In the Linux kernel, the following vulnerability has been resolved: wifi: mac80211: reset state when starting AP fails ieee80211_start_ap() can set enable_beacon (and beacon_int) and fail later, leaving it set forever. Scanning can then attempt to restore beaconing on such an interface, leading to: Oops: divide error: 0000 [#1] SMP KASAN NOPTI RIP: 0010:mac80211_hwsim_link_info_changed+0xca7/0xf00 Call Trace: drv_link_info_changed+0x413/0x860 net/mac80211/driver-ops.c:495 ieee80211_link_info_change_notify+0x24b/0x3c0 net/mac80211/main.c:427 ieee80211_offchannel_return+0x381/0x580 net/mac80211/offchannel.c:160 __ieee80211_scan_completed+0x993/0xe30 net/mac80211/scan.c:519 ieee80211_scan_work+0x472/0x2010 net/mac80211/scan.c:1193 cfg80211_wiphy_work+0x2b7/0x550 net/wireless/core.c:538 in hwsim. Also, cfg80211 then allows changing the interface type, and the off-channel path getgs confused about beaconing as well, leading to another warning: WARNING: net/mac80211/driver-ops.c:468 at drv_link_info_changed+0x583/0x880 ieee80211_link_info_change_notify+0x24b/0x3c0 net/mac80211/main.c:427 ieee80211_offchannel_stop_vifs+0x328/0x5c0 net/mac80211/offchannel.c:122 ieee80211_start_sw_scan net/mac80211/scan.c:583 [inline] __ieee80211_start_scan+0xfb6/0x1af0 net/mac80211/scan.c:882 Reset the state on failures to always have it correct.
In the Linux kernel, the following vulnerability has been resolved: wifi: mac80211: don't allow injecting frames wider than the chanctx Frames injected on a monitor interface can carry a radiotap field requesting a bandwidth, which mac80211 passes down to the driver regardless of the the actual operational bandwidth. If the bandwidth requested is too wide, that triggers a warning in hwsim: WARN_ON(hwsim_get_chanwidth(bw) > hwsim_get_chanwidth(confbw)) Drop such frames entirely instead since they cannot be sent.
In the Linux kernel, the following vulnerability has been resolved: wifi: mac80211: mesh: reset the CSA state when leaving ifmsh->csa is allocated in ieee80211_mesh_csa_beacon() and only freed in ieee80211_mesh_finish_csa(), i.e. when the channel switch completes. Leaving the mesh while a switch is still pending therefore leaks it. Additionally, ifmsh->csa_role and ifmsh->chsw_ttl have their state leak in this case, so things can get mixed up in addition to the memory leak. Refactor the reset and call it in ieee80211_stop_mesh() to fix it all.
In the Linux kernel, the following vulnerability has been resolved: drm/vc4: Use managed KMS polling to fix UAF on unbind vc4_kms_load() calls drm_kms_helper_poll_init() but the driver provides no matching drm_kms_helper_poll_fini(). The output poll work stays scheduled after unbind and runs on the freed drm_device: # modprobe vc4; rmmod vc4; sleep 10 BUG: KASAN: slab-use-after-free in delayed_work_timer_fn BUG: KASAN: slab-use-after-free in drm_client_dev_hotplug [drm] Workqueue: events output_poll_execute [drm_kms_helper] Allocated by task 171: __devm_drm_dev_alloc Freed by task 262 (rmmod): drm_dev_put / component_del Use drmm_kms_helper_poll_init() so polling is finalized with the device, as other drivers do.
In the Linux kernel, the following vulnerability has been resolved: wifi: ath11k: cleanup arsta in ath11k_mac_peer_cleanup_all() When mac80211 removes a sta, it calls .sta_state() which in turn calls ath11k_mac_station_remove(). In that function we clean up both peers & arsta related resources. But when the firmware crashes, ath11k calls ieee80211_restart_hw(), which assumes that all driver related resources are cleaned up beforehand. This cleanup is supposedly done by ath11k_mac_peer_cleanup_all() but does not in fact free arsta->rx_stats / tx_stats. Extract the arsta cleanup from ath11k_mac_station_remove() into a new ath11k_mac_station_cleanup() and call it from both there and ath11k_mac_peer_cleanup_all(). This should handle kmemleaks reports like: unreferenced object 0xffffff801ae66400 (size 1024): comm "hostapd", pid 1306, jiffies 4295011565 hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace (crc d61c08ec): kmemleak_alloc+0x3c/0x50 __kmalloc_cache_noprof+0x2b0/0x3e0 ath11k_mac_op_sta_state+0x1dc/0xb10 drv_sta_state+0xac/0x6f8 sta_info_insert_rcu+0x314/0x5e0 sta_info_insert+0x14/0x38 ieee80211_add_station+0x10c/0x1a0 nl80211_new_station+0x3e8/0x680 genl_family_rcv_msg_doit+0xc0/0x120 genl_rcv_msg+0x1b4/0x258 netlink_rcv_skb+0x4c/0x108 genl_rcv+0x38/0x60 netlink_unicast+0x190/0x278 netlink_sendmsg+0x15c/0x370 ____sys_sendmsg+0x120/0x290 ___sys_sendmsg+0x70/0xa0 Tested-on: QCN9074 hw1.0 PCI WLAN.HK.2.9.0.1-01977-QCAHKSWPL_SILICONZ-1
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: coredump: Quiesce dump work on unregister hci_devcd_handle_pkt_init() arms dump_timeout and coredump producers queue dump_rx without holding an hdev reference. Unregister leaves both works live, so disconnecting during an active dump lets them access hdev after hci_release_dev() frees it. Shut down coredump processing during unregister. Close the producer gate under dump_q.lock before disabling both works, then free the active buffer and queued packets under hci_dev_lock. Serializing the gate with enqueue prevents controller-specific workers from adding packets after the final purge.
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: ISO: Fix parent socket leak in iso_conn_ready() iso_get_sock() returns the parent socket with a reference held, which is dropped by sock_put() once the child socket has been set up. The error path taken when iso_sock_alloc() fails only calls release_sock() and returns, leaking the reference and thus the parent socket itself. Drop the reference on that path as well.
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: btintel_pcie: fix off-by-one bounds check in RX submit btintel_pcie_submit_rx() used frbd_index > rxq->count to guard the FRBD array access, allowing frbd_index == rxq->count to pass through and index one element past the end of the array. Change the check to >= rxq->count so every out-of-range index is rejected. This issue was reported by Claude Mythos.
In the Linux kernel, the following vulnerability has been resolved: net: skbuff: do not leave stale header offsets after pskb_carve() pskb_carve_inside_header() and pskb_carve_inside_nonlinear() remove the first bytes of a packet and reallocate skb->head. All the headers that were present before the operation are gone, but both functions call skb_headers_offset_update(skb, 0), which is a no-op : skb->mac_header, skb->network_header, skb->transport_header and skb->csum_start keep their old values and now describe bytes which are no longer there. Both helpers size the new head from the old skb_end_offset(), so the stale offsets still land inside the new allocation. They point past skb_tail_pointer() though, to bytes that were never initialized. pskb_carve_inside_nonlinear() is the worst case, because it leaves a zombie skb with an empty linear part (skb->data == skb_tail_pointer(skb), skb_headlen(skb) == 0), while skb_mac_header_was_set() is still true and skb->mac_header is way ahead of skb->data. The only user of pskb_extract() is rds_tcp_data_recv(), and the carved skb is queued on tinc->ti_skb_list. When the RDS incoming message is released, rds_tcp_inc_free() calls skb_queue_purge(), which frees the skbs with SKB_DROP_REASON_QUEUE_PURGE. This is visible from drop_monitor, which then tries to pull back to the (bogus) mac header : skbuff: __skb_pull(len=234) skb len=6968 data_len=6968 headroom=0 headlen=0 tailroom=0 end-tail=384 mac=(234,14) mac_len=14 net=(248,40) trans=288 shinfo(txflags=0 nr_frags=1 gso(size=1428 type=16 segs=5)) csum(0x100120 start=288 offset=16 ip_summed=3 complete_sw=0 valid=1 level=0) hash(0x7b446c6c sw=0 l4=1) proto=0x86dd pkttype=0 iif=60 kernel BUG at ./include/linux/skbuff.h:2847! Add skb_carve_reset_headers() to mark the mac and transport headers as not set, reset the network header, clear skb->mac_len, and drop a now meaningless CHECKSUM_PARTIAL (csum_start no longer describes anything). Invalidate the inner offsets as well. Unlike mac_header and transport_header they have no "unset" sentinel, so a leftover non-zero value still looks like a real header. Zero skb->inner_mac_header, skb->inner_network_header, skb->inner_transport_header, skb->inner_protocol and skb->encapsulation, so that all the header state is invalidated in one place. v2: fixed an inaccurate changelog. The stale offsets stay inside the new skb->head, which is never smaller than the old one, they simply point past skb_tail_pointer() to bytes that are gone. Thanks to Xuanqiang Luo for insisting on this. Also invalidate the inner header state, as suggested by the netdev AI review : https://netdev-ai.bots.linux.dev/sashiko/#/patchset/20260911114922.621937-1-edumazet%40google.com
In the Linux kernel, the following vulnerability has been resolved: drm/amdgpu: check ras and obj before dereference nbio_v7_9_handle_ras_controller_intr_no_bifring() dereferences ras and obj without checking either for NULL. Both amdgpu_ras_get_context() and amdgpu_ras_find_obj() can return NULL, e.g. during the window between adev->nbio.ras being set (early in amdgpu_ras_init(), by design, to enable the fatal-error interrupt as soon as possible) and the PCIE_BIF ras object actually being created in RAS late_init. Any interrupt in that window crashes in hard-IRQ context. This is analogous to commit d190b459b2a4 ("drm/amdgpu: the warning dereferencing obj for nbio_v7_4"), which fixed the same issue in the nbio_v7_4 handler. Found by Linux Verification Center (linuxtesting.org) with SVACE. (cherry picked from commit c7071767a50a32ed727cf800ac84372429e3b4b3)
In the Linux kernel, the following vulnerability has been resolved: btrfs: abort transaction on failure to update inode for hole punching and reflinking If we fail to update the inode we error out without aborting the transaction, which can result in a persistent inconsistency if after the failure the transaction is committed, as we have dropped file extent items from a range and either punched a hole or insert a new file extent item for that range (for reflinks). So add the missing transaction abort.
In the Linux kernel, the following vulnerability has been resolved: 9p: Fix v9fs_issue_write() to update i_size and remote_i_size Fix v9fs_issue_write() to update i_size and remote_i_size to the new size of the server file if we made it larger, using the start fpos and the count returned by p9_client_write() to calculate the new minimum file size. This assumes that if the 9P server makes a short write (say it hits ENOSPC), a reduced count is returned.
In the Linux kernel, the following vulnerability has been resolved: ALSA: usb-audio: Clamp implicit feedback packet count to URB capacity data_ep_set_params() allocates each data URB for exactly u->packets isochronous frames, so urb->iso_frame_desc[] has u->packets slots and ctx->packets is the driver's only record of that limit. For an implicit feedback sink, snd_usb_queue_pending_output_urbs() overwrites it with the sync source's packet count, which is calculated independently from the capture endpoint's parameters. When that count is larger, prepare_playback_urb() and prepare_silent_urb() can write iso_frame_desc[] past the allocation; their existing bounds limit payload bytes, not the descriptor index. The reproducer uses a high-speed UAC2 device declaring bInterval 1 for implicit feedback capture (8 packets) and bInterval 4 for playback (1 packet). On the first capture completion after the stream starts, it accesses seven descriptors spanning 112 bytes beyond the one-packet URB: BUG: KASAN: slab-out-of-bounds in prepare_playback_urb (sound/usb/pcm.c:1560) Write of size 4 at addr ffff88801e696ad0 by task vhci_rx/178 prepare_playback_urb (sound/usb/pcm.c:1560) prepare_outbound_urb (sound/usb/endpoint.c:340) snd_usb_queue_pending_output_urbs (sound/usb/endpoint.c:501) snd_complete_urb (sound/usb/endpoint.c:1834) __usb_hcd_giveback_urb (drivers/usb/core/hcd.c:1657) usb_hcd_giveback_urb (drivers/usb/core/hcd.c:1741) vhci_rx_loop (drivers/usb/usbip/vhci_rx.c:107) kthread (kernel/kthread.c:436) The buggy address belongs to the object at ffff88801e696a00 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 0 bytes to the right of allocated 208-byte region [ffff88801e696a00, ffff88801e696ad0) Record the allocated packet count per endpoint and clamp both the adopted count and the packet-size copy to it. Fold the Format Type II delimiter into urb_packs before the allocation loop so the recorded limit matches every URB.
In the Linux kernel, the following vulnerability has been resolved: ASoC: codecs: rt712-sdca-dmic: fix uninitialized stream_config->type stream_config is not initialized before being passed to sdw_stream_add_slave(). The type field may contain garbage and is later copied to stream->type by sdw_config_stream(). Zero-initialize stream_config so type defaults to SDW_STREAM_PCM. While at it, use snd_sdw_params_to_config() helper instead of open-coding the same logic.
In the Linux kernel, the following vulnerability has been resolved: net/sched: act_api: release tail references on DELACTION failure A batched RTM_DELACTION request takes a temporary reference on each action before attempting any deletion. tcf_action_delete() clears each processed slot and drops its temporary reference before attempting the deletion. If deletion fails, tca_action_gd() calls tcf_action_put_many() to release the remaining references, but its tcf_act_for_each_action() iterator stops at the first NULL slot. When a batch stops at an action bound to a filter, this leaks a reference on each subsequent action. A later delete of an unbound action can then return success without removing it from the IDR. Walk the full array in tcf_action_put_many() and skip NULL slots to release the references held on the unprocessed actions.
In the Linux kernel, the following vulnerability has been resolved: scsi: core: Validate MODE SENSE lengths in scsi_cdl_enable() scsi_cdl_enable() uses length fields returned by MODE SENSE to locate the ATA feature mode page in a 64-byte stack buffer. A target can report a total length shorter than its mode header and block descriptors. The unsigned subtraction used for the MODE SELECT length can wrap, and the separately computed buf_data can point beyond buf. During automatic scan, enable is false, so the read-modify-write of buf_data[4] can clear the low two bits of a target-selected out-of-bounds stack byte. scsi_mode_select() can then copy up to 64 bytes from outside the buffer into the outgoing MODE SELECT payload, disclosing stack contents to the target. This is reachable while scanning a USB storage device that identifies as an ATA device and advertises CDL support. No filesystem mount or userspace access to the block device is required. On upstream commit cee9395acd80 ("Linux 7.3-rc1"), a build-specific, one-vCPU QEMU/Raw Gadget proof using QEMU-only multi-UDC allocator sampling executed a fixed proof command inside the guest and created a UID-0-owned marker during automatic enumeration, with KASLR and NX enabled. The issue was independently found during security research at Drivesec S.r.l. Cap the available length to the buffer size. Validate and consume the mode header and block descriptor lengths before using the page, and require the five bytes needed to access the CDL field.
In the Linux kernel, the following vulnerability has been resolved: i2c: atr: fix dangling adapter pointer on add failure i2c_atr_add_adapter() stores atr->adapter[chan_id] before i2c_add_adapter() so that the I2C bus notifier can match child clients during registration. On failure the channel is freed but the slot was left pointing at freed memory, which can lead to use-after-free in i2c_atr_del_adapter() / cleanup and also block reuse with -EEXIST. Clear the slot on the i2c_add_adapter() error path before freeing chan.
In the Linux kernel, the following vulnerability has been resolved: Input: cyttsp5 - clamp the HID report size before memcpy The size field comes from the device and is used as the memcpy() length into response_buf, which is CY_MAX_INPUT bytes.
In the Linux kernel, the following vulnerability has been resolved: hwmon: (hp-wmi-sensors) Fix use-after-free in fungible_show() nsensor->current_state is dynamically replaced as the sensor's state changes. update_numeric_sensor_from_wobj() does this by freeing the old string and installing a new one: if (strcmp(trimmed, nsensor->current_state)) { new_string = hp_wmi_strdup(dev, trimmed); if (new_string) { devm_kfree(dev, nsensor->current_state); nsensor->current_state = new_string; } } This function is only ever called from hp_wmi_update_info() while state->lock is held, so the free-and-replace itself is properly serialized against concurrent updates. fungible_show(), however, reads the same pointer after the lock has already been dropped: err = hp_wmi_update_info(state, info); if (err) return err; switch (prop) { ... case HP_WMI_PROPERTY_CURRENT_STATE: seq_printf(seqf, "%s\n", nsensor->current_state); break; hp_wmi_update_info() takes state->lock internally and releases it before returning, so by the time fungible_show() dereferences nsensor->current_state in seq_printf(), no lock is held. Two processes reading a sensor's current_state debugfs entry at overlapping times (or one reading it while another read of the same sensor triggers a refresh) can race: one thread's seq_printf() can be part-way through printing the string at the moment another thread's call into update_numeric_sensor_from_wobj() frees it with devm_kfree() and installs a new pointer, causing a use-after-free read. Take state->lock around the read in fungible_show() as well, so it can never run concurrently with the free-and-replace in update_numeric_sensor_from_wobj().
In the Linux kernel, the following vulnerability has been resolved: hwmon: (pwm-fan) Stop RPM timer before freeing tach data sample_timer() rearms the RPM timer and accesses the devm-managed ctx->tachs and ctx->pulses_per_revolution arrays. The cleanup action which stops the timer is registered before those arrays are allocated. Since devres releases entries in reverse order, driver detach can free the arrays before pwm_fan_cleanup() shuts down the timer. A timer expiry in that window accesses the freed tach data. With a KASAN kernel, a test-only kprobe delayed entry to pwm_fan_cleanup() while normal sysfs unbind ran. Each of three runs reported three four-byte reads and two four-byte writes in sample_timer() after its backing devm allocations had been freed. The helper did not invoke the timer callback, cleanup actions or free functions. With the fix, three matching unbind runs completed without KASAN, BUG, WARNING, Oops or panic. Instrumentation confirmed that timer retirement completed before the first timer backing allocation was released. Split timer retirement from the power cleanup and register its devres action after the timer backing data and IRQ actions are installed. This preserves the early power rollback action while ensuring the timer is retired before its backing data is released. Use timer_shutdown_sync() because the callback can rearm itself.
In the Linux kernel, the following vulnerability has been resolved: wifi: libipw: reject TKIP frames without a full MIC libipw_michael_mic_verify() assumes that an skb contains an eight-byte Michael MIC. A short TKIP frame makes the unsigned payload length wrap, causing michael_mic() to read past the skb. Check that the MIC is present before verifying it, and use the existing MICHAEL_MIC_LEN constant for all MIC lengths in the verifier.
In the Linux kernel, the following vulnerability has been resolved: wifi: wcn36xx: Fix potential use-after-free in TX ack timer teardown wcn36xx_dxe_deinit() tears down the TX ack timer with timer_delete(), which only dequeues the timer and does not wait for a callback that is already executing; the preceding free_irq() calls synchronize the interrupt handlers only. The callback, wcn36xx_dxe_tx_timer(), can therefore be running past the teardown and use the wcn freed along with the ieee80211_hw in wcn36xx_remove(): it takes wcn->dxe_lock, reads wcn->tx_ack_skb and passes wcn->hw to ieee80211_tx_status_irqsafe(). Fix this by using timer_shutdown_sync(), which waits for a running callback and also prevents the timer from being rearmed again. The timer is set up again by wcn36xx_dxe_init() on the next start, so the start/stop cycle is unaffected. This issue was found by an in-house static analysis tool.
In the Linux kernel, the following vulnerability has been resolved: wifi: mac80211: refuse to make a monitor active when it has no queue A monitor interface only gets a TXQ if it's created active, and one can't be added later. Setting the flag on a down interface is still allowed, so the driver is handed a monitor with no queue. ath9k dereferences it: BUG: kernel NULL pointer dereference, address: 0000000000000066 RIP: 0010:ath_tx_node_init+0x49/0x170 [ath9k] ath9k_add_interface+0x10c/0x140 [ath9k] drv_add_interface+0x54/0x250 [mac80211] ieee80211_do_open+0x32f/0x800 [mac80211] Reached with CAP_NET_ADMIN by "iw dev X set monitor active" followed by "ip link set X up". RTNL is held, so netlink operations block behind it. Refuse the flag when there is no queue to give.
In the Linux kernel, the following vulnerability has been resolved: drm/amdgpu: fix rmmio iounmap skipped on device removal amdgpu_pci_remove() calls drm_dev_unplug() before fini_sw(), so drm_dev_enter() is already false there and the iounmap() guarded by it is skipped. This .remove path runs on both hot-unplug and plain rmmod, so the register BAR ioremap mapping leaks one instance per unload. Unmap rmmio unconditionally (guard only on non-NULL) and drop the now unused idx. (cherry picked from commit dd6f86a97260e5207d3329ad03aa89fdad61b1e6)
In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_nat: unregister and release hooks on error If nf_hook_entries_insert_raw() fails, the NAT hooks get never released, resulting in a memleak. Postpone setting nat_proto_net->nat_hook_ops when the hooks are registered to simplify the error path to decide whether the nat hooks need unwinding.
In the Linux kernel, the following vulnerability has been resolved: drm/msm/dp: skip PUSH_IDLE when the link was never enabled msm_dp_display_atomic_enable() returns early when link training fails, leaving ->power_on false and the main link down. msm_dp_display_atomic_disable() nevertheless writes DP_STATE_CTRL_PUSH_IDLE and waits for an idle-pattern completion that cannot arrive, so every failed enable is followed by "PUSH_IDLE pattern timedout". Every other step of the teardown is already gated on that flag: msm_dp_display_disable(), called from .atomic_post_disable(), returns early on !power_on. The PUSH_IDLE write is the only one that is not, so the controller's runtime-PM reference is then dropped without the link having been taken down. On glymur (Snapdragon X2 Elite) the consequence is not a warning. The SoC does not survive it: TrustZone force-stops the SOCCP and ADSP remote processors and the machine resets silently about 50 ms later, with no oops and no panic. On an ASUS Zenbook A16 (UX3607OA), whose eDP panel does not currently train, this reproduces without any compositor or GPU involvement: # eDP enable has already failed with "Failed link training (rc=-104)" echo 1 > /sys/class/graphics/fb0/blank [535.645455] === marker === [535.694833] qcom_q6v5_pas d00000.remoteproc: fatal error received: \ sys_m_smsm.c:512:TZ force stop [535.694875] remoteproc remoteproc0: crash detected in soccp: type fatal error [535.728857] qcom_q6v5_pas 6800000.remoteproc: fatal error received: \ sys_m_smsm.c:783:err fatal notification received from TZ <SoC reset> Gate the PUSH_IDLE write on ->power_on so the disable path is consistent with the rest of the teardown. With this applied the same sequence is harmless and the machine stays up; without it, it resets every time. The unconditional write dates back to the original DP driver (c943b4948b58 ("drm/msm/dp: add displayPort driver support")), but the surrounding code has been restructured several times since, so no Fixes: tag is offered. Note that the eDP link-training failure that exposes this on the A16 is a separate problem in the glymur eDP PHY and is reported separately; this change is about not damaging the machine when training fails, for whatever reason. Tested on ASUS Zenbook A16 (UX3607OA), Snapdragon X2 Elite Extreme, on linux-next next-20260803 and next-20260807. The machine has since been running next-20260807 with this patch as its daily driver. Patchwork: https://patchwork.freedesktop.org/patch/745167/
In the Linux kernel, the following vulnerability has been resolved: net: bcmgenet: restore the hardware filters on open bcmgenet_hfb_init() runs INIT_LIST_HEAD() on priv->rxnfc_list, which drops every rule off the list, and bcmgenet_open() calls it on each ifup. Every rule the user configured is silently lost: # ethtool -N eth0 flow-type ether dst $MAC action 0 Added rule with ID 0 # ethtool -n eth0 | grep -c Filter: 1 # ip link set eth0 down && ip link set eth0 up # ethtool -n eth0 | grep -c Filter: 0 Initialise the lists once at probe and restore the rules on open, as bcmgenet_resume() already does.
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_qca: Do not write to the serial port after it is closed hci_uart_close() closes the serdev port if HCI_QUIRK_NON_PERSISTENT_SETUP is set (for example, for the WCN399x family). A failed hci_dev_open_sync() following a successful qca_setup() calls hdev->close() but not hdev->shutdown(), so the port is closed while power->vregs_on is left true. qca_serdev_remove() then passes its power->vregs_on test and calls qca_power_off(), which writes to the closed port unconditionally. Seen on a WCN3988 by unbinding the driver after a controller failure. The trace below is from a 7.0.0 based kernel, where qca_power_off() was still named qca_power_shutdown(): Unable to handle kernel NULL pointer dereference at virtual address 0000000000000038 Call trace: tty_set_termios+0x50/0x238 (P) ttyport_set_baudrate+0x84/0xc0 serdev_device_set_baudrate+0x24/0x40 qca_power_shutdown+0x158/0x1fc [hci_uart] qca_serdev_remove+0x54/0x68 [hci_uart] serdev_drv_remove+0x1c/0x2c device_remove+0x4c/0x80 device_release_driver_internal+0x1cc/0x224 device_driver_detach+0x18/0x24 unbind_store+0xb4/0xc0 Check HCI_UART_PROTO_READY, which hci_uart_close() clears in the same place it closes the port, before writing to it. The regulator disable is left unconditional so the controller is still powered down. The dangling serport->tty that turns this into a use-after-free is addressed in a separate patch.
In the Linux kernel, the following vulnerability has been resolved: af_unix: Unify scc_index when finalising SCC in __unix_walk_scc(). Commit bfdb01283ee8 ("af_unix: Assign a unique index to SCC.") changed Tarjan's algorithm to update lowlink with lowlink, which is called lowpoint (unix_vertex.scc_index). unix_vertex_dead() assumes all vertices in an SCC share the same lowpoint, but this is not always true if an SCC has two or more back edges, depending on the order of DFS. For example, the graph below has two back edges from B to A and from C to B. A --> B --> C ^ | ^ | `----' `----' If DFS walks through A -> B -> C -> B (-> C -> B) -> A (-> B -> A), each index and scc_index will be updated as follows. A --> B --> C C = (3, 3) (index, scc_index) B = (2, 2) A = (1, 1) A ... B ... C C = (3, 2)<-. ^ | B = (2, 2) -' `----' A = (1, 1) A ... B ... C C = (3, 2) ^ | . . B = (2, 1)<-. `----' .... A = (1, 1) -' Then, unix_vertex_dead() thinks that B is passed to another SCC with scc_index 2, and the SCC is not garbage-collected. This does not happen if DFS walks in a different order below or starts from B. 1 3 A --> B --> C ^ | ^ | `----' `----' 2 4 Let's unify scc_index across the SCC when finalising it. Note that updating v->index was previously done in unix_scc_dead(), when called from __unix_walk_scc(), just to save one loop. Since __unix_walk_scc() now iterates over the SCC anyway, the update is moved back to __unix_walk_scc() and 'fast' argument is dropped.
In the Linux kernel, the following vulnerability has been resolved: drop_monitor: use timer_shutdown_sync() to prevent timer rearming during teardown In drop_monitor teardown paths (net_dm_trace_off_set(), net_dm_hw_monitor_stop(), and error unwind paths in net_dm_trace_on_set() and net_dm_hw_monitor_start()), per-CPU timers are stopped using timer_delete_sync() followed by cancel_work_sync(). However, there is a circular dependency between send_timer and dm_alert_work: 1) sched_send_work() (timer callback) schedules dm_alert_work. 2) send_dm_alert() / net_dm_hw_summary_work() calls reset_per_cpu_data() or net_dm_hw_reset_per_cpu_data(). 3) If memory allocation fails under memory pressure in the reset function, it re-arms the timer via mod_timer(&data->send_timer, ...). If dm_alert_work is running concurrently while timer_delete_sync() executes on another CPU, an allocation failure in the worker will re-arm the timer after timer_delete_sync() has already returned. Once cancel_work_sync() completes and module_put() is called, the timer remains active in the timer wheel. If the module is then unloaded, the timer will fire and execute sched_send_work() in freed memory, triggering a kernel panic / use-after-free. Switch from timer_delete_sync() to timer_shutdown_sync(). This guarantees that any in-flight timer handler has finished and prevents subsequent re-arming attempts from running workers from succeeding. When monitoring is restarted later, timer_setup() is invoked, which cleanly re-initializes the timer.
In the Linux kernel, the following vulnerability has been resolved: btrfs: handle lack of space when cleaning up verity items When enable_verity() hits the qgroup limit, rollback_verity() needs its own metadata reservation. When the qgroup limit or lack of space refuses the rollback, the whole filesystem is forced read-only even though the qgroup limit was for one subvolume only. Also orphan cleanup at the next mount fails the same way, so the leftover items are never removed: with -EDQUOT the subvolume stays unreachable, and with -ENOSPC on a full filesystem the next read-write mount fails. Start transactions with btrfs_start_transaction_fallback_global_rsv() in btrfs_orphan_cleanup(), drop_verity_items() and rollback_verity(). Those calls only delete items and free the space in the end, so they may use the global reserve and skip the qgroup limit, which avoids -ENOSPC and -EDQUOT.
In the Linux kernel, the following vulnerability has been resolved: net: psp: avoid conflicts with skb->decrypted and sk_validate_xmit_skb() PSP conflicts with TLS ULP in its usage of both skb->decrypted and sk->sk_validate_xmit_skb(). Make PSP mutually exclusive with TLS ULP, the only other user of either of these. As other users of skb->decrypted come along, they can be added to sk_has_decrypt_user(). It would make sense to also assert that sk->sk_validate_xmit_skb() is also NULL in both of these setup paths for similar future proofing, but the PSP listener/sk_clone() path is still broken and it could be seen as a regression to not allow rx assoc to run on a child of a listener socket with PSP tx assoc state. Include all TCP ULPs in the sk_has_decrypt_user() check, even though TLS is the only one that conflicts with PSP via the decrypted bit. This is intentional because PSP was not designed to be used with ULPs. It is best to close off surface area that may make bugs reachable, until someone wishes to design and test an actual user of PSP with ULPs.
In the Linux kernel, the following vulnerability has been resolved: x86/kprobes: Fix crash when probing CS CALL instructions When using eBPF to probe CS CALL instructions within a function, a crash can be triggered. The eBPF tool probes offset 257 of the __hrtimer_run_queues() function: <__hrtimer_run_queues+249>: nopl 0x0(%rax,%rax,1) <__hrtimer_run_queues+254>: mov %r14,%rdi <__hrtimer_run_queues+257>: cs call <__x86_indirect_thunk_r12> <__hrtimer_run_queues+263>: mov %eax,%r12d <__hrtimer_run_queues+266>: xchg %ax,%ax <__hrtimer_run_queues+268>: mov %r13,%rdi Which triggers this crash: BUG: unable to handle page fault for address: 00000000000f41c9 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 0 P4D 0 Oops: 0002 [#1] SMP NOPTI CPU: 1 PID: 0 Comm: swapper/1 Kdump: loaded Tainted: P RIP: 0010:__hrtimer_run_queues+0x106/0x230 Note that __hrtimer_run_queues+0x106 is __hrtimer_run_queues+262, which is at the 6th byte of the above CS CALL instruction. Since the CS CALL instruction occupies 6 bytes, the exception occurred in the middle of that call instruction. The root cause is that when using eBPF tools to probe in the middle of a function, a kprobe with INT3 is used as the underlying implementation. During single-step emulation of the original CALL instruction, int3_emulate_call() assumes that the probed CALL instruction is 5 bytes long. However, the actual CS-prefixed CALL instruction occupies 6 bytes, so it constructs an incorrect exception return address. When the CPU returns from the kprobe handler, the next instruction to be executed is at the address of the last byte of that CS CALL instruction. Coincidentally, starting from that address, the CPU fetches and decodes a completely different instruction, which ultimately triggers a kernel crash. Fix the issue by using the actual instruction length obtained from the instruction decoder when constructing the exception return address, rather than relying on the hardcoded CALL_INSN_SIZE macro. [ mingo: Refined the changelog ]
In the Linux kernel, the following vulnerability has been resolved: mm, swap: fix SWAP_USAGE_OFFLIST_BIT collision with real usage count SWAP_USAGE_OFFLIST_BIT is embedded in the si->inuse_pages usage counter, and is meant to sit above any value that counter can reach. However, it is defined from BITS_PER_TYPE(atomic_t), so it is bit 30. On a system with 4 KiB pages the flag collides with the usage count once that count reaches 4 TiB. swap_usage_in_pages() masks bit 30 out, so whenever the real count has that bit set, every caller of it reads 4 TiB low: * /proc/swaps understates Used by 4 TiB. * A raw count of exactly 2^30 masks to zero, so try_to_unuse() takes its "if (!swap_usage_in_pages(si)) goto success;" early exit and swapoff tears the device down while pages are still swapped out. Nothing in the rest of swapoff aborts the teardown, so those pages are lost. Independently of swapoff, the collision also corrupts the counter and the plist. On a device in normal use, a free that leaves bit 30 set in the count makes swap_usage_sub() see the flag where there is only count, and call add_to_avail_list(). It clears the bit with fetch_and(~SWAP_USAGE_OFFLIST_BIT), leaving the stored count 4 TiB below the real one, and calls plist_add() on a device that is already listed, tripping the WARN_ON(!plist_node_empty(node)) in plist_add() and linking the node a second time. Change the definition of SWAP_USAGE_OFFLIST_BIT to be based on atomic_long_t instead. Note that the usage counter field itself is of this same type, so it is still a valid bit.
In the Linux kernel, the following vulnerability has been resolved: mm/vma: correctly unaccount on mmap_prepare() failure __mmap_setup() accounts memory for relevant mappings via: security_vm_enough_memory_mm() -> __vm_enough_memory() -> vm_acct_memory() If __mmap_setup() fails, this indicates that this accounting did not take place, and thus it's appropriate for __mmap_region() to jump to abort_munmap. However if call_mmap_prepare() fails, it also jumps there and any accounted memory is not correctly unaccounted. Fix this by handling each error separately.
In the Linux kernel, the following vulnerability has been resolved: mm: filemap: retain mapped dropbehind folios Fault-around can map ready dropbehind folios without going through the normal page-cache lookup that clears dropbehind. A mapping represents a competing cached user, so retain the folio instead of forcibly unmapping it when writeback completes. For a mapped folio, folio_unmap_invalidate() can call unmap_mapping_folio(), which takes i_mmap_rwsem and may sleep. Retaining mapped folios avoids this path when folio_end_dropbehind() runs in non-preemptible task context. Tal was able to trigger a sleeping-in-atomic warning due to this [1]. Unmapped dropbehind folios continue through the existing invalidation path.
In the Linux kernel, the following vulnerability has been resolved: xfrm: fix compat ALLOCSPI request use-after-free xfrm_state_netlink() builds the ALLOCSPI response with dump_one_state(), which already calls alloc_compat() with the response skb and header. xfrm_alloc_userspi() then calls alloc_compat() again, but passes the original request skb and its header. For a compat request, the translator therefore interprets the 228-byte compat xfrm_userspi_info as the 232-byte native layout and reads four bytes past the declared payload. It also publishes the translated child through the request's frag_list. A multicast clone of the request shares skb_shared_info and can observe that child. xfrm_user_rcv_msg() frees it after the request handler returns, racing a compat receiver which may still be copying from it and resulting in a use-after-free. Remove the redundant conversion. The response keeps its correct compat translation from dump_one_state(), and no child is attached to the inbound request.
In the Linux kernel, the following vulnerability has been resolved: firmware: arm_scpi: reject DVFS OPP count above MAX_DVFS_OPPS scpi_dvfs_get_info() already rejected a zero opp_count, but still trusted any larger value from the SCP firmware. The shared-memory reply only holds MAX_DVFS_OPPS entries in buf.opps[]; a bigger count over-reads that array and then sizes the allocated OPP table incorrectly (garbage OPPs / OOB). The missing upper bound dates back to the original SCPI DVFS support. Reject zero and out-of-range counts in one check and return -EINVAL.
In the Linux kernel, the following vulnerability has been resolved: clk: scpi: bound-check DVFS index in scpi_dvfs_recalc_rate dvfs_get_idx() may return an out-of-range index if the SCP firmware is buggy or returns a stale value. Only negative indexes were rejected, so a large index walked past info->opps and could treat garbage as a clock rate (KASAN OOB / wrong frequency to consumers). The missing upper bound dates back to the original SCPI clock driver. Treat indexes >= opp count as invalid and return 0, same as idx < 0.
In the Linux kernel, the following vulnerability has been resolved: RDMA/mad: Fix receive buffer leak when PKey enforcement fails ib_mad_complete_recv() initializes mad_recv_wc->rmpp_list and then runs ib_mad_enforce_security() before linking recv_buf onto that list. On failure it calls ib_free_recv_mad(), which only walks rmpp_list and frees the ib_mad_private of every buffer found there. As the list is still empty at that point, nothing is freed at all. The caller cannot clean up either: ib_mad_recv_done() sets recv to NULL right after ib_mad_complete_recv() returns, assuming the MAD layer took ownership of the buffer. Every MAD that fails the PKey check therefore leaks one ib_mad_private (about 300 bytes per IB port MAD, ~2K for OPA), and a remote node can trigger this repeatedly by sending MADs with a wrong PKey. Link recv_buf onto rmpp_list right after the list is initialized, so the error path has something to free.
In the Linux kernel, the following vulnerability has been resolved: wifi: virt_wifi: free skb when disconnected When the simulated link is disconnected, virt_wifi_start_xmit() returns NET_XMIT_DROP without freeing the skb. dev_hard_start_xmit() treats this return value as consumed, so every packet sent while disconnected leaks its skb. Free the skb before returning the drop status.
In the Linux kernel, the following vulnerability has been resolved: RDMA/rtrs-clt: Fix CQ pool leak when connect is interrupted The client borrows shared CQ credits in the ADDR_RESOLVED handler via ib_cq_pool_get(), before the peer is connected. create_cm() can return -ERESTARTSYS from wait_event_interruptible_timeout() without destroying the CM ID. The init_conns() and stop-and-destroy paths then call destroy_con_cq_qp() while cq is still NULL (no PUT) and only afterwards rdma_destroy_id(). CMA serializes the handler against rdma_destroy_id() with handler_mutex, but that does not order the GET against destroy_con_cq_qp(). If ADDR_RESOLVED has already passed the DESTROYING check, it can take con_mutex, GET credits, and then lose the con to kfree. Device unregister later hits WARN_ON(cq->cqe_used) in ib_cq_pool_cleanup(). Set a per-connection flag under con_mutex before CQ/QP teardown so a racing ADDR_RESOLVED cannot borrow credits after teardown has begun.
In the Linux kernel, the following vulnerability has been resolved: IB/iser: reject a remote invalidation of an unregistered direction A write command whose data is sent entirely as immediate data is not registered. iser_reg_mem_fastreg() takes the DMA key path and leaves rdma_reg[ISER_DIR_OUT].desc at NULL, while iser_dma_map_task_data() has already set dir[ISER_DIR_OUT]. iser_check_remote_inv() looks at dir[] alone and hands the descriptor to iser_inv_desc(), which reads desc->sig_protected. A target that answers such a command with IB_WR_SEND_WITH_INV faults the initiator. Leaving those commands unregistered is deliberate. The same function already terminates the connection when a target sends a remote invalidation the initiator did not ask for. A target that invalidates a direction that was never registered is in the same class, so give it the same answer. Oops: general protection fault, probably for non-canonical address 0xdffffc0000000004: 0000 [#1] SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000020-0x0000000000000027] CPU: 0 UID: 0 PID: 40 Comm: kworker/u8:2 Not tainted 7.2.0-rc5-ISERHOST-gf5098b6bae76-dirty #3 PREEMPT(lazy) Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Workqueue: rxe_wq do_work RIP: 0010:iser_task_rsp+0x6d6/0xec0 Code: 48 c1 ea 03 80 3c 02 00 0f 85 ba 06 00 00 48 8b 9b 78 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 8d 7b 20 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 06 0f 8e 76 06 00 00 80 7b 20 00 0f 84 3d 04 RSP: 0018:ffff88811b008db8 EFLAGS: 00010202 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000001848 RDX: 0000000000000004 RSI: 1ffff11021587b12 RDI: 0000000000000020 RBP: ffff88810adc1ae4 R08: ffff888109b7f860 R09: ffffffff90a922c0 R10: ffff88810adc1a1c R11: 000000000000003c R12: ffff888109b7f800 R13: ffff88810adc1acc R14: ffff888109b7f820 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff88818a676000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000005afe2b CR3: 000000010af23005 CR4: 0000000000770ef0 PKRU: 55555554 Call Trace: <IRQ> __ib_process_cq+0xe1/0x390 ib_poll_handler+0x6e/0x200 irq_poll_softirq+0x1df/0x480 ? clockevents_program_event+0x2ba/0x860 ? __pfx_irq_poll_softirq+0x10/0x10 handle_softirqs+0x18e/0x590 ? __pfx_handle_softirqs+0x10/0x10 ? __hrtimer_rearm_deferred+0x156/0x450 do_softirq+0x3b/0x60 </IRQ> <TASK> __local_bh_enable_ip+0x61/0x70 __alloc_skb+0x732/0x890 ? _raw_spin_lock_irqsave+0x85/0xe0 ? __pfx___alloc_skb+0x10/0x10 ? _raw_read_unlock_irqrestore+0x16/0x50 rxe_init_packet+0x16b/0x4f0 prepare_ack_packet+0xb8/0x830 rxe_receiver+0x499/0x9980 ? __pfx_rxe_receiver+0x10/0x10 ? rxe_completer+0x29e5/0x38c0 ? hrtimer_start_range_ns_common+0x75f/0x1730 ? hrtimer_start_range_ns+0xa6/0x2c0 ? __pfx__raw_spin_lock_irqsave+0x10/0x10 ? __pfx_rxe_receiver+0x10/0x10 do_work+0x144/0x470 process_one_work+0x633/0x1030 ? assign_work+0x11d/0x370 worker_thread+0x45b/0xd10 ? __pfx_worker_thread+0x10/0x10 kthread+0x2c6/0x3b0 ? recalc_sigpending+0x15c/0x1e0 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x36e/0x5a0 ? __pfx_ret_from_fork+0x10/0x10 ? __switch_to+0x572/0xdd0 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1a/0x30 </TASK> Modules linked in: ---[ end trace 0000000000000000 ]---
In the Linux kernel, the following vulnerability has been resolved: wifi: cfg80211: ibss: ref BSS entry for joined event When the IBSS is joined, we only record the BSSID/channel in the event and look up the BSS entry when processing it. However, that's racy, e.g. a new scan with NL80211_SCAN_FLAG_FLUSH can remove it, causing a warning in the event work: !bss WARNING: net/wireless/ibss.c:37 at __cfg80211_ibss_joined+0x3d3/0x440 Workqueue: cfg80211 cfg80211_event_work cfg80211_process_wdev_events+0x39f/0x5b0 net/wireless/util.c:1144 cfg80211_process_rdev_events+0xa1/0x110 net/wireless/util.c:1179 cfg80211_event_work+0x2f/0x40 net/wireless/core.c:393 Do the lookup early (the driver is expected to only join an IBSS that has a BSS entry) and keep a reference to it.
In the Linux kernel, the following vulnerability has been resolved: wifi: mac80211: reset the LED state when ifup fails When the first interface comes up, the radio LED is turned on. This can start the TPT trigger timer, which continues running. But if bringing up the interface fails then the timer keeps running and won't be stopped by anything, eventually it can be freed: ODEBUG: free active (active state 0) object: ffff888127e12130 object type: timer_list hint: tpt_trig_timer+0x0/0x300 net/mac80211/led.c:145 WARNING: CPU: 0 PID: 5923 at lib/debugobjects.c:612 debug_print_object+0x1a2/0x2b0 debug_check_no_obj_freed+0x4b7/0x600 lib/debugobjects.c:1129 kfree+0x436/0x670 mm/slub.c:6818 ieee80211_led_exit+0x162/0x1c0 net/mac80211/led.c:210 ieee80211_unregister_hw+0x27e/0x3a0 net/mac80211/main.c:1706 rt2x00lib_remove_dev+0x55b/0x670 Undo the LED state in the error path.
In the Linux kernel, the following vulnerability has been resolved: wifi: mac80211: only operate on TDLS peers in the TDLS code ieee80211_tdls_oper() can operate on the AP station, which then yields various warnings when the AP station is removed then or at a later point in time after being confused for a TDLS peer. Always check that the station is a TDLS peer.
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: btmtksdio, btmtkuart: validate WMT event length before struct access btmtksdio.c and btmtkuart.c cast a received WMT event straight to struct btmtk_hci_wmt_evt and read its op/flag fields without checking the event is long enough to contain them, unlike btmtk.c. The FUNC_CTRL case then further casts to struct btmtk_hci_wmt_evt_funcc and reads its 2-byte status field, again without a length check. Firmware that sends a short or malformed WMT event makes both drivers read past the end of the received SKB. Mirror btmtk.c: validate the base WMT header with skb_pull_data() before touching any of its fields, and when a FUNC_CTRL event turns out to be the short, header-only form (a plain enable/disable ack with no status word), decode the result from the header's own flag byte instead (0 = success, otherwise failure). Verified setup on MT7920, MT7921, MT7922 and MT7925: no regression.
In the Linux kernel, the following vulnerability has been resolved: net: stmmac: fix TSO header length truncation stmmac_tso_xmit() stores the protocol header length returned by stmmac_tso_header_size() in a u8. stmmac_tso_valid_packet() admits headers up to 1023 bytes, so a header longer than 255 bytes wraps modulo 256 (486 becomes 230, 256 becomes 0). A TCP over IPv6 socket carrying a few hundred bytes of sticky destination/hop-by-hop options makes skb_tcp_all_headers() exceed 255 while staying below the 1023-byte limit, so such an skb reaches stmmac_tso_xmit(). Widen proto_hdr_len to unsigned int, which is sufficient since the value is bounded by the hardware limit, and adjust the debug print specifier accordingly.
In the Linux kernel, the following vulnerability has been resolved: net: bridge: vlan: fix bugs caused by switchdev deletion errors Allowing switchdev to prevent vlan deletion and error out in __vlan_del could cause multiple different issues - inconsistent state, memory leaks when flushing, NULL pointer dereference on bridge error when flushing. It doesn't make sense to allow it to stop __vlan_del, so log the error and continue with software vlan deletion. This is also consistent with 8021q behaviour.
In the Linux kernel, the following vulnerability has been resolved: netlink: do not free nlk->groups while lockless readers can use it netlink_realloc_groups() uses krealloc() under netlink_table_grab(). Whenever NLGRPSZ(groups) lands in a different kmalloc bucket, the old bitmap is freed immediately. Two readers of nlk->groups / nlk->ngroups do not hold the netlink table lock: 1) sk_diag_dump_groups(). Hashed (bound) sockets are dumped from the rhashtable walk in __netlink_diag_dump(), which only holds RCU. Only the mc_list part of the dump takes nl_table_lock. 2) netlink_native_seq_show() (/proc/net/netlink), whose walk has been lockless since commit 21e4902aea80 ("netlink: Lockless lookup with RCU grace period in socket release"). Both can read a freed buffer, and sk_diag_dump_groups() can also read past the end of the old (smaller) buffer if it happens to load the old @groups pointer together with the new @ngroups value, copying the result into a NETLINK_DIAG_GROUPS attribute. This is the same class of bug that commit f773608026ee ("netlink: access nlk groups safely in netlink bind and getname") fixed for bind() and getname(); these two readers were missed. Simply grabbing the table lock in sk_diag_dump_groups() is not an option, because it is also called with nl_table_lock already held from the mc_list section of the dump. Make the lockless readers safe instead: - Allocate a new bitmap and free the old one after an RCU grace period, instead of relying on the implicit kfree() done by krealloc(). - Publish @groups before @ngroups, both with release semantics, and have the lockless readers load @ngroups first. A reader can then never pair the new (bigger) size with the old (smaller) buffer, and a reader picking up the new pointer while still seeing the old size is guaranteed to see the initialized bitmap. netlink_realloc_groups() is called from process context (bind() and setsockopt()), so kfree_rcu_mightsleep() can be used, once the table has been released.