CVE-2025-21868

Published Mar 27, 2025

Last updated 7 months ago

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: net: allow small head cache usage with large MAX_SKB_FRAGS values Sabrina reported the following splat: WARNING: CPU: 0 PID: 1 at net/core/dev.c:6935 netif_napi_add_weight_locked+0x8f2/0xba0 Modules linked in: CPU: 0 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.14.0-rc1-net-00092-g011b03359038 #996 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014 RIP: 0010:netif_napi_add_weight_locked+0x8f2/0xba0 Code: e8 c3 e6 6a fe 48 83 c4 28 5b 5d 41 5c 41 5d 41 5e 41 5f c3 cc cc cc cc c7 44 24 10 ff ff ff ff e9 8f fb ff ff e8 9e e6 6a fe <0f> 0b e9 d3 fe ff ff e8 92 e6 6a fe 48 8b 04 24 be ff ff ff ff 48 RSP: 0000:ffffc9000001fc60 EFLAGS: 00010293 RAX: 0000000000000000 RBX: ffff88806ce48128 RCX: 1ffff11001664b9e RDX: ffff888008f00040 RSI: ffffffff8317ca42 RDI: ffff88800b325cb6 RBP: ffff88800b325c40 R08: 0000000000000001 R09: ffffed100167502c R10: ffff88800b3a8163 R11: 0000000000000000 R12: ffff88800ac1c168 R13: ffff88800ac1c168 R14: ffff88800ac1c168 R15: 0000000000000007 FS: 0000000000000000(0000) GS:ffff88806ce00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff888008201000 CR3: 0000000004c94001 CR4: 0000000000370ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> gro_cells_init+0x1ba/0x270 xfrm_input_init+0x4b/0x2a0 xfrm_init+0x38/0x50 ip_rt_init+0x2d7/0x350 ip_init+0xf/0x20 inet_init+0x406/0x590 do_one_initcall+0x9d/0x2e0 do_initcalls+0x23b/0x280 kernel_init_freeable+0x445/0x490 kernel_init+0x20/0x1d0 ret_from_fork+0x46/0x80 ret_from_fork_asm+0x1a/0x30 </TASK> irq event stamp: 584330 hardirqs last enabled at (584338): [<ffffffff8168bf87>] __up_console_sem+0x77/0xb0 hardirqs last disabled at (584345): [<ffffffff8168bf6c>] __up_console_sem+0x5c/0xb0 softirqs last enabled at (583242): [<ffffffff833ee96d>] netlink_insert+0x14d/0x470 softirqs last disabled at (583754): [<ffffffff8317c8cd>] netif_napi_add_weight_locked+0x77d/0xba0 on kernel built with MAX_SKB_FRAGS=45, where SKB_WITH_OVERHEAD(1024) is smaller than GRO_MAX_HEAD. Such built additionally contains the revert of the single page frag cache so that napi_get_frags() ends up using the page frag allocator, triggering the splat. Note that the underlying issue is independent from the mentioned revert; address it ensuring that the small head cache will fit either TCP and GRO allocation and updating napi_alloc_skb() and __netdev_alloc_skb() to select kmalloc() usage for any allocation fitting such cache.
Source
416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD status
Modified
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-noinfo

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