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CVE Vendors Products Updated CVSS v3.1
CVE-2025-68302 1 Linux 1 Linux Kernel 2026-04-15 N/A
In the Linux kernel, the following vulnerability has been resolved: net: sxgbe: fix potential NULL dereference in sxgbe_rx() Currently, when skb is null, the driver prints an error and then dereferences skb on the next line. To fix this, let's add a 'break' after the error message to switch to sxgbe_rx_refill(), which is similar to the approach taken by the other drivers in this particular case, e.g. calxeda with xgmac_rx(). Found during a code review.
CVE-2025-40350 1 Linux 1 Linux Kernel 2026-04-15 7.0 High
In the Linux kernel, the following vulnerability has been resolved: net/mlx5e: RX, Fix generating skb from non-linear xdp_buff for striding RQ XDP programs can change the layout of an xdp_buff through bpf_xdp_adjust_tail() and bpf_xdp_adjust_head(). Therefore, the driver cannot assume the size of the linear data area nor fragments. Fix the bug in mlx5 by generating skb according to xdp_buff after XDP programs run. Currently, when handling multi-buf XDP, the mlx5 driver assumes the layout of an xdp_buff to be unchanged. That is, the linear data area continues to be empty and fragments remain the same. This may cause the driver to generate erroneous skb or triggering a kernel warning. When an XDP program added linear data through bpf_xdp_adjust_head(), the linear data will be ignored as mlx5e_build_linear_skb() builds an skb without linear data and then pull data from fragments to fill the linear data area. When an XDP program has shrunk the non-linear data through bpf_xdp_adjust_tail(), the delta passed to __pskb_pull_tail() may exceed the actual nonlinear data size and trigger the BUG_ON in it. To fix the issue, first record the original number of fragments. If the number of fragments changes after the XDP program runs, rewind the end fragment pointer by the difference and recalculate the truesize. Then, build the skb with the linear data area matching the xdp_buff. Finally, only pull data in if there is non-linear data and fill the linear part up to 256 bytes.
CVE-2025-40348 1 Linux 1 Linux Kernel 2026-04-15 7.0 High
In the Linux kernel, the following vulnerability has been resolved: slab: Avoid race on slab->obj_exts in alloc_slab_obj_exts If two competing threads enter alloc_slab_obj_exts() and one of them fails to allocate the object extension vector, it might override the valid slab->obj_exts allocated by the other thread with OBJEXTS_ALLOC_FAIL. This will cause the thread that lost this race and expects a valid pointer to dereference a NULL pointer later on. Update slab->obj_exts atomically using cmpxchg() to avoid slab->obj_exts overrides by racing threads. Thanks for Vlastimil and Suren's help with debugging.
CVE-2025-40346 1 Linux 1 Linux Kernel 2026-04-15 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: arch_topology: Fix incorrect error check in topology_parse_cpu_capacity() Fix incorrect use of PTR_ERR_OR_ZERO() in topology_parse_cpu_capacity() which causes the code to proceed with NULL clock pointers. The current logic uses !PTR_ERR_OR_ZERO(cpu_clk) which evaluates to true for both valid pointers and NULL, leading to potential NULL pointer dereference in clk_get_rate(). Per include/linux/err.h documentation, PTR_ERR_OR_ZERO(ptr) returns: "The error code within @ptr if it is an error pointer; 0 otherwise." This means PTR_ERR_OR_ZERO() returns 0 for both valid pointers AND NULL pointers. Therefore !PTR_ERR_OR_ZERO(cpu_clk) evaluates to true (proceed) when cpu_clk is either valid or NULL, causing clk_get_rate(NULL) to be called when of_clk_get() returns NULL. Replace with !IS_ERR_OR_NULL(cpu_clk) which only proceeds for valid pointers, preventing potential NULL pointer dereference in clk_get_rate().
CVE-2025-40320 1 Linux 1 Linux Kernel 2026-04-15 7.0 High
In the Linux kernel, the following vulnerability has been resolved: smb: client: fix potential cfid UAF in smb2_query_info_compound When smb2_query_info_compound() retries, a previously allocated cfid may have been freed in the first attempt. Because cfid wasn't reset on replay, later cleanup could act on a stale pointer, leading to a potential use-after-free. Reinitialize cfid to NULL under the replay label. Example trace (trimmed): refcount_t: underflow; use-after-free. WARNING: CPU: 1 PID: 11224 at ../lib/refcount.c:28 refcount_warn_saturate+0x9c/0x110 [...] RIP: 0010:refcount_warn_saturate+0x9c/0x110 [...] Call Trace: <TASK> smb2_query_info_compound+0x29c/0x5c0 [cifs f90b72658819bd21c94769b6a652029a07a7172f] ? step_into+0x10d/0x690 ? __legitimize_path+0x28/0x60 smb2_queryfs+0x6a/0xf0 [cifs f90b72658819bd21c94769b6a652029a07a7172f] smb311_queryfs+0x12d/0x140 [cifs f90b72658819bd21c94769b6a652029a07a7172f] ? kmem_cache_alloc+0x18a/0x340 ? getname_flags+0x46/0x1e0 cifs_statfs+0x9f/0x2b0 [cifs f90b72658819bd21c94769b6a652029a07a7172f] statfs_by_dentry+0x67/0x90 vfs_statfs+0x16/0xd0 user_statfs+0x54/0xa0 __do_sys_statfs+0x20/0x50 do_syscall_64+0x58/0x80
CVE-2023-53800 1 Linux 1 Linux Kernel 2026-04-15 7.0 High
In the Linux kernel, the following vulnerability has been resolved: ubi: Fix use-after-free when volume resizing failed There is an use-after-free problem reported by KASAN: ================================================================== BUG: KASAN: use-after-free in ubi_eba_copy_table+0x11f/0x1c0 [ubi] Read of size 8 at addr ffff888101eec008 by task ubirsvol/4735 CPU: 2 PID: 4735 Comm: ubirsvol Not tainted 6.1.0-rc1-00003-g84fa3304a7fc-dirty #14 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-1.fc33 04/01/2014 Call Trace: <TASK> dump_stack_lvl+0x34/0x44 print_report+0x171/0x472 kasan_report+0xad/0x130 ubi_eba_copy_table+0x11f/0x1c0 [ubi] ubi_resize_volume+0x4f9/0xbc0 [ubi] ubi_cdev_ioctl+0x701/0x1850 [ubi] __x64_sys_ioctl+0x11d/0x170 do_syscall_64+0x35/0x80 entry_SYSCALL_64_after_hwframe+0x46/0xb0 </TASK> When ubi_change_vtbl_record() returns an error in ubi_resize_volume(), "new_eba_tbl" will be freed on error handing path, but it is holded by "vol->eba_tbl" in ubi_eba_replace_table(). It means that the liftcycle of "vol->eba_tbl" and "vol" are different, so when resizing volume in next time, it causing an use-after-free fault. Fix it by not freeing "new_eba_tbl" after it replaced in ubi_eba_replace_table(), while will be freed in next volume resizing.
CVE-2023-53811 1 Linux 1 Linux Kernel 2026-04-15 7.0 High
In the Linux kernel, the following vulnerability has been resolved: RDMA/irdma: Cap MSIX used to online CPUs + 1 The irdma driver can use a maximum number of msix vectors equal to num_online_cpus() + 1 and the kernel warning stack below is shown if that number is exceeded. The kernel throws a warning as the driver tries to update the affinity hint with a CPU mask greater than the max CPU IDs. Fix this by capping the MSIX vectors to num_online_cpus() + 1. WARNING: CPU: 7 PID: 23655 at include/linux/cpumask.h:106 irdma_cfg_ceq_vector+0x34c/0x3f0 [irdma] RIP: 0010:irdma_cfg_ceq_vector+0x34c/0x3f0 [irdma] Call Trace: irdma_rt_init_hw+0xa62/0x1290 [irdma] ? irdma_alloc_local_mac_entry+0x1a0/0x1a0 [irdma] ? __is_kernel_percpu_address+0x63/0x310 ? rcu_read_lock_held_common+0xe/0xb0 ? irdma_lan_unregister_qset+0x280/0x280 [irdma] ? irdma_request_reset+0x80/0x80 [irdma] ? ice_get_qos_params+0x84/0x390 [ice] irdma_probe+0xa40/0xfc0 [irdma] ? rcu_read_lock_bh_held+0xd0/0xd0 ? irdma_remove+0x140/0x140 [irdma] ? rcu_read_lock_sched_held+0x62/0xe0 ? down_write+0x187/0x3d0 ? auxiliary_match_id+0xf0/0x1a0 ? irdma_remove+0x140/0x140 [irdma] auxiliary_bus_probe+0xa6/0x100 __driver_probe_device+0x4a4/0xd50 ? __device_attach_driver+0x2c0/0x2c0 driver_probe_device+0x4a/0x110 __driver_attach+0x1aa/0x350 bus_for_each_dev+0x11d/0x1b0 ? subsys_dev_iter_init+0xe0/0xe0 bus_add_driver+0x3b1/0x610 driver_register+0x18e/0x410 ? 0xffffffffc0b88000 irdma_init_module+0x50/0xaa [irdma] do_one_initcall+0x103/0x5f0 ? perf_trace_initcall_level+0x420/0x420 ? do_init_module+0x4e/0x700 ? __kasan_kmalloc+0x7d/0xa0 ? kmem_cache_alloc_trace+0x188/0x2b0 ? kasan_unpoison+0x21/0x50 do_init_module+0x1d1/0x700 load_module+0x3867/0x5260 ? layout_and_allocate+0x3990/0x3990 ? rcu_read_lock_held_common+0xe/0xb0 ? rcu_read_lock_sched_held+0x62/0xe0 ? rcu_read_lock_bh_held+0xd0/0xd0 ? __vmalloc_node_range+0x46b/0x890 ? lock_release+0x5c8/0xba0 ? alloc_vm_area+0x120/0x120 ? selinux_kernel_module_from_file+0x2a5/0x300 ? __inode_security_revalidate+0xf0/0xf0 ? __do_sys_init_module+0x1db/0x260 __do_sys_init_module+0x1db/0x260 ? load_module+0x5260/0x5260 ? do_syscall_64+0x22/0x450 do_syscall_64+0xa5/0x450 entry_SYSCALL_64_after_hwframe+0x66/0xdb
CVE-2023-53815 1 Linux 1 Linux Kernel 2026-04-15 7.0 High
In the Linux kernel, the following vulnerability has been resolved: posix-timers: Prevent RT livelock in itimer_delete() itimer_delete() has a retry loop when the timer is concurrently expired. On non-RT kernels this just spin-waits until the timer callback has completed, except for posix CPU timers which have HAVE_POSIX_CPU_TIMERS_TASK_WORK enabled. In that case and on RT kernels the existing task could live lock when preempting the task which does the timer delivery. Replace spin_unlock() with an invocation of timer_wait_running() to handle it the same way as the other retry loops in the posix timer code.
CVE-2023-53832 1 Linux 1 Linux Kernel 2026-04-15 7.0 High
In the Linux kernel, the following vulnerability has been resolved: md/raid10: fix null-ptr-deref in raid10_sync_request init_resync() inits mempool and sets conf->have_replacemnt at the beginning of sync, close_sync() frees the mempool when sync is completed. After [1] recovery might be skipped and init_resync() is called but close_sync() is not. null-ptr-deref occurs with r10bio->dev[i].repl_bio. The following is one way to reproduce the issue. 1) create a array, wait for resync to complete, mddev->recovery_cp is set to MaxSector. 2) recovery is woken and it is skipped. conf->have_replacement is set to 0 in init_resync(). close_sync() not called. 3) some io errors and rdev A is set to WantReplacement. 4) a new device is added and set to A's replacement. 5) recovery is woken, A have replacement, but conf->have_replacemnt is 0. r10bio->dev[i].repl_bio will not be alloced and null-ptr-deref occurs. Fix it by not calling init_resync() if recovery skipped. [1] commit 7e83ccbecd60 ("md/raid10: Allow skipping recovery when clean arrays are assembled")
CVE-2023-53845 1 Linux 1 Linux Kernel 2026-04-15 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: nilfs2: fix infinite loop in nilfs_mdt_get_block() If the disk image that nilfs2 mounts is corrupted and a virtual block address obtained by block lookup for a metadata file is invalid, nilfs_bmap_lookup_at_level() may return the same internal return code as -ENOENT, meaning the block does not exist in the metadata file. This duplication of return codes confuses nilfs_mdt_get_block(), causing it to read and create a metadata block indefinitely. In particular, if this happens to the inode metadata file, ifile, semaphore i_rwsem can be left held, causing task hangs in lock_mount. Fix this issue by making nilfs_bmap_lookup_at_level() treat virtual block address translation failures with -ENOENT as metadata corruption instead of returning the error code.
CVE-2023-53848 1 Linux 1 Linux Kernel 2026-04-15 7.0 High
In the Linux kernel, the following vulnerability has been resolved: md/raid5-cache: fix a deadlock in r5l_exit_log() Commit b13015af94cf ("md/raid5-cache: Clear conf->log after finishing work") introduce a new problem: // caller hold reconfig_mutex r5l_exit_log flush_work(&log->disable_writeback_work) r5c_disable_writeback_async wait_event /* * conf->log is not NULL, and mddev_trylock() * will fail, wait_event() can never pass. */ conf->log = NULL Fix this problem by setting 'config->log' to NULL before wake_up() as it used to be, so that wait_event() from r5c_disable_writeback_async() can exist. In the meantime, move forward md_unregister_thread() so that null-ptr-deref this commit fixed can still be fixed.
CVE-2023-53850 1 Linux 1 Linux Kernel 2026-04-15 7.0 High
In the Linux kernel, the following vulnerability has been resolved: iavf: use internal state to free traffic IRQs If the system tries to close the netdev while iavf_reset_task() is running, __LINK_STATE_START will be cleared and netif_running() will return false in iavf_reinit_interrupt_scheme(). This will result in iavf_free_traffic_irqs() not being called and a leak as follows: [7632.489326] remove_proc_entry: removing non-empty directory 'irq/999', leaking at least 'iavf-enp24s0f0v0-TxRx-0' [7632.490214] WARNING: CPU: 0 PID: 10 at fs/proc/generic.c:718 remove_proc_entry+0x19b/0x1b0 is shown when pci_disable_msix() is later called. Fix by using the internal adapter state. The traffic IRQs will always exist if state == __IAVF_RUNNING.
CVE-2023-53854 1 Linux 1 Linux Kernel 2026-04-15 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: ASoC: mediatek: mt8186: Fix use-after-free in driver remove path When devm runs function in the "remove" path for a device it runs them in the reverse order. That means that if you have parts of your driver that aren't using devm or are using "roll your own" devm w/ devm_add_action_or_reset() you need to keep that in mind. The mt8186 audio driver didn't quite get this right. Specifically, in mt8186_init_clock() it called mt8186_audsys_clk_register() and then went on to call a bunch of other devm function. The caller of mt8186_init_clock() used devm_add_action_or_reset() to call mt8186_deinit_clock() but, because of the intervening devm functions, the order was wrong. Specifically at probe time, the order was: 1. mt8186_audsys_clk_register() 2. afe_priv->clk = devm_kcalloc(...) 3. afe_priv->clk[i] = devm_clk_get(...) At remove time, the order (which should have been 3, 2, 1) was: 1. mt8186_audsys_clk_unregister() 3. Free all of afe_priv->clk[i] 2. Free afe_priv->clk The above seemed to be causing a use-after-free. Luckily, it's easy to fix this by simply using devm more correctly. Let's move the devm_add_action_or_reset() to the right place. In addition to fixing the use-after-free, code inspection shows that this fixes a leak (missing call to mt8186_audsys_clk_unregister()) that would have happened if any of the syscon_regmap_lookup_by_phandle() calls in mt8186_init_clock() had failed.
CVE-2023-53859 1 Linux 1 Linux Kernel 2026-04-15 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: s390/idle: mark arch_cpu_idle() noinstr linux-next commit ("cpuidle: tracing: Warn about !rcu_is_watching()") adds a new warning which hits on s390's arch_cpu_idle() function: RCU not on for: arch_cpu_idle+0x0/0x28 WARNING: CPU: 2 PID: 0 at include/linux/trace_recursion.h:162 arch_ftrace_ops_list_func+0x24c/0x258 Modules linked in: CPU: 2 PID: 0 Comm: swapper/2 Not tainted 6.2.0-rc6-next-20230202 #4 Hardware name: IBM 8561 T01 703 (z/VM 7.3.0) Krnl PSW : 0404d00180000000 00000000002b55c0 (arch_ftrace_ops_list_func+0x250/0x258) R:0 T:1 IO:0 EX:0 Key:0 M:1 W:0 P:0 AS:3 CC:1 PM:0 RI:0 EA:3 Krnl GPRS: c0000000ffffbfff 0000000080000002 0000000000000026 0000000000000000 0000037ffffe3a28 0000037ffffe3a20 0000000000000000 0000000000000000 0000000000000000 0000000000f4acf6 00000000001044f0 0000037ffffe3cb0 0000000000000000 0000000000000000 00000000002b55bc 0000037ffffe3bb8 Krnl Code: 00000000002b55b0: c02000840051 larl %r2,0000000001335652 00000000002b55b6: c0e5fff512d1 brasl %r14,0000000000157b58 #00000000002b55bc: af000000 mc 0,0 >00000000002b55c0: a7f4ffe7 brc 15,00000000002b558e 00000000002b55c4: 0707 bcr 0,%r7 00000000002b55c6: 0707 bcr 0,%r7 00000000002b55c8: eb6ff0480024 stmg %r6,%r15,72(%r15) 00000000002b55ce: b90400ef lgr %r14,%r15 Call Trace: [<00000000002b55c0>] arch_ftrace_ops_list_func+0x250/0x258 ([<00000000002b55bc>] arch_ftrace_ops_list_func+0x24c/0x258) [<0000000000f5f0fc>] ftrace_common+0x1c/0x20 [<00000000001044f6>] arch_cpu_idle+0x6/0x28 [<0000000000f4acf6>] default_idle_call+0x76/0x128 [<00000000001cc374>] do_idle+0xf4/0x1b0 [<00000000001cc6ce>] cpu_startup_entry+0x36/0x40 [<0000000000119d00>] smp_start_secondary+0x140/0x150 [<0000000000f5d2ae>] restart_int_handler+0x6e/0x90 Mark arch_cpu_idle() noinstr like all other architectures with CONFIG_ARCH_WANTS_NO_INSTR (should) have it to fix this.
CVE-2023-53866 1 Linux 1 Linux Kernel 2026-04-15 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: ASoC: soc-compress: Reposition and add pcm_mutex If panic_on_warn is set and compress stream(DPCM) is started, then kernel panic occurred because card->pcm_mutex isn't held appropriately. In the following functions, warning were issued at this line "snd_soc_dpcm_mutex_assert_held". static int dpcm_be_connect(struct snd_soc_pcm_runtime *fe, struct snd_soc_pcm_runtime *be, int stream) { ... snd_soc_dpcm_mutex_assert_held(fe); ... } void dpcm_be_disconnect(struct snd_soc_pcm_runtime *fe, int stream) { ... snd_soc_dpcm_mutex_assert_held(fe); ... } void snd_soc_runtime_action(struct snd_soc_pcm_runtime *rtd, int stream, int action) { ... snd_soc_dpcm_mutex_assert_held(rtd); ... } int dpcm_dapm_stream_event(struct snd_soc_pcm_runtime *fe, int dir, int event) { ... snd_soc_dpcm_mutex_assert_held(fe); ... } These functions are called by soc_compr_set_params_fe, soc_compr_open_fe and soc_compr_free_fe without pcm_mutex locking. And this is call stack. [ 414.527841][ T2179] pc : dpcm_process_paths+0x5a4/0x750 [ 414.527848][ T2179] lr : dpcm_process_paths+0x37c/0x750 [ 414.527945][ T2179] Call trace: [ 414.527949][ T2179] dpcm_process_paths+0x5a4/0x750 [ 414.527955][ T2179] soc_compr_open_fe+0xb0/0x2cc [ 414.527972][ T2179] snd_compr_open+0x180/0x248 [ 414.527981][ T2179] snd_open+0x15c/0x194 [ 414.528003][ T2179] chrdev_open+0x1b0/0x220 [ 414.528023][ T2179] do_dentry_open+0x30c/0x594 [ 414.528045][ T2179] vfs_open+0x34/0x44 [ 414.528053][ T2179] path_openat+0x914/0xb08 [ 414.528062][ T2179] do_filp_open+0xc0/0x170 [ 414.528068][ T2179] do_sys_openat2+0x94/0x18c [ 414.528076][ T2179] __arm64_sys_openat+0x78/0xa4 [ 414.528084][ T2179] invoke_syscall+0x48/0x10c [ 414.528094][ T2179] el0_svc_common+0xbc/0x104 [ 414.528099][ T2179] do_el0_svc+0x34/0xd8 [ 414.528103][ T2179] el0_svc+0x34/0xc4 [ 414.528125][ T2179] el0t_64_sync_handler+0x8c/0xfc [ 414.528133][ T2179] el0t_64_sync+0x1a0/0x1a4 [ 414.528142][ T2179] Kernel panic - not syncing: panic_on_warn set ... So, I reposition and add pcm_mutex to resolve lockdep error.
CVE-2025-40285 1 Linux 1 Linux Kernel 2026-04-15 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: smb/server: fix possible refcount leak in smb2_sess_setup() Reference count of ksmbd_session will leak when session need reconnect. Fix this by adding the missing ksmbd_user_session_put().
CVE-2025-40318 1 Linux 1 Linux Kernel 2026-04-15 7.0 High
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_sync: fix race in hci_cmd_sync_dequeue_once hci_cmd_sync_dequeue_once() does lookup and then cancel the entry under two separate lock sections. Meanwhile, hci_cmd_sync_work() can also delete the same entry, leading to double list_del() and "UAF". Fix this by holding cmd_sync_work_lock across both lookup and cancel, so that the entry cannot be removed concurrently.
CVE-2025-40322 1 Linux 1 Linux Kernel 2026-04-15 7.0 High
In the Linux kernel, the following vulnerability has been resolved: fbdev: bitblit: bound-check glyph index in bit_putcs* bit_putcs_aligned()/unaligned() derived the glyph pointer from the character value masked by 0xff/0x1ff, which may exceed the actual font's glyph count and read past the end of the built-in font array. Clamp the index to the actual glyph count before computing the address. This fixes a global out-of-bounds read reported by syzbot.
CVE-2025-40105 1 Linux 1 Linux Kernel 2026-04-15 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: vfs: Don't leak disconnected dentries on umount When user calls open_by_handle_at() on some inode that is not cached, we will create disconnected dentry for it. If such dentry is a directory, exportfs_decode_fh_raw() will then try to connect this dentry to the dentry tree through reconnect_path(). It may happen for various reasons (such as corrupted fs or race with rename) that the call to lookup_one_unlocked() in reconnect_one() will fail to find the dentry we are trying to reconnect and instead create a new dentry under the parent. Now this dentry will not be marked as disconnected although the parent still may well be disconnected (at least in case this inconsistency happened because the fs is corrupted and .. doesn't point to the real parent directory). This creates inconsistency in disconnected flags but AFAICS it was mostly harmless. At least until commit f1ee616214cb ("VFS: don't keep disconnected dentries on d_anon") which removed adding of most disconnected dentries to sb->s_anon list. Thus after this commit cleanup of disconnected dentries implicitely relies on the fact that dput() will immediately reclaim such dentries. However when some leaf dentry isn't marked as disconnected, as in the scenario described above, the reclaim doesn't happen and the dentries are "leaked". Memory reclaim can eventually reclaim them but otherwise they stay in memory and if umount comes first, we hit infamous "Busy inodes after unmount" bug. Make sure all dentries created under a disconnected parent are marked as disconnected as well.
CVE-2025-40048 1 Linux 1 Linux Kernel 2026-04-15 7.0 High
In the Linux kernel, the following vulnerability has been resolved: uio_hv_generic: Let userspace take care of interrupt mask Remove the logic to set interrupt mask by default in uio_hv_generic driver as the interrupt mask value is supposed to be controlled completely by the user space. If the mask bit gets changed by the driver, concurrently with user mode operating on the ring, the mask bit may be set when it is supposed to be clear, and the user-mode driver will miss an interrupt which will cause a hang. For eg- when the driver sets inbound ring buffer interrupt mask to 1, the host does not interrupt the guest on the UIO VMBus channel. However, setting the mask does not prevent the host from putting a message in the inbound ring buffer. So let’s assume that happens, the host puts a message into the ring buffer but does not interrupt. Subsequently, the user space code in the guest sets the inbound ring buffer interrupt mask to 0, saying “Hey, I’m ready for interrupts”. User space code then calls pread() to wait for an interrupt. Then one of two things happens: * The host never sends another message. So the pread() waits forever. * The host does send another message. But because there’s already a message in the ring buffer, it doesn’t generate an interrupt. This is the correct behavior, because the host should only send an interrupt when the inbound ring buffer transitions from empty to not-empty. Adding an additional message to a ring buffer that is not empty is not supposed to generate an interrupt on the guest. Since the guest is waiting in pread() and not removing messages from the ring buffer, the pread() waits forever. This could be easily reproduced in hv_fcopy_uio_daemon if we delay setting interrupt mask to 0. Similarly if hv_uio_channel_cb() sets the interrupt_mask to 1, there’s a race condition. Once user space empties the inbound ring buffer, but before user space sets interrupt_mask to 0, the host could put another message in the ring buffer but it wouldn’t interrupt. Then the next pread() would hang. Fix these by removing all instances where interrupt_mask is changed, while keeping the one in set_event() unchanged to enable userspace control the interrupt mask by writing 0/1 to /dev/uioX.