Messages in this thread Patch in this message | | | From | Michael Ellerman <> | Subject | [PATCH] perf_event: Don't allow vmalloc backed perf on powerpc | Date | Mon, 4 May 2015 16:26:39 +1000 |
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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
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