* [tip:perf/urgent] perf/core: Fix impossible ring-buffer sizes warning
@ 2019-02-13 7:10 tip-bot for Ingo Molnar
0 siblings, 0 replies; 2+ messages in thread
From: tip-bot for Ingo Molnar @ 2019-02-13 7:10 UTC (permalink / raw)
To: linux-tip-commits
Cc: torvalds, julien.thierry, peterz, alexander.shishkin, mingo,
namhyung, hpa, stable, mark.rutland, acme, gregkh, yao.jin, bp,
tglx, jolsa
Commit-ID: 528871b456026e6127d95b1b2bd8e3a003dc1614
Gitweb: https://git.kernel.org/tip/528871b456026e6127d95b1b2bd8e3a003dc1614
Author: Ingo Molnar <mingo@kernel.org>
AuthorDate: Wed, 13 Feb 2019 07:57:02 +0100
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Wed, 13 Feb 2019 08:05:02 +0100
perf/core: Fix impossible ring-buffer sizes warning
The following commit:
9dff0aa95a32 ("perf/core: Don't WARN() for impossible ring-buffer sizes")
results in perf recording failures with larger mmap areas:
root@skl:/tmp# perf record -g -a
failed to mmap with 12 (Cannot allocate memory)
The root cause is that the following condition is buggy:
if (order_base_2(size) >= MAX_ORDER)
goto fail;
The problem is that @size is in bytes and MAX_ORDER is in pages,
so the right test is:
if (order_base_2(size) >= PAGE_SHIFT+MAX_ORDER)
goto fail;
Fix it.
Reported-by: "Jin, Yao" <yao.jin@linux.intel.com>
Bisected-by: Borislav Petkov <bp@alien8.de>
Analyzed-by: Peter Zijlstra <peterz@infradead.org>
Cc: Julien Thierry <julien.thierry@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: <stable@vger.kernel.org>
Fixes: 9dff0aa95a32 ("perf/core: Don't WARN() for impossible ring-buffer sizes")
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
kernel/events/ring_buffer.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c
index 309ef5a64af5..5ab4fe3b1dcc 100644
--- a/kernel/events/ring_buffer.c
+++ b/kernel/events/ring_buffer.c
@@ -734,7 +734,7 @@ struct ring_buffer *rb_alloc(int nr_pages, long watermark, int cpu, int flags)
size = sizeof(struct ring_buffer);
size += nr_pages * sizeof(void *);
- if (order_base_2(size) >= MAX_ORDER)
+ if (order_base_2(size) >= PAGE_SHIFT+MAX_ORDER)
goto fail;
rb = kzalloc(size, GFP_KERNEL);
^ permalink raw reply related [flat|nested] 2+ messages in thread* [tip:perf/urgent] perf/core: Fix impossible ring-buffer sizes warning
@ 2019-02-13 7:07 tip-bot for Ingo Molnar
0 siblings, 0 replies; 2+ messages in thread
From: tip-bot for Ingo Molnar @ 2019-02-13 7:07 UTC (permalink / raw)
To: linux-tip-commits
Cc: alexander.shishkin, mingo, namhyung, bp, julien.thierry, gregkh,
hpa, jolsa, stable, mark.rutland, tglx, yao.jin, peterz, acme,
torvalds
Commit-ID: 528467ac19b279c06a55f3da99a24ebcb6e2adb1
Gitweb: https://git.kernel.org/tip/528467ac19b279c06a55f3da99a24ebcb6e2adb1
Author: Ingo Molnar <mingo@kernel.org>
AuthorDate: Wed, 13 Feb 2019 07:57:02 +0100
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Wed, 13 Feb 2019 08:03:55 +0100
perf/core: Fix impossible ring-buffer sizes warning
The following commit:
9dff0aa95a32 ("perf/core: Don't WARN() for impossible ring-buffer sizes")
results in perf recording failures with larger mmap areas:
root@skl:/tmp# perf record -g -a
failed to mmap with 12 (Cannot allocate memory)
The root cause is that the following condition is buggy:
if (order_base_2(size) >= MAX_ORDER)
goto fail;
The problem is that @size is in bytes and MAX_ORDER is in pages,
so the right test is:
if (order_base_2(size) >= PAGE_SHIFT+MAX_ORDER)
goto fail;
Fix it.
Reported-by: "Jin, Yao" <yao.jin@linux.intel.com>
Bisected-by: Borislav Petkov <bp@alien8.de>
Analyzed-by: Peter Zijlstra <peterz@infradead.org>
Cc: Julien Thierry <julien.thierry@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
kernel/events/ring_buffer.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c
index 309ef5a64af5..5ab4fe3b1dcc 100644
--- a/kernel/events/ring_buffer.c
+++ b/kernel/events/ring_buffer.c
@@ -734,7 +734,7 @@ struct ring_buffer *rb_alloc(int nr_pages, long watermark, int cpu, int flags)
size = sizeof(struct ring_buffer);
size += nr_pages * sizeof(void *);
- if (order_base_2(size) >= MAX_ORDER)
+ if (order_base_2(size) >= PAGE_SHIFT+MAX_ORDER)
goto fail;
rb = kzalloc(size, GFP_KERNEL);
^ permalink raw reply related [flat|nested] 2+ messages in thread
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