This is a note to let you know that I've just added the patch titled
perf/x86/intel: Don't accidentally clear high bits in bdw_limit_period()
to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: perf-x86-intel-don-t-accidentally-clear-high-bits-in-bdw_limit_period.patch and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From e5ea9b54a055619160bbfe527ebb7d7191823d66 Mon Sep 17 00:00:00 2001
From: Dan Carpenter dan.carpenter@oracle.com Date: Sat, 17 Mar 2018 14:52:16 +0300 Subject: perf/x86/intel: Don't accidentally clear high bits in bdw_limit_period()
From: Dan Carpenter dan.carpenter@oracle.com
commit e5ea9b54a055619160bbfe527ebb7d7191823d66 upstream.
We intended to clear the lowest 6 bits but because of a type bug we clear the high 32 bits as well. Andi says that periods are rarely more than U32_MAX so this bug probably doesn't have a huge runtime impact.
Signed-off-by: Dan Carpenter dan.carpenter@oracle.com Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Cc: Alexander Shishkin alexander.shishkin@linux.intel.com Cc: Arnaldo Carvalho de Melo acme@redhat.com Cc: H. Peter Anvin hpa@zytor.com Cc: Jiri Olsa jolsa@redhat.com Cc: Kan Liang kan.liang@linux.intel.com Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Peter Zijlstra peterz@infradead.org Cc: Sebastian Andrzej Siewior bigeasy@linutronix.de Cc: Stephane Eranian eranian@google.com Cc: Thomas Gleixner tglx@linutronix.de Cc: Vince Weaver vincent.weaver@maine.edu Fixes: 294fe0f52a44 ("perf/x86/intel: Add INST_RETIRED.ALL workarounds") Link: http://lkml.kernel.org/r/20180317115216.GB4035@mwanda Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/x86/kernel/cpu/perf_event_intel.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/x86/kernel/cpu/perf_event_intel.c +++ b/arch/x86/kernel/cpu/perf_event_intel.c @@ -2716,7 +2716,7 @@ static unsigned bdw_limit_period(struct X86_CONFIG(.event=0xc0, .umask=0x01)) { if (left < 128) left = 128; - left &= ~0x3fu; + left &= ~0x3fULL; } return left; }
Patches currently in stable-queue which might be from dan.carpenter@oracle.com are
queue-4.4/perf-x86-intel-don-t-accidentally-clear-high-bits-in-bdw_limit_period.patch queue-4.4/staging-ncpfs-memory-corruption-in-ncp_read_kernel.patch