Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
perf/core: Bail out early if the request AUX area is out of bound
When perf-record with a large AUX area, e.g 4GB, it fails with:
#perf record -C 0 -m ,4G -e arm_spe_0// – sleep 1 failed to mmap with 12 (Cannot allocate memory)
and it reveals a WARNING with __alloc_pages():
————[ cut here ]———— WARNING: CPU: 44 PID: 17573 at mm/page_alloc.c:5568 __alloc_pages+0x1ec/0x248 Call trace: __alloc_pages+0x1ec/0x248 __kmalloc_large_node+0xc0/0x1f8 __kmalloc_node+0x134/0x1e8 rb_alloc_aux+0xe0/0x298 perf_mmap+0x440/0x660 mmap_region+0x308/0x8a8 do_mmap+0x3c0/0x528 vm_mmap_pgoff+0xf4/0x1b8 ksys_mmap_pgoff+0x18c/0x218 __arm64_sys_mmap+0x38/0x58 invoke_syscall+0x50/0x128 el0_svc_common.constprop.0+0x58/0x188 do_el0_svc+0x34/0x50 el0_svc+0x34/0x108 el0t_64_sync_handler+0xb8/0xc0 el0t_64_sync+0x1a4/0x1a8
‘rb->aux_pages’ allocated by kcalloc() is a pointer array which is used to maintains AUX trace pages. The allocated page for this array is physically contiguous (and virtually contiguous) with an order of 0..MAX_ORDER. If the size of pointer array crosses the limitation set by MAX_ORDER, it reveals a WARNING.
So bail out early with -ENOMEM if the request AUX area is out of bound, e.g.:
#perf record -C 0 -m ,4G -e arm_spe_0// – sleep 1 failed to mmap with 12 (Cannot allocate memory)
Details
- Affected product:
- AlmaLinux 9.2 ESU , CentOS 6 ELS , CentOS 7 ELS , CentOS 8.4 ELS , CentOS 8.5 ELS , CentOS Stream 8 ELS , CloudLinux 6 ELS , Oracle Linux 6 ELS , Oracle Linux 7 ELS , RHEL 7 ELS , Ubuntu 16.04 ELS , Ubuntu 18.04 ELS
- Affected packages:
- kernel @ 3.10.0 (+13 more)
In the Linux kernel, the following vulnerability has been resolved:
perf/core: Bail out early if the request AUX area is out of bound
When perf-record with a large AUX area, e.g 4GB, it fails with:
#perf record -C 0 -m ,4G -e arm_spe_0// – sleep 1 failed to mmap with 12 (Cannot allocate memory)
and it reveals a WARNING with __alloc_pages():
————[ cut here ]———— WARNING: CPU: 44 PID: 17573 at mm/page_alloc.c:5568 __alloc_pages+0x1ec/0x248 Call trace: __alloc_pages+0x1ec/0x248 __kmalloc_large_node+0xc0/0x1f8 __kmalloc_node+0x134/0x1e8 rb_alloc_aux+0xe0/0x298 perf_mmap+0x440/0x660 mmap_region+0x308/0x8a8 do_mmap+0x3c0/0x528 vm_mmap_pgoff+0xf4/0x1b8 ksys_mmap_pgoff+0x18c/0x218 __arm64_sys_mmap+0x38/0x58 invoke_syscall+0x50/0x128 el0_svc_common.constprop.0+0x58/0x188 do_el0_svc+0x34/0x50 el0_svc+0x34/0x108 el0t_64_sync_handler+0xb8/0xc0 el0t_64_sync+0x1a4/0x1a8
‘rb->aux_pages’ allocated by kcalloc() is a pointer array which is used to maintains AUX trace pages. The allocated page for this array is physically contiguous (and virtually contiguous) with an order of 0..MAX_ORDER. If the size of pointer array crosses the limitation set by MAX_ORDER, it reveals a WARNING.
So bail out early with -ENOMEM if the request AUX area is out of bound, e.g.:
#perf record -C 0 -m ,4G -e arm_spe_0// – sleep 1 failed to mmap with 12 (Cannot allocate memory)