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authorZhipeng Xie <xiezhipeng1@huawei.com>2022-02-09 09:54:17 -0500
committerPeter Zijlstra <peterz@infradead.org>2022-04-19 21:15:42 +0200
commit60490e7966659b26d74bf1fa4aa8693d9a94ca88 (patch)
treea14ccb4487d1e3938f0cc525803dd989999f12fb /kernel
parentb2d229d4ddb17db541098b83524d901257e93845 (diff)
downloadlinux-60490e7966659b26d74bf1fa4aa8693d9a94ca88.tar.bz2
perf/core: Fix perf_mmap fail when CONFIG_PERF_USE_VMALLOC enabled
This problem can be reproduced with CONFIG_PERF_USE_VMALLOC enabled on both x86_64 and aarch64 arch when using sysdig -B(using ebpf)[1]. sysdig -B works fine after rebuilding the kernel with CONFIG_PERF_USE_VMALLOC disabled. I tracked it down to the if condition event->rb->nr_pages != nr_pages in perf_mmap is true when CONFIG_PERF_USE_VMALLOC is enabled where event->rb->nr_pages = 1 and nr_pages = 2048 resulting perf_mmap to return -EINVAL. This is because when CONFIG_PERF_USE_VMALLOC is enabled, rb->nr_pages is always equal to 1. Arch with CONFIG_PERF_USE_VMALLOC enabled by default: arc/arm/csky/mips/sh/sparc/xtensa Arch with CONFIG_PERF_USE_VMALLOC disabled by default: x86_64/aarch64/... Fix this problem by using data_page_nr() [1] https://github.com/draios/sysdig Fixes: 906010b2134e ("perf_event: Provide vmalloc() based mmap() backing") Signed-off-by: Zhipeng Xie <xiezhipeng1@huawei.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20220209145417.6495-1-xiezhipeng1@huawei.com
Diffstat (limited to 'kernel')
-rw-r--r--kernel/events/core.c2
-rw-r--r--kernel/events/internal.h5
-rw-r--r--kernel/events/ring_buffer.c5
3 files changed, 6 insertions, 6 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 23bb19716ad3..7858bafffa9d 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -6247,7 +6247,7 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma)
again:
mutex_lock(&event->mmap_mutex);
if (event->rb) {
- if (event->rb->nr_pages != nr_pages) {
+ if (data_page_nr(event->rb) != nr_pages) {
ret = -EINVAL;
goto unlock;
}
diff --git a/kernel/events/internal.h b/kernel/events/internal.h
index 082832738c8f..5150d5f84c03 100644
--- a/kernel/events/internal.h
+++ b/kernel/events/internal.h
@@ -116,6 +116,11 @@ static inline int page_order(struct perf_buffer *rb)
}
#endif
+static inline int data_page_nr(struct perf_buffer *rb)
+{
+ return rb->nr_pages << page_order(rb);
+}
+
static inline unsigned long perf_data_size(struct perf_buffer *rb)
{
return rb->nr_pages << (PAGE_SHIFT + page_order(rb));
diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c
index 52868716ec35..fb35b926024c 100644
--- a/kernel/events/ring_buffer.c
+++ b/kernel/events/ring_buffer.c
@@ -859,11 +859,6 @@ void rb_free(struct perf_buffer *rb)
}
#else
-static int data_page_nr(struct perf_buffer *rb)
-{
- return rb->nr_pages << page_order(rb);
-}
-
static struct page *
__perf_mmap_to_page(struct perf_buffer *rb, unsigned long pgoff)
{