lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:   Fri, 3 May 2019 03:49:18 -0700
From:   tip-bot for Alexander Shishkin <>
Subject: [tip:perf/urgent] perf/ring_buffer: Fix AUX software double

Commit-ID:  26ae4f4406f88d82d79c85c11ac5fae18213cd38
Author:     Alexander Shishkin <>
AuthorDate: Fri, 3 May 2019 11:55:35 +0300
Committer:  Ingo Molnar <>
CommitDate: Fri, 3 May 2019 12:46:10 +0200

perf/ring_buffer: Fix AUX software double buffering

This recent commit:

  5768402fd9c6e87 ("perf/ring_buffer: Use high order allocations for AUX buffers optimistically")

overlooked the fact that the previous one page granularity of the AUX buffer
provided an implicit double buffering capability to the PMU driver, which
went away when the entire buffer became one high-order page.

Always make the full-trace mode AUX allocation at least two-part to preserve
the previous behavior and allow the implicit double buffering to continue.

Reported-by: Ammy Yi <>
Signed-off-by: Alexander Shishkin <>
Acked-by: Peter Zijlstra <>
Cc: Arnaldo Carvalho de Melo <>
Cc: Jiri Olsa <>
Cc: Linus Torvalds <>
Cc: Stephane Eranian <>
Cc: Thomas Gleixner <>
Cc: Vince Weaver <>
Fixes: 5768402fd9c6e87 ("perf/ring_buffer: Use high order allocations for AUX buffers optimistically")
Signed-off-by: Ingo Molnar <>
 kernel/events/ring_buffer.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c
index 5eedb49a65ea..674b35383491 100644
--- a/kernel/events/ring_buffer.c
+++ b/kernel/events/ring_buffer.c
@@ -610,8 +610,7 @@ int rb_alloc_aux(struct ring_buffer *rb, struct perf_event *event,
 	 * PMU requests more than one contiguous chunks of memory
 	 * for SW double buffering
-	if ((event->pmu->capabilities & PERF_PMU_CAP_AUX_SW_DOUBLEBUF) &&
-	    !overwrite) {
+	if (!overwrite) {
 		if (!max_order)
 			return -EINVAL;

Powered by blists - more mailing lists