CVE Database

In the Linux kernel, the following vulnerability has been resolved: net: macb: put the "mdio" child node reference on success macb_mii_init() holds the reference returned by of_get_child_by_name() for macb_mdiobus_register() and drops it only on the error paths, so every successful probe leaks a node reference. On a CM5, overlay removal after four bind cycles reports OF: ERROR: memory leak, expected refcount 1 instead of 5 Drop the reference after registration, where __mdiobus_register() has already taken its own for the lifetime of the bus.

In the Linux kernel, the following vulnerability has been resolved: nstree: check listing permission before taking a namespace reference legitimize_ns() takes a reference on the candidate namespace before may_list_ns() has decided whether the caller may see it. The __free(ns_put) cleanup on the denied path can drop the last reference to a mount namespace while we still hold the rcu read lock, and put_mnt_ns() may sleep there. This is the same problem commit 2ec2aff3c8e2 ("ns: make sure reference are dropped outside of rcu lock") fixed for the put_user() path. Neither ns_requested() nor may_list_ns() needs a reference, both only look at the namespace type and at the caller's own namespaces, so do the checks first and take the reference last. Splat: Voluntary context switch within RCU read-side critical section! WARNING: kernel/rcu/tree_plugin.h:332 at rcu_note_context_switch+0x238/0x2a0, CPU#5: a/3442 CPU: 5 UID: 1000 PID: 3442 Comm: a Not tainted 7.0.0-30-generic #30-Ubuntu PREEMPT(lazy) RIP: 0010:rcu_note_context_switch+0x238/0x2a0 Call Trace: <TASK> __schedule+0xcf/0x650 schedule+0x27/0x90 schedule_preempt_disabled+0x15/0x30 __mutex_lock.constprop.0+0x550/0xaf0 __mutex_lock_slowpath+0x13/0x20 mutex_lock+0x3b/0x50 exp_funnel_lock+0xb2/0x260 synchronize_rcu_expedited+0xe7/0x220 namespace_unlock+0x26a/0x320 put_mnt_ns+0xd3/0x120 mntns_put+0xe/0x20 do_listns+0x13e/0x560 __do_sys_listns+0x126/0x2d0 __x64_sys_listns+0x20/0x30 x64_sys_call+0x2366/0x2390 do_syscall_64+0x105/0x5a0 entry_SYSCALL_64_after_hwframe+0x76/0x7e </TASK>

In the Linux kernel, the following vulnerability has been resolved: watchdog: msc313e: Avoid division by zero clk_get_rate() could return 0. Avoid a division by zero panic.

In the Linux kernel, the following vulnerability has been resolved: watchdog: msc313e: Fix clock leak and spurious timer in settimeout() msc313e_wdt_settimeout() unconditionally calls msc313e_wdt_start() which introduces two severe bugs: 1. If the watchdog is already active, calling start() again will increase the reference count of the clock again. However stop() is only called once, the reference count is unbalance. 2. If the watchdog is stopped, calling settimeout() will start the hardware timer accidentally. Factor out the register-writing logic into a helper function. Only call it in settimeout() if the watchdog is running. Otherwise, simply update `wdev->timeout`.

In the Linux kernel, the following vulnerability has been resolved: hwmon: (corsair-cpro) Create debugfs entries after hwmon registration ccp_debugfs_init() registers debugfs files whose private data is the devm allocated ccp. It runs before hwmon_device_register_with_info(), so when that registration fails, ccp_probe() returns with the files still in place. The HID core then frees ccp, and ccp_remove() is not called for a failed probe, so nothing removes them later either. Reading one of the files dereferences the freed pointer. Create the debugfs entries only after the hwmon device has been registered, so no failing path can leave them behind. The two version queries stay where they are. They send USB commands without holding ccp->mutex, which is only safe as long as nothing else can call send_usb_cmd(); once the hwmon device is registered its callbacks can do so concurrently. Only the debugfs creation moves, and it is told which queries succeeded.

In the Linux kernel, the following vulnerability has been resolved: hwmon: (corsair-cpro) Remove debugfs entries when probe fails ccp_debugfs_init() registers debugfs files whose private data is the devm allocated ccp. If hwmon_device_register_with_info() fails right after it, ccp_probe() returns without removing them: the HID core then frees ccp, and ccp_remove() is not called for a failed probe, so the files stay behind. Reading one of them dereferences the freed pointer. Remove the debugfs entries on that error path. debugfs_remove_recursive() waits for readers already inside the show callbacks, so ccp is no longer reachable through debugfs by the time probe returns.

In the Linux kernel, the following vulnerability has been resolved: octeontx2-pf: reset HTB scheduler topology before freeing queues HTB offload programs NIX_AF_TLxX_TOPOLOGY on QoS-allocated scheduler queues via otx2_qos_txschq_set_parent_topology(), but teardown freed those queues without clearing TOPOLOGY. The AF only restores PARENT and SCHEDULE on free, so PRIO_ANCHOR/RR_PRIO settings can survive in the shared scheduler pool and affect later allocations. Add otx2_qos_reset_schq_topology() and otx2_qos_free_hw_schq() to zero TL4 through TL2 TOPOLOGY before each schq is returned to the AF during hierarchy teardown and cfg rollback. Skip the aggregation level (TL1): it is a per-tx-link queue shared by the PF, default Tx hierarchy and VFs, and is not freed back to the AF by nix_txschq_free_one().

In the Linux kernel, the following vulnerability has been resolved: ppp_synctty: ensure a writeable skb header ppp_sync_txmunge() checks headroom before prepending the address and control bytes, but does not ensure that the skb header is writable. A received skb can reach this function through PPP channel bridging without passing through ppp_start_xmit(), which calls skb_cow_head(). For example, a PPPoE frame may share its buffer with a clone queued to an AF_PACKET socket. If it is bridged to a synchronous tty channel, the address/control bytes can overwrite data still visible to that socket. Use skb_cow_head() to ensure both sufficient headroom and a writable header.

In the Linux kernel, the following vulnerability has been resolved: net: stmmac: initialize ptp_lock at probe time priv->ptp_lock is only initialized in stmmac_ptp_register(), which runs during __stmmac_open(). However, the lock is also used while the interface is down and has never been opened: tc_taprio_configure() invokes the PTP gettime64() callback to compute the EST base time when offloading a TAPRIO schedule, and stmmac_get_time() takes priv->ptp_lock. Using an uninitialized rwlock is undefined behaviour. Move the rwlock_init() to __stmmac_dvr_probe(), together with the other private locks, so that ptp_lock is always valid regardless of the interface state.

In the Linux kernel, the following vulnerability has been resolved: net/sched: cls_route: free emptied bucket on filter move route4_change can move an existing filter to a different top-level bucket: route4_set_parms recomputes the handle from TCA_ROUTE4_TO/ FROM/IIF, and the handle-mismatch check is gated on the 'new' flag, so for an existing filter the new handle may differ from the old one and land in a different bucket. When this happens, the filter is unlinked from the old bucket, but the bucket itself is never freed once it goes empty. The stale empty bucket remains in head->table[], causing route4_delete to report *last=false even after the last live filter is gone. That pins the empty tcf_proto and causes a leak. Fix this by refcounting the filters linked to a bucket and freeing the bucket when the count drops to zero. The existing scan in route4_delete goes away with it. The count is updated at all sites that link or unlink a filter during add, change and delete, and the bucket is dropped from head->table[] as soon as it reaches zero. Conditions to recreate the bug: CONFIG_NET_CLS_ROUTE4=y, CONFIG_NET_SCH_INGRESS=y, CONFIG_NET_CLS_ACT=y. tc qdisc replace dev lo clsact tc filter add dev lo ingress protocol ip pref 100 route from 1 to 1 tc filter change dev lo ingress protocol ip pref 100 handle 0x10001 \ route from 1 to 2 tc filter del dev lo ingress protocol ip pref 100 handle 0x10002 \ route from 1 to 2 tc filter show dev lo ingress | grep -c 'pref 100 route chain 0 '

In the Linux kernel, the following vulnerability has been resolved: net/sched: cls_api: Don't replay RTM_GETCHAIN in tc_ctl_chain(). If a netlink socket sends RTM_GETCHAIN requests repeatedly without recv()ing the responses, tc_ctl_chain() hogs CPU and triggers Hung Task splat. [0] As caught in the stack trace, netlink_attachskb() could confuse tc_ctl_chain() by returning -EAGAIN when the userspace netlink socket's receive buffer is full. The replay: label exists since commit 32a4f5ecd738 ("net: sched: introduce chain object to uapi") but was not used initially. Since commit 9f407f1768d3 ("net: sched: introduce chain templates"), the label is needed for RTM_NEWCHAIN because tcf_proto_lookup_ops() may release RTNL to call request_module(). However, the replay logic is unnecessary for RTM_GETCHAIN. Let's apply the replay logic only for RTM_NEWCHAIN. [0]: INFO: task repro:1018 is blocked on a mutex likely owned by task repro:1022. task:repro state:R running task stack:14096 pid:1022 tgid:1014 ppid:961 task_flags:0x400040 flags:0x00080000 Call Trace: <TASK> ? clockevents_program_event (kernel/time/clockevents.c:372) ? pskb_expand_head (net/core/skbuff.c:615) ? skb_release_data (net/core/skbuff.c:1122) ? netlink_attachskb (./include/linux/skbuff.h:1323 ./include/linux/skbuff.h:1332 net/netlink/af_netlink.c:1232) ? __netlink_lookup (./include/linux/rcupdate.h:882 ./include/linux/rhashtable.h:711 net/netlink/af_netlink.c:499) ? tc_chain_notify (net/sched/cls_api.c:3045) ? tc_chain_notify (./include/linux/skbuff.h:1384 net/sched/cls_api.c:3041) ? netlink_unicast (net/netlink/af_netlink.c:1335) ? rtnl_unicast (./include/net/netlink.h:1198 net/core/rtnetlink.c:985) ? tc_ctl_chain (net/sched/cls_api.c:3242) ? rtnetlink_rcv_msg (net/core/rtnetlink.c:7146) ? netlink_unicast (net/netlink/af_netlink.c:1354) ? __pfx_rtnetlink_rcv_msg (net/core/rtnetlink.c:7177) ? netlink_rcv_skb (net/netlink/af_netlink.c:2556) ? netlink_unicast (net/netlink/af_netlink.c:1319) ? netlink_sendmsg (net/netlink/af_netlink.c:1900) ? __sock_sendmsg (net/socket.c:800) ? __sys_sendto (net/socket.c:2281) ? __x64_sys_sendto (net/socket.c:2288 net/socket.c:2284 net/socket.c:2284) ? do_syscall_64 (arch/x86/entry/syscall_64.c:61 arch/x86/entry/syscall_64.c:84) ? entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121) </TASK>

In the Linux kernel, the following vulnerability has been resolved: net: hinic: fix mailbox segment buffer overflow check_mbox_seq_id_and_seg_len() validates that seq_id does not exceed SEQ_ID_MAX_VAL (42) and seg_len does not exceed MBOX_SEG_LEN (48). However, this allows the last segment (seq_id=42) to carry a full 48-byte payload, writing to offset 42*48=2016 for 48 bytes (ending at byte 2064). The receive buffer is only MBOX_MAX_BUF_SZ (2048) bytes, resulting in a 16-byte heap buffer overflow. The hinic3 driver already handles this correctly by defining MBOX_LAST_SEG_MAX_LEN and rejecting the last segment when it exceeds the remaining buffer space. Apply the same fix to the hinic driver.

In the Linux kernel, the following vulnerability has been resolved: net: net_failover: Fix the deadlock in net_failover_slave_name_change() This is a sibling fix of commit b84c5632c7b3 ("net: net_failover: Fix the deadlock in slave register"). There is netdev_lock_ops() in the upper callers, so using netif_open() instead of dev_open(). Call Trace: __schedule+0x2bb/0x650 schedule+0x27/0xb0 schedule_preempt_disabled+0x15/0x30 __mutex_lock.constprop.0+0x550/0xaf0 __mutex_lock_slowpath+0x13/0x20 mutex_lock+0x3b/0x50 dev_open+0x3b/0xe0 net_failover_slave_name_change+0x22/0x40 failover_event+0xd4/0x1e0 notifier_call_chain+0x62/0xf0 raw_notifier_call_chain+0x16/0x30 call_netdevice_notifiers_info+0x50/0x80 netif_change_name+0x200/0x330 do_setlink.isra.0+0xb12/0xdf0 ? security_capable+0x9a/0x1e0 ? ns_capable+0x31/0x60 rtnl_setlink+0x302/0x670 ? netlink_recvmsg+0x296/0x340 ? security_capable+0x9a/0x1e0 ? __pfx_rtnl_setlink+0x10/0x10 rtnetlink_rcv_msg+0x384/0x460 ? __pfx_rtnetlink_rcv_msg+0x10/0x10 netlink_rcv_skb+0x61/0x120 rtnetlink_rcv+0x15/0x30 netlink_unicast+0x28f/0x3c0 netlink_sendmsg+0x216/0x450 __sys_sendto+0x222/0x230 __x64_sys_sendto+0x24/0x40 x64_sys_call+0x1d5d/0x2390 do_syscall_64+0x105/0x5a0 ? do_syscall_64+0x140/0x5a0 ? exc_page_fault+0x94/0x1e0 entry_SYSCALL_64_after_hwframe+0x76/0x7e

In the Linux kernel, the following vulnerability has been resolved: net: mana: restore the XDP program pointer when pre-allocation fails mana_xdp_set() publishes the new program into apc->bpf_prog before it allocates anything, because mana_pre_alloc_rxbufs() sizes the buffers from it via mana_get_rxbuf_cfg(). When that allocation fails the function returns the error directly, skipping the err_dealloc_rxbuffs label which is the only place that restores the previous pointer. The attach is reported as failed, so the BPF core drops the reference it held for the caller and the program can be freed, while apc->bpf_prog still points at it. The next consumer of mana_xdp_get() - typically mana_chn_setxdp() from mana_alloc_queues() on the following ifup, or after a TX timeout reset - then calls bpf_prog_add() on freed memory. This is reachable from an ordinary "ip link set dev ethX xdp obj ..." whenever the per-queue RX buffer pre-allocation cannot be satisfied. Restore the previous program on that error path.

In the Linux kernel, the following vulnerability has been resolved: net/rds: fix tcp stream corruption with large pages rds_message_map_pages() assigns PAGE_SIZE bytes to every scatterlist entry, even when total_len ends in a partial page. The RDS congestion map is defined as 8192 bytes, so on systems with PAGE_SIZE greater than 8192 the scatterlist maps bytes beyond the end of the congestion map. RDS-TCP transmits the SG contents according to those lengths, so the extra bytes become part of the TCP RDS stream and are interpreted as subsequent RDS message headers, corrupting the stream. Limit the final scatterlist mapping to the number of bytes remaining. This has no effect on systems with a 4K page size and allows RDS-TCP to be used on systems with 16K and larger page sizes. The RDS selftest, which previously hung on 16K pages, now passes.

In the Linux kernel, the following vulnerability has been resolved: sunvdc: unmap LDC cookies when the descriptor send fails __send_request() maps the request's pages into the LDC channel's map table (ldc_map_sg()), fills in the descriptor and marks it VIO_DESC_READY before ringing the doorbell via __vdc_tx_trigger(). When the trigger fails, the error path only prints a message: the descriptor stays READY and the cookies are never unmapped. The mapping is normally released in vdc_end_one() when the peer completes the descriptor - but a descriptor whose doorbell was never sent will never complete, and since dr->prod is not advanced on failure, the reset path (vdc_requeue_inflight(), which walks [cons, prod)) never visits it either. The map table entries are leaked permanently. Since commit a11f6ca9aef9 ("sunvdc: Do not spin in an infinite loop when vio_ldc_send() returns EAGAIN") trigger failures occur in practice under load, so every resulting I/O error also leaks one request's worth of entries from the fixed-size (8192 entries per channel) map table. Because the allocator hands out contiguous ranges, fragmentation makes large multi-segment requests fail first as the table drains, until ldc_map_sg() fails permanently and the disk is dead until reboot. It also makes any retry-based recovery unusable: requeuing the request on -EAGAIN remaps the pages on every attempt, overwriting desc->cookies and orphaning the previous mapping, so the table drains at the retry rate. This is the memory exhaustion observed when the requeue approach was first tested in October 2025. Roll back on failure: unmap the cookies, mark the descriptor FREE again and clear the request entry. If the trigger failed with -ENOTCONN, __vdc_tx_trigger() has already reset the port, which tears down and reallocates both the dring and the LDC channel including its map table - nothing to roll back, and the stale descriptor must not be touched.

In the Linux kernel, the following vulnerability has been resolved: scsi: target: iscsi: Fix hang for aborted WRITE_PENDING commands When a LUN_RESET aborts a WRITE command that is in the TRANSPORT_WRITE_PENDING state, the target core sets CMD_T_ABORTED and waits for the frontend to finish processing. If the initiator subsequently sends the remaining dataout PDUs, __iscsit_check_dataout_hdr() catches the payload, stops the dataout timer if the sequence is final and finally dumps the data. However, the iSCSI target doesn't trigger the completion process for these aborted commands. Because of this, the abort path hangs indefinitely in target_put_cmd_and_wait(), leading to a deadlocked target worker thread. Fix this by explicitly calling target_complete_cmd() when the final dataout PDU is received for an aborted WRITE command. target_complete_cmd() detects the CMD_T_ABORTED flag and cleanly routes the command into target_abort_work, allowing the abort completion to successfully unblock.

In the Linux kernel, the following vulnerability has been resolved: configfs: pin the symlink target's dirent instead of chasing ->ci_dentry create_link() reads the target's configfs_dirent from item->ci_dentry->d_fsdata, relying on the item reference taken by get_target(). That reference pins the item, not its dentry: the dentry is pinned by DCACHE_PERSISTENT, which configfs_remove_dir() releases via simple_rmdir() while the item is still alive. A symlink racing with rmdir of its target can therefore find ->ci_dentry freed and its dirent released, triggering WARN_ON(!atomic_read(&sd->s_count)) in configfs_get(). Take the dirent in get_target() as well, under ->d_lock and atomically with the item reference, and pass it down to create_link(). A hashed dentry has not been killed yet, so its ->d_fsdata reference keeps the dirent alive there.

In the Linux kernel, the following vulnerability has been resolved: configfs: unhash the dentry before dropping the item in rmdir configfs_get_config_item() treats a hashed dentry as proof that sd->s_element is a live config_item. configfs_rmdir() breaks that: simple_rmdir() leaves the dentry hashed, the last reference to the item is dropped right after, and the dentry is only unhashed by d_delete() once ->rmdir() has returned. configfs_symlink() resolves its target holding no lock on it, so get_target() can land in that window: BUG: KASAN: slab-use-after-free in config_item_get+0x26/0x90 get_target fs/configfs/symlink.c:128 [inline] configfs_symlink+0x4ab/0x1030 fs/configfs/symlink.c:185 Unhash in configfs_remove_dir(), while the item is still guaranteed to be there. A reference obtained just before that stays harmless, as create_link() rechecks CONFIGFS_USET_DROPPING, already set by configfs_detach_prep(). Both configfs_unregister_subsystem() paths d_drop() after detaching, so this only makes rmdir match them.

In the Linux kernel, the following vulnerability has been resolved: powerpc/eeh: Fix recursive locking on devices without EEH sensitive driver The commit 1010b4c012b0 ("powerpc/eeh: Make EEH driver device hotplug safe") refactored the EEH code such that the pci_rescan_remove_lock is held at the beginning of eeh_handle_normal_event() and the eeh_reset_device() is called with that lock being held. Looks like the commit missed to remove the existing lock/unlock inside eeh_rmv_device() which is no longer necessary. This is causing the eehd to hang on the lock which it actually holds when that code path is taken. [<0>] 0xc00000011c78f870 [<0>] __switch_to+0xfc/0x1a0 [<0>] pci_lock_rescan_remove+0x30/0x44 [<0>] eeh_rmv_device+0x290/0x2e0 [<0>] eeh_pe_dev_traverse+0x80/0x130 [<0>] eeh_reset_device+0xcc/0x23c [<0>] eeh_handle_normal_event+0x830/0xa80 [<0>] eeh_event_handler+0xf8/0x190 [<0>] kthread+0x194/0x1b0 [<0>] start_kernel_thread+0x14/0x18 The issue is seen for cases where the errors are detected on the PHB directly AND|OR for devices where the driver error_detected() returns PCI_ERS_RESULT_NEED_RESET, and driver being not EEH sensitive(i.e no error handlers like slot_reset(), resume() etc defined).

In the Linux kernel, the following vulnerability has been resolved: x86/amd_node: Fix potential NULL pointer dereference amd_smn_read/write() are exported functions around __amd_smn_rw(), so they are always available even if amd_smn_init() fails. In that case, 'amd_roots' is NULL and __amd_smn_rw() will access uninitialized memory. Then, commit: 83518453074d ("x86/amd_node: Add SMN offsets to exclusive region access") added the 'smn_exclusive' flag, which indicated the calls to pci_request_config_region_exclusive() succeeded, to prevent concurrent userspace access. Commit: 0a4b61d9c2e4 ("x86/amd_node: Fix AMD root device caching") re-ordered initialization so pci_request_config_region_exclusive() is called earlier and a failure exits amd_smn_init() before allocating 'amd_roots'. The setting of 'smn_exclusive' moved to the end of amd_smn_init(), after 'amd_roots' is allocated. It became redundant and can be removed. Replace 'smn_exclusive' with directly checking 'amd_roots', to fix a potential NULL pointer dereference and to simplify the logic. [ bp: Reorg commit message, touchup comment. ] [ mingo: Rebase & further touchups. ]

In the Linux kernel, the following vulnerability has been resolved: x86/amd_node: Fix PCI device reference counting in amd_smn_init() The local "root" pointer is a temporary variable used during the device search. Therefore, refcount related to the search iterators should be cleaned up after the search is complete. Use the __free() cleanup macro to ensure the refcount is decremented when the temporary pointer goes out of scope. Additionally, increment the refcount when caching a root pointer. This ensures the in-use refcount is separate from the temporary search refcounting. Finally, drop the redundant "root = NULL" before the second search loop. The pci_get_class() iterator always decrements the refcount of its "from" argument, so the first loop can only fall through with "root" already NULL.

In the Linux kernel, the following vulnerability has been resolved: x86/mm: Fix user-space data loss with MADV_FREE and THP Some of users of Polars (a data analytics library) have lost production data from this bug. They seem to have just the right combination of huge pages, MADV_FREE and heavy reclaim pressure. pmd_modify() masks the old value with (_HPAGE_CHG_MASK & ~_PAGE_DIRTY), silently discarding the hardware dirty bit. The subsequent pmd_mksaveddirty() call is supposed to transfer _PAGE_DIRTY into _PAGE_SAVED_DIRTY when write-protecting, but the dirty bit was already stripped from the value, so there is nothing left to transfer. Contrast with pte_modify(), which keeps _PAGE_DIRTY_BITS in its mask, and pud_modify(), which keeps _HPAGE_CHG_MASK untouched: pmd_modify() is the odd one out. Any pmd_modify() on a writable, dirty PMD loses the dirty state. One visible consequence is data loss with MADV_FREE on PMD-mapped THP: memset(buf, 0x5A, size); // PMD-mapped THP, PMD dirty madvise(buf, size, MADV_FREE); // PMD cleaned but left writable, // folio marked lazyfree memset(buf, 0x5A, size); // hardware sets _PAGE_DIRTY again mprotect(buf, size, PROT_READ); // pmd_modify() drops the dirty bit mprotect(buf, size, PROT_READ|PROT_WRITE); // ... memory pressure ... Reclaim (e.g. under memcg pressure) then finds the lazyfree folio with no dirty bit set anywhere and frees it in __discard_anon_folio_pmd_locked(), even though the data was rewritten after MADV_FREE; subsequent reads fault in fresh zero pages. NUMA hinting alone can trigger the same loss, as do_huge_pmd_numa_page() restores the PMD through pmd_modify() as well. PMD-mapped file THPs are affected too: mprotect()/NUMA hinting dropping the dirty bit means rewritten data is never written back. Fix it by keeping _PAGE_DIRTY in the preserved mask, exactly like pte_modify() and pud_modify() do. The existing pmd_mksaveddirty()/pmd_clear_saveddirty() pair then performs the hardware-dirty <-> saved-dirty transition based on the write bit, preserving the shadow-stack encoding rules.

In the Linux kernel, the following vulnerability has been resolved: x86/cfi: Fix FineIBT hash offset in cfi_get_func_hash() The switch of the FineIBT preamble from "subl $hash, %r10d" to the shorter "subl $hash, %eax" moved the hash immediate from offset 7 to offset 5 of the preamble. fineibt_preamble_hash was updated to match, but the open-coded offset in cfi_get_func_hash() was missed and it still reads the hash at offset 7. cfi_get_func_hash() is used by the BPF JIT to give a struct_ops trampoline the CFI hash of the stub function it stands in for. With FineIBT the trampoline now gets the upper half of the real hash followed by the first two bytes of the next instruction, so the first indirect call from the kernel into a struct_ops program, tcp_init_congestion_control() calling ->init() of a BPF congestion control for example, fails the FineIBT check and the kernel dies with a CFI failure. Move the FineIBT preamble template and its offset defines above cfi_get_func_hash() and use fineibt_preamble_hash there, so every reader of the preamble shares one definition of its layout. The CFI_FINEIBT arm is only built with CONFIG_FINEIBT, the only configuration in which cfi_mode can take that value. cfi_get_func_arity() does not need the same treatment: the __bhi_args call whose displacement it reads still ends at the function address.

In the Linux kernel, the following vulnerability has been resolved: x86/mm/pat: Acquire init_mm write lock on collapse to avoid UAF x86 implements page attribute modification using its Change Page Attributes (CPA) mechanism. This tracks properties of ranges such as cache mode through x86 page attributes, and as part of that logic manipulates kernel page tables. Since commit: 41d88484c71c ("x86/mm/pat: restore large ROX pages after fragmentation") ranges of kernel page table entries can be collapsed into huge page table entries as part of this logic. As part of this collapse, it frees the page tables which the collapsed entries previously pointed to, and it does so without any relevant locks being held to preclude concurrent kernel page table walkers. The only way this code can be reached is if CPA_COLLAPSE is specified, and this is only set in set_memory_rox() via: set_memory_rox() -> change_page_attr_set_clr() -> cpa_flush() -> cpa_collapse_large_pages() Notable users of this are execmem and BPF when manipulating executable mappings. However, this is problematic for ptdump as it walks ranges it does not own and thus runs the risk of a use-after-free on page tables freed underneath it. In addition, concurrent CPA collapse operations are possible which can also cause races. Resolve the issue by acquiring the mmap write lock on init_mm across the whole operation. It is safe to acquire a sleeping lock as all the callers invoke set_memory_rox() from process context and in any case, change_page_attr_set_clr() calls vm_unmap_alias() which ultimately takes a mutex, disallowing atomic context here.