CVE-2025-37807 — bpf: Fix kmemleak warning for percpu hashmap

Affected: Linux

In the Linux kernel, the following vulnerability has been resolved:

bpf: Fix kmemleak warning for percpu hashmap

Vlad Poenaru reported the following kmemleak issue:

unreferenced object 0x606fd7c44ac8 (size 32): backtrace (crc 0): pcpu_alloc_noprof+0x730/0xeb0 bpf_map_alloc_percpu+0x69/0xc0 prealloc_init+0x9d/0x1b0 htab_map_alloc+0x363/0x510 map_create+0x215/0x3a0 __sys_bpf+0x16b/0x3e0 __x64_sys_bpf+0x18/0x20 do_syscall_64+0x7b/0x150 entry_SYSCALL_64_after_hwframe+0x4b/0x53

Further investigation shows the reason is due to not 8-byte aligned store of percpu pointer in htab_elem_set_ptr(): *(void __percpu **)(l->key + key_size) = pptr;

Note that the whole htab_elem alignment is 8 (for x86_64). If the key_size is 4, that means pptr is stored in a location which is 4 byte aligned but not 8 byte aligned. In mm/kmemleak.c, scan_block() scans the memory based on 8 byte stride, so it won't detect above pptr, hence reporting the memory leak.

In htab_map_alloc(), we already have

htab->elem_size = sizeof(struct htab_elem) + round_up(htab->map.key_size, 8); if (percpu) htab->elem_size += sizeof(void *); else htab->elem_size += round_up(htab->map.value_size, 8);

So storing pptr with 8-byte alignment won't cause any problem and can fix kmemleak too.

The issue can be reproduced with bpf selftest as well: 1. Enable CONFIG_DEBUG_KMEMLEAK co…

USN-7594-1 — linux, linux-gcp, linux-raspi, linux-realtime vulnerabilities

Affected: Ubuntu:25.04: linux, Ubuntu:25.04: linux-gcp, Ubuntu:25.04: linux-raspi, Ubuntu:25.04: linux-realtime

Several security issues were discovered in the Linux kernel. An attacker could possibly use these to compromise the system. This update corrects flaws in the following subsystems: - ARM32 architecture; - ARM64 architecture; - PowerPC architecture; - RISC-V architecture; - User-Mode Linux (UML); - x86 architecture; - Block layer subsystem; - Cryptographic API; - Compute Acceleration Framework; - ACPI drivers; - Serial ATA and Parallel ATA drivers; - Drivers core; - Ublk userspace block driver; - Bluetooth drivers; - Bus devices; - TPM device driver; - Clock framework and drivers; - CPU frequency scaling framework; - Buffer Sharing and Synchronization framework; - DMA engine subsystem; - GPU drivers; - HID subsystem; - HSI subsystem; - I2C subsystem; - I3C subsystem; - IIO subsystem; - InfiniBand drivers; - IOMMU subsystem; - IRQ chip drivers; - MCB driver; - Multiple devices driver; - Media drivers; - MemoryStick subsystem; - Multifunction device drivers; - Microchip PCI driver; - Intel Management Engine Interface driver; - PCI Endpoint Test driver; - MTD block device drivers; - Network drivers; - Ethernet bonding driver; - Mellanox network drivers; - STMicroelectronics network drivers; - NTB driver; - NVME drivers; - PCI subsystem; - Synopsys DesignWare PCIe PMU; - Mellanox platform drivers; - PWM drivers; - Remote Processor subsystem; - S/390 drivers; - SCSI subsystem; -…

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CVE-2025-37807 — bpf: Fix kmemleak warning for percpu hashmap

USN-7594-1 — linux, linux-gcp, linux-raspi, linux-realtime vulnerabilities