* [PATCH] perf_event: Don't allow vmalloc backed perf on powerpc
@ 2015-05-04 6:26 Michael Ellerman
2015-05-08 13:24 ` [tip:perf/core] perf_event: Don't allow vmalloc() " tip-bot for Michael Ellerman
0 siblings, 1 reply; 2+ messages in thread
From: Michael Ellerman @ 2015-05-04 6:26 UTC (permalink / raw)
To: linuxppc-dev
Cc: Andrew Morton, a.p.zijlstra, linux-kernel, Paul Mackerras,
Anton Blanchard, acme, sukadev, mingo
On powerpc the perf event interrupt is not masked when interrupts are
disabled, allowing it to function as an NMI.
This causes problems if perf is using vmalloc. If we take a page fault
on the vmalloc region the fault handler will fail the page fault because
it detects we are coming in from an NMI (see do_hash_page()).
We don't actually need or want vmalloc backed perf so just disable it on
powerpc.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
init/Kconfig | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/init/Kconfig b/init/Kconfig
index dc24dec60232..81050e4d9941 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1637,7 +1637,7 @@ config PERF_EVENTS
config DEBUG_PERF_USE_VMALLOC
default n
bool "Debug: use vmalloc to back perf mmap() buffers"
- depends on PERF_EVENTS && DEBUG_KERNEL
+ depends on PERF_EVENTS && DEBUG_KERNEL && !PPC
select PERF_USE_VMALLOC
help
Use vmalloc memory to back perf mmap() buffers.
--
2.1.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* [tip:perf/core] perf_event: Don't allow vmalloc() backed perf on powerpc
2015-05-04 6:26 [PATCH] perf_event: Don't allow vmalloc backed perf on powerpc Michael Ellerman
@ 2015-05-08 13:24 ` tip-bot for Michael Ellerman
0 siblings, 0 replies; 2+ messages in thread
From: tip-bot for Michael Ellerman @ 2015-05-08 13:24 UTC (permalink / raw)
To: linux-tip-commits
Cc: akpm, peterz, linux-kernel, linuxppc-dev, paulus, anton, hpa, bp,
tglx, mingo
Commit-ID: cb307113746b4d184155d2c412e8069aeaa60d42
Gitweb: http://git.kernel.org/tip/cb307113746b4d184155d2c412e8069aeaa60d42
Author: Michael Ellerman <mpe@ellerman.id.au>
AuthorDate: Mon, 4 May 2015 16:26:39 +1000
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Fri, 8 May 2015 12:26:01 +0200
perf_event: Don't allow vmalloc() backed perf on powerpc
On powerpc the perf event interrupt is not masked when interrupts are
disabled, allowing it to function as an NMI.
This causes problems if perf is using vmalloc. If we take a page fault
on the vmalloc region the fault handler will fail the page fault because
it detects we are coming in from an NMI (see do_hash_page()).
We don't actually need or want vmalloc backed perf so just disable it on
powerpc.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <linuxppc-dev@ozlabs.org>
Cc: Andrew Morton <akpm@osdl.org>
Cc: Anton Blanchard <anton@samba.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: acme@ghostprotocols.net
Cc: sukadev@linux.vnet.ibm.com
Link: http://lkml.kernel.org/r/1430720799-18426-1-git-send-email-mpe@ellerman.id.au
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
init/Kconfig | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/init/Kconfig b/init/Kconfig
index dc24dec..81050e4 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1637,7 +1637,7 @@ config PERF_EVENTS
config DEBUG_PERF_USE_VMALLOC
default n
bool "Debug: use vmalloc to back perf mmap() buffers"
- depends on PERF_EVENTS && DEBUG_KERNEL
+ depends on PERF_EVENTS && DEBUG_KERNEL && !PPC
select PERF_USE_VMALLOC
help
Use vmalloc memory to back perf mmap() buffers.
^ permalink raw reply related [flat|nested] 2+ messages in thread
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2015-05-08 13:24 ` [tip:perf/core] perf_event: Don't allow vmalloc() " tip-bot for Michael Ellerman
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