kernel-hacking-2024-linux-s.../kernel/events
Shuai Xue 54aee5f15b 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)

Signed-off-by: Shuai Xue <xueshuai@linux.alibaba.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2023-09-12 17:46:31 +02:00
..
callchain.c
core.c Perf events changes for v6.6: 2023-08-28 16:35:01 -07:00
hw_breakpoint.c perf/hw_breakpoint: Annotate tsk->perf_event_mutex vs ctx->mutex 2022-10-04 13:32:09 +02:00
hw_breakpoint_test.c perf/hw_breakpoint: remove MODULE_LICENSE in non-modules 2023-04-13 13:13:52 -07:00
internal.h
Makefile
ring_buffer.c perf/core: Bail out early if the request AUX area is out of bound 2023-09-12 17:46:31 +02:00
uprobes.c mm: ptep_get() conversion 2023-06-19 16:19:25 -07:00