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From: kan.liang@intel.com To: acme@redhat.com Cc: linux-kernel@vger.kernel.org, xiakaixu@huawei.com, a.p.zijlstra@chello.nl, ak@linux.intel.com, Kan Liang <kan.liang@intel.com> Subject: [PATCH 1/1] Revert "perf: Remove the extra validity check on nr_pages" Date: Mon, 2 Mar 2015 02:14:26 -0500 [thread overview] Message-ID: <1425280466-7830-1-git-send-email-kan.liang@intel.com> (raw) From: Kan Liang <kan.liang@intel.com> This reverts commit 74390aa55678 ("perf: Remove the extra validity check on nr_pages") nr_pages equals to number of pages - 1 in perf_mmap. So nr_pages = 0 is valide. So the nr_pages != 0 && !is_power_of_2(nr_pages) are all needed for checking. Otherwise, for example, perf test 6 failed. perf test 6 6: x86 rdpmc test :Error: mmap() syscall returned with (Invalid argument) FAILED! Signed-off-by: Kan Liang <kan.liang@intel.com> --- kernel/events/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index 89f0f16..a83581c 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -4423,7 +4423,7 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma) * If we have rb pages ensure they're a power-of-two number, so we * can do bitmasks instead of modulo. */ - if (!is_power_of_2(nr_pages)) + if (nr_pages != 0 && !is_power_of_2(nr_pages)) return -EINVAL; if (vma_size != PAGE_SIZE * (1 + nr_pages)) -- 1.8.3.1
next reply other threads:[~2015-03-02 14:23 UTC|newest] Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top 2015-03-02 7:14 kan.liang [this message] 2015-03-02 21:03 ` [PATCH 1/1] Revert "perf: Remove the extra validity check on nr_pages" Arnaldo Carvalho de Melo 2015-03-03 6:26 ` [tip:perf/core] " tip-bot for Kan Liang 2015-03-03 8:44 ` Ingo Molnar 2015-03-03 20:04 ` Liang, Kan 2015-03-04 4:46 ` Ingo Molnar 2015-03-04 14:06 ` Liang, Kan 2015-03-04 20:28 ` Ingo Molnar
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