LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
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 ` 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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1425280466-7830-1-git-send-email-kan.liang@intel.com \
--to=kan.liang@intel.com \
--cc=a.p.zijlstra@chello.nl \
--cc=acme@redhat.com \
--cc=ak@linux.intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=xiakaixu@huawei.com \
--subject='Re: [PATCH 1/1] Revert "perf: Remove the extra validity check on nr_pages"' \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).