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Message-ID: <20231106231514.3735077-1-sashal@kernel.org>
Date: Mon, 6 Nov 2023 18:14:54 -0500
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc: Shuai Xue <xueshuai@...ux.alibaba.com>,
Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...nel.org>,
Sasha Levin <sashal@...nel.org>, mingo@...hat.com,
acme@...nel.org, linux-perf-users@...r.kernel.org
Subject: [PATCH AUTOSEL 6.5 01/13] perf/core: Bail out early if the request AUX area is out of bound
From: Shuai Xue <xueshuai@...ux.alibaba.com>
[ Upstream commit 54aee5f15b83437f23b2b2469bcf21bdd9823916 ]
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@...ux.alibaba.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Signed-off-by: Ingo Molnar <mingo@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
kernel/events/ring_buffer.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c
index a0433f37b0243..4a260ceed9c73 100644
--- a/kernel/events/ring_buffer.c
+++ b/kernel/events/ring_buffer.c
@@ -699,6 +699,12 @@ int rb_alloc_aux(struct perf_buffer *rb, struct perf_event *event,
watermark = 0;
}
+ /*
+ * kcalloc_node() is unable to allocate buffer if the size is larger
+ * than: PAGE_SIZE << MAX_ORDER; directly bail out in this case.
+ */
+ if (get_order((unsigned long)nr_pages * sizeof(void *)) > MAX_ORDER)
+ return -ENOMEM;
rb->aux_pages = kcalloc_node(nr_pages, sizeof(void *), GFP_KERNEL,
node);
if (!rb->aux_pages)
--
2.42.0
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