In the Linux kernel, the following vulnerability has been resolved: HID: intel-ish-hid: Fix use-after-free issue in ishtp_hid_remove() The system can experience a random crash a few minutes after the driver is removed. This issue occurs due to improper handling of memory freeing in the ishtp_hid_remove() function. The function currently frees the `driver_data` directly within the loop that destroys the HID devices, which can lead to accessing freed memory. Specifically, `hid_destroy_device()` uses `driver_data` when it calls `hid_ishtp_set_feature()` to power off the sensor, so freeing `driver_data` beforehand can result in accessing invalid memory. This patch resolves the issue by storing the `driver_data` in a temporary variable before calling `hid_destroy_device()`, and then freeing the `driver_data` after the device is destroyed.

In the Linux kernel, the following vulnerability has been resolved: ipvlan: Fix use-after-free in ipvlan_get_iflink(). syzbot presented an use-after-free report [0] regarding ipvlan and linkwatch. ipvlan does not hold a refcnt of the lower device unlike vlan and macvlan. If the linkwatch work is triggered for the ipvlan dev, the lower dev might have already been freed, resulting in UAF of ipvlan->phy_dev in ipvlan_get_iflink(). We can delay the lower dev unregistration like vlan and macvlan by holding the lower dev's refcnt in dev->netdev_ops->ndo_init() and releasing it in dev->priv_destructor(). Jakub pointed out calling .ndo_XXX after unregister_netdevice() has returned is error prone and suggested [1] addressing this UAF in the core by taking commit 750e51603395 ("net: avoid potential UAF in default_operstate()") further. Let's assume unregistering devices DOWN and use RCU protection in default_operstate() not to race with the device unregistration. [0]: BUG: KASAN: slab-use-after-free in ipvlan_get_iflink+0x84/0x88 drivers/net/ipvlan/ipvlan_main.c:353 Read of size 4 at addr ffff0000d768c0e0 by task kworker/u8:35/6944 CPU: 0 UID: 0 PID: 6944 Comm: kworker/u8:35 Not tainted 6.13.0-rc2-g9bc5c9515b48 #12 4c3cb9e8b4565456f6a355f312ff91f4f29b3c47 Hardware name: linux,dummy-virt (DT) Workqueue: events_unbound linkwatch_event Call trace: show_stack+0x38/0x50 arch/arm64/kernel/stacktrace.c:484 (C) __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0xbc/0x108 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0x16c/0x6f0 mm/kasan/report.c:489 kasan_report+0xc0/0x120 mm/kasan/report.c:602 __asan_report_load4_noabort+0x20/0x30 mm/kasan/report_generic.c:380 ipvlan_get_iflink+0x84/0x88 drivers/net/ipvlan/ipvlan_main.c:353 dev_get_iflink+0x7c/0xd8 net/core/dev.c:674 default_operstate net/core/link_watch.c:45 [inline] rfc2863_policy+0x144/0x360 net/core/link_watch.c:72 linkwatch_do_dev+0x60/0x228 net/core/link_watch.c:175 __linkwatch_run_queue+0x2f4/0x5b8 net/core/link_watch.c:239 linkwatch_event+0x64/0xa8 net/core/link_watch.c:282 process_one_work+0x700/0x1398 kernel/workqueue.c:3229 process_scheduled_works kernel/workqueue.c:3310 [inline] worker_thread+0x8c4/0xe10 kernel/workqueue.c:3391 kthread+0x2b0/0x360 kernel/kthread.c:389 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:862 Allocated by task 9303: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x30/0x68 mm/kasan/common.c:68 kasan_save_alloc_info+0x44/0x58 mm/kasan/generic.c:568 poison_kmalloc_redzone mm/kasan/common.c:377 [inline] __kasan_kmalloc+0x84/0xa0 mm/kasan/common.c:394 kasan_kmalloc include/linux/kasan.h:260 [inline] __do_kmalloc_node mm/slub.c:4283 [inline] __kmalloc_node_noprof+0x2a0/0x560 mm/slub.c:4289 __kvmalloc_node_noprof+0x9c/0x230 mm/util.c:650 alloc_netdev_mqs+0xb4/0x1118 net/core/dev.c:11209 rtnl_create_link+0x2b8/0xb60 net/core/rtnetlink.c:3595 rtnl_newlink_create+0x19c/0x868 net/core/rtnetlink.c:3771 __rtnl_newlink net/core/rtnetlink.c:3896 [inline] rtnl_newlink+0x122c/0x15c0 net/core/rtnetlink.c:4011 rtnetlink_rcv_msg+0x61c/0x918 net/core/rtnetlink.c:6901 netlink_rcv_skb+0x1dc/0x398 net/netlink/af_netlink.c:2542 rtnetlink_rcv+0x34/0x50 net/core/rtnetlink.c:6928 netlink_unicast_kernel net/netlink/af_netlink.c:1321 [inline] netlink_unicast+0x618/0x838 net/netlink/af_netlink.c:1347 netlink_sendmsg+0x5fc/0x8b0 net/netlink/af_netlink.c:1891 sock_sendmsg_nosec net/socket.c:711 [inline] __sock_sendmsg net/socket.c:726 [inline] __sys_sendto+0x2ec/0x438 net/socket.c:2197 __do_sys_sendto net/socket.c:2204 [inline] __se_sys_sendto net/socket.c:2200 [inline] __arm64_sys_sendto+0xe4/0x110 net/socket.c:2200 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x90/0x278 arch/arm64/kernel/syscall.c:49 el0_svc_common+0x13c/0x250 arch/arm64/kernel/syscall.c:132 do_el0_svc+0x54/0x70 arch/arm64/kernel/syscall.c:151 el ---truncated---

In the Linux kernel, the following vulnerability has been resolved: netem: Update sch->q.qlen before qdisc_tree_reduce_backlog() qdisc_tree_reduce_backlog() notifies parent qdisc only if child qdisc becomes empty, therefore we need to reduce the backlog of the child qdisc before calling it. Otherwise it would miss the opportunity to call cops->qlen_notify(), in the case of DRR, it resulted in UAF since DRR uses ->qlen_notify() to maintain its active list.

In the Linux kernel, the following vulnerability has been resolved: nfsd: fix management of listener transports Currently, when no active threads are running, a root user using nfsdctl command can try to remove a particular listener from the list of previously added ones, then start the server by increasing the number of threads, it leads to the following problem: [ 158.835354] refcount_t: addition on 0; use-after-free. [ 158.835603] WARNING: CPU: 2 PID: 9145 at lib/refcount.c:25 refcount_warn_saturate+0x160/0x1a0 [ 158.836017] Modules linked in: rpcrdma rdma_cm iw_cm ib_cm ib_core nfsd auth_rpcgss nfs_acl lockd grace overlay isofs uinput snd_seq_dummy snd_hrtimer nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_ct nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 rfkill ip_set nf_tables qrtr sunrpc vfat fat uvcvideo videobuf2_vmalloc videobuf2_memops uvc videobuf2_v4l2 videodev videobuf2_common snd_hda_codec_generic mc e1000e snd_hda_intel snd_intel_dspcfg snd_hda_codec snd_hda_core snd_hwdep snd_seq snd_seq_device snd_pcm snd_timer snd soundcore sg loop dm_multipath dm_mod nfnetlink vsock_loopback vmw_vsock_virtio_transport_common vmw_vsock_vmci_transport vmw_vmci vsock xfs libcrc32c crct10dif_ce ghash_ce vmwgfx sha2_ce sha256_arm64 sr_mod sha1_ce cdrom nvme drm_client_lib drm_ttm_helper ttm nvme_core drm_kms_helper nvme_auth drm fuse [ 158.840093] CPU: 2 UID: 0 PID: 9145 Comm: nfsd Kdump: loaded Tainted: G B W 6.13.0-rc6+ #7 [ 158.840624] Tainted: [B]=BAD_PAGE, [W]=WARN [ 158.840802] Hardware name: VMware, Inc. VMware20,1/VBSA, BIOS VMW201.00V.24006586.BA64.2406042154 06/04/2024 [ 158.841220] pstate: 61400005 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--) [ 158.841563] pc : refcount_warn_saturate+0x160/0x1a0 [ 158.841780] lr : refcount_warn_saturate+0x160/0x1a0 [ 158.842000] sp : ffff800089be7d80 [ 158.842147] x29: ffff800089be7d80 x28: ffff00008e68c148 x27: ffff00008e68c148 [ 158.842492] x26: ffff0002e3b5c000 x25: ffff600011cd1829 x24: ffff00008653c010 [ 158.842832] x23: ffff00008653c000 x22: 1fffe00011cd1829 x21: ffff00008653c028 [ 158.843175] x20: 0000000000000002 x19: ffff00008653c010 x18: 0000000000000000 [ 158.843505] x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000 [ 158.843836] x14: 0000000000000000 x13: 0000000000000001 x12: ffff600050a26493 [ 158.844143] x11: 1fffe00050a26492 x10: ffff600050a26492 x9 : dfff800000000000 [ 158.844475] x8 : 00009fffaf5d9b6e x7 : ffff000285132493 x6 : 0000000000000001 [ 158.844823] x5 : ffff000285132490 x4 : ffff600050a26493 x3 : ffff8000805e72bc [ 158.845174] x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff000098588000 [ 158.845528] Call trace: [ 158.845658] refcount_warn_saturate+0x160/0x1a0 (P) [ 158.845894] svc_recv+0x58c/0x680 [sunrpc] [ 158.846183] nfsd+0x1fc/0x348 [nfsd] [ 158.846390] kthread+0x274/0x2f8 [ 158.846546] ret_from_fork+0x10/0x20 [ 158.846714] ---[ end trace 0000000000000000 ]--- nfsd_nl_listener_set_doit() would manipulate the list of transports of server's sv_permsocks and close the specified listener but the other list of transports (server's sp_xprts list) would not be changed leading to the problem above. Instead, determined if the nfsdctl is trying to remove a listener, in which case, delete all the existing listener transports and re-create all-but-the-removed ones.

In the Linux kernel, the following vulnerability has been resolved: igb: Fix use-after-free error during reset Cleans the next descriptor to watch (next_to_watch) when cleaning the TX ring. Failure to do so can cause invalid memory accesses. If igb_poll() runs while the controller is reset this can lead to the driver try to free a skb that was already freed. (The crash is harder to reproduce with the igb driver, but the same potential problem exists as the code is identical to igc)

In the Linux kernel, the following vulnerability has been resolved: btrfs: fix use-after-free on inode when scanning root during em shrinking At btrfs_scan_root() we are accessing the inode's root (and fs_info) in a call to btrfs_fs_closing() after we have scheduled the inode for a delayed iput, and that can result in a use-after-free on the inode in case the cleaner kthread does the iput before we dereference the inode in the call to btrfs_fs_closing(). Fix this by using the fs_info stored already in a local variable instead of doing inode->root->fs_info.

In the Linux kernel, the following vulnerability has been resolved: ndisc: use RCU protection in ndisc_alloc_skb() ndisc_alloc_skb() can be called without RTNL or RCU being held. Add RCU protection to avoid possible UAF.

In the Linux kernel, the following vulnerability has been resolved: zram: fix potential UAF of zram table If zram_meta_alloc failed early, it frees allocated zram->table without setting it NULL. Which will potentially cause zram_meta_free to access the table if user reset an failed and uninitialized device.

In the Linux kernel, the following vulnerability has been resolved: HID: hid-steam: Fix use-after-free when detaching device When a hid-steam device is removed it must clean up the client_hdev used for intercepting hidraw access. This can lead to scheduling deferred work to reattach the input device. Though the cleanup cancels the deferred work, this was done before the client_hdev itself is cleaned up, so it gets rescheduled. This patch fixes the ordering to make sure the deferred work is properly canceled.

In the Linux kernel, the following vulnerability has been resolved: wifi: rtw89: fix race between cancel_hw_scan and hw_scan completion The rtwdev->scanning flag isn't protected by mutex originally, so cancel_hw_scan can pass the condition, but suddenly hw_scan completion unset the flag and calls ieee80211_scan_completed() that will free local->hw_scan_req. Then, cancel_hw_scan raises null-ptr-deref and use-after-free. Fix it by moving the check condition to where protected by mutex. KASAN: null-ptr-deref in range [0x0000000000000088-0x000000000000008f] CPU: 2 PID: 6922 Comm: kworker/2:2 Tainted: G OE Hardware name: LENOVO 2356AD1/2356AD1, BIOS G7ETB6WW (2.76 ) 09/10/2019 Workqueue: events cfg80211_conn_work [cfg80211] RIP: 0010:rtw89_fw_h2c_scan_offload_be+0xc33/0x13c3 [rtw89_core] Code: 00 45 89 6c 24 1c 0f 85 23 01 00 00 48 8b 85 20 ff ff ff 48 8d RSP: 0018:ffff88811fd9f068 EFLAGS: 00010206 RAX: dffffc0000000000 RBX: ffff88811fd9f258 RCX: 0000000000000001 RDX: 0000000000000011 RSI: 0000000000000001 RDI: 0000000000000089 RBP: ffff88811fd9f170 R08: 0000000000000000 R09: 0000000000000000 R10: ffff88811fd9f108 R11: 0000000000000000 R12: ffff88810e47f960 R13: 0000000000000000 R14: 000000000000ffff R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881d6f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007531dfca55b0 CR3: 00000001be296004 CR4: 00000000001706e0 Call Trace: <TASK> ? show_regs+0x61/0x73 ? __die_body+0x20/0x73 ? die_addr+0x4f/0x7b ? exc_general_protection+0x191/0x1db ? asm_exc_general_protection+0x27/0x30 ? rtw89_fw_h2c_scan_offload_be+0xc33/0x13c3 [rtw89_core] ? rtw89_fw_h2c_scan_offload_be+0x458/0x13c3 [rtw89_core] ? __pfx_rtw89_fw_h2c_scan_offload_be+0x10/0x10 [rtw89_core] ? do_raw_spin_lock+0x75/0xdb ? __pfx_do_raw_spin_lock+0x10/0x10 rtw89_hw_scan_offload+0xb5e/0xbf7 [rtw89_core] ? _raw_spin_unlock+0xe/0x24 ? __mutex_lock.constprop.0+0x40c/0x471 ? __pfx_rtw89_hw_scan_offload+0x10/0x10 [rtw89_core] ? __mutex_lock_slowpath+0x13/0x1f ? mutex_lock+0xa2/0xdc ? __pfx_mutex_lock+0x10/0x10 rtw89_hw_scan_abort+0x58/0xb7 [rtw89_core] rtw89_ops_cancel_hw_scan+0x120/0x13b [rtw89_core] ieee80211_scan_cancel+0x468/0x4d0 [mac80211] ieee80211_prep_connection+0x858/0x899 [mac80211] ieee80211_mgd_auth+0xbea/0xdde [mac80211] ? __pfx_ieee80211_mgd_auth+0x10/0x10 [mac80211] ? cfg80211_find_elem+0x15/0x29 [cfg80211] ? is_bss+0x1b7/0x1d7 [cfg80211] ieee80211_auth+0x18/0x27 [mac80211] cfg80211_mlme_auth+0x3bb/0x3e7 [cfg80211] cfg80211_conn_do_work+0x410/0xb81 [cfg80211] ? __pfx_cfg80211_conn_do_work+0x10/0x10 [cfg80211] ? __kasan_check_read+0x11/0x1f ? psi_group_change+0x8bc/0x944 ? __kasan_check_write+0x14/0x22 ? mutex_lock+0x8e/0xdc ? __pfx_mutex_lock+0x10/0x10 ? __pfx___radix_tree_lookup+0x10/0x10 cfg80211_conn_work+0x245/0x34d [cfg80211] ? __pfx_cfg80211_conn_work+0x10/0x10 [cfg80211] ? update_cfs_rq_load_avg+0x3bc/0x3d7 ? sched_clock_noinstr+0x9/0x1a ? sched_clock+0x10/0x24 ? sched_clock_cpu+0x7e/0x42e ? newidle_balance+0x796/0x937 ? __pfx_sched_clock_cpu+0x10/0x10 ? __pfx_newidle_balance+0x10/0x10 ? __kasan_check_read+0x11/0x1f ? psi_group_change+0x8bc/0x944 ? _raw_spin_unlock+0xe/0x24 ? raw_spin_rq_unlock+0x47/0x54 ? raw_spin_rq_unlock_irq+0x9/0x1f ? finish_task_switch.isra.0+0x347/0x586 ? __schedule+0x27bf/0x2892 ? mutex_unlock+0x80/0xd0 ? do_raw_spin_lock+0x75/0xdb ? __pfx___schedule+0x10/0x10 process_scheduled_works+0x58c/0x821 worker_thread+0x4c7/0x586 ? __kasan_check_read+0x11/0x1f kthread+0x285/0x294 ? __pfx_worker_thread+0x10/0x10 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x29/0x6f ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1b/0x30 </TASK>

In the Linux kernel, the following vulnerability has been resolved: RDMA/core: Fix use-after-free when rename device name Syzbot reported a slab-use-after-free with the following call trace: ================================================================== BUG: KASAN: slab-use-after-free in nla_put+0xd3/0x150 lib/nlattr.c:1099 Read of size 5 at addr ffff888140ea1c60 by task syz.0.988/10025 CPU: 0 UID: 0 PID: 10025 Comm: syz.0.988 Not tainted 6.14.0-rc4-syzkaller-00859-gf77f12010f67 #0 Hardware name: Google Compute Engine, BIOS Google 02/12/2025 Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:408 [inline] print_report+0x16e/0x5b0 mm/kasan/report.c:521 kasan_report+0x143/0x180 mm/kasan/report.c:634 kasan_check_range+0x282/0x290 mm/kasan/generic.c:189 __asan_memcpy+0x29/0x70 mm/kasan/shadow.c:105 nla_put+0xd3/0x150 lib/nlattr.c:1099 nla_put_string include/net/netlink.h:1621 [inline] fill_nldev_handle+0x16e/0x200 drivers/infiniband/core/nldev.c:265 rdma_nl_notify_event+0x561/0xef0 drivers/infiniband/core/nldev.c:2857 ib_device_notify_register+0x22/0x230 drivers/infiniband/core/device.c:1344 ib_register_device+0x1292/0x1460 drivers/infiniband/core/device.c:1460 rxe_register_device+0x233/0x350 drivers/infiniband/sw/rxe/rxe_verbs.c:1540 rxe_net_add+0x74/0xf0 drivers/infiniband/sw/rxe/rxe_net.c:550 rxe_newlink+0xde/0x1a0 drivers/infiniband/sw/rxe/rxe.c:212 nldev_newlink+0x5ea/0x680 drivers/infiniband/core/nldev.c:1795 rdma_nl_rcv_skb drivers/infiniband/core/netlink.c:239 [inline] rdma_nl_rcv+0x6dd/0x9e0 drivers/infiniband/core/netlink.c:259 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline] netlink_unicast+0x7f6/0x990 net/netlink/af_netlink.c:1339 netlink_sendmsg+0x8de/0xcb0 net/netlink/af_netlink.c:1883 sock_sendmsg_nosec net/socket.c:709 [inline] __sock_sendmsg+0x221/0x270 net/socket.c:724 ____sys_sendmsg+0x53a/0x860 net/socket.c:2564 ___sys_sendmsg net/socket.c:2618 [inline] __sys_sendmsg+0x269/0x350 net/socket.c:2650 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f42d1b8d169 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 ... RSP: 002b:00007f42d2960038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f42d1da6320 RCX: 00007f42d1b8d169 RDX: 0000000000000000 RSI: 00004000000002c0 RDI: 000000000000000c RBP: 00007f42d1c0e2a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f42d1da6320 R15: 00007ffe399344a8 </TASK> Allocated by task 10025: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:377 [inline] __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:394 kasan_kmalloc include/linux/kasan.h:260 [inline] __do_kmalloc_node mm/slub.c:4294 [inline] __kmalloc_node_track_caller_noprof+0x28b/0x4c0 mm/slub.c:4313 __kmemdup_nul mm/util.c:61 [inline] kstrdup+0x42/0x100 mm/util.c:81 kobject_set_name_vargs+0x61/0x120 lib/kobject.c:274 dev_set_name+0xd5/0x120 drivers/base/core.c:3468 assign_name drivers/infiniband/core/device.c:1202 [inline] ib_register_device+0x178/0x1460 drivers/infiniband/core/device.c:1384 rxe_register_device+0x233/0x350 drivers/infiniband/sw/rxe/rxe_verbs.c:1540 rxe_net_add+0x74/0xf0 drivers/infiniband/sw/rxe/rxe_net.c:550 rxe_newlink+0xde/0x1a0 drivers/infiniband/sw/rxe/rxe.c:212 nldev_newlink+0x5ea/0x680 drivers/infiniband/core/nldev.c:1795 rdma_nl_rcv_skb drivers/infiniband/core/netlink.c:239 [inline] rdma_nl_rcv+0x6dd/0x9e0 drivers/infiniband/core/netlink.c:259 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline] netlink_unicast+0x7f6/0x990 net/netlink/af_netlink.c:1339 netlink_sendmsg+0x8de/0xcb0 net ---truncated---

In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix use-after-free in smb2_lock If smb_lock->zero_len has value, ->llist of smb_lock is not delete and flock is old one. It will cause use-after-free on error handling routine.

In the Linux kernel, the following vulnerability has been resolved: drm/vkms: Fix use after free and double free on init error If the driver initialization fails, the vkms_exit() function might access an uninitialized or freed default_config pointer and it might double free it. Fix both possible errors by initializing default_config only when the driver initialization succeeded.

In the Linux kernel, the following vulnerability has been resolved: ipv6: mcast: extend RCU protection in igmp6_send() igmp6_send() can be called without RTNL or RCU being held. Extend RCU protection so that we can safely fetch the net pointer and avoid a potential UAF. Note that we no longer can use sock_alloc_send_skb() because ipv6.igmp_sk uses GFP_KERNEL allocations which can sleep. Instead use alloc_skb() and charge the net->ipv6.igmp_sk socket under RCU protection.

In the Linux kernel, the following vulnerability has been resolved: padata: avoid UAF for reorder_work Although the previous patch can avoid ps and ps UAF for _do_serial, it can not avoid potential UAF issue for reorder_work. This issue can happen just as below: crypto_request crypto_request crypto_del_alg padata_do_serial ... padata_reorder // processes all remaining // requests then breaks while (1) { if (!padata) break; ... } padata_do_serial // new request added list_add // sees the new request queue_work(reorder_work) padata_reorder queue_work_on(squeue->work) ... <kworker context> padata_serial_worker // completes new request, // no more outstanding // requests crypto_del_alg // free pd <kworker context> invoke_padata_reorder // UAF of pd To avoid UAF for 'reorder_work', get 'pd' ref before put 'reorder_work' into the 'serial_wq' and put 'pd' ref until the 'serial_wq' finish.

In the Linux kernel, the following vulnerability has been resolved: neighbour: use RCU protection in __neigh_notify() __neigh_notify() can be called without RTNL or RCU protection. Use RCU protection to avoid potential UAF.

In the Linux kernel, the following vulnerability has been resolved: workqueue: Put the pwq after detaching the rescuer from the pool The commit 68f83057b913("workqueue: Reap workers via kthread_stop() and remove detach_completion") adds code to reap the normal workers but mistakenly does not handle the rescuer and also removes the code waiting for the rescuer in put_unbound_pool(), which caused a use-after-free bug reported by Cheung Wall. To avoid the use-after-free bug, the pool’s reference must be held until the detachment is complete. Therefore, move the code that puts the pwq after detaching the rescuer from the pool.

In the Linux kernel, the following vulnerability has been resolved: padata: fix UAF in padata_reorder A bug was found when run ltp test: BUG: KASAN: slab-use-after-free in padata_find_next+0x29/0x1a0 Read of size 4 at addr ffff88bbfe003524 by task kworker/u113:2/3039206 CPU: 0 PID: 3039206 Comm: kworker/u113:2 Kdump: loaded Not tainted 6.6.0+ Workqueue: pdecrypt_parallel padata_parallel_worker Call Trace: <TASK> dump_stack_lvl+0x32/0x50 print_address_description.constprop.0+0x6b/0x3d0 print_report+0xdd/0x2c0 kasan_report+0xa5/0xd0 padata_find_next+0x29/0x1a0 padata_reorder+0x131/0x220 padata_parallel_worker+0x3d/0xc0 process_one_work+0x2ec/0x5a0 If 'mdelay(10)' is added before calling 'padata_find_next' in the 'padata_reorder' function, this issue could be reproduced easily with ltp test (pcrypt_aead01). This can be explained as bellow: pcrypt_aead_encrypt ... padata_do_parallel refcount_inc(&pd->refcnt); // add refcnt ... padata_do_serial padata_reorder // pd while (1) { padata_find_next(pd, true); // using pd queue_work_on ... padata_serial_worker crypto_del_alg padata_put_pd_cnt // sub refcnt padata_free_shell padata_put_pd(ps->pd); // pd is freed // loop again, but pd is freed // call padata_find_next, UAF } In the padata_reorder function, when it loops in 'while', if the alg is deleted, the refcnt may be decreased to 0 before entering 'padata_find_next', which leads to UAF. As mentioned in [1], do_serial is supposed to be called with BHs disabled and always happen under RCU protection, to address this issue, add synchronize_rcu() in 'padata_free_shell' wait for all _do_serial calls to finish. [1] https://lore.kernel.org/all/20221028160401.cccypv4euxikusiq@parnassus.localdomain/ [2] https://lore.kernel.org/linux-kernel/jfjz5d7zwbytztackem7ibzalm5lnxldi2eofeiczqmqs2m7o6@fq426cwnjtkm/

In the Linux kernel, the following vulnerability has been resolved: net/mlx5e: Fix use-after-free of encap entry in neigh update handler Function mlx5e_rep_neigh_update() wasn't updated to accommodate rtnl lock removal from TC filter update path and properly handle concurrent encap entry insertion/deletion which can lead to following use-after-free: [23827.464923] ================================================================== [23827.469446] BUG: KASAN: use-after-free in mlx5e_encap_take+0x72/0x140 [mlx5_core] [23827.470971] Read of size 4 at addr ffff8881d132228c by task kworker/u20:6/21635 [23827.472251] [23827.472615] CPU: 9 PID: 21635 Comm: kworker/u20:6 Not tainted 5.13.0-rc3+ #5 [23827.473788] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 [23827.475639] Workqueue: mlx5e mlx5e_rep_neigh_update [mlx5_core] [23827.476731] Call Trace: [23827.477260] dump_stack+0xbb/0x107 [23827.477906] print_address_description.constprop.0+0x18/0x140 [23827.478896] ? mlx5e_encap_take+0x72/0x140 [mlx5_core] [23827.479879] ? mlx5e_encap_take+0x72/0x140 [mlx5_core] [23827.480905] kasan_report.cold+0x7c/0xd8 [23827.481701] ? mlx5e_encap_take+0x72/0x140 [mlx5_core] [23827.482744] kasan_check_range+0x145/0x1a0 [23827.493112] mlx5e_encap_take+0x72/0x140 [mlx5_core] [23827.494054] ? mlx5e_tc_tun_encap_info_equal_generic+0x140/0x140 [mlx5_core] [23827.495296] mlx5e_rep_neigh_update+0x41e/0x5e0 [mlx5_core] [23827.496338] ? mlx5e_rep_neigh_entry_release+0xb80/0xb80 [mlx5_core] [23827.497486] ? read_word_at_a_time+0xe/0x20 [23827.498250] ? strscpy+0xa0/0x2a0 [23827.498889] process_one_work+0x8ac/0x14e0 [23827.499638] ? lockdep_hardirqs_on_prepare+0x400/0x400 [23827.500537] ? pwq_dec_nr_in_flight+0x2c0/0x2c0 [23827.501359] ? rwlock_bug.part.0+0x90/0x90 [23827.502116] worker_thread+0x53b/0x1220 [23827.502831] ? process_one_work+0x14e0/0x14e0 [23827.503627] kthread+0x328/0x3f0 [23827.504254] ? _raw_spin_unlock_irq+0x24/0x40 [23827.505065] ? __kthread_bind_mask+0x90/0x90 [23827.505912] ret_from_fork+0x1f/0x30 [23827.506621] [23827.506987] Allocated by task 28248: [23827.507694] kasan_save_stack+0x1b/0x40 [23827.508476] __kasan_kmalloc+0x7c/0x90 [23827.509197] mlx5e_attach_encap+0xde1/0x1d40 [mlx5_core] [23827.510194] mlx5e_tc_add_fdb_flow+0x397/0xc40 [mlx5_core] [23827.511218] __mlx5e_add_fdb_flow+0x519/0xb30 [mlx5_core] [23827.512234] mlx5e_configure_flower+0x191c/0x4870 [mlx5_core] [23827.513298] tc_setup_cb_add+0x1d5/0x420 [23827.514023] fl_hw_replace_filter+0x382/0x6a0 [cls_flower] [23827.514975] fl_change+0x2ceb/0x4a51 [cls_flower] [23827.515821] tc_new_tfilter+0x89a/0x2070 [23827.516548] rtnetlink_rcv_msg+0x644/0x8c0 [23827.517300] netlink_rcv_skb+0x11d/0x340 [23827.518021] netlink_unicast+0x42b/0x700 [23827.518742] netlink_sendmsg+0x743/0xc20 [23827.519467] sock_sendmsg+0xb2/0xe0 [23827.520131] ____sys_sendmsg+0x590/0x770 [23827.520851] ___sys_sendmsg+0xd8/0x160 [23827.521552] __sys_sendmsg+0xb7/0x140 [23827.522238] do_syscall_64+0x3a/0x70 [23827.522907] entry_SYSCALL_64_after_hwframe+0x44/0xae [23827.523797] [23827.524163] Freed by task 25948: [23827.524780] kasan_save_stack+0x1b/0x40 [23827.525488] kasan_set_track+0x1c/0x30 [23827.526187] kasan_set_free_info+0x20/0x30 [23827.526968] __kasan_slab_free+0xed/0x130 [23827.527709] slab_free_freelist_hook+0xcf/0x1d0 [23827.528528] kmem_cache_free_bulk+0x33a/0x6e0 [23827.529317] kfree_rcu_work+0x55f/0xb70 [23827.530024] process_one_work+0x8ac/0x14e0 [23827.530770] worker_thread+0x53b/0x1220 [23827.531480] kthread+0x328/0x3f0 [23827.532114] ret_from_fork+0x1f/0x30 [23827.532785] [23827.533147] Last potentially related work creation: [23827.534007] kasan_save_stack+0x1b/0x40 [23827.534710] kasan_record_aux_stack+0xab/0xc0 [23827.535492] kvfree_call_rcu+0x31/0x7b0 [23827.536206] mlx5e_tc_del ---truncated---

In the Linux kernel, the following vulnerability has been resolved: net: sched: Disallow replacing of child qdisc from one parent to another Lion Ackermann was able to create a UAF which can be abused for privilege escalation with the following script Step 1. create root qdisc tc qdisc add dev lo root handle 1:0 drr step2. a class for packet aggregation do demonstrate uaf tc class add dev lo classid 1:1 drr step3. a class for nesting tc class add dev lo classid 1:2 drr step4. a class to graft qdisc to tc class add dev lo classid 1:3 drr step5. tc qdisc add dev lo parent 1:1 handle 2:0 plug limit 1024 step6. tc qdisc add dev lo parent 1:2 handle 3:0 drr step7. tc class add dev lo classid 3:1 drr step 8. tc qdisc add dev lo parent 3:1 handle 4:0 pfifo step 9. Display the class/qdisc layout tc class ls dev lo class drr 1:1 root leaf 2: quantum 64Kb class drr 1:2 root leaf 3: quantum 64Kb class drr 3:1 root leaf 4: quantum 64Kb tc qdisc ls qdisc drr 1: dev lo root refcnt 2 qdisc plug 2: dev lo parent 1:1 qdisc pfifo 4: dev lo parent 3:1 limit 1000p qdisc drr 3: dev lo parent 1:2 step10. trigger the bug <=== prevented by this patch tc qdisc replace dev lo parent 1:3 handle 4:0 step 11. Redisplay again the qdiscs/classes tc class ls dev lo class drr 1:1 root leaf 2: quantum 64Kb class drr 1:2 root leaf 3: quantum 64Kb class drr 1:3 root leaf 4: quantum 64Kb class drr 3:1 root leaf 4: quantum 64Kb tc qdisc ls qdisc drr 1: dev lo root refcnt 2 qdisc plug 2: dev lo parent 1:1 qdisc pfifo 4: dev lo parent 3:1 refcnt 2 limit 1000p qdisc drr 3: dev lo parent 1:2 Observe that a) parent for 4:0 does not change despite the replace request. There can only be one parent. b) refcount has gone up by two for 4:0 and c) both class 1:3 and 3:1 are pointing to it. Step 12. send one packet to plug echo "" | socat -u STDIN UDP4-DATAGRAM:127.0.0.1:8888,priority=$((0x10001)) step13. send one packet to the grafted fifo echo "" | socat -u STDIN UDP4-DATAGRAM:127.0.0.1:8888,priority=$((0x10003)) step14. lets trigger the uaf tc class delete dev lo classid 1:3 tc class delete dev lo classid 1:1 The semantics of "replace" is for a del/add _on the same node_ and not a delete from one node(3:1) and add to another node (1:3) as in step10. While we could "fix" with a more complex approach there could be consequences to expectations so the patch takes the preventive approach of "disallow such config". Joint work with Lion Ackermann <nnamrec@gmail.com>

In the Linux kernel, the following vulnerability has been resolved: mm: zswap: properly synchronize freeing resources during CPU hotunplug In zswap_compress() and zswap_decompress(), the per-CPU acomp_ctx of the current CPU at the beginning of the operation is retrieved and used throughout. However, since neither preemption nor migration are disabled, it is possible that the operation continues on a different CPU. If the original CPU is hotunplugged while the acomp_ctx is still in use, we run into a UAF bug as some of the resources attached to the acomp_ctx are freed during hotunplug in zswap_cpu_comp_dead() (i.e. acomp_ctx.buffer, acomp_ctx.req, or acomp_ctx.acomp). The problem was introduced in commit 1ec3b5fe6eec ("mm/zswap: move to use crypto_acomp API for hardware acceleration") when the switch to the crypto_acomp API was made. Prior to that, the per-CPU crypto_comp was retrieved using get_cpu_ptr() which disables preemption and makes sure the CPU cannot go away from under us. Preemption cannot be disabled with the crypto_acomp API as a sleepable context is needed. Use the acomp_ctx.mutex to synchronize CPU hotplug callbacks allocating and freeing resources with compression/decompression paths. Make sure that acomp_ctx.req is NULL when the resources are freed. In the compression/decompression paths, check if acomp_ctx.req is NULL after acquiring the mutex (meaning the CPU was offlined) and retry on the new CPU. The initialization of acomp_ctx.mutex is moved from the CPU hotplug callback to the pool initialization where it belongs (where the mutex is allocated). In addition to adding clarity, this makes sure that CPU hotplug cannot reinitialize a mutex that is already locked by compression/decompression. Previously a fix was attempted by holding cpus_read_lock() [1]. This would have caused a potential deadlock as it is possible for code already holding the lock to fall into reclaim and enter zswap (causing a deadlock). A fix was also attempted using SRCU for synchronization, but Johannes pointed out that synchronize_srcu() cannot be used in CPU hotplug notifiers [2]. Alternative fixes that were considered/attempted and could have worked: - Refcounting the per-CPU acomp_ctx. This involves complexity in handling the race between the refcount dropping to zero in zswap_[de]compress() and the refcount being re-initialized when the CPU is onlined. - Disabling migration before getting the per-CPU acomp_ctx [3], but that's discouraged and is a much bigger hammer than needed, and could result in subtle performance issues. [1]https://lkml.kernel.org/20241219212437.2714151-1-yosryahmed@google.com/ [2]https://lkml.kernel.org/20250107074724.1756696-2-yosryahmed@google.com/ [3]https://lkml.kernel.org/20250107222236.2715883-2-yosryahmed@google.com/ [yosryahmed@google.com: remove comment]

In the Linux kernel, the following vulnerability has been resolved: ublk: make sure ubq->canceling is set when queue is frozen Now ublk driver depends on `ubq->canceling` for deciding if the request can be dispatched via uring_cmd & io_uring_cmd_complete_in_task(). Once ubq->canceling is set, the uring_cmd can be done via ublk_cancel_cmd() and io_uring_cmd_done(). So set ubq->canceling when queue is frozen, this way makes sure that the flag can be observed from ublk_queue_rq() reliably, and avoids use-after-free on uring_cmd.

In the Linux kernel, the following vulnerability has been resolved: mm/migrate_device: don't add folio to be freed to LRU in migrate_device_finalize() If migration succeeded, we called folio_migrate_flags()->mem_cgroup_migrate() to migrate the memcg from the old to the new folio. This will set memcg_data of the old folio to 0. Similarly, if migration failed, memcg_data of the dst folio is left unset. If we call folio_putback_lru() on such folios (memcg_data == 0), we will add the folio to be freed to the LRU, making memcg code unhappy. Running the hmm selftests: # ./hmm-tests ... # RUN hmm.hmm_device_private.migrate ... [ 102.078007][T14893] page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x7ff27d200 pfn:0x13cc00 [ 102.079974][T14893] anon flags: 0x17ff00000020018(uptodate|dirty|swapbacked|node=0|zone=2|lastcpupid=0x7ff) [ 102.082037][T14893] raw: 017ff00000020018 dead000000000100 dead000000000122 ffff8881353896c9 [ 102.083687][T14893] raw: 00000007ff27d200 0000000000000000 00000001ffffffff 0000000000000000 [ 102.085331][T14893] page dumped because: VM_WARN_ON_ONCE_FOLIO(!memcg && !mem_cgroup_disabled()) [ 102.087230][T14893] ------------[ cut here ]------------ [ 102.088279][T14893] WARNING: CPU: 0 PID: 14893 at ./include/linux/memcontrol.h:726 folio_lruvec_lock_irqsave+0x10e/0x170 [ 102.090478][T14893] Modules linked in: [ 102.091244][T14893] CPU: 0 UID: 0 PID: 14893 Comm: hmm-tests Not tainted 6.13.0-09623-g6c216bc522fd #151 [ 102.093089][T14893] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-2.fc40 04/01/2014 [ 102.094848][T14893] RIP: 0010:folio_lruvec_lock_irqsave+0x10e/0x170 [ 102.096104][T14893] Code: ... [ 102.099908][T14893] RSP: 0018:ffffc900236c37b0 EFLAGS: 00010293 [ 102.101152][T14893] RAX: 0000000000000000 RBX: ffffea0004f30000 RCX: ffffffff8183f426 [ 102.102684][T14893] RDX: ffff8881063cb880 RSI: ffffffff81b8117f RDI: ffff8881063cb880 [ 102.104227][T14893] RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000 [ 102.105757][T14893] R10: 0000000000000001 R11: 0000000000000002 R12: ffffc900236c37d8 [ 102.107296][T14893] R13: ffff888277a2bcb0 R14: 000000000000001f R15: 0000000000000000 [ 102.108830][T14893] FS: 00007ff27dbdd740(0000) GS:ffff888277a00000(0000) knlGS:0000000000000000 [ 102.110643][T14893] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 102.111924][T14893] CR2: 00007ff27d400000 CR3: 000000010866e000 CR4: 0000000000750ef0 [ 102.113478][T14893] PKRU: 55555554 [ 102.114172][T14893] Call Trace: [ 102.114805][T14893] <TASK> [ 102.115397][T14893] ? folio_lruvec_lock_irqsave+0x10e/0x170 [ 102.116547][T14893] ? __warn.cold+0x110/0x210 [ 102.117461][T14893] ? folio_lruvec_lock_irqsave+0x10e/0x170 [ 102.118667][T14893] ? report_bug+0x1b9/0x320 [ 102.119571][T14893] ? handle_bug+0x54/0x90 [ 102.120494][T14893] ? exc_invalid_op+0x17/0x50 [ 102.121433][T14893] ? asm_exc_invalid_op+0x1a/0x20 [ 102.122435][T14893] ? __wake_up_klogd.part.0+0x76/0xd0 [ 102.123506][T14893] ? dump_page+0x4f/0x60 [ 102.124352][T14893] ? folio_lruvec_lock_irqsave+0x10e/0x170 [ 102.125500][T14893] folio_batch_move_lru+0xd4/0x200 [ 102.126577][T14893] ? __pfx_lru_add+0x10/0x10 [ 102.127505][T14893] __folio_batch_add_and_move+0x391/0x720 [ 102.128633][T14893] ? __pfx_lru_add+0x10/0x10 [ 102.129550][T14893] folio_putback_lru+0x16/0x80 [ 102.130564][T14893] migrate_device_finalize+0x9b/0x530 [ 102.131640][T14893] dmirror_migrate_to_device.constprop.0+0x7c5/0xad0 [ 102.133047][T14893] dmirror_fops_unlocked_ioctl+0x89b/0xc80 Likely, nothing else goes wrong: putting the last folio reference will remove the folio from the LRU again. So besides memcg complaining, adding the folio to be freed to the LRU is just an unnecessary step. The new flow resembles what we have in migrate_folio_move(): add the dst to the lru, rem ---truncated---

In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix session use-after-free in multichannel connection There is a race condition between session setup and ksmbd_sessions_deregister. The session can be freed before the connection is added to channel list of session. This patch check reference count of session before freeing it.

A use-after-free vulnerability in the Linux kernel's netfilter: nf_tables component can be exploited to achieve local privilege escalation. When nf_tables_delrule() is flushing table rules, it is not checked whether the chain is bound and the chain's owner rule can also release the objects in certain circumstances. We recommend upgrading past commit 6eaf41e87a223ae6f8e7a28d6e78384ad7e407f8.

In the Linux kernel, the following vulnerability has been resolved: btrfs: fix use-after-free after failure to create a snapshot At ioctl.c:create_snapshot(), we allocate a pending snapshot structure and then attach it to the transaction's list of pending snapshots. After that we call btrfs_commit_transaction(), and if that returns an error we jump to 'fail' label, where we kfree() the pending snapshot structure. This can result in a later use-after-free of the pending snapshot: 1) We allocated the pending snapshot and added it to the transaction's list of pending snapshots; 2) We call btrfs_commit_transaction(), and it fails either at the first call to btrfs_run_delayed_refs() or btrfs_start_dirty_block_groups(). In both cases, we don't abort the transaction and we release our transaction handle. We jump to the 'fail' label and free the pending snapshot structure. We return with the pending snapshot still in the transaction's list; 3) Another task commits the transaction. This time there's no error at all, and then during the transaction commit it accesses a pointer to the pending snapshot structure that the snapshot creation task has already freed, resulting in a user-after-free. This issue could actually be detected by smatch, which produced the following warning: fs/btrfs/ioctl.c:843 create_snapshot() warn: '&pending_snapshot->list' not removed from list So fix this by not having the snapshot creation ioctl directly add the pending snapshot to the transaction's list. Instead add the pending snapshot to the transaction handle, and then at btrfs_commit_transaction() we add the snapshot to the list only when we can guarantee that any error returned after that point will result in a transaction abort, in which case the ioctl code can safely free the pending snapshot and no one can access it anymore.

In the Linux kernel, the following vulnerability has been resolved: sctp: do asoc update earlier in sctp_sf_do_dupcook_a There's a panic that occurs in a few of envs, the call trace is as below: [] general protection fault, ... 0x29acd70f1000a: 0000 [#1] SMP PTI [] RIP: 0010:sctp_ulpevent_notify_peer_addr_change+0x4b/0x1fa [sctp] [] sctp_assoc_control_transport+0x1b9/0x210 [sctp] [] sctp_do_8_2_transport_strike.isra.16+0x15c/0x220 [sctp] [] sctp_cmd_interpreter.isra.21+0x1231/0x1a10 [sctp] [] sctp_do_sm+0xc3/0x2a0 [sctp] [] sctp_generate_timeout_event+0x81/0xf0 [sctp] This is caused by a transport use-after-free issue. When processing a duplicate COOKIE-ECHO chunk in sctp_sf_do_dupcook_a(), both COOKIE-ACK and SHUTDOWN chunks are allocated with the transort from the new asoc. However, later in the sideeffect machine, the old asoc is used to send them out and old asoc's shutdown_last_sent_to is set to the transport that SHUTDOWN chunk attached to in sctp_cmd_setup_t2(), which actually belongs to the new asoc. After the new_asoc is freed and the old asoc T2 timeout, the old asoc's shutdown_last_sent_to that is already freed would be accessed in sctp_sf_t2_timer_expire(). Thanks Alexander and Jere for helping dig into this issue. To fix it, this patch is to do the asoc update first, then allocate the COOKIE-ACK and SHUTDOWN chunks with the 'updated' old asoc. This would make more sense, as a chunk from an asoc shouldn't be sent out with another asoc. We had fixed quite a few issues caused by this.

A use-after-free vulnerability in the Linux kernel's net/sched: cls_u32 component can be exploited to achieve local privilege escalation. If tcf_change_indev() fails, u32_set_parms() will immediately return an error after incrementing or decrementing the reference counter in tcf_bind_filter(). If an attacker can control the reference counter and set it to zero, they can cause the reference to be freed, leading to a use-after-free vulnerability. We recommend upgrading past commit 04c55383fa5689357bcdd2c8036725a55ed632bc.

A use-after-free vulnerability was found in the Linux kernel's netfilter subsystem in net/netfilter/nf_tables_api.c. Mishandled error handling with NFT_MSG_NEWRULE makes it possible to use a dangling pointer in the same transaction causing a use-after-free vulnerability. This flaw allows a local attacker with user access to cause a privilege escalation issue. We recommend upgrading past commit 1240eb93f0616b21c675416516ff3d74798fdc97.

A use-after-free vulnerability in the Linux Kernel io_uring subsystem can be exploited to achieve local privilege escalation. Racing a io_uring cancel poll request with a linked timeout can cause a UAF in a hrtimer. We recommend upgrading past commit ef7dfac51d8ed961b742218f526bd589f3900a59 (4716c73b188566865bdd79c3a6709696a224ac04 for 5.10 stable and 0e388fce7aec40992eadee654193cad345d62663 for 5.15 stable).

In Ubuntu's accountsservice an unprivileged local attacker can trigger a use-after-free vulnerability in accountsservice by sending a D-Bus message to the accounts-daemon process.

In the Linux kernel, the following vulnerability has been resolved: crypto: iaa - Fix potential use after free bug The free_device_compression_mode(iaa_device, device_mode) function frees "device_mode" but it iss passed to iaa_compression_modes[i]->free() a few lines later resulting in a use after free. The good news is that, so far as I can tell, nothing implements the ->free() function and the use after free happens in dead code. But, with this fix, when something does implement it, we'll be ready. :)

A use after free vulnerability was found in prepare_to_relocate in fs/btrfs/relocation.c in btrfs in the Linux Kernel. This possible flaw can be triggered by calling btrfs_ioctl_balance() before calling btrfs_ioctl_defrag().

Linux Kernel nftables Use-After-Free Local Privilege Escalation Vulnerability; `nft_chain_lookup_byid()` failed to check whether a chain was active and CAP_NET_ADMIN is in any user or network namespace

In the Linux kernel, the following vulnerability has been resolved: btrfs: fix a use-after-free when hitting errors inside btrfs_submit_chunk() [BUG] There is an internal report that KASAN is reporting use-after-free, with the following backtrace: BUG: KASAN: slab-use-after-free in btrfs_check_read_bio+0xa68/0xb70 [btrfs] Read of size 4 at addr ffff8881117cec28 by task kworker/u16:2/45 CPU: 1 UID: 0 PID: 45 Comm: kworker/u16:2 Not tainted 6.11.0-rc2-next-20240805-default+ #76 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.2-3-gd478f380-rebuilt.opensuse.org 04/01/2014 Workqueue: btrfs-endio btrfs_end_bio_work [btrfs] Call Trace: dump_stack_lvl+0x61/0x80 print_address_description.constprop.0+0x5e/0x2f0 print_report+0x118/0x216 kasan_report+0x11d/0x1f0 btrfs_check_read_bio+0xa68/0xb70 [btrfs] process_one_work+0xce0/0x12a0 worker_thread+0x717/0x1250 kthread+0x2e3/0x3c0 ret_from_fork+0x2d/0x70 ret_from_fork_asm+0x11/0x20 Allocated by task 20917: kasan_save_stack+0x37/0x60 kasan_save_track+0x10/0x30 __kasan_slab_alloc+0x7d/0x80 kmem_cache_alloc_noprof+0x16e/0x3e0 mempool_alloc_noprof+0x12e/0x310 bio_alloc_bioset+0x3f0/0x7a0 btrfs_bio_alloc+0x2e/0x50 [btrfs] submit_extent_page+0x4d1/0xdb0 [btrfs] btrfs_do_readpage+0x8b4/0x12a0 [btrfs] btrfs_readahead+0x29a/0x430 [btrfs] read_pages+0x1a7/0xc60 page_cache_ra_unbounded+0x2ad/0x560 filemap_get_pages+0x629/0xa20 filemap_read+0x335/0xbf0 vfs_read+0x790/0xcb0 ksys_read+0xfd/0x1d0 do_syscall_64+0x6d/0x140 entry_SYSCALL_64_after_hwframe+0x4b/0x53 Freed by task 20917: kasan_save_stack+0x37/0x60 kasan_save_track+0x10/0x30 kasan_save_free_info+0x37/0x50 __kasan_slab_free+0x4b/0x60 kmem_cache_free+0x214/0x5d0 bio_free+0xed/0x180 end_bbio_data_read+0x1cc/0x580 [btrfs] btrfs_submit_chunk+0x98d/0x1880 [btrfs] btrfs_submit_bio+0x33/0x70 [btrfs] submit_one_bio+0xd4/0x130 [btrfs] submit_extent_page+0x3ea/0xdb0 [btrfs] btrfs_do_readpage+0x8b4/0x12a0 [btrfs] btrfs_readahead+0x29a/0x430 [btrfs] read_pages+0x1a7/0xc60 page_cache_ra_unbounded+0x2ad/0x560 filemap_get_pages+0x629/0xa20 filemap_read+0x335/0xbf0 vfs_read+0x790/0xcb0 ksys_read+0xfd/0x1d0 do_syscall_64+0x6d/0x140 entry_SYSCALL_64_after_hwframe+0x4b/0x53 [CAUSE] Although I cannot reproduce the error, the report itself is good enough to pin down the cause. The call trace is the regular endio workqueue context, but the free-by-task trace is showing that during btrfs_submit_chunk() we already hit a critical error, and is calling btrfs_bio_end_io() to error out. And the original endio function called bio_put() to free the whole bio. This means a double freeing thus causing use-after-free, e.g.: 1. Enter btrfs_submit_bio() with a read bio The read bio length is 128K, crossing two 64K stripes. 2. The first run of btrfs_submit_chunk() 2.1 Call btrfs_map_block(), which returns 64K 2.2 Call btrfs_split_bio() Now there are two bios, one referring to the first 64K, the other referring to the second 64K. 2.3 The first half is submitted. 3. The second run of btrfs_submit_chunk() 3.1 Call btrfs_map_block(), which by somehow failed Now we call btrfs_bio_end_io() to handle the error 3.2 btrfs_bio_end_io() calls the original endio function Which is end_bbio_data_read(), and it calls bio_put() for the original bio. Now the original bio is freed. 4. The submitted first 64K bio finished Now we call into btrfs_check_read_bio() and tries to advance the bio iter. But since the original bio (thus its iter) is already freed, we trigger the above use-after free. And even if the memory is not poisoned/corrupted, we will later call the original endio function, causing a double freeing. [FIX] Instead of calling btrfs_bio_end_io(), call btrfs_orig_bbio_end_io(), which has the extra check on split bios and do the pr ---truncated---

In the Linux kernel, the following vulnerability has been resolved: usb: dwc3: st: fix probed platform device ref count on probe error path The probe function never performs any paltform device allocation, thus error path "undo_platform_dev_alloc" is entirely bogus. It drops the reference count from the platform device being probed. If error path is triggered, this will lead to unbalanced device reference counts and premature release of device resources, thus possible use-after-free when releasing remaining devm-managed resources.

A use after free flaw was found in hfsplus_put_super in fs/hfsplus/super.c in the Linux Kernel. This flaw could allow a local user to cause a denial of service problem.

In the Linux kernel, the following vulnerability has been resolved: sctp: use call_rcu to free endpoint This patch is to delay the endpoint free by calling call_rcu() to fix another use-after-free issue in sctp_sock_dump(): BUG: KASAN: use-after-free in __lock_acquire+0x36d9/0x4c20 Call Trace: __lock_acquire+0x36d9/0x4c20 kernel/locking/lockdep.c:3218 lock_acquire+0x1ed/0x520 kernel/locking/lockdep.c:3844 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline] _raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:168 spin_lock_bh include/linux/spinlock.h:334 [inline] __lock_sock+0x203/0x350 net/core/sock.c:2253 lock_sock_nested+0xfe/0x120 net/core/sock.c:2774 lock_sock include/net/sock.h:1492 [inline] sctp_sock_dump+0x122/0xb20 net/sctp/diag.c:324 sctp_for_each_transport+0x2b5/0x370 net/sctp/socket.c:5091 sctp_diag_dump+0x3ac/0x660 net/sctp/diag.c:527 __inet_diag_dump+0xa8/0x140 net/ipv4/inet_diag.c:1049 inet_diag_dump+0x9b/0x110 net/ipv4/inet_diag.c:1065 netlink_dump+0x606/0x1080 net/netlink/af_netlink.c:2244 __netlink_dump_start+0x59a/0x7c0 net/netlink/af_netlink.c:2352 netlink_dump_start include/linux/netlink.h:216 [inline] inet_diag_handler_cmd+0x2ce/0x3f0 net/ipv4/inet_diag.c:1170 __sock_diag_cmd net/core/sock_diag.c:232 [inline] sock_diag_rcv_msg+0x31d/0x410 net/core/sock_diag.c:263 netlink_rcv_skb+0x172/0x440 net/netlink/af_netlink.c:2477 sock_diag_rcv+0x2a/0x40 net/core/sock_diag.c:274 This issue occurs when asoc is peeled off and the old sk is freed after getting it by asoc->base.sk and before calling lock_sock(sk). To prevent the sk free, as a holder of the sk, ep should be alive when calling lock_sock(). This patch uses call_rcu() and moves sock_put and ep free into sctp_endpoint_destroy_rcu(), so that it's safe to try to hold the ep under rcu_read_lock in sctp_transport_traverse_process(). If sctp_endpoint_hold() returns true, it means this ep is still alive and we have held it and can continue to dump it; If it returns false, it means this ep is dead and can be freed after rcu_read_unlock, and we should skip it. In sctp_sock_dump(), after locking the sk, if this ep is different from tsp->asoc->ep, it means during this dumping, this asoc was peeled off before calling lock_sock(), and the sk should be skipped; If this ep is the same with tsp->asoc->ep, it means no peeloff happens on this asoc, and due to lock_sock, no peeloff will happen either until release_sock. Note that delaying endpoint free won't delay the port release, as the port release happens in sctp_endpoint_destroy() before calling call_rcu(). Also, freeing endpoint by call_rcu() makes it safe to access the sk by asoc->base.sk in sctp_assocs_seq_show() and sctp_rcv(). Thanks Jones to bring this issue up. v1->v2: - improve the changelog. - add kfree(ep) into sctp_endpoint_destroy_rcu(), as Jakub noticed.

In the Linux kernel, the following vulnerability has been resolved: drm/i915/gt: Fix potential UAF by revoke of fence registers CI has been sporadically reporting the following issue triggered by igt@i915_selftest@live@hangcheck on ADL-P and similar machines: <6> [414.049203] i915: Running intel_hangcheck_live_selftests/igt_reset_evict_fence ... <6> [414.068804] i915 0000:00:02.0: [drm] GT0: GUC: submission enabled <6> [414.068812] i915 0000:00:02.0: [drm] GT0: GUC: SLPC enabled <3> [414.070354] Unable to pin Y-tiled fence; err:-4 <3> [414.071282] i915_vma_revoke_fence:301 GEM_BUG_ON(!i915_active_is_idle(&fence->active)) ... <4>[ 609.603992] ------------[ cut here ]------------ <2>[ 609.603995] kernel BUG at drivers/gpu/drm/i915/gt/intel_ggtt_fencing.c:301! <4>[ 609.604003] invalid opcode: 0000 [#1] PREEMPT SMP NOPTI <4>[ 609.604006] CPU: 0 PID: 268 Comm: kworker/u64:3 Tainted: G U W 6.9.0-CI_DRM_14785-g1ba62f8cea9c+ #1 <4>[ 609.604008] Hardware name: Intel Corporation Alder Lake Client Platform/AlderLake-P DDR4 RVP, BIOS RPLPFWI1.R00.4035.A00.2301200723 01/20/2023 <4>[ 609.604010] Workqueue: i915 __i915_gem_free_work [i915] <4>[ 609.604149] RIP: 0010:i915_vma_revoke_fence+0x187/0x1f0 [i915] ... <4>[ 609.604271] Call Trace: <4>[ 609.604273] <TASK> ... <4>[ 609.604716] __i915_vma_evict+0x2e9/0x550 [i915] <4>[ 609.604852] __i915_vma_unbind+0x7c/0x160 [i915] <4>[ 609.604977] force_unbind+0x24/0xa0 [i915] <4>[ 609.605098] i915_vma_destroy+0x2f/0xa0 [i915] <4>[ 609.605210] __i915_gem_object_pages_fini+0x51/0x2f0 [i915] <4>[ 609.605330] __i915_gem_free_objects.isra.0+0x6a/0xc0 [i915] <4>[ 609.605440] process_scheduled_works+0x351/0x690 ... In the past, there were similar failures reported by CI from other IGT tests, observed on other platforms. Before commit 63baf4f3d587 ("drm/i915/gt: Only wait for GPU activity before unbinding a GGTT fence"), i915_vma_revoke_fence() was waiting for idleness of vma->active via fence_update(). That commit introduced vma->fence->active in order for the fence_update() to be able to wait selectively on that one instead of vma->active since only idleness of fence registers was needed. But then, another commit 0d86ee35097a ("drm/i915/gt: Make fence revocation unequivocal") replaced the call to fence_update() in i915_vma_revoke_fence() with only fence_write(), and also added that GEM_BUG_ON(!i915_active_is_idle(&fence->active)) in front. No justification was provided on why we might then expect idleness of vma->fence->active without first waiting on it. The issue can be potentially caused by a race among revocation of fence registers on one side and sequential execution of signal callbacks invoked on completion of a request that was using them on the other, still processed in parallel to revocation of those fence registers. Fix it by waiting for idleness of vma->fence->active in i915_vma_revoke_fence(). (cherry picked from commit 24bb052d3dd499c5956abad5f7d8e4fd07da7fb1)

In the Linux kernel 6.0.8, there is a use-after-free in inode_cgwb_move_to_attached in fs/fs-writeback.c, related to __list_del_entry_valid.

In the Linux kernel, the following vulnerability has been resolved: scsi: mpt3sas: Fix use-after-free warning Fix the following use-after-free warning which is observed during controller reset: refcount_t: underflow; use-after-free. WARNING: CPU: 23 PID: 5399 at lib/refcount.c:28 refcount_warn_saturate+0xa6/0xf0

In the Linux kernel, the following vulnerability has been resolved: iommu: Fix potential use-after-free during probe Kasan has reported the following use after free on dev->iommu. when a device probe fails and it is in process of freeing dev->iommu in dev_iommu_free function, a deferred_probe_work_func runs in parallel and tries to access dev->iommu->fwspec in of_iommu_configure path thus causing use after free. BUG: KASAN: use-after-free in of_iommu_configure+0xb4/0x4a4 Read of size 8 at addr ffffff87a2f1acb8 by task kworker/u16:2/153 Workqueue: events_unbound deferred_probe_work_func Call trace: dump_backtrace+0x0/0x33c show_stack+0x18/0x24 dump_stack_lvl+0x16c/0x1e0 print_address_description+0x84/0x39c __kasan_report+0x184/0x308 kasan_report+0x50/0x78 __asan_load8+0xc0/0xc4 of_iommu_configure+0xb4/0x4a4 of_dma_configure_id+0x2fc/0x4d4 platform_dma_configure+0x40/0x5c really_probe+0x1b4/0xb74 driver_probe_device+0x11c/0x228 __device_attach_driver+0x14c/0x304 bus_for_each_drv+0x124/0x1b0 __device_attach+0x25c/0x334 device_initial_probe+0x24/0x34 bus_probe_device+0x78/0x134 deferred_probe_work_func+0x130/0x1a8 process_one_work+0x4c8/0x970 worker_thread+0x5c8/0xaec kthread+0x1f8/0x220 ret_from_fork+0x10/0x18 Allocated by task 1: ____kasan_kmalloc+0xd4/0x114 __kasan_kmalloc+0x10/0x1c kmem_cache_alloc_trace+0xe4/0x3d4 __iommu_probe_device+0x90/0x394 probe_iommu_group+0x70/0x9c bus_for_each_dev+0x11c/0x19c bus_iommu_probe+0xb8/0x7d4 bus_set_iommu+0xcc/0x13c arm_smmu_bus_init+0x44/0x130 [arm_smmu] arm_smmu_device_probe+0xb88/0xc54 [arm_smmu] platform_drv_probe+0xe4/0x13c really_probe+0x2c8/0xb74 driver_probe_device+0x11c/0x228 device_driver_attach+0xf0/0x16c __driver_attach+0x80/0x320 bus_for_each_dev+0x11c/0x19c driver_attach+0x38/0x48 bus_add_driver+0x1dc/0x3a4 driver_register+0x18c/0x244 __platform_driver_register+0x88/0x9c init_module+0x64/0xff4 [arm_smmu] do_one_initcall+0x17c/0x2f0 do_init_module+0xe8/0x378 load_module+0x3f80/0x4a40 __se_sys_finit_module+0x1a0/0x1e4 __arm64_sys_finit_module+0x44/0x58 el0_svc_common+0x100/0x264 do_el0_svc+0x38/0xa4 el0_svc+0x20/0x30 el0_sync_handler+0x68/0xac el0_sync+0x160/0x180 Freed by task 1: kasan_set_track+0x4c/0x84 kasan_set_free_info+0x28/0x4c ____kasan_slab_free+0x120/0x15c __kasan_slab_free+0x18/0x28 slab_free_freelist_hook+0x204/0x2fc kfree+0xfc/0x3a4 __iommu_probe_device+0x284/0x394 probe_iommu_group+0x70/0x9c bus_for_each_dev+0x11c/0x19c bus_iommu_probe+0xb8/0x7d4 bus_set_iommu+0xcc/0x13c arm_smmu_bus_init+0x44/0x130 [arm_smmu] arm_smmu_device_probe+0xb88/0xc54 [arm_smmu] platform_drv_probe+0xe4/0x13c really_probe+0x2c8/0xb74 driver_probe_device+0x11c/0x228 device_driver_attach+0xf0/0x16c __driver_attach+0x80/0x320 bus_for_each_dev+0x11c/0x19c driver_attach+0x38/0x48 bus_add_driver+0x1dc/0x3a4 driver_register+0x18c/0x244 __platform_driver_register+0x88/0x9c init_module+0x64/0xff4 [arm_smmu] do_one_initcall+0x17c/0x2f0 do_init_module+0xe8/0x378 load_module+0x3f80/0x4a40 __se_sys_finit_module+0x1a0/0x1e4 __arm64_sys_finit_module+0x44/0x58 el0_svc_common+0x100/0x264 do_el0_svc+0x38/0xa4 el0_svc+0x20/0x30 el0_sync_handler+0x68/0xac el0_sync+0x160/0x180 Fix this by setting dev->iommu to NULL first and then freeing dev_iommu structure in dev_iommu_free function.

In the Linux kernel, the following vulnerability has been resolved: net: arc_emac: Fix use after free in arc_mdio_probe() If bus->state is equal to MDIOBUS_ALLOCATED, mdiobus_free(bus) will free the "bus". But bus->name is still used in the next line, which will lead to a use after free. We can fix it by putting the name in a local variable and make the bus->name point to the rodata section "name",then use the name in the error message without referring to bus to avoid the uaf.

In the Linux kernel, the following vulnerability has been resolved: s390/qeth: fix use-after-free in hsci KASAN found that addr was dereferenced after br2dev_event_work was freed. ================================================================== BUG: KASAN: use-after-free in qeth_l2_br2dev_worker+0x5ba/0x6b0 Read of size 1 at addr 00000000fdcea440 by task kworker/u760:4/540 CPU: 17 PID: 540 Comm: kworker/u760:4 Tainted: G E 6.1.0-20221128.rc7.git1.5aa3bed4ce83.300.fc36.s390x+kasan #1 Hardware name: IBM 8561 T01 703 (LPAR) Workqueue: 0.0.8000_event qeth_l2_br2dev_worker Call Trace: [<000000016944d4ce>] dump_stack_lvl+0xc6/0xf8 [<000000016942cd9c>] print_address_description.constprop.0+0x34/0x2a0 [<000000016942d118>] print_report+0x110/0x1f8 [<0000000167a7bd04>] kasan_report+0xfc/0x128 [<000000016938d79a>] qeth_l2_br2dev_worker+0x5ba/0x6b0 [<00000001673edd1e>] process_one_work+0x76e/0x1128 [<00000001673ee85c>] worker_thread+0x184/0x1098 [<000000016740718a>] kthread+0x26a/0x310 [<00000001672c606a>] __ret_from_fork+0x8a/0xe8 [<00000001694711da>] ret_from_fork+0xa/0x40 Allocated by task 108338: kasan_save_stack+0x40/0x68 kasan_set_track+0x36/0x48 __kasan_kmalloc+0xa0/0xc0 qeth_l2_switchdev_event+0x25a/0x738 atomic_notifier_call_chain+0x9c/0xf8 br_switchdev_fdb_notify+0xf4/0x110 fdb_notify+0x122/0x180 fdb_add_entry.constprop.0.isra.0+0x312/0x558 br_fdb_add+0x59e/0x858 rtnl_fdb_add+0x58a/0x928 rtnetlink_rcv_msg+0x5f8/0x8d8 netlink_rcv_skb+0x1f2/0x408 netlink_unicast+0x570/0x790 netlink_sendmsg+0x752/0xbe0 sock_sendmsg+0xca/0x110 ____sys_sendmsg+0x510/0x6a8 ___sys_sendmsg+0x12a/0x180 __sys_sendmsg+0xe6/0x168 __do_sys_socketcall+0x3c8/0x468 do_syscall+0x22c/0x328 __do_syscall+0x94/0xf0 system_call+0x82/0xb0 Freed by task 540: kasan_save_stack+0x40/0x68 kasan_set_track+0x36/0x48 kasan_save_free_info+0x4c/0x68 ____kasan_slab_free+0x14e/0x1a8 __kasan_slab_free+0x24/0x30 __kmem_cache_free+0x168/0x338 qeth_l2_br2dev_worker+0x154/0x6b0 process_one_work+0x76e/0x1128 worker_thread+0x184/0x1098 kthread+0x26a/0x310 __ret_from_fork+0x8a/0xe8 ret_from_fork+0xa/0x40 Last potentially related work creation: kasan_save_stack+0x40/0x68 __kasan_record_aux_stack+0xbe/0xd0 insert_work+0x56/0x2e8 __queue_work+0x4ce/0xd10 queue_work_on+0xf4/0x100 qeth_l2_switchdev_event+0x520/0x738 atomic_notifier_call_chain+0x9c/0xf8 br_switchdev_fdb_notify+0xf4/0x110 fdb_notify+0x122/0x180 fdb_add_entry.constprop.0.isra.0+0x312/0x558 br_fdb_add+0x59e/0x858 rtnl_fdb_add+0x58a/0x928 rtnetlink_rcv_msg+0x5f8/0x8d8 netlink_rcv_skb+0x1f2/0x408 netlink_unicast+0x570/0x790 netlink_sendmsg+0x752/0xbe0 sock_sendmsg+0xca/0x110 ____sys_sendmsg+0x510/0x6a8 ___sys_sendmsg+0x12a/0x180 __sys_sendmsg+0xe6/0x168 __do_sys_socketcall+0x3c8/0x468 do_syscall+0x22c/0x328 __do_syscall+0x94/0xf0 system_call+0x82/0xb0 Second to last potentially related work creation: kasan_save_stack+0x40/0x68 __kasan_record_aux_stack+0xbe/0xd0 kvfree_call_rcu+0xb2/0x760 kernfs_unlink_open_file+0x348/0x430 kernfs_fop_release+0xc2/0x320 __fput+0x1ae/0x768 task_work_run+0x1bc/0x298 exit_to_user_mode_prepare+0x1a0/0x1a8 __do_syscall+0x94/0xf0 system_call+0x82/0xb0 The buggy address belongs to the object at 00000000fdcea400 which belongs to the cache kmalloc-96 of size 96 The buggy address is located 64 bytes inside of 96-byte region [00000000fdcea400, 00000000fdcea460) The buggy address belongs to the physical page: page:000000005a9c26e8 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0xfdcea flags: 0x3ffff00000000200(slab|node=0|zone=1|lastcpupid=0x1ffff) raw: 3ffff00000000200 0000000000000000 0000000100000122 000000008008cc00 raw: 0000000000000000 0020004100000000 ffffffff00000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: 00000000fdcea300: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc 00000000fdcea380: fb fb fb fb fb fb f ---truncated---

In the Linux kernel, the following vulnerability has been resolved: moxart: fix potential use-after-free on remove path It was reported that the mmc host structure could be accessed after it was freed in moxart_remove(), so fix this by saving the base register of the device and using it instead of the pointer dereference.

In the Linux kernel, the following vulnerability has been resolved: bnxt: prevent skb UAF after handing over to PTP worker When reading the timestamp is required bnxt_tx_int() hands over the ownership of the completed skb to the PTP worker. The skb should not be used afterwards, as the worker may run before the rest of our code and free the skb, leading to a use-after-free. Since dev_kfree_skb_any() accepts NULL make the loss of ownership more obvious and set skb to NULL.

In the Linux kernel, the following vulnerability has been resolved: dmaengine: idxd: Prevent use after free on completion memory On driver unload any pending descriptors are flushed at the time the interrupt is freed: idxd_dmaengine_drv_remove() -> drv_disable_wq() -> idxd_wq_free_irq() -> idxd_flush_pending_descs(). If there are any descriptors present that need to be flushed this flow triggers a "not present" page fault as below: BUG: unable to handle page fault for address: ff391c97c70c9040 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page The address that triggers the fault is the address of the descriptor that was freed moments earlier via: drv_disable_wq()->idxd_wq_free_resources() Fix the use after free by freeing the descriptors after any possible usage. This is done after idxd_wq_reset() to ensure that the memory remains accessible during possible completion writes by the device.

In the Linux kernel, the following vulnerability has been resolved: peci: cpu: Fix use-after-free in adev_release() When auxiliary_device_add() returns an error, auxiliary_device_uninit() is called, which causes refcount for device to be decremented and .release callback will be triggered. Because adev_release() re-calls auxiliary_device_uninit(), it will cause use-after-free: [ 1269.455172] WARNING: CPU: 0 PID: 14267 at lib/refcount.c:28 refcount_warn_saturate+0x110/0x15 [ 1269.464007] refcount_t: underflow; use-after-free.

In the Linux kernel, the following vulnerability has been resolved: perf: Fix perf_pending_task() UaF Per syzbot it is possible for perf_pending_task() to run after the event is free()'d. There are two related but distinct cases: - the task_work was already queued before destroying the event; - destroying the event itself queues the task_work. The first cannot be solved using task_work_cancel() since perf_release() itself might be called from a task_work (____fput), which means the current->task_works list is already empty and task_work_cancel() won't be able to find the perf_pending_task() entry. The simplest alternative is extending the perf_event lifetime to cover the task_work. The second is just silly, queueing a task_work while you know the event is going away makes no sense and is easily avoided by re-arranging how the event is marked STATE_DEAD and ensuring it goes through STATE_OFF on the way down.

In the Linux kernel, the following vulnerability has been resolved: net: hisilicon: Fix potential use-after-free in hisi_femac_rx() The skb is delivered to napi_gro_receive() which may free it, after calling this, dereferencing skb may trigger use-after-free.