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author | Zhipeng Xie <xiezhipeng1@huawei.com> | 2022-02-09 17:54:17 +0300 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-04-27 15:38:58 +0300 |
commit | 56637084e8a551e7896d846f1e96415681973cbd (patch) | |
tree | 5a0f4a22ebd877a319b2783072f4445ec6b46ca3 /drivers | |
parent | b1b929468229d286b6cd7b09673ef2556d5332bb (diff) | |
download | linux-56637084e8a551e7896d846f1e96415681973cbd.tar.xz |
perf/core: Fix perf_mmap fail when CONFIG_PERF_USE_VMALLOC enabled
[ Upstream commit 60490e7966659b26d74bf1fa4aa8693d9a94ca88 ]
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
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers')
0 files changed, 0 insertions, 0 deletions