Filtered by vendor Linux Subscriptions
Total 17084 CVE
CVE Vendors Products Updated CVSS v3.1
CVE-2025-71202 1 Linux 1 Linux Kernel 2026-02-18 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: iommu/sva: invalidate stale IOTLB entries for kernel address space Introduce a new IOMMU interface to flush IOTLB paging cache entries for the CPU kernel address space. This interface is invoked from the x86 architecture code that manages combined user and kernel page tables, specifically before any kernel page table page is freed and reused. This addresses the main issue with vfree() which is a common occurrence and can be triggered by unprivileged users. While this resolves the primary problem, it doesn't address some extremely rare case related to memory unplug of memory that was present as reserved memory at boot, which cannot be triggered by unprivileged users. The discussion can be found at the link below. Enable SVA on x86 architecture since the IOMMU can now receive notification to flush the paging cache before freeing the CPU kernel page table pages.
CVE-2025-71200 1 Linux 1 Linux Kernel 2026-02-18 N/A
In the Linux kernel, the following vulnerability has been resolved: mmc: sdhci-of-dwcmshc: Prevent illegal clock reduction in HS200/HS400 mode When operating in HS200 or HS400 timing modes, reducing the clock frequency below 52MHz will lead to link broken as the Rockchip DWC MSHC controller requires maintaining a minimum clock of 52MHz in these modes. Add a check to prevent illegal clock reduction through debugfs: root@debian:/# echo 50000000 > /sys/kernel/debug/mmc0/clock root@debian:/# [ 30.090146] mmc0: running CQE recovery mmc0: cqhci: Failed to halt mmc0: cqhci: spurious TCN for tag 0 WARNING: drivers/mmc/host/cqhci-core.c:797 at cqhci_irq+0x254/0x818, CPU#1: kworker/1:0H/24 Modules linked in: CPU: 1 UID: 0 PID: 24 Comm: kworker/1:0H Not tainted 6.19.0-rc1-00001-g09db0998649d-dirty #204 PREEMPT Hardware name: Rockchip RK3588 EVB1 V10 Board (DT) Workqueue: kblockd blk_mq_run_work_fn pstate: 604000c9 (nZCv daIF +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : cqhci_irq+0x254/0x818 lr : cqhci_irq+0x254/0x818 ...
CVE-2026-23162 1 Linux 1 Linux Kernel 2026-02-18 7.0 High
In the Linux kernel, the following vulnerability has been resolved: drm/xe/nvm: Fix double-free on aux add failure After a successful auxiliary_device_init(), aux_dev->dev.release (xe_nvm_release_dev()) is responsible for the kfree(nvm). When there is failure with auxiliary_device_add(), driver will call auxiliary_device_uninit(), which call put_device(). So that the .release callback will be triggered to free the memory associated with the auxiliary_device. Move the kfree(nvm) into the auxiliary_device_init() failure path and remove the err goto path to fix below error. " [ 13.232905] ================================================================== [ 13.232911] BUG: KASAN: double-free in xe_nvm_init+0x751/0xf10 [xe] [ 13.233112] Free of addr ffff888120635000 by task systemd-udevd/273 [ 13.233120] CPU: 8 UID: 0 PID: 273 Comm: systemd-udevd Not tainted 6.19.0-rc2-lgci-xe-kernel+ #225 PREEMPT(voluntary) ... [ 13.233125] Call Trace: [ 13.233126] <TASK> [ 13.233127] dump_stack_lvl+0x7f/0xc0 [ 13.233132] print_report+0xce/0x610 [ 13.233136] ? kasan_complete_mode_report_info+0x5d/0x1e0 [ 13.233139] ? xe_nvm_init+0x751/0xf10 [xe] ... " v2: drop err goto path. (Alexander) (cherry picked from commit a3187c0c2bbd947ffff97f90d077ac88f9c2a215)
CVE-2026-23115 1 Linux 1 Linux Kernel 2026-02-18 N/A
In the Linux kernel, the following vulnerability has been resolved: serial: Fix not set tty->port race condition Revert commit bfc467db60b7 ("serial: remove redundant tty_port_link_device()") because the tty_port_link_device() is not redundant: the tty->port has to be confured before we call uart_configure_port(), otherwise user-space can open console without TTY linked to the driver. This tty_port_link_device() was added explicitly to avoid this exact issue in commit fb2b90014d78 ("tty: link tty and port before configuring it as console"), so offending commit basically reverted the fix saying it is redundant without addressing the actual race condition presented there. Reproducible always as tty->port warning on Qualcomm SoC with most of devices disabled, so with very fast boot, and one serial device being the console: printk: legacy console [ttyMSM0] enabled printk: legacy console [ttyMSM0] enabled printk: legacy bootconsole [qcom_geni0] disabled printk: legacy bootconsole [qcom_geni0] disabled ------------[ cut here ]------------ tty_init_dev: ttyMSM driver does not set tty->port. This would crash the kernel. Fix the driver! WARNING: drivers/tty/tty_io.c:1414 at tty_init_dev.part.0+0x228/0x25c, CPU#2: systemd/1 Modules linked in: socinfo tcsrcc_eliza gcc_eliza sm3_ce fuse ipv6 CPU: 2 UID: 0 PID: 1 Comm: systemd Tainted: G S 6.19.0-rc4-next-20260108-00024-g2202f4d30aa8 #73 PREEMPT Tainted: [S]=CPU_OUT_OF_SPEC Hardware name: Qualcomm Technologies, Inc. Eliza (DT) ... tty_init_dev.part.0 (drivers/tty/tty_io.c:1414 (discriminator 11)) (P) tty_open (arch/arm64/include/asm/atomic_ll_sc.h:95 (discriminator 3) drivers/tty/tty_io.c:2073 (discriminator 3) drivers/tty/tty_io.c:2120 (discriminator 3)) chrdev_open (fs/char_dev.c:411) do_dentry_open (fs/open.c:962) vfs_open (fs/open.c:1094) do_open (fs/namei.c:4634) path_openat (fs/namei.c:4793) do_filp_open (fs/namei.c:4820) do_sys_openat2 (fs/open.c:1391 (discriminator 3)) ... Starting Network Name Resolution... Apparently the flow with this small Yocto-based ramdisk user-space is: driver (qcom_geni_serial.c): user-space: ============================ =========== qcom_geni_serial_probe() uart_add_one_port() serial_core_register_port() serial_core_add_one_port() uart_configure_port() register_console() | | open console | ... | tty_init_dev() | driver->ports[idx] is NULL | tty_port_register_device_attr_serdev() tty_port_link_device() <- set driver->ports[idx]
CVE-2026-23118 1 Linux 1 Linux Kernel 2026-02-18 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: rxrpc: Fix data-race warning and potential load/store tearing Fix the following: BUG: KCSAN: data-race in rxrpc_peer_keepalive_worker / rxrpc_send_data_packet which is reporting an issue with the reads and writes to ->last_tx_at in: conn->peer->last_tx_at = ktime_get_seconds(); and: keepalive_at = peer->last_tx_at + RXRPC_KEEPALIVE_TIME; The lockless accesses to these to values aren't actually a problem as the read only needs an approximate time of last transmission for the purposes of deciding whether or not the transmission of a keepalive packet is warranted yet. Also, as ->last_tx_at is a 64-bit value, tearing can occur on a 32-bit arch. Fix both of these by switching to an unsigned int for ->last_tx_at and only storing the LSW of the time64_t. It can then be reconstructed at need provided no more than 68 years has elapsed since the last transmission.
CVE-2026-23135 1 Linux 1 Linux Kernel 2026-02-18 7.0 High
In the Linux kernel, the following vulnerability has been resolved: wifi: ath12k: fix dma_free_coherent() pointer dma_alloc_coherent() allocates a DMA mapped buffer and stores the addresses in XXX_unaligned fields. Those should be reused when freeing the buffer rather than the aligned addresses.
CVE-2026-23142 1 Linux 1 Linux Kernel 2026-02-18 7.0 High
In the Linux kernel, the following vulnerability has been resolved: mm/damon/sysfs-scheme: cleanup access_pattern subdirs on scheme dir setup failure When a DAMOS-scheme DAMON sysfs directory setup fails after setup of access_pattern/ directory, subdirectories of access_pattern/ directory are not cleaned up. As a result, DAMON sysfs interface is nearly broken until the system reboots, and the memory for the unremoved directory is leaked. Cleanup the directories under such failures.
CVE-2026-23121 1 Linux 1 Linux Kernel 2026-02-18 7.0 High
In the Linux kernel, the following vulnerability has been resolved: mISDN: annotate data-race around dev->work dev->work can re read locklessly in mISDN_read() and mISDN_poll(). Add READ_ONCE()/WRITE_ONCE() annotations. BUG: KCSAN: data-race in mISDN_ioctl / mISDN_read write to 0xffff88812d848280 of 4 bytes by task 10864 on cpu 1: misdn_add_timer drivers/isdn/mISDN/timerdev.c:175 [inline] mISDN_ioctl+0x2fb/0x550 drivers/isdn/mISDN/timerdev.c:233 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xce/0x140 fs/ioctl.c:583 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:583 x64_sys_call+0x14b0/0x3000 arch/x86/include/generated/asm/syscalls_64.h:17 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xd8/0x2c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f read to 0xffff88812d848280 of 4 bytes by task 10857 on cpu 0: mISDN_read+0x1f2/0x470 drivers/isdn/mISDN/timerdev.c:112 do_loop_readv_writev fs/read_write.c:847 [inline] vfs_readv+0x3fb/0x690 fs/read_write.c:1020 do_readv+0xe7/0x210 fs/read_write.c:1080 __do_sys_readv fs/read_write.c:1165 [inline] __se_sys_readv fs/read_write.c:1162 [inline] __x64_sys_readv+0x45/0x50 fs/read_write.c:1162 x64_sys_call+0x2831/0x3000 arch/x86/include/generated/asm/syscalls_64.h:20 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xd8/0x2c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f value changed: 0x00000000 -> 0x00000001
CVE-2026-23122 1 Linux 1 Linux Kernel 2026-02-18 7.0 High
In the Linux kernel, the following vulnerability has been resolved: igc: Reduce TSN TX packet buffer from 7KB to 5KB per queue The previous 7 KB per queue caused TX unit hangs under heavy timestamping load. Reducing to 5 KB avoids these hangs and matches the TSN recommendation in I225/I226 SW User Manual Section 7.5.4. The 8 KB "freed" by this change is currently unused. This reduction is not expected to impact throughput, as the i226 is PCIe-limited for small TSN packets rather than TX-buffer-limited.
CVE-2026-23131 1 Linux 1 Linux Kernel 2026-02-18 N/A
In the Linux kernel, the following vulnerability has been resolved: platform/x86: hp-bioscfg: Fix kobject warnings for empty attribute names The hp-bioscfg driver attempts to register kobjects with empty names when the HP BIOS returns attributes with empty name strings. This causes multiple kernel warnings: kobject: (00000000135fb5e6): attempted to be registered with empty name! WARNING: CPU: 14 PID: 3336 at lib/kobject.c:219 kobject_add_internal+0x2eb/0x310 Add validation in hp_init_bios_buffer_attribute() to check if the attribute name is empty after parsing it from the WMI buffer. If empty, log a debug message and skip registration of that attribute, allowing the module to continue processing other valid attributes.
CVE-2026-23132 1 Linux 1 Linux Kernel 2026-02-18 N/A
In the Linux kernel, the following vulnerability has been resolved: drm/bridge: synopsys: dw-dp: fix error paths of dw_dp_bind Fix several issues in dw_dp_bind() error handling: 1. Missing return after drm_bridge_attach() failure - the function continued execution instead of returning an error. 2. Resource leak: drm_dp_aux_register() is not a devm function, so drm_dp_aux_unregister() must be called on all error paths after aux registration succeeds. This affects errors from: - drm_bridge_attach() - phy_init() - devm_add_action_or_reset() - platform_get_irq() - devm_request_threaded_irq() 3. Bug fix: platform_get_irq() returns the IRQ number or a negative error code, but the error path was returning ERR_PTR(ret) instead of ERR_PTR(dp->irq). Use a goto label for cleanup to ensure consistent error handling.
CVE-2026-23147 1 Linux 1 Linux Kernel 2026-02-18 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: btrfs: zlib: fix the folio leak on S390 hardware acceleration [BUG] After commit aa60fe12b4f4 ("btrfs: zlib: refactor S390x HW acceleration buffer preparation"), we no longer release the folio of the page cache of folio returned by btrfs_compress_filemap_get_folio() for S390 hardware acceleration path. [CAUSE] Before that commit, we call kumap_local() and folio_put() after handling each folio. Although the timing is not ideal (it release previous folio at the beginning of the loop, and rely on some extra cleanup out of the loop), it at least handles the folio release correctly. Meanwhile the refactored code is easier to read, it lacks the call to release the filemap folio. [FIX] Add the missing folio_put() for copy_data_into_buffer().
CVE-2026-23152 1 Linux 1 Linux Kernel 2026-02-18 7.1 High
In the Linux kernel, the following vulnerability has been resolved: wifi: mac80211: correctly decode TTLM with default link map TID-To-Link Mapping (TTLM) elements do not contain any link mapping presence indicator if a default mapping is used and parsing needs to be skipped. Note that access points should not explicitly report an advertised TTLM with a default mapping as that is the implied mapping if the element is not included, this is even the case when switching back to the default mapping. However, mac80211 would incorrectly parse the frame and would also read one byte beyond the end of the element.
CVE-2026-23153 1 Linux 1 Linux Kernel 2026-02-18 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: firewire: core: fix race condition against transaction list The list of transaction is enumerated without acquiring card lock when processing AR response event. This causes a race condition bug when processing AT request completion event concurrently. This commit fixes the bug by put timer start for split transaction expiration into the scope of lock. The value of jiffies in card structure is referred before acquiring the lock.
CVE-2026-23158 1 Linux 1 Linux Kernel 2026-02-18 N/A
In the Linux kernel, the following vulnerability has been resolved: gpio: virtuser: fix UAF in configfs release path The gpio-virtuser configfs release path uses guard(mutex) to protect the device structure. However, the device is freed before the guard cleanup runs, causing mutex_unlock() to operate on freed memory. Specifically, gpio_virtuser_device_config_group_release() destroys the mutex and frees the device while still inside the guard(mutex) scope. When the function returns, the guard cleanup invokes mutex_unlock(&dev->lock), resulting in a slab use-after-free. Limit the mutex lifetime by using a scoped_guard() only around the activation check, so that the lock is released before mutex_destroy() and kfree() are called.
CVE-2026-23160 1 Linux 1 Linux Kernel 2026-02-18 7.0 High
In the Linux kernel, the following vulnerability has been resolved: octeon_ep: Fix memory leak in octep_device_setup() In octep_device_setup(), if octep_ctrl_net_init() fails, the function returns directly without unmapping the mapped resources and freeing the allocated configuration memory. Fix this by jumping to the unsupported_dev label, which performs the necessary cleanup. This aligns with the error handling logic of other paths in this function. Compile tested only. Issue found using a prototype static analysis tool and code review.
CVE-2026-23166 1 Linux 1 Linux Kernel 2026-02-18 7.0 High
In the Linux kernel, the following vulnerability has been resolved: ice: Fix NULL pointer dereference in ice_vsi_set_napi_queues Add NULL pointer checks in ice_vsi_set_napi_queues() to prevent crashes during resume from suspend when rings[q_idx]->q_vector is NULL. Tested adaptor: 60:00.0 Ethernet controller [0200]: Intel Corporation Ethernet Controller E810-XXV for SFP [8086:159b] (rev 02) Subsystem: Intel Corporation Ethernet Network Adapter E810-XXV-2 [8086:4003] SR-IOV state: both disabled and enabled can reproduce this issue. kernel version: v6.18 Reproduce steps: Boot up and execute suspend like systemctl suspend or rtcwake. Log: <1>[ 231.443607] BUG: kernel NULL pointer dereference, address: 0000000000000040 <1>[ 231.444052] #PF: supervisor read access in kernel mode <1>[ 231.444484] #PF: error_code(0x0000) - not-present page <6>[ 231.444913] PGD 0 P4D 0 <4>[ 231.445342] Oops: Oops: 0000 [#1] SMP NOPTI <4>[ 231.446635] RIP: 0010:netif_queue_set_napi+0xa/0x170 <4>[ 231.447067] Code: 31 f6 31 ff c3 cc cc cc cc 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 44 00 00 48 85 c9 74 0b <48> 83 79 30 00 0f 84 39 01 00 00 55 41 89 d1 49 89 f8 89 f2 48 89 <4>[ 231.447513] RSP: 0018:ffffcc780fc078c0 EFLAGS: 00010202 <4>[ 231.447961] RAX: ffff8b848ca30400 RBX: ffff8b848caf2028 RCX: 0000000000000010 <4>[ 231.448443] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8b848dbd4000 <4>[ 231.448896] RBP: ffffcc780fc078e8 R08: 0000000000000000 R09: 0000000000000000 <4>[ 231.449345] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 <4>[ 231.449817] R13: ffff8b848dbd4000 R14: ffff8b84833390c8 R15: 0000000000000000 <4>[ 231.450265] FS: 00007c7b29e9d740(0000) GS:ffff8b8c068e2000(0000) knlGS:0000000000000000 <4>[ 231.450715] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 <4>[ 231.451179] CR2: 0000000000000040 CR3: 000000030626f004 CR4: 0000000000f72ef0 <4>[ 231.451629] PKRU: 55555554 <4>[ 231.452076] Call Trace: <4>[ 231.452549] <TASK> <4>[ 231.452996] ? ice_vsi_set_napi_queues+0x4d/0x110 [ice] <4>[ 231.453482] ice_resume+0xfd/0x220 [ice] <4>[ 231.453977] ? __pfx_pci_pm_resume+0x10/0x10 <4>[ 231.454425] pci_pm_resume+0x8c/0x140 <4>[ 231.454872] ? __pfx_pci_pm_resume+0x10/0x10 <4>[ 231.455347] dpm_run_callback+0x5f/0x160 <4>[ 231.455796] ? dpm_wait_for_superior+0x107/0x170 <4>[ 231.456244] device_resume+0x177/0x270 <4>[ 231.456708] dpm_resume+0x209/0x2f0 <4>[ 231.457151] dpm_resume_end+0x15/0x30 <4>[ 231.457596] suspend_devices_and_enter+0x1da/0x2b0 <4>[ 231.458054] enter_state+0x10e/0x570 Add defensive checks for both the ring pointer and its q_vector before dereferencing, allowing the system to resume successfully even when q_vectors are unmapped.
CVE-2026-23113 1 Linux 1 Linux Kernel 2026-02-18 7.0 High
In the Linux kernel, the following vulnerability has been resolved: io_uring/io-wq: check IO_WQ_BIT_EXIT inside work run loop Currently this is checked before running the pending work. Normally this is quite fine, as work items either end up blocking (which will create a new worker for other items), or they complete fairly quickly. But syzbot reports an issue where io-wq takes seemingly forever to exit, and with a bit of debugging, this turns out to be because it queues a bunch of big (2GB - 4096b) reads with a /dev/msr* file. Since this file type doesn't support ->read_iter(), loop_rw_iter() ends up handling them. Each read returns 16MB of data read, which takes 20 (!!) seconds. With a bunch of these pending, processing the whole chain can take a long time. Easily longer than the syzbot uninterruptible sleep timeout of 140 seconds. This then triggers a complaint off the io-wq exit path: INFO: task syz.4.135:6326 blocked for more than 143 seconds. Not tainted syzkaller #0 Blocked by coredump. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.4.135 state:D stack:26824 pid:6326 tgid:6324 ppid:5957 task_flags:0x400548 flags:0x00080000 Call Trace: <TASK> context_switch kernel/sched/core.c:5256 [inline] __schedule+0x1139/0x6150 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6960 schedule_timeout+0x257/0x290 kernel/time/sleep_timeout.c:75 do_wait_for_common kernel/sched/completion.c:100 [inline] __wait_for_common+0x2fc/0x4e0 kernel/sched/completion.c:121 io_wq_exit_workers io_uring/io-wq.c:1328 [inline] io_wq_put_and_exit+0x271/0x8a0 io_uring/io-wq.c:1356 io_uring_clean_tctx+0x10d/0x190 io_uring/tctx.c:203 io_uring_cancel_generic+0x69c/0x9a0 io_uring/cancel.c:651 io_uring_files_cancel include/linux/io_uring.h:19 [inline] do_exit+0x2ce/0x2bd0 kernel/exit.c:911 do_group_exit+0xd3/0x2a0 kernel/exit.c:1112 get_signal+0x2671/0x26d0 kernel/signal.c:3034 arch_do_signal_or_restart+0x8f/0x7e0 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:41 [inline] exit_to_user_mode_loop+0x8c/0x540 kernel/entry/common.c:75 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline] do_syscall_64+0x4ee/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fa02738f749 RSP: 002b:00007fa0281ae0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007fa0275e6098 RCX: 00007fa02738f749 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fa0275e6098 RBP: 00007fa0275e6090 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fa0275e6128 R14: 00007fff14e4fcb0 R15: 00007fff14e4fd98 There's really nothing wrong here, outside of processing these reads will take a LONG time. However, we can speed up the exit by checking the IO_WQ_BIT_EXIT inside the io_worker_handle_work() loop, as syzbot will exit the ring after queueing up all of these reads. Then once the first item is processed, io-wq will simply cancel the rest. That should avoid syzbot running into this complaint again.
CVE-2026-23123 1 Linux 1 Linux Kernel 2026-02-18 5.5 Medium
In the Linux kernel, the following vulnerability has been resolved: interconnect: debugfs: initialize src_node and dst_node to empty strings The debugfs_create_str() API assumes that the string pointer is either NULL or points to valid kmalloc() memory. Leaving the pointer uninitialized can cause problems. Initialize src_node and dst_node to empty strings before creating the debugfs entries to guarantee that reads and writes are safe.
CVE-2026-23127 1 Linux 1 Linux Kernel 2026-02-18 7.0 High
In the Linux kernel, the following vulnerability has been resolved: perf: Fix refcount warning on event->mmap_count increment When calling refcount_inc(&event->mmap_count) inside perf_mmap_rb(), the following warning is triggered: refcount_t: addition on 0; use-after-free. WARNING: lib/refcount.c:25 PoC: struct perf_event_attr attr = {0}; int fd = syscall(__NR_perf_event_open, &attr, 0, -1, -1, 0); mmap(NULL, 0x3000, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); int victim = syscall(__NR_perf_event_open, &attr, 0, -1, fd, PERF_FLAG_FD_OUTPUT); mmap(NULL, 0x3000, PROT_READ | PROT_WRITE, MAP_SHARED, victim, 0); This occurs when creating a group member event with the flag PERF_FLAG_FD_OUTPUT. The group leader should be mmap-ed and then mmap-ing the event triggers the warning. Since the event has copied the output_event in perf_event_set_output(), event->rb is set. As a result, perf_mmap_rb() calls refcount_inc(&event->mmap_count) when event->mmap_count = 0. Disallow the case when event->mmap_count = 0. This also prevents two events from updating the same user_page.