CVE-2025-21886

Published Mar 27, 2025

Last updated 8 months ago

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: RDMA/mlx5: Fix implicit ODP hang on parent deregistration Fix the destroy_unused_implicit_child_mr() to prevent hanging during parent deregistration as of below [1]. Upon entering destroy_unused_implicit_child_mr(), the reference count for the implicit MR parent is incremented using: refcount_inc_not_zero(). A corresponding decrement must be performed if free_implicit_child_mr_work() is not called. The code has been updated to properly manage the reference count that was incremented. [1] INFO: task python3:2157 blocked for more than 120 seconds. Not tainted 6.12.0-rc7+ #1633 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:python3 state:D stack:0 pid:2157 tgid:2157 ppid:1685 flags:0x00000000 Call Trace: <TASK> __schedule+0x420/0xd30 schedule+0x47/0x130 __mlx5_ib_dereg_mr+0x379/0x5d0 [mlx5_ib] ? __pfx_autoremove_wake_function+0x10/0x10 ib_dereg_mr_user+0x5f/0x120 [ib_core] ? lock_release+0xc6/0x280 destroy_hw_idr_uobject+0x1d/0x60 [ib_uverbs] uverbs_destroy_uobject+0x58/0x1d0 [ib_uverbs] uobj_destroy+0x3f/0x70 [ib_uverbs] ib_uverbs_cmd_verbs+0x3e4/0xbb0 [ib_uverbs] ? __pfx_uverbs_destroy_def_handler+0x10/0x10 [ib_uverbs] ? lock_acquire+0xc1/0x2f0 ? ib_uverbs_ioctl+0xcb/0x170 [ib_uverbs] ? ib_uverbs_ioctl+0x116/0x170 [ib_uverbs] ? lock_release+0xc6/0x280 ib_uverbs_ioctl+0xe7/0x170 [ib_uverbs] ? ib_uverbs_ioctl+0xcb/0x170 [ib_uverbs] __x64_sys_ioctl+0x1b0/0xa70 ? kmem_cache_free+0x221/0x400 do_syscall_64+0x6b/0x140 entry_SYSCALL_64_after_hwframe+0x76/0x7e RIP: 0033:0x7f20f21f017b RSP: 002b:00007ffcfc4a77c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007ffcfc4a78d8 RCX: 00007f20f21f017b RDX: 00007ffcfc4a78c0 RSI: 00000000c0181b01 RDI: 0000000000000003 RBP: 00007ffcfc4a78a0 R08: 000056147d125190 R09: 00007f20f1f14c60 R10: 0000000000000001 R11: 0000000000000246 R12: 00007ffcfc4a7890 R13: 000000000000001c R14: 000056147d100fc0 R15: 00007f20e365c9d0 </TASK>
Source
416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD status
Analyzed
Products
linux_kernel

Risk scores

CVSS 3.1

Type
Primary
Base score
5.5
Impact score
3.6
Exploitability score
1.8
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Severity
MEDIUM

Weaknesses

nvd@nist.gov
NVD-CWE-Other

Social media

Hype score
Not currently trending

Configurations

  1. In the Linux kernel, the following vulnerability has been resolved: coresight: tmc-etr: Fix race condition between sysfs and perf mode When trying to run perf and sysfs mode simultaneously, the WARN_ON() in tmc_etr_enable_hw() is triggered sometimes: WARNING: CPU: 42 PID: 3911571 at drivers/hwtracing/coresight/coresight-tmc-etr.c:1060 tmc_etr_enable_hw+0xc0/0xd8 [coresight_tmc] [..snip..] Call trace: tmc_etr_enable_hw+0xc0/0xd8 [coresight_tmc] (P) tmc_enable_etr_sink+0x11c/0x250 [coresight_tmc] (L) tmc_enable_etr_sink+0x11c/0x250 [coresight_tmc] coresight_enable_path+0x1c8/0x218 [coresight] coresight_enable_sysfs+0xa4/0x228 [coresight] enable_source_store+0x58/0xa8 [coresight] dev_attr_store+0x20/0x40 sysfs_kf_write+0x4c/0x68 kernfs_fop_write_iter+0x120/0x1b8 vfs_write+0x2c8/0x388 ksys_write+0x74/0x108 __arm64_sys_write+0x24/0x38 el0_svc_common.constprop.0+0x64/0x148 do_el0_svc+0x24/0x38 el0_svc+0x3c/0x130 el0t_64_sync_handler+0xc8/0xd0 el0t_64_sync+0x1ac/0x1b0 ---[ end trace 0000000000000000 ]--- Since the enablement of sysfs mode is separeted into two critical regions, one for sysfs buffer allocation and another for hardware enablement, it's possible to race with the perf mode. Fix this by double check whether the perf mode's been used before enabling the hardware in sysfs mode. mode: [sysfs mode] [perf mode] tmc_etr_get_sysfs_buffer() spin_lock(&drvdata->spinlock) [sysfs buffer allocation] spin_unlock(&drvdata->spinlock) spin_lock(&drvdata->spinlock) tmc_etr_enable_hw() drvdata->etr_buf = etr_perf->etr_buf spin_unlock(&drvdata->spinlock) spin_lock(&drvdata->spinlock) tmc_etr_enable_hw() WARN_ON(drvdata->etr_buf) // WARN sicne etr_buf initialized at the perf side spin_unlock(&drvdata->spinlock) With this fix, we retain the check for CS_MODE_PERF in get_etr_sysfs_buf. This ensures we verify whether the perf mode's already running before we actually allocate the buffer. Then we can save the time of allocating/freeing the sysfs buffer if race with the perf mode.CVE-2026-46272