An issue was discovered in the Linux kernel before 5.0.9. There is a use-after-free in atalk_proc_exit, related to net/appletalk/atalk_proc.c, net/appletalk/ddp.c, and net/appletalk/sysctl_net_atalk.c.

In the Linux kernel, the following vulnerability has been resolved: tracing: Have format file honor EVENT_FILE_FL_FREED When eventfs was introduced, special care had to be done to coordinate the freeing of the file meta data with the files that are exposed to user space. The file meta data would have a ref count that is set when the file is created and would be decremented and freed after the last user that opened the file closed it. When the file meta data was to be freed, it would set a flag (EVENT_FILE_FL_FREED) to denote that the file is freed, and any new references made (like new opens or reads) would fail as it is marked freed. This allowed other meta data to be freed after this flag was set (under the event_mutex). All the files that were dynamically created in the events directory had a pointer to the file meta data and would call event_release() when the last reference to the user space file was closed. This would be the time that it is safe to free the file meta data. A shortcut was made for the "format" file. It's i_private would point to the "call" entry directly and not point to the file's meta data. This is because all format files are the same for the same "call", so it was thought there was no reason to differentiate them. The other files maintain state (like the "enable", "trigger", etc). But this meant if the file were to disappear, the "format" file would be unaware of it. This caused a race that could be trigger via the user_events test (that would create dynamic events and free them), and running a loop that would read the user_events format files: In one console run: # cd tools/testing/selftests/user_events # while true; do ./ftrace_test; done And in another console run: # cd /sys/kernel/tracing/ # while true; do cat events/user_events/__test_event/format; done 2>/dev/null With KASAN memory checking, it would trigger a use-after-free bug report (which was a real bug). This was because the format file was not checking the file's meta data flag "EVENT_FILE_FL_FREED", so it would access the event that the file meta data pointed to after the event was freed. After inspection, there are other locations that were found to not check the EVENT_FILE_FL_FREED flag when accessing the trace_event_file. Add a new helper function: event_file_file() that will make sure that the event_mutex is held, and will return NULL if the trace_event_file has the EVENT_FILE_FL_FREED flag set. Have the first reference of the struct file pointer use event_file_file() and check for NULL. Later uses can still use the event_file_data() helper function if the event_mutex is still held and was not released since the event_file_file() call.

A use-after-free flaw was found in ndlc_remove in drivers/nfc/st-nci/ndlc.c in the Linux Kernel. This flaw could allow an attacker to crash the system due to a race problem.

A use-after-free flaw was found in qdisc_graft in net/sched/sch_api.c in the Linux Kernel due to a race problem. This flaw leads to a denial of service issue. If patch ebda44da44f6 ("net: sched: fix race condition in qdisc_graft()") not applied yet, then kernel could be affected.

A use-after-free flaw was found in io_uring/poll.c in io_poll_check_events in the io_uring subcomponent in the Linux Kernel due to a race condition of poll_refs. This flaw may cause a NULL pointer dereference.

In the Linux kernel, the following vulnerability has been resolved: ieee802154/adf7242: defer destroy_workqueue call There is a possible race condition (use-after-free) like below (FREE) | (USE) adf7242_remove | adf7242_channel cancel_delayed_work_sync | destroy_workqueue (1) | adf7242_cmd_rx | mod_delayed_work (2) | The root cause for this race is that the upper layer (ieee802154) is unaware of this detaching event and the function adf7242_channel can be called without any checks. To fix this, we can add a flag write at the beginning of adf7242_remove and add flag check in adf7242_channel. Or we can just defer the destructive operation like other commit 3e0588c291d6 ("hamradio: defer ax25 kfree after unregister_netdev") which let the ieee802154_unregister_hw() to handle the synchronization. This patch takes the second option. runs")

In the Linux kernel, the following vulnerability has been resolved: USB: gadgetfs: Fix race between mounting and unmounting The syzbot fuzzer and Gerald Lee have identified a use-after-free bug in the gadgetfs driver, involving processes concurrently mounting and unmounting the gadgetfs filesystem. In particular, gadgetfs_fill_super() can race with gadgetfs_kill_sb(), causing the latter to deallocate the_device while the former is using it. The output from KASAN says, in part: BUG: KASAN: use-after-free in instrument_atomic_read_write include/linux/instrumented.h:102 [inline] BUG: KASAN: use-after-free in atomic_fetch_sub_release include/linux/atomic/atomic-instrumented.h:176 [inline] BUG: KASAN: use-after-free in __refcount_sub_and_test include/linux/refcount.h:272 [inline] BUG: KASAN: use-after-free in __refcount_dec_and_test include/linux/refcount.h:315 [inline] BUG: KASAN: use-after-free in refcount_dec_and_test include/linux/refcount.h:333 [inline] BUG: KASAN: use-after-free in put_dev drivers/usb/gadget/legacy/inode.c:159 [inline] BUG: KASAN: use-after-free in gadgetfs_kill_sb+0x33/0x100 drivers/usb/gadget/legacy/inode.c:2086 Write of size 4 at addr ffff8880276d7840 by task syz-executor126/18689 CPU: 0 PID: 18689 Comm: syz-executor126 Not tainted 6.1.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 Call Trace: <TASK> ... atomic_fetch_sub_release include/linux/atomic/atomic-instrumented.h:176 [inline] __refcount_sub_and_test include/linux/refcount.h:272 [inline] __refcount_dec_and_test include/linux/refcount.h:315 [inline] refcount_dec_and_test include/linux/refcount.h:333 [inline] put_dev drivers/usb/gadget/legacy/inode.c:159 [inline] gadgetfs_kill_sb+0x33/0x100 drivers/usb/gadget/legacy/inode.c:2086 deactivate_locked_super+0xa7/0xf0 fs/super.c:332 vfs_get_super fs/super.c:1190 [inline] get_tree_single+0xd0/0x160 fs/super.c:1207 vfs_get_tree+0x88/0x270 fs/super.c:1531 vfs_fsconfig_locked fs/fsopen.c:232 [inline] The simplest solution is to ensure that gadgetfs_fill_super() and gadgetfs_kill_sb() are serialized by making them both acquire a new mutex.

In the Linux kernel, the following vulnerability has been resolved: drm/virtio: Fix GEM handle creation UAF Userspace can guess the handle value and try to race GEM object creation with handle close, resulting in a use-after-free if we dereference the object after dropping the handle's reference. For that reason, dropping the handle's reference must be done *after* we are done dereferencing the object.

In the Linux kernel, the following vulnerability has been resolved: nvme: fix SRCU protection of nvme_ns_head list Walking the nvme_ns_head siblings list is protected by the head's srcu in nvme_ns_head_submit_bio() but not nvme_mpath_revalidate_paths(). Removing namespaces from the list also fails to synchronize the srcu. Concurrent scan work can therefore cause use-after-frees. Hold the head's srcu lock in nvme_mpath_revalidate_paths() and synchronize with the srcu, not the global RCU, in nvme_ns_remove(). Observed the following panic when making NVMe/RDMA connections with native multipath on the Rocky Linux 8.6 kernel (it seems the upstream kernel has the same race condition). Disassembly shows the faulting instruction is cmp 0x50(%rdx),%rcx; computing capacity != get_capacity(ns->disk). Address 0x50 is dereferenced because ns->disk is NULL. The NULL disk appears to be the result of concurrent scan work freeing the namespace (note the log line in the middle of the panic). [37314.206036] BUG: unable to handle kernel NULL pointer dereference at 0000000000000050 [37314.206036] nvme0n3: detected capacity change from 0 to 11811160064 [37314.299753] PGD 0 P4D 0 [37314.299756] Oops: 0000 [#1] SMP PTI [37314.299759] CPU: 29 PID: 322046 Comm: kworker/u98:3 Kdump: loaded Tainted: G W X --------- - - 4.18.0-372.32.1.el8test86.x86_64 #1 [37314.299762] Hardware name: Dell Inc. PowerEdge R720/0JP31P, BIOS 2.7.0 05/23/2018 [37314.299763] Workqueue: nvme-wq nvme_scan_work [nvme_core] [37314.299783] RIP: 0010:nvme_mpath_revalidate_paths+0x26/0xb0 [nvme_core] [37314.299790] Code: 1f 44 00 00 66 66 66 66 90 55 53 48 8b 5f 50 48 8b 83 c8 c9 00 00 48 8b 13 48 8b 48 50 48 39 d3 74 20 48 8d 42 d0 48 8b 50 20 <48> 3b 4a 50 74 05 f0 80 60 70 ef 48 8b 50 30 48 8d 42 d0 48 39 d3 [37315.058803] RSP: 0018:ffffabe28f913d10 EFLAGS: 00010202 [37315.121316] RAX: ffff927a077da800 RBX: ffff92991dd70000 RCX: 0000000001600000 [37315.206704] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff92991b719800 [37315.292106] RBP: ffff929a6b70c000 R08: 000000010234cd4a R09: c0000000ffff7fff [37315.377501] R10: 0000000000000001 R11: ffffabe28f913a30 R12: 0000000000000000 [37315.462889] R13: ffff92992716600c R14: ffff929964e6e030 R15: ffff92991dd70000 [37315.548286] FS: 0000000000000000(0000) GS:ffff92b87fb80000(0000) knlGS:0000000000000000 [37315.645111] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [37315.713871] CR2: 0000000000000050 CR3: 0000002208810006 CR4: 00000000000606e0 [37315.799267] Call Trace: [37315.828515] nvme_update_ns_info+0x1ac/0x250 [nvme_core] [37315.892075] nvme_validate_or_alloc_ns+0x2ff/0xa00 [nvme_core] [37315.961871] ? __blk_mq_free_request+0x6b/0x90 [37316.015021] nvme_scan_work+0x151/0x240 [nvme_core] [37316.073371] process_one_work+0x1a7/0x360 [37316.121318] ? create_worker+0x1a0/0x1a0 [37316.168227] worker_thread+0x30/0x390 [37316.212024] ? create_worker+0x1a0/0x1a0 [37316.258939] kthread+0x10a/0x120 [37316.297557] ? set_kthread_struct+0x50/0x50 [37316.347590] ret_from_fork+0x35/0x40 [37316.390360] Modules linked in: nvme_rdma nvme_tcp(X) nvme_fabrics nvme_core netconsole iscsi_tcp libiscsi_tcp dm_queue_length dm_service_time nf_conntrack_netlink br_netfilter bridge stp llc overlay nft_chain_nat ipt_MASQUERADE nf_nat xt_addrtype xt_CT nft_counter xt_state xt_conntrack nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 xt_comment xt_multiport nft_compat nf_tables libcrc32c nfnetlink dm_multipath tg3 rpcrdma sunrpc rdma_ucm ib_srpt ib_isert iscsi_target_mod target_core_mod ib_iser libiscsi scsi_transport_iscsi ib_umad rdma_cm ib_ipoib iw_cm ib_cm intel_rapl_msr iTCO_wdt iTCO_vendor_support dcdbas intel_rapl_common sb_edac x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel ipmi_ssif kvm irqbypass crct10dif_pclmul crc32_pclmul mlx5_ib ghash_clmulni_intel ib_uverbs rapl intel_cstate intel_uncore ib_core ipmi_si joydev mei_me pcspkr ipmi_devintf mei lpc_ich wmi ipmi_msghandler acpi_power_meter ex ---truncated---

roccat_report_event in drivers/hid/hid-roccat.c in the Linux kernel through 5.19.12 has a race condition and resultant use-after-free in certain situations where a report is received while copying a report->value is in progress.

A vulnerability was found in Linux kernel, where a use-after-frees in nouveau's postclose() handler could happen if removing device (that is not common to remove video card physically without power-off, but same happens if "unbind" the driver).

An issue was discovered in the Linux kernel through 5.9.1, as used with Xen through 4.14.x. drivers/xen/events/events_base.c allows event-channel removal during the event-handling loop (a race condition). This can cause a use-after-free or NULL pointer dereference, as demonstrated by a dom0 crash via events for an in-reconfiguration paravirtualized device, aka CID-073d0552ead5.

A NULL pointer dereference flaw was found in the Linux kernel’s Amateur Radio AX.25 protocol functionality in the way a user connects with the protocol. This flaw allows a local user to crash the system.

In the Linux kernel, the following vulnerability has been resolved: btrfs: fix race between transaction aborts and fsyncs leading to use-after-free There is a race between a task aborting a transaction during a commit, a task doing an fsync and the transaction kthread, which leads to an use-after-free of the log root tree. When this happens, it results in a stack trace like the following: BTRFS info (device dm-0): forced readonly BTRFS warning (device dm-0): Skipping commit of aborted transaction. BTRFS: error (device dm-0) in cleanup_transaction:1958: errno=-5 IO failure BTRFS warning (device dm-0): lost page write due to IO error on /dev/mapper/error-test (-5) BTRFS warning (device dm-0): Skipping commit of aborted transaction. BTRFS warning (device dm-0): direct IO failed ino 261 rw 0,0 sector 0xa4e8 len 4096 err no 10 BTRFS error (device dm-0): error writing primary super block to device 1 BTRFS warning (device dm-0): direct IO failed ino 261 rw 0,0 sector 0x12e000 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 261 rw 0,0 sector 0x12e008 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 261 rw 0,0 sector 0x12e010 len 4096 err no 10 BTRFS: error (device dm-0) in write_all_supers:4110: errno=-5 IO failure (1 errors while writing supers) BTRFS: error (device dm-0) in btrfs_sync_log:3308: errno=-5 IO failure general protection fault, probably for non-canonical address 0x6b6b6b6b6b6b6b68: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC PTI CPU: 2 PID: 2458471 Comm: fsstress Not tainted 5.12.0-rc5-btrfs-next-84 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 RIP: 0010:__mutex_lock+0x139/0xa40 Code: c0 74 19 (...) RSP: 0018:ffff9f18830d7b00 EFLAGS: 00010202 RAX: 6b6b6b6b6b6b6b68 RBX: 0000000000000001 RCX: 0000000000000002 RDX: ffffffffb9c54d13 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffff9f18830d7bc0 R08: 0000000000000000 R09: 0000000000000000 R10: ffff9f18830d7be0 R11: 0000000000000001 R12: ffff8c6cd199c040 R13: ffff8c6c95821358 R14: 00000000fffffffb R15: ffff8c6cbcf01358 FS: 00007fa9140c2b80(0000) GS:ffff8c6fac600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fa913d52000 CR3: 000000013d2b4003 CR4: 0000000000370ee0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: ? __btrfs_handle_fs_error+0xde/0x146 [btrfs] ? btrfs_sync_log+0x7c1/0xf20 [btrfs] ? btrfs_sync_log+0x7c1/0xf20 [btrfs] btrfs_sync_log+0x7c1/0xf20 [btrfs] btrfs_sync_file+0x40c/0x580 [btrfs] do_fsync+0x38/0x70 __x64_sys_fsync+0x10/0x20 do_syscall_64+0x33/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7fa9142a55c3 Code: 8b 15 09 (...) RSP: 002b:00007fff26278d48 EFLAGS: 00000246 ORIG_RAX: 000000000000004a RAX: ffffffffffffffda RBX: 0000563c83cb4560 RCX: 00007fa9142a55c3 RDX: 00007fff26278cb0 RSI: 00007fff26278cb0 RDI: 0000000000000005 RBP: 0000000000000005 R08: 0000000000000001 R09: 00007fff26278d5c R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000340 R13: 00007fff26278de0 R14: 00007fff26278d96 R15: 0000563c83ca57c0 Modules linked in: btrfs dm_zero dm_snapshot dm_thin_pool (...) ---[ end trace ee2f1b19327d791d ]--- The steps that lead to this crash are the following: 1) We are at transaction N; 2) We have two tasks with a transaction handle attached to transaction N. Task A and Task B. Task B is doing an fsync; 3) Task B is at btrfs_sync_log(), and has saved fs_info->log_root_tree into a local variable named 'log_root_tree' at the top of btrfs_sync_log(). Task B is about to call write_all_supers(), but before that... 4) Task A calls btrfs_commit_transaction(), and after it sets the transaction state to TRANS_STATE_COMMIT_START, an error happens before it w ---truncated---

A use-after-free flaw was found in the Linux kernel's Memory Management subsystem when a user wins two races at the same time with a fail in the mas_prev_slot function. This issue could allow a local user to crash the system.

In the Linux kernel, the following vulnerability has been resolved: io_uring/eventfd: ensure io_eventfd_signal() defers another RCU period io_eventfd_do_signal() is invoked from an RCU callback, but when dropping the reference to the io_ev_fd, it calls io_eventfd_free() directly if the refcount drops to zero. This isn't correct, as any potential freeing of the io_ev_fd should be deferred another RCU grace period. Just call io_eventfd_put() rather than open-code the dec-and-test and free, which will correctly defer it another RCU grace period.

A flaw was found in the MCTP protocol in the Linux kernel. The function mctp_unregister() reclaims the device's relevant resource when a netcard detaches. However, a running routine may be unaware of this and cause the use-after-free of the mdev->addrs object, potentially leading to a denial of service.

An issue was discovered in the Linux kernel before 6.2.9. A use-after-free was found in bq24190_remove in drivers/power/supply/bq24190_charger.c. It could allow a local attacker to crash the system due to a race condition.

A race condition was discovered in get_old_root in fs/btrfs/ctree.c in the Linux kernel through 5.11.8. It allows attackers to cause a denial of service (BUG) because of a lack of locking on an extent buffer before a cloning operation, aka CID-dbcc7d57bffc.

Race condition in ip_vs_conn_flush in Linux 2.6 before 2.6.13 and 2.4 before 2.4.32-pre2, when running on SMP systems, allows local users to cause a denial of service (null dereference) by causing a connection timer to expire while the connection table is being flushed before the appropriate lock is acquired.

In the Linux kernel, the following vulnerability has been resolved: fgraph: Add READ_ONCE() when accessing fgraph_array[] In __ftrace_return_to_handler(), a loop iterates over the fgraph_array[] elements, which are fgraph_ops. The loop checks if an element is a fgraph_stub to prevent using a fgraph_stub afterward. However, if the compiler reloads fgraph_array[] after this check, it might race with an update to fgraph_array[] that introduces a fgraph_stub. This could result in the stub being processed, but the stub contains a null "func_hash" field, leading to a NULL pointer dereference. To ensure that the gops compared against the fgraph_stub matches the gops processed later, add a READ_ONCE(). A similar patch appears in commit 63a8dfb ("function_graph: Add READ_ONCE() when accessing fgraph_array[]").

In the Linux kernel, the following vulnerability has been resolved: usb: gadget: f_fs: Remove WARN_ON in functionfs_bind This commit addresses an issue related to below kernel panic where panic_on_warn is enabled. It is caused by the unnecessary use of WARN_ON in functionsfs_bind, which easily leads to the following scenarios. 1.adb_write in adbd 2. UDC write via configfs ================= ===================== ->usb_ffs_open_thread() ->UDC write ->open_functionfs() ->configfs_write_iter() ->adb_open() ->gadget_dev_desc_UDC_store() ->adb_write() ->usb_gadget_register_driver_owner ->driver_register() ->StartMonitor() ->bus_add_driver() ->adb_read() ->gadget_bind_driver() <times-out without BIND event> ->configfs_composite_bind() ->usb_add_function() ->open_functionfs() ->ffs_func_bind() ->adb_open() ->functionfs_bind() <ffs->state !=FFS_ACTIVE> The adb_open, adb_read, and adb_write operations are invoked from the daemon, but trying to bind the function is a process that is invoked by UDC write through configfs, which opens up the possibility of a race condition between the two paths. In this race scenario, the kernel panic occurs due to the WARN_ON from functionfs_bind when panic_on_warn is enabled. This commit fixes the kernel panic by removing the unnecessary WARN_ON. Kernel panic - not syncing: kernel: panic_on_warn set ... [ 14.542395] Call trace: [ 14.542464] ffs_func_bind+0x1c8/0x14a8 [ 14.542468] usb_add_function+0xcc/0x1f0 [ 14.542473] configfs_composite_bind+0x468/0x588 [ 14.542478] gadget_bind_driver+0x108/0x27c [ 14.542483] really_probe+0x190/0x374 [ 14.542488] __driver_probe_device+0xa0/0x12c [ 14.542492] driver_probe_device+0x3c/0x220 [ 14.542498] __driver_attach+0x11c/0x1fc [ 14.542502] bus_for_each_dev+0x104/0x160 [ 14.542506] driver_attach+0x24/0x34 [ 14.542510] bus_add_driver+0x154/0x270 [ 14.542514] driver_register+0x68/0x104 [ 14.542518] usb_gadget_register_driver_owner+0x48/0xf4 [ 14.542523] gadget_dev_desc_UDC_store+0xf8/0x144 [ 14.542526] configfs_write_iter+0xf0/0x138

drivers/net/wireless/intel/iwlwifi/pcie/trans.c in the Linux kernel 5.2.14 does not check the alloc_workqueue return value, leading to a NULL pointer dereference.

In the Linux kernel, the following vulnerability has been resolved: iommu/arm-smmu: Defer probe of clients after smmu device bound Null pointer dereference occurs due to a race between smmu driver probe and client driver probe, when of_dma_configure() for client is called after the iommu_device_register() for smmu driver probe has executed but before the driver_bound() for smmu driver has been called. Following is how the race occurs: T1:Smmu device probe T2: Client device probe really_probe() arm_smmu_device_probe() iommu_device_register() really_probe() platform_dma_configure() of_dma_configure() of_dma_configure_id() of_iommu_configure() iommu_probe_device() iommu_init_device() arm_smmu_probe_device() arm_smmu_get_by_fwnode() driver_find_device_by_fwnode() driver_find_device() next_device() klist_next() /* null ptr assigned to smmu */ /* null ptr dereference while smmu->streamid_mask */ driver_bound() klist_add_tail() When this null smmu pointer is dereferenced later in arm_smmu_probe_device, the device crashes. Fix this by deferring the probe of the client device until the smmu device has bound to the arm smmu driver. [will: Add comment]

In the Linux kernel, the following vulnerability has been resolved: net: fix data-races around sk->sk_forward_alloc Syzkaller reported this warning: ------------[ cut here ]------------ WARNING: CPU: 0 PID: 16 at net/ipv4/af_inet.c:156 inet_sock_destruct+0x1c5/0x1e0 Modules linked in: CPU: 0 UID: 0 PID: 16 Comm: ksoftirqd/0 Not tainted 6.12.0-rc5 #26 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 RIP: 0010:inet_sock_destruct+0x1c5/0x1e0 Code: 24 12 4c 89 e2 5b 48 c7 c7 98 ec bb 82 41 5c e9 d1 18 17 ff 4c 89 e6 5b 48 c7 c7 d0 ec bb 82 41 5c e9 bf 18 17 ff 0f 0b eb 83 <0f> 0b eb 97 0f 0b eb 87 0f 0b e9 68 ff ff ff 66 66 2e 0f 1f 84 00 RSP: 0018:ffffc9000008bd90 EFLAGS: 00010206 RAX: 0000000000000300 RBX: ffff88810b172a90 RCX: 0000000000000007 RDX: 0000000000000002 RSI: 0000000000000300 RDI: ffff88810b172a00 RBP: ffff88810b172a00 R08: ffff888104273c00 R09: 0000000000100007 R10: 0000000000020000 R11: 0000000000000006 R12: ffff88810b172a00 R13: 0000000000000004 R14: 0000000000000000 R15: ffff888237c31f78 FS: 0000000000000000(0000) GS:ffff888237c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffc63fecac8 CR3: 000000000342e000 CR4: 00000000000006f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> ? __warn+0x88/0x130 ? inet_sock_destruct+0x1c5/0x1e0 ? report_bug+0x18e/0x1a0 ? handle_bug+0x53/0x90 ? exc_invalid_op+0x18/0x70 ? asm_exc_invalid_op+0x1a/0x20 ? inet_sock_destruct+0x1c5/0x1e0 __sk_destruct+0x2a/0x200 rcu_do_batch+0x1aa/0x530 ? rcu_do_batch+0x13b/0x530 rcu_core+0x159/0x2f0 handle_softirqs+0xd3/0x2b0 ? __pfx_smpboot_thread_fn+0x10/0x10 run_ksoftirqd+0x25/0x30 smpboot_thread_fn+0xdd/0x1d0 kthread+0xd3/0x100 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x34/0x50 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1a/0x30 </TASK> ---[ end trace 0000000000000000 ]--- Its possible that two threads call tcp_v6_do_rcv()/sk_forward_alloc_add() concurrently when sk->sk_state == TCP_LISTEN with sk->sk_lock unlocked, which triggers a data-race around sk->sk_forward_alloc: tcp_v6_rcv tcp_v6_do_rcv skb_clone_and_charge_r sk_rmem_schedule __sk_mem_schedule sk_forward_alloc_add() skb_set_owner_r sk_mem_charge sk_forward_alloc_add() __kfree_skb skb_release_all skb_release_head_state sock_rfree sk_mem_uncharge sk_forward_alloc_add() sk_mem_reclaim // set local var reclaimable __sk_mem_reclaim sk_forward_alloc_add() In this syzkaller testcase, two threads call tcp_v6_do_rcv() with skb->truesize=768, the sk_forward_alloc changes like this: (cpu 1) | (cpu 2) | sk_forward_alloc ... | ... | 0 __sk_mem_schedule() | | +4096 = 4096 | __sk_mem_schedule() | +4096 = 8192 sk_mem_charge() | | -768 = 7424 | sk_mem_charge() | -768 = 6656 ... | ... | sk_mem_uncharge() | | +768 = 7424 reclaimable=7424 | | | sk_mem_uncharge() | +768 = 8192 | reclaimable=8192 | __sk_mem_reclaim() | | -4096 = 4096 | __sk_mem_reclaim() | -8192 = -4096 != 0 The skb_clone_and_charge_r() should not be called in tcp_v6_do_rcv() when sk->sk_state is TCP_LISTEN, it happens later in tcp_v6_syn_recv_sock(). Fix the same issue in dccp_v6_do_rcv().

In the Linux kernel, the following vulnerability has been resolved: i40e: fix race condition by adding filter's intermediate sync state Fix a race condition in the i40e driver that leads to MAC/VLAN filters becoming corrupted and leaking. Address the issue that occurs under heavy load when multiple threads are concurrently modifying MAC/VLAN filters by setting mac and port VLAN. 1. Thread T0 allocates a filter in i40e_add_filter() within i40e_ndo_set_vf_port_vlan(). 2. Thread T1 concurrently frees the filter in __i40e_del_filter() within i40e_ndo_set_vf_mac(). 3. Subsequently, i40e_service_task() calls i40e_sync_vsi_filters(), which refers to the already freed filter memory, causing corruption. Reproduction steps: 1. Spawn multiple VFs. 2. Apply a concurrent heavy load by running parallel operations to change MAC addresses on the VFs and change port VLANs on the host. 3. Observe errors in dmesg: "Error I40E_AQ_RC_ENOSPC adding RX filters on VF XX, please set promiscuous on manually for VF XX". Exact code for stable reproduction Intel can't open-source now. The fix involves implementing a new intermediate filter state, I40E_FILTER_NEW_SYNC, for the time when a filter is on a tmp_add_list. These filters cannot be deleted from the hash list directly but must be removed using the full process.

In the Linux kernel, the following vulnerability has been resolved: dm: fix a crash if blk_alloc_disk fails If blk_alloc_disk fails, the variable md->disk is set to an error value. cleanup_mapped_device will see that md->disk is non-NULL and it will attempt to access it, causing a crash on this statement "md->disk->private_data = NULL;".

In the Linux kernel, the following vulnerability has been resolved: fork: do not invoke uffd on fork if error occurs Patch series "fork: do not expose incomplete mm on fork". During fork we may place the virtual memory address space into an inconsistent state before the fork operation is complete. In addition, we may encounter an error during the fork operation that indicates that the virtual memory address space is invalidated. As a result, we should not be exposing it in any way to external machinery that might interact with the mm or VMAs, machinery that is not designed to deal with incomplete state. We specifically update the fork logic to defer khugepaged and ksm to the end of the operation and only to be invoked if no error arose, and disallow uffd from observing fork events should an error have occurred. This patch (of 2): Currently on fork we expose the virtual address space of a process to userland unconditionally if uffd is registered in VMAs, regardless of whether an error arose in the fork. This is performed in dup_userfaultfd_complete() which is invoked unconditionally, and performs two duties - invoking registered handlers for the UFFD_EVENT_FORK event via dup_fctx(), and clearing down userfaultfd_fork_ctx objects established in dup_userfaultfd(). This is problematic, because the virtual address space may not yet be correctly initialised if an error arose. The change in commit d24062914837 ("fork: use __mt_dup() to duplicate maple tree in dup_mmap()") makes this more pertinent as we may be in a state where entries in the maple tree are not yet consistent. We address this by, on fork error, ensuring that we roll back state that we would otherwise expect to clean up through the event being handled by userland and perform the memory freeing duty otherwise performed by dup_userfaultfd_complete(). We do this by implementing a new function, dup_userfaultfd_fail(), which performs the same loop, only decrementing reference counts. Note that we perform mmgrab() on the parent and child mm's, however userfaultfd_ctx_put() will mmdrop() this once the reference count drops to zero, so we will avoid memory leaks correctly here.

In the Linux kernel, the following vulnerability has been resolved: drm/panthor: Fix race when converting group handle to group object XArray provides it's own internal lock which protects the internal array when entries are being simultaneously added and removed. However there is still a race between retrieving the pointer from the XArray and incrementing the reference count. To avoid this race simply hold the internal XArray lock when incrementing the reference count, this ensures there cannot be a racing call to xa_erase().

Race condition in Linux 2.6, when threads are sharing memory mapping via CLONE_VM (such as linuxthreads and vfork), might allow local users to cause a denial of service (deadlock) by triggering a core dump while waiting for a thread that has just performed an exec.

In the Linux kernel, the following vulnerability has been resolved: scsi: lpfc: Ensure DA_ID handling completion before deleting an NPIV instance Deleting an NPIV instance requires all fabric ndlps to be released before an NPIV's resources can be torn down. Failure to release fabric ndlps beforehand opens kref imbalance race conditions. Fix by forcing the DA_ID to complete synchronously with usage of wait_queue.

In the Linux kernel before 5.1.13, there is a memory leak in drivers/scsi/libsas/sas_expander.c when SAS expander discovery fails. This will cause a BUG and denial of service.

In the Linux kernel before 5.0, a memory leak exists in sit_init_net() in net/ipv6/sit.c when register_netdev() fails to register sitn->fb_tunnel_dev, which may cause denial of service, aka CID-07f12b26e21a.

In the Linux kernel, the following vulnerability has been resolved: net: xilinx: axienet: Enqueue Tx packets in dql before dmaengine starts Enqueue packets in dql after dma engine starts causes race condition. Tx transfer starts once dma engine is started and may execute dql dequeue in completion before it gets queued. It results in following kernel crash while running iperf stress test: kernel BUG at lib/dynamic_queue_limits.c:99! <snip> Internal error: Oops - BUG: 00000000f2000800 [#1] SMP pc : dql_completed+0x238/0x248 lr : dql_completed+0x3c/0x248 Call trace: dql_completed+0x238/0x248 axienet_dma_tx_cb+0xa0/0x170 xilinx_dma_do_tasklet+0xdc/0x290 tasklet_action_common+0xf8/0x11c tasklet_action+0x30/0x3c handle_softirqs+0xf8/0x230 <snip> Start dmaengine after enqueue in dql fixes the crash.

In the Linux kernel, the following vulnerability has been resolved: net: dsa: improve shutdown sequence Alexander Sverdlin presents 2 problems during shutdown with the lan9303 driver. One is specific to lan9303 and the other just happens to reproduce there. The first problem is that lan9303 is unique among DSA drivers in that it calls dev_get_drvdata() at "arbitrary runtime" (not probe, not shutdown, not remove): phy_state_machine() -> ... -> dsa_user_phy_read() -> ds->ops->phy_read() -> lan9303_phy_read() -> chip->ops->phy_read() -> lan9303_mdio_phy_read() -> dev_get_drvdata() But we never stop the phy_state_machine(), so it may continue to run after dsa_switch_shutdown(). Our common pattern in all DSA drivers is to set drvdata to NULL to suppress the remove() method that may come afterwards. But in this case it will result in an NPD. The second problem is that the way in which we set dp->conduit->dsa_ptr = NULL; is concurrent with receive packet processing. dsa_switch_rcv() checks once whether dev->dsa_ptr is NULL, but afterwards, rather than continuing to use that non-NULL value, dev->dsa_ptr is dereferenced again and again without NULL checks: dsa_conduit_find_user() and many other places. In between dereferences, there is no locking to ensure that what was valid once continues to be valid. Both problems have the common aspect that closing the conduit interface solves them. In the first case, dev_close(conduit) triggers the NETDEV_GOING_DOWN event in dsa_user_netdevice_event() which closes user ports as well. dsa_port_disable_rt() calls phylink_stop(), which synchronously stops the phylink state machine, and ds->ops->phy_read() will thus no longer call into the driver after this point. In the second case, dev_close(conduit) should do this, as per Documentation/networking/driver.rst: | Quiescence | ---------- | | After the ndo_stop routine has been called, the hardware must | not receive or transmit any data. All in flight packets must | be aborted. If necessary, poll or wait for completion of | any reset commands. So it should be sufficient to ensure that later, when we zeroize conduit->dsa_ptr, there will be no concurrent dsa_switch_rcv() call on this conduit. The addition of the netif_device_detach() function is to ensure that ioctls, rtnetlinks and ethtool requests on the user ports no longer propagate down to the driver - we're no longer prepared to handle them. The race condition actually did not exist when commit 0650bf52b31f ("net: dsa: be compatible with masters which unregister on shutdown") first introduced dsa_switch_shutdown(). It was created later, when we stopped unregistering the user interfaces from a bad spot, and we just replaced that sequence with a racy zeroization of conduit->dsa_ptr (one which doesn't ensure that the interfaces aren't up).

In the Linux kernel, the following vulnerability has been resolved: irqchip/gic-v4: Don't allow a VMOVP on a dying VPE Kunkun Jiang reported that there is a small window of opportunity for userspace to force a change of affinity for a VPE while the VPE has already been unmapped, but the corresponding doorbell interrupt still visible in /proc/irq/. Plug the race by checking the value of vmapp_count, which tracks whether the VPE is mapped ot not, and returning an error in this case. This involves making vmapp_count common to both GICv4.1 and its v4.0 ancestor.

drivers/gpu/drm/radeon/radeon_display.c in the Linux kernel 5.2.14 does not check the alloc_workqueue return value, leading to a NULL pointer dereference. NOTE: A third-party software maintainer states that the work queue allocation is happening during device initialization, which for a graphics card occurs during boot. It is not attacker controllable and OOM at that time is highly unlikely

In the Linux kernel, the following vulnerability has been resolved: rxrpc: Fix a race between socket set up and I/O thread creation In rxrpc_open_socket(), it sets up the socket and then sets up the I/O thread that will handle it. This is a problem, however, as there's a gap between the two phases in which a packet may come into rxrpc_encap_rcv() from the UDP packet but we oops when trying to wake the not-yet created I/O thread. As a quick fix, just make rxrpc_encap_rcv() discard the packet if there's no I/O thread yet. A better, but more intrusive fix would perhaps be to rearrange things such that the socket creation is done by the I/O thread.

In the Linux kernel, the following vulnerability has been resolved: f2fs: fix to check atomic_file in f2fs ioctl interfaces Some f2fs ioctl interfaces like f2fs_ioc_set_pin_file(), f2fs_move_file_range(), and f2fs_defragment_range() missed to check atomic_write status, which may cause potential race issue, fix it.

An issue was discovered in the Linux kernel before 5.0.6. There is a memory leak issue when idr_alloc() fails in genl_register_family() in net/netlink/genetlink.c.

In the Linux kernel, the following vulnerability has been resolved: mm/gup: fix memfd_pin_folios alloc race panic If memfd_pin_folios tries to create a hugetlb page, but someone else already did, then folio gets the value -EEXIST here: folio = memfd_alloc_folio(memfd, start_idx); if (IS_ERR(folio)) { ret = PTR_ERR(folio); if (ret != -EEXIST) goto err; then on the next trip through the "while start_idx" loop we panic here: if (folio) { folio_put(folio); To fix, set the folio to NULL on error.

In the Linux kernel, the following vulnerability has been resolved: lib/generic-radix-tree.c: Fix rare race in __genradix_ptr_alloc() If we need to increase the tree depth, allocate a new node, and then race with another thread that increased the tree depth before us, we'll still have a preallocated node that might be used later. If we then use that node for a new non-root node, it'll still have a pointer to the old root instead of being zeroed - fix this by zeroing it in the cmpxchg failure path.

In the Linux kernel, the following vulnerability has been resolved: fsnotify: clear PARENT_WATCHED flags lazily In some setups directories can have many (usually negative) dentries. Hence __fsnotify_update_child_dentry_flags() function can take a significant amount of time. Since the bulk of this function happens under inode->i_lock this causes a significant contention on the lock when we remove the watch from the directory as the __fsnotify_update_child_dentry_flags() call from fsnotify_recalc_mask() races with __fsnotify_update_child_dentry_flags() calls from __fsnotify_parent() happening on children. This can lead upto softlockup reports reported by users. Fix the problem by calling fsnotify_update_children_dentry_flags() to set PARENT_WATCHED flags only when parent starts watching children. When parent stops watching children, clear false positive PARENT_WATCHED flags lazily in __fsnotify_parent() for each accessed child.

In the Linux kernel, the following vulnerability has been resolved: btrfs: fix race between direct IO write and fsync when using same fd If we have 2 threads that are using the same file descriptor and one of them is doing direct IO writes while the other is doing fsync, we have a race where we can end up either: 1) Attempt a fsync without holding the inode's lock, triggering an assertion failures when assertions are enabled; 2) Do an invalid memory access from the fsync task because the file private points to memory allocated on stack by the direct IO task and it may be used by the fsync task after the stack was destroyed. The race happens like this: 1) A user space program opens a file descriptor with O_DIRECT; 2) The program spawns 2 threads using libpthread for example; 3) One of the threads uses the file descriptor to do direct IO writes, while the other calls fsync using the same file descriptor. 4) Call task A the thread doing direct IO writes and task B the thread doing fsyncs; 5) Task A does a direct IO write, and at btrfs_direct_write() sets the file's private to an on stack allocated private with the member 'fsync_skip_inode_lock' set to true; 6) Task B enters btrfs_sync_file() and sees that there's a private structure associated to the file which has 'fsync_skip_inode_lock' set to true, so it skips locking the inode's VFS lock; 7) Task A completes the direct IO write, and resets the file's private to NULL since it had no prior private and our private was stack allocated. Then it unlocks the inode's VFS lock; 8) Task B enters btrfs_get_ordered_extents_for_logging(), then the assertion that checks the inode's VFS lock is held fails, since task B never locked it and task A has already unlocked it. The stack trace produced is the following: assertion failed: inode_is_locked(&inode->vfs_inode), in fs/btrfs/ordered-data.c:983 ------------[ cut here ]------------ kernel BUG at fs/btrfs/ordered-data.c:983! Oops: invalid opcode: 0000 [#1] PREEMPT SMP PTI CPU: 9 PID: 5072 Comm: worker Tainted: G U OE 6.10.5-1-default #1 openSUSE Tumbleweed 69f48d427608e1c09e60ea24c6c55e2ca1b049e8 Hardware name: Acer Predator PH315-52/Covini_CFS, BIOS V1.12 07/28/2020 RIP: 0010:btrfs_get_ordered_extents_for_logging.cold+0x1f/0x42 [btrfs] Code: 50 d6 86 c0 e8 (...) RSP: 0018:ffff9e4a03dcfc78 EFLAGS: 00010246 RAX: 0000000000000054 RBX: ffff9078a9868e98 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffff907dce4a7800 RDI: ffff907dce4a7800 RBP: ffff907805518800 R08: 0000000000000000 R09: ffff9e4a03dcfb38 R10: ffff9e4a03dcfb30 R11: 0000000000000003 R12: ffff907684ae7800 R13: 0000000000000001 R14: ffff90774646b600 R15: 0000000000000000 FS: 00007f04b96006c0(0000) GS:ffff907dce480000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f32acbfc000 CR3: 00000001fd4fa005 CR4: 00000000003726f0 Call Trace: <TASK> ? __die_body.cold+0x14/0x24 ? die+0x2e/0x50 ? do_trap+0xca/0x110 ? do_error_trap+0x6a/0x90 ? btrfs_get_ordered_extents_for_logging.cold+0x1f/0x42 [btrfs bb26272d49b4cdc847cf3f7faadd459b62caee9a] ? exc_invalid_op+0x50/0x70 ? btrfs_get_ordered_extents_for_logging.cold+0x1f/0x42 [btrfs bb26272d49b4cdc847cf3f7faadd459b62caee9a] ? asm_exc_invalid_op+0x1a/0x20 ? btrfs_get_ordered_extents_for_logging.cold+0x1f/0x42 [btrfs bb26272d49b4cdc847cf3f7faadd459b62caee9a] ? btrfs_get_ordered_extents_for_logging.cold+0x1f/0x42 [btrfs bb26272d49b4cdc847cf3f7faadd459b62caee9a] btrfs_sync_file+0x21a/0x4d0 [btrfs bb26272d49b4cdc847cf3f7faadd459b62caee9a] ? __seccomp_filter+0x31d/0x4f0 __x64_sys_fdatasync+0x4f/0x90 do_syscall_64+0x82/0x160 ? do_futex+0xcb/0x190 ? __x64_sys_futex+0x10e/0x1d0 ? switch_fpu_return+0x4f/0xd0 ? syscall_exit_to_user_mode+0x72/0x220 ? do_syscall_64+0x8e/0x160 ? syscall_exit_to_user_mod ---truncated---

In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Avoid race between dcn35_set_drr() and dc_state_destruct() dc_state_destruct() nulls the resource context of the DC state. The pipe context passed to dcn35_set_drr() is a member of this resource context. If dc_state_destruct() is called parallel to the IRQ processing (which calls dcn35_set_drr() at some point), we can end up using already nulled function callback fields of struct stream_resource. The logic in dcn35_set_drr() already tries to avoid this, by checking tg against NULL. But if the nulling happens exactly after the NULL check and before the next access, then we get a race. Avoid this by copying tg first to a local variable, and then use this variable for all the operations. This should work, as long as nobody frees the resource pool where the timing generators live. (cherry picked from commit 0607a50c004798a96e62c089a4c34c220179dcb5)

In the Linux kernel, the following vulnerability has been resolved: ethtool: check device is present when getting link settings A sysfs reader can race with a device reset or removal, attempting to read device state when the device is not actually present. eg: [exception RIP: qed_get_current_link+17] #8 [ffffb9e4f2907c48] qede_get_link_ksettings at ffffffffc07a994a [qede] #9 [ffffb9e4f2907cd8] __rh_call_get_link_ksettings at ffffffff992b01a3 #10 [ffffb9e4f2907d38] __ethtool_get_link_ksettings at ffffffff992b04e4 #11 [ffffb9e4f2907d90] duplex_show at ffffffff99260300 #12 [ffffb9e4f2907e38] dev_attr_show at ffffffff9905a01c #13 [ffffb9e4f2907e50] sysfs_kf_seq_show at ffffffff98e0145b #14 [ffffb9e4f2907e68] seq_read at ffffffff98d902e3 #15 [ffffb9e4f2907ec8] vfs_read at ffffffff98d657d1 #16 [ffffb9e4f2907f00] ksys_read at ffffffff98d65c3f #17 [ffffb9e4f2907f38] do_syscall_64 at ffffffff98a052fb crash> struct net_device.state ffff9a9d21336000 state = 5, state 5 is __LINK_STATE_START (0b1) and __LINK_STATE_NOCARRIER (0b100). The device is not present, note lack of __LINK_STATE_PRESENT (0b10). This is the same sort of panic as observed in commit 4224cfd7fb65 ("net-sysfs: add check for netdevice being present to speed_show"). There are many other callers of __ethtool_get_link_ksettings() which don't have a device presence check. Move this check into ethtool to protect all callers.

In the Linux kernel, the following vulnerability has been resolved: drm/vmwgfx: Prevent unmapping active read buffers The kms paths keep a persistent map active to read and compare the cursor buffer. These maps can race with each other in simple scenario where: a) buffer "a" mapped for update b) buffer "a" mapped for compare c) do the compare d) unmap "a" for compare e) update the cursor f) unmap "a" for update At step "e" the buffer has been unmapped and the read contents is bogus. Prevent unmapping of active read buffers by simply keeping a count of how many paths have currently active maps and unmap only when the count reaches 0.

In the Linux kernel, the following vulnerability has been resolved: ALSA: line6: Fix racy access to midibuf There can be concurrent accesses to line6 midibuf from both the URB completion callback and the rawmidi API access. This could be a cause of KMSAN warning triggered by syzkaller below (so put as reported-by here). This patch protects the midibuf call of the former code path with a spinlock for avoiding the possible races.

In the Linux kernel, the following vulnerability has been resolved: net/mlx5: Always drain health in shutdown callback There is no point in recovery during device shutdown. if health work started need to wait for it to avoid races and NULL pointer access. Hence, drain health WQ on shutdown callback.

In the Linux kernel, the following vulnerability has been resolved: media: streamzap: fix race between device disconnection and urb callback Syzkaller has reported a general protection fault at function ir_raw_event_store_with_filter(). This crash is caused by a NULL pointer dereference of dev->raw pointer, even though it is checked for NULL in the same function, which means there is a race condition. It occurs due to the incorrect order of actions in the streamzap_disconnect() function: rc_unregister_device() is called before usb_kill_urb(). The dev->raw pointer is freed and set to NULL in rc_unregister_device(), and only after that usb_kill_urb() waits for in-progress requests to finish. If rc_unregister_device() is called while streamzap_callback() handler is not finished, this can lead to accessing freed resources. Thus rc_unregister_device() should be called after usb_kill_urb(). Found by Linux Verification Center (linuxtesting.org) with Syzkaller.