linux kernel, the following vulnerability has been resolved: arm64: mm: Fix the lockless page-table walk in show_pte() show_pte() walks page tables locklessly and can run with interrupts enabled. A concurrent teardown can free a table page while it is being walked. It can also clear a parent entry after show_pte() checked it; the regular pXd_offset() helpers then reread the cleared entry and can derive a bogus lower-level pointer and fault again. Use the lockless offset helpers with the saved parent entries, as gup_fast() does, and pass the saved PMD to pte_offset_map(). For task page tables, arm64 selects MMU_GATHER_RCU_TABLE_FREE. Disable local interrupts around the walk to hold off RCU-deferred table frees and block the tlb_remove_table_sync_one() IPI until the walk is finished. Place the IRQ guard after the header print. This does not make the output a consistent snapshot, but prevents the task page-table walk from dereferencing a released table page or deriving a pointer from a different parent value.

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In the Linux kernel, the following vulnerability has been resolved: memcg: make the v1 soft limit knob inert The v1 soft limit has been deprecated since v6.12 and nobody has reported depending on it. Start the removal by decoupling the interface from the implementation: keep memory.soft_limit_in_bytes, but ignore writes to it and always report the maximum value on read similar to what memory.kmem.limit_in_bytes already does. Writes are still parsed, so malformed input keeps returning -EINVAL. The knob now also behaves the same everywhere: it used to return -EOPNOTSUPP on PREEMPT_RT, where soft limit reclaim has always been disabled. This also fixes the syzbot report linked below. Soft limit reclaim is the only caller that runs shrink_lruvec() from kswapd against a specific memcg, so it is the only way to reach lru_gen_shrink_lruvec() and in turn set_mm_walk(), which warns when called from kswapd.

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In the Linux kernel, the following vulnerability has been resolved: memcg: bypass the reclaim and oom killer for dying tasks once oom_reaper is done At Meta, we are seeing instances where an OOM killed job is stuck in the exit path for several hours. In one particular case, the job was stuck for more than 8 hours and I had to manually remove the memory.max limits to allow the process to exit. The job was a single process job and had ~55 GiB memory.max and zswap enabled. It had almost 0 anon in memory and ~111 GiB in zswap compressed to ~51 GiB zswap pool (i.e. almost all of memory.current was zswap). Nothing was left on the LRUs to reclaim. On further inspection, I observed ~20k threads of that process stuck with the following stack: [<0>] mem_cgroup_out_of_memory+0x4e/0xa0 [<0>] charge_memcg+0x8bf/0x990 [<0>] mem_cgroup_swapin_charge_folio+0x4e/0x80 [<0>] __read_swap_cache_async+0x10c/0x260 [<0>] swapin_readahead+0x116/0x3f0 [<0>] do_swap_page+0x13c/0x1ce0 [<0>] handle_mm_fault+0x61d/0x11f0 [<0>] do_user_addr_fault+0x3e7/0x6d0 [<0>] exc_page_fault+0x8f/0x110 [<0>] asm_exc_page_fault+0x22/0x30 [<0>] __get_user_8+0x14/0x20 [<0>] futex_cleanup+0x27/0x1c0 [<0>] futex_exit_release+0x47/0x60 [<0>] do_exit+0x107/0x940 [<0>] do_group_exit+0x81/0xa0 [<0>] get_signal+0x2b1/0x6e0 [<0>] arch_do_signal_or_restart+0x1a/0x1c0 [<0>] exit_to_user_mode_loop+0xa8/0x1c0 [<0>] do_syscall_64+0x152/0x250 [<0>] entry_SYSCALL_64_after_hwframe+0x4b/0x53 In addition the dmesg was filled with "Out of memory and no killable processes..." messages. I have no idea why oom reaper was not able to reap/unmap the process. My guess is that since oom reaper tries to acquire mmap_lock in read mode limited number of times and then gives up, there might be a thread of that process which had mmap_lock in write mode at that time. My initial suspicion was the futex_cleanup and kernel page fault causing infinite fault and charge retries but that was put to rest in previous discussions happened on similar problem [1]. My current theory is that it is just a simple slow serialization behind the oom_lock. Unlike page allocator, memcg charge code takes the oom_lock without the "try". Though memcg oom code uses mutex_lock_killable(), note that in the call stack get_signal() consumes SIGKILL (or sigdelset(SIGKILL)) before calling do_group_exit(). So this mutex_lock_killable() is just a mutex_lock() here. Therefore 10s of thousands of threads are waiting on oom_lock and one by one they get -EFAULT from get_user() in the futex cleanup code and bails out. Discussion from [1] led to commit a75ffa26122b ("memcg, oom: do not bypass oom killer for dying tasks") which routes dying tasks into the OOM path precisely so the oom_reaper can reap their mm and free the memory asynchronously. But the reaper is best-effort and one-shot: if it cannot take mmap_lock for read (e.g. a sibling thread holds it for write) it sets MMF_OOM_SKIP and never retries, leaving only the glacial oom_lock-serialized synchronous drain. Once MMF_OOM_SKIP is set there is no more asynchronous reclaim coming for the mm, so a dying task charging against it has nothing left to wait for: it frees its memory only once it finishes exiting. Running reclaim and the (no-victim) OOM killer for it is then pointless, and doing it for 10s of thousands of exiting threads is what serializes them behind oom_lock. So before reclaim, if current is an OOM victim whose reaper is done, fail the charge. Reproduced with 20k threads, each parking a robust futex head on its own zswapped page, OOM-group-killed while a sibling holds mmap_lock for write so the reaper gives up and sets MMF_OOM_SKIP. Tested on next-20260728 and baseline show ~90 seconds exit time while with the patch the exit time reduced to ~3 seconds.

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In the Linux kernel, the following vulnerability has been resolved: scsi: qla2xxx: Fix response queue over-consumption in __qla_consume_iocb() qla24xx_process_response_queue() advances ring_ptr past the head IOCB before dispatching, so by the time __qla_consume_iocb() runs, ring_ptr already points at the first continuation IOCB. The function however looped purex->entry_count times starting at ring_ptr. As entry_count includes the head, this consumed one entry too many: it stamped RESPONSE_PROCESSED on the next, unrelated IOCB and advanced the ring past it, silently dropping a legitimate firmware response. The head IOCB's signature was also never marked. Mark the head processed and account for it, then consume only the entry_count - 1 continuation IOCBs, matching __qla_copy_purex_to_buffer().

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In the Linux kernel, the following vulnerability has been resolved: mm/secretmem: properly account locked pages secretmem accounts folios by treating memory as if it were mlock()'d and thus limited by the RLIMIT_MEMLOCK limit. However the folios are unevictable and remain so until the inode is evicted, eliminating usual mlock() semantics - mapping folios then unmapping them does not clear their unevictable state, since it depends on AS_UNEVICTABLE, not PG_mlocked. A user can therefore easily work around the RLIMIT_MEMLOCK limit - simply map then unmap and VmLck no longer counts the secretmem range. Worse, folios are not accounted in the process's RSS, meaning the OOM killer won't know to kill the process. Repeatedly mapping/unmapping (or forking) can then result in the consumption of all available system memory with unevictable folios and cause system instability. A secretmem fd can be passed between processes and over fork so a per-process limit simply does not make sense, so follow the precedent set by io_uring, perf, skbuff, iommufd and xdp by tracking the number of locked pages in user_struct->locked_vm. Since the scope tracked is actually inode lifetime, the RLIMIT_MEMLOCK applies per-user not per-process, so it doesn't make sense to bypass for users with CAP_IPC_LOCK, therefore remove this bypass. There is simply no reason to carry on marking the mapping as mlock()'d since it's misleading and the lifecycle is now correctly handled, so remove this too. Note that secretmem does not support any form of truncation (including hole punching) and the folios are unreclaimable, so the folios need only be accounted on fault and unaccounted on inode destruction. __secretmem_account_pages() is more or less a duplicate of the code that io_uring etc. use, but since this is a bug fix that needs backporting, defer any de-duplication efforts to a follow-up. test_mlock_limit() asserts mlock_future_ok() on mmap(), however this has been removed, so remove the test altogether for the fix. A new test will be sent separately for upstream.

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In the Linux kernel, the following vulnerability has been resolved: drm/sysfb: simpledrm: Improve stride validation Validate the computed stride against the maximum value INT_MAX.

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In the Linux kernel, the following vulnerability has been resolved: apparmor: policy_int make sure list heads are initialized before fail path If profile create fails before policy_init is complete the list heads are not properly initialized causing profile_free() sanity checks to trigger the following splat. AppArmor WARN aa_policy_destroy: (((!list_empty(&policy->profiles) && (&policy->profiles)->prev != ((void *) 0x122 + (0xdead000000000000UL))))): WARNING: security/apparmor/lib.c:509 at aa_policy_destroy+0x164/0x1b0 security/apparmor/lib.c:509, CPU#0: syz.0.17/5541 Modules linked in: CPU: 0 UID: 0 PID: 5541 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 RIP: 0010:aa_policy_destroy+0x16b/0x1b0 security/apparmor/lib.c:509 Code: 85 ed 7e 4d e8 96 bc 37 fd 5b 41 5c 41 5e 41 5f 5d e9 19 27 4e 07 cc e8 83 bc 37 fd 48 8d 3d 0c f0 d3 0b 48 c7 c6 a4 eb 38 8e <67> 48 0f b9 3a e9 04 ff ff ff e8 66 bc 37 fd 48 8d 3d ff ef d3 0b RSP: 0018:ffffc9000345eaa0 EFLAGS: 00010293 RAX: ffffffff848f530d RBX: ffff88803f734800 RCX: ffff88801af2a580 RDX: 0000000000000000 RSI: ffffffff8e38eba4 RDI: ffffffff90634320 RBP: 0000000000000000 R08: 0000000000000cc0 R09: 00000000ffffffff R10: dffffc0000000000 R11: fffffbfff1d95913 R12: dead000000000122 R13: ffff88803f734800 R14: ffff88803f734828 R15: dffffc0000000000 FS: 00007f5f6a1836c0(0000) GS:ffff88808c519000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055d02407b048 CR3: 0000000012aa9000 CR4: 0000000000352ef0 Call Trace: <TASK> aa_free_profile+0x9d/0x9f0 security/apparmor/policy.c:334 aa_alloc_profile+0x1e4/0x3e0 security/apparmor/policy.c:416 unpack_profile security/apparmor/policy_unpack.c:1153 [inline] aa_unpack+0x17db/0x7430 security/apparmor/policy_unpack.c:1748 aa_replace_profiles+0x226/0x2a20 security/apparmor/policy.c:1183 policy_update+0x234/0x4a0 security/apparmor/apparmorfs.c:505 profile_load+0x1cb/0x320 security/apparmor/apparmorfs.c:522 vfs_write+0x296/0xba0 fs/read_write.c:685 ksys_write+0x150/0x270 fs/read_write.c:739 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f5f6939e0d9 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f5f6a183028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f5f69625fa0 RCX: 00007f5f6939e0d9 RDX: 0000000000000041 RSI: 0000200000000400 RDI: 0000000000000003 RBP: 00007f5f6a183090 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007f5f69626038 R14: 00007f5f69625fa0 R15: 00007ffe23725c18

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In the Linux kernel, the following vulnerability has been resolved: octeontx2-af: fix out-of-bounds read setting MSI-X irq affinity rvu_register_interrupts() walks every MSI-X vector and uses strstr() to match "Mbox" or "FLR" in irq_name before pinning those interrupts to CPU 0. irq_name is a per-vector NAME_SIZE buffer, but not every slot is populated before this loop runs. strstr() keeps scanning until it finds a NUL terminator, so an uninitialized slot can trigger a KASAN slab-out-of-bounds read at boot when debug options are enabled. Use strnstr() with NAME_SIZE to bound the search within each vector's name buffer.

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In the Linux kernel, the following vulnerability has been resolved: Bluetooth: mgmt: fix 'hdev->discovery.uuids' NULL dereference 'uuid_count' member of struct 'discovery_state' is assigned and read without any locks, so there is a chance of situation when uuid_count != 0, but uuids is NULL and there will be NULL pointer dereference. Possible race: 'hci_update_passive_scan_sync' 'hci_discovery_filter_clear' hdev->discovery.uuid_count = 0; <----------------------preempted-----------------------------> 'start_service_discovery' // Set uuid_count to value != 0 hdev->discovery.uuid_count = uuid_count; hdev->discovery.uuids = kmemdup(...); <----------------------preempted-----------------------------> spin_lock(&hdev->discovery.lock); kfree(hdev->discovery.uuids); hdev->discovery.uuids = NULL; spin_unlock(&hdev->discovery.lock); Now uuids == NULL and uuid_count != 0. So 'mgmt_device_found' -> 'is_filter_match' -> 'eir_has_uuids' receives non consistent discovery state, where NULL dereference of uuids happens. To fix it let's add discovery.lock around every read/write of uuid_count, uuids pair of struct members. It is also important to assign uuid_count value only after success kmemdup() allocation in start_service_discovery(), otherwise uuids is NULL, because kmemdup failed, but uuid_count is already assigned to non zero value. The following panic happens: [ ] ------------[ cut here ]------------ [ ] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 [ ] Internal error: Oops: 0000000096000006 [#1] PREEMPT SMP [ ] CPU: 0 PID: 15056 Comm: kworker/u9:2 [ ] Workqueue: hci0 hci_rx_work [ ] pstate: 10400009 (nzcV daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ ] pc : eir_has_uuids+0x2d8/0x590 [ ] lr : is_filter_match+0x258/0x320 ... [ ] Call trace: [ ] eir_has_uuids+0x2d8/0x590 [ ] is_filter_match+0x258/0x320 [ ] mgmt_device_found+0x5b0/0xafc [ ] process_adv_report.part.0+0x8c8/0xf14 [ ] hci_le_adv_report_evt+0x338/0x3f0 [ ] hci_le_meta_evt+0x1f0/0x4c8 [ ] hci_event_packet+0x440/0xc9c [ ] hci_rx_work+0x44c/0xaf8 [ ] process_one_work+0x54c/0x103c [ ] worker_thread+0x6c4/0x10c4 [ ] kthread+0x274/0x2ec [ ] ret_from_fork+0x10/0x20 [ ] Code: 14000004 91004021 eb14003f 54000180 (f9400024) [ ] ---[ end trace 0000000000000000 ]---

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In the Linux kernel, the following vulnerability has been resolved: drm/xe: don't WARN on kernel job timeout when device already wedged igt@xe_wedged@wedged-at-any-timeout wedges the device in mode 2 (UPON_ANY_HANG_NO_RESET) and then rebinds the driver. During unbind, a GSC proxy kernel submission can still time out; with the device wedged and the GuC CT stopped it can never complete, so its kernel job times out. Tile0: GT1: Kernel-submitted job timed out WARNING: drivers/gpu/drm/xe/xe_guc_submit.c:... at guc_exec_queue_timedout_job() Workqueue: gt-ordered-wq drm_sched_job_timedout Killed queues skip guc_submit_hint_wedged(), leaving 'wedged' false even though the device is already wedged. The timeout handler then treats the kernel queue timeout as unexpected and taints the kernel. Honour an already-wedged device even for killed queues so the expected teardown timeout no longer trips the WARN. (cherry picked from commit a1c1dbd0f047bb05de6aaf6abe9103031179bf19)

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In the Linux kernel, the following vulnerability has been resolved: spi: amlogic-spisg: Make sure clk_init_data is fully initialized The clk_init_data structure contains several mutually-exclusive members for different methods to specify the possible parents of a clock, prompting drivers to initialize only the members they need. However, not initializing all members may cause subtle issues, which are only exposed when CONFIG_INIT_STACK_ALL_PATTERN or CONFIG_INIT_STACK_NONE is enabled. aml_spisg_clk_init() fills in init.parent_data, and assumes that init.parent_names is NULL. However, the latter in uninitialized, and thus may cause a crash. Make sure all members are fully initialized, to fix such bugs, and to avoid future breakage when converting drivers to a different method for specifying the parents.

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In the Linux kernel, the following vulnerability has been resolved: ACPI: bus: Introduce acpi_bus_get_primary_device() The function used for obtaining the first "physical" device for which the given ACPI one is the ACPI companion, acpi_get_first_physical_node(), may return a stale device pointer (mostly in theory) because acpi_unbind_one() may run as a whole after dropping the ACPI device's physical_node_lock in acpi_get_first_physical_node() and before it returns. The last reference to the "physical" device may be dropped then before the pointer to it is returned to the caller. If that happens and the acpi_get_first_physical_node() caller invokes get_device() on the pointer obtained from it, which is done by the majority of its callers, a use-after-free will occur. To prepare for addressing this problem, introduce a new function for getting the first "physical" device associated with the given ACPI one (the "primary physical device") that will also reference count the device in question before returning a pointer to it. Make that new function and acpi_get_first_physical_node() share the physical node list lookup code. No intentional functional impact.

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In the Linux kernel, the following vulnerability has been resolved: ocfs2: fix circular locking dependency in ocfs2_init_acl() A lockdep warning indicates a circular locking dependency between `&oi->ip_xattr_sem` and `&journal->j_trans_barrier`: WARNING: possible circular locking dependency detected is trying to acquire lock: (&oi->ip_xattr_sem){++++}-{4:4}, at: ocfs2_init_acl+0x2fd/0x7e0 fs/ocfs2/acl.c:367 but task is already holding lock: (&journal->j_trans_barrier){.+.+}-{4:4}, at: ocfs2_start_trans+0x3ab/0x700 fs/ocfs2/journal.c:369 The deadlock involves two code paths: Path 1 (setxattr) where `ocfs2_xattr_set()` acquires `ip_xattr_sem` (write) and then starts a transaction, which acquires `j_trans_barrier` (read); and Path 2 (mkdir/mknod) where `ocfs2_mknod()` starts a transaction (`j_trans_barrier` read) and then calls `ocfs2_init_acl()`, which attempts to acquire `ip_xattr_sem` (read) on the parent directory to retrieve the default ACL. Because rw_semaphores are subject to writer priority, a pending writer on `j_trans_barrier` (e.g., the journal commit thread) can cause Path 1 to block, while Path 2 is blocked waiting for Path 1 to release `ip_xattr_sem`. The patch fixes the lock ordering by precomputing the ACL state before starting the OCFS2 transaction, while preserving POSIX ACL storage semantics and the existing inode/security initialization order. By reading the parent directory's default ACL and preparing the new inode's ACLs outside the transaction, `ip_xattr_sem` is always acquired before `j_trans_barrier`. `struct ocfs2_acl_state` encapsulates the prepared ACL state, while `ocfs2_acl_init_prepare()` and `ocfs2_acl_init_release()` avoid code duplication between `ocfs2_mknod()` and `ocfs2_init_security_and_acl()`. `ocfs2_calc_xattr_init()` and `ocfs2_init_acl()` use this precomputed state, removing internal `ip_xattr_sem` acquisition and redundant disk reads. Additionally, remove the `ip_xattr_sem` acquisition from `ocfs2_xattr_set_handle()`. This function is only used while initializing a new inode that has not yet been inserted into the inode hash or attached to a dentry, meaning there is no risk of concurrent access and the lock is unnecessary.

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In the Linux kernel, the following vulnerability has been resolved: sched/isolation: Defer freeing of cpumask memblock memory to initcall When testing a linux-next kernel with commit 59bd1d914bb5 ("memblock: warn when freeing reserved memory before memory map is initialized"), the following warning was hit when there was a "nohz_full" kernel boot parameter. Cannot free reserved memory because of deferred initialization of the memory map WARNING: mm/memblock.c:904 at __free_reserved_area+0xde/0xf0, CPU#0: swapper/0/0 : Call Trace: <TASK> memblock_phys_free+0xcb/0x100 housekeeping_init+0x14c/0x170 start_kernel+0x207/0x450 x86_64_start_reservations+0x24/0x30 x86_64_start_kernel+0xda/0xe0 common_startup_64+0x13e/0x141 </TASK> IOW, we shouldn't free memblock allocated memory so early in the boot process when memory map isn't fully initialized in deferred_init_memmap(). Fix it by saving the housekeeping cpumask memblock memory to be freed into a llist free list in housekeeping_init() and add a new housekeeping_late_init() helper to defer the actual freeing of memblock memory to when initcall's are being processed. The cpumask memblock memory is treated as a llist_node with the size of a "long" type which is also smallest cpumask size that can be allocated. The non-atomic version of the llist APIs are used as there is no contention. This commit depends on the presence of commit 7c2eee9c1367 ("memblock: don't touch memblock arrays when memblock_free() is called late") to prevent a KASAN UAF bug report [1]. [1] https://lore.kernel.org/lkml/[email protected]/

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In the Linux kernel, the following vulnerability has been resolved: arm64: entry: Avoid unnecessary local_irq_disable() on kernel exit Currently, when exiting to kernel mode, we attempt involuntary preemption. The preemption logic expects IRQs to be disabled, which is why we call local_irq_disable() before attempting preemption. However, depending on the context, local_irq_disable() may be unnecessary: - __el1_irq(), the non-NMI EL1 IRQ path, already has IRQs disabled, so local_irq_disable() is redundant. - irqentry_exit_to_kernel_mode_preempt() immediately returns when exiting from an NMI-like context, so calling local_irq_disable() beforehand is unnecessary work. Furthermore, it confuses the pNMI state tracking when we are in a context with interrupts disabled and the GIC_PRIO_PSR_I_SET bit is set in the PMR, leading to a warning when CONFIG_ARM64_DEBUG_PRIORITY_MASKING=y: WARNING: ./arch/arm64/include/asm/irqflags.h:63 at arm64_exit_to_kernel_mode+0xb8/0xc0, CPU#40: retsnoop/31805 CPU: 40 UID: 0 PID: 31805 Comm: retsnoop Not tainted 7.2.0-rc6-next-20260805 #7 PREEMPTLAZY pstate: 234013c9 (nzCv DAIF +PAN -UAO +TCO +DIT +SSBS BTYPE=--) pc : arm64_exit_to_kernel_mode (arch/arm64/kernel/entry-common.c:63) lr : el1_abort (arch/arm64/kernel/entry-common.c:323) pmr: 000000f0 Call trace: arm64_exit_to_kernel_mode (arch/arm64/kernel/entry-common.c:63) (P) el1_abort (arch/arm64/kernel/entry-common.c:323) el1h_64_sync_handler (arch/arm64/kernel/entry-common.c:449) el1h_64_sync (arch/arm64/kernel/entry.S:589) [...] Split arm64_exit_to_kernel_mode() into preempt, non-preempt, and dispatch parts so that we can avoid this extra work where it is not needed and avoid breaking the pNMI tracking logic.

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In the Linux kernel, the following vulnerability has been resolved: btrfs: make sure EXTENT_BUFFER_READING is cleared under refs_lock [FALSE ALERTS] There is a bug report that the warning inside invalidate_and_check_btree_folios() got triggered during btrfs/298: BTRFS info (device sdd): first mount of filesystem f9bf732a-a19b-44b9-99a7-614ddff168e2 BTRFS info (device sdd): using crc32c checksum algorithm BTRFS error (device sdd): failed to find fsid cb2fdb42-b638-4f2f-badd-4127467ba674 when attempting to open seed devices BTRFS error (device sdd): failed to read chunk tree: -2 ------------[ cut here ]------------ WARNING: disk-io.c:3342 at invalidate_and_check_btree_folios+0x260/0x3c0 [btrfs], CPU#4: mount/125993 CPU: 4 UID: 0 PID: 125993 Comm: mount Tainted: G W OE 7.1.0-rc7-custom+ #1 PREEMPT(full) Hardware name: QEMU KVM Virtual Machine, BIOS edk2-20250812-19.fc42 08/12/2025 Call trace: invalidate_and_check_btree_folios+0x260/0x3c0 [btrfs] (P) open_ctree+0x1f50/0x23b0 [btrfs] btrfs_get_tree+0x89c/0xc48 [btrfs] vfs_get_tree+0x30/0x110 vfs_cmd_create+0x58/0xe8 __arm64_sys_fsconfig+0x39c/0x518 invoke_syscall.constprop.0+0x48/0x120 el0_svc_common.constprop.0+0x40/0xe8 do_el0_svc+0x24/0x38 el0_svc+0x50/0x310 el0t_64_sync_handler+0xa0/0xe8 el0t_64_sync+0x198/0x1a0 ---[ end trace 0000000000000000 ]--- BTRFS warning (device sdd): unable to release extent buffer 365985792 owner 3 gen 17 refs 3 flags 0x5 [CAUSE] In that invalidate_and_check_btree_folios() we wait for the eb to finish its read, then check if it's only held by us and the btree inode. If not, then do a warning as it may be still held, and could cause problems. But there is a small window where the check can lead to false alerts: Thread A (Read endio) | Thread B (Unmount) ----------------------------------+------------------------------------- end_bbio_meta_read() | | The eb has one extra ref held | | by the reader, and has | | EXTENT_BUFFER_READING flag set | invalidate_and_check_btree_folios() | | | |- clear_extent_buffer_reading() | | | | |- wait_on_bit_io(); | | | The EXTENT_BUFFER_READING flag is | | | cleared | | |- if (refcount_read(eb->refs) > 2) | | The eb is held by the read, us | | and btree inode, thus it | | will trigger the warning |- free_extent_buffer() | [FIX] Introduce a helper, free_extent_buffer_clear_reading(). If the new parameter, @clear_reading, is set, we will hold the spinlock at the beginning of free_extent_buffer_clear_reading() to make sure the EXTENT_BUFFER_READING flag is cleared inside the same critical section of decreasing refs. Now free_extent_buffer() will just call free_extent_buffer_clear_reading() with @clear_reading set to false, so no behavior change. But for end_bbio_meta_read(), it will not clear_extent_buffer_reading() directly, but pass @clear_reading as true. Then inside invalidate_and_check_btree_folios(), hold the refs_lock before reading refs. So that we eliminate the race window completely.

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In the Linux kernel, the following vulnerability has been resolved: arm64: hibernate: mask DAIF before restoring hibernated kernel The arm64 hibernate code manages the exception masking in an unsound way, leading to potential crashes and/or warnings during resume. When a hibernation image is saved in `swsusp_arch_suspend()`, all DAIF exceptions are masked (by virtue of `local_daif_save()`), and the suspended image is saved assuming that all DAIF exceptions will remain masked when the image is restored. When a hibernation image is resumed by `swsusp_arch_resume()`, only interrupts are masked (by virtue of `local_irq_disable()` in `resume_target_kernel()`). When pseudo-NMI is enabled the DAIF.IF bits will be clear, and regardless of pseudo-NMI the DAIF.DA bits will be clear. This means that there are two problems: (1) It is possible to take Debug, SError, or pseudo-NMI exceptions during the resume process. This is unsafe, as during the resume process both the old ane new kernels will tranisently be in an inconsistent state, and swsusp_arch_suspend_exit() won't retain an executable mapping of any exception vectors. Any exception taken here will be fatal and silent. (2) When re-entering the resumed kernel, some DAIF bits will be clear unexpectedly. This permits Debug, SError, or pseudo-NMI exceptions to be taken for a short period while the resumed kernel is not yet in a consistent state. This is detected by CONFIG_ARM64_DEBUG_PRIORITY_MASKING. Avoid these issues by masking all DAIF exceptions during resume.

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In the Linux kernel, the following vulnerability has been resolved: block: handle nogenerate/noverify properly in fs-integrity Check the BIP_CHECK flags before generating or verifying PI information, otherwise this can be incorrectly called for non-PI metadata and cause generation of incorrect metadata and crashed in the verification handler. The new behavior matches that of the block layer auto-generated metadata.

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In the Linux kernel, the following vulnerability has been resolved: ocfs2: do not use make_bad_inode() in ocfs2_read_inode_block_full() This reverts commit 58b6fcd2ab34 ("ocfs2: mark inode bad upon validation failure during read"). Since 'make_bad_inode()' resets inode type to S_IFREG, doing this for directory inode during active VFS lookup is likely to confuse the latter, including VFS_BUG_ON_INODE() triggered in this case.

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In the Linux kernel, the following vulnerability has been resolved: powerpc/irq: Fix missing r2 clobber in PCREL inline assembly In CONFIG_PPC_KERNEL_PCREL mode, r2 is no longer reserved for the TOC pointer and is available as a caller-saved register [0]. Both call_do_irq() and call_do_softirq() use inline assembly to call functions with stack switching, but fail to list r2 in their clobber lists. This causes the compiler to assume r2 is preserved across these calls, leading to register corruption when the called functions (__do_irq and __do_softirq) clobber r2. As a result of this kernel crash during interrupt handling is seen and the kernel fails to boot: BUG: Unable to handle kernel data access on write at 0xc000000404697638 Faulting instruction address: 0xc0000000000181ec Oops: Kernel access of bad area, sig: 11 [#1] NIP [c0000000000181ec] __do_IRQ+0x6c/0xc0 With older GCC, the compiler would conservatively allocate callee-saved registers (like r31) for values spanning function calls, accidentally avoiding the bug: <__do_IRQ>: 00 00 00 60 nop a6 02 08 7c mflr r0 f8 ff e1 fb std r31,-8(r1) f0 ff c1 fb std r30,-16(r1) 2d 03 10 06 pla r31,53297316 ... 3d e8 ff 4b bl c0000000000165ac <__do_irq> 00 00 21 e8 ld r1,0(r1) 28 00 4d e9 ld r10,40(r13) 40 00 21 38 addi r1,r1,64 2a f9 aa 7f stdx r29,r10,r31 With newer GCC 14, the compiler uses r2 for such values, exposing the missing clobber specification: <__do_IRQ>: 00 00 00 60 nop a6 02 08 7c mflr r0 f0 ff c1 fb std r30,-16(r1) f8 ff e1 fb std r31,-8(r1) 29 02 10 06 pla r2,36252592 # c0000000022aadc0 <__irq_regs> ... 85 dc ff 4b bl c000000000015ee0 <__do_irq> 00 00 21 e8 ld r1,0(r1) 28 00 2d e9 ld r9,40(r13) 30 00 21 38 addi r1,r1,48 2a 11 c9 7f stdx r30,r9,r2 Fix this by adding r2 to the clobber list for both call_do_irq() and call_do_softirq() when CONFIG_PPC_KERNEL_PCREL is enabled. [0]: https://www.mail-archive.com/[email protected]/msg313226.html

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In the Linux kernel, the following vulnerability has been resolved: locking/lockdep: Fix NULL pointer dereference in __lock_set_class() register_lock_class() can return NULL when the lock class pool is exhausted, graph_lock() fails, or key validation fails. However, __lock_set_class() uses the return value directly in pointer arithmetic without a NULL check: class = register_lock_class(lock, subclass, 0); hlock->class_idx = class - lock_classes; If class is NULL, this computes a wild offset that corrupts hlock->class_idx. The subsequent reacquire_held_locks() call will invoke hlock_class() with this corrupted index, leading to a NULL or out-of-bounds pointer dereference. Add the missing NULL check, consistent with how __lock_acquire() already handles this case at the same call site.

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In the Linux kernel, the following vulnerability has been resolved: clk: eswin: Zero-initialize stack-allocated clk_init_data eswin_clk_register_pll() and eswin_register_clkdiv() declare a struct clk_init_data on the stack and only initialize some of its fields (parent_data respectively parent_hws). clk_core_populate_parent_map() checks parent_names first and parent_data second before falling back to parent_hws, so leftover stack garbage in the uninitialized fields hijacks parent resolution and the clk core dereferences a bogus pointer: Unable to handle kernel NULL pointer dereference at virtual address 000000000000000c Oops [#1] epc : __clk_register+0x31a/0x7f0 [<ffffffff805dc774>] __clk_register+0x31a/0x7f0 [<ffffffff805dcd76>] devm_clk_hw_register+0x2a/0x94 [<ffffffff805e319a>] eswin_register_clkdiv+0x80/0xd0 [<ffffffff805e34a0>] eswin_clk_register_clks+0x162/0x1a0 [<ffffffff805e3736>] eic7700_clk_probe+0x146/0x180 [<ffffffff8065d23c>] platform_probe+0x3c/0x7a Observed on EIC7700 hardware (with the driver backported to a 6.17 tree); whether the bug triggers depends entirely on what the stack happens to contain when the registration helpers run. Zero-initialize both structures.

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