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linux/arch
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Peter Zijlstra 602cae04c4 perf/x86/intel: Delay memory deallocation until x86_pmu_dead_cpu() 
intel_pmu_cpu_prepare() allocated memory for ->shared_regs among other
members of struct cpu_hw_events. This memory is released in
intel_pmu_cpu_dying() which is wrong. The counterpart of the
intel_pmu_cpu_prepare() callback is x86_pmu_dead_cpu().

Otherwise if the CPU fails on the UP path between CPUHP_PERF_X86_PREPARE
and CPUHP_AP_PERF_X86_STARTING then it won't release the memory but
allocate new memory on the next attempt to online the CPU (leaking the
old memory).
Also, if the CPU down path fails between CPUHP_AP_PERF_X86_STARTING and
CPUHP_PERF_X86_PREPARE then the CPU will go back online but never
allocate the memory that was released in x86_pmu_dying_cpu().

Make the memory allocation/free symmetrical in regard to the CPU hotplug
notifier by moving the deallocation to intel_pmu_cpu_dead().

This started in commit:

   a7e3ed1e47 ("perf: Add support for supplementary event registers").

In principle the bug was introduced in v2.6.39 (!), but it will almost
certainly not backport cleanly across the big CPU hotplug rewrite between v4.7-v4.15...

[ bigeasy: Added patch description. ]
[ mingo: Added backporting guidance. ]

Reported-by: He Zhe <zhe.he@windriver.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> # With developer hat on
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> # With maintainer hat on
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: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: acme@kernel.org
Cc: bp@alien8.de
Cc: hpa@zytor.com
Cc: jolsa@kernel.org
Cc: kan.liang@linux.intel.com
Cc: namhyung@kernel.org
Cc: <stable@vger.kernel.org>
Fixes: a7e3ed1e47 ("perf: Add support for supplementary event registers").
Link: https://lkml.kernel.org/r/20181219165350.6s3jvyxbibpvlhtq@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-02-04 08:44:51 +01:00
..
alpha Kbuild late updates for v4.21 2019-01-06 16:33:10 -08:00
arc ARCv2: lib: memeset: fix doing prefetchw outside of buffer 2019-01-17 16:24:39 -08:00
arm pci-v5.0-fixes-3 2019-01-31 23:06:17 -08:00
arm64 arm64: hibernate: Clean the __hyp_text to PoC after resume 2019-02-01 14:10:02 +00:00
c6x arch: unexport asm/shmparam.h for all architectures 2019-02-01 15:46:22 -08:00
csky csky: fixup compile error with CPU 810. 2019-01-10 04:37:37 -08:00
h8300 arch: unexport asm/shmparam.h for all architectures 2019-02-01 15:46:22 -08:00
hexagon arch: unexport asm/shmparam.h for all architectures 2019-02-01 15:46:22 -08:00
ia64 ia64: remove redundant 'export AWK' 2019-01-16 23:31:18 +09:00
m68k arch: unexport asm/shmparam.h for all architectures 2019-02-01 15:46:22 -08:00
microblaze arch: unexport asm/shmparam.h for all architectures 2019-02-01 15:46:22 -08:00
mips A few MIPS fixes for 5.0: 2019-01-20 10:33:18 +12:00
nds32 nds32: remove unneeded code in arch/nds32/Makefile 2019-01-17 23:42:37 +09:00
nios2 arch: remove redundant UAPI generic-y defines 2019-01-06 10:22:15 +09:00
openrisc arch: unexport asm/shmparam.h for all architectures 2019-02-01 15:46:22 -08:00
parisc arch: remove redundant UAPI generic-y defines 2019-01-06 10:22:15 +09:00
powerpc A single build fix for powerpc due to device_node.type removal 2019-01-20 10:28:46 +12:00
riscv riscv: Adjust mmap base address at a third of task size 2019-01-25 10:50:53 -08:00
s390 s390/smp: Fix calling smp_call_ipl_cpu() from ipl CPU 2019-01-11 17:12:03 +01:00
sh Kbuild late updates for v4.21 2019-01-06 16:33:10 -08:00
sparc arch: remove redundant UAPI generic-y defines 2019-01-06 10:22:15 +09:00
um Merge branch 'akpm' (patches from Andrew) 2019-01-05 09:16:18 -08:00
unicore32 arch: unexport asm/shmparam.h for all architectures 2019-02-01 15:46:22 -08:00
x86 perf/x86/intel: Delay memory deallocation until x86_pmu_dead_cpu() 2019-02-04 08:44:51 +01:00
xtensa xtensa: SMP: limit number of possible CPUs by NR_CPUS 2019-01-27 10:04:30 -08:00
.gitignore
Kconfig jump_label: move 'asm goto' support test to Kconfig 2019-01-06 09:46:51 +09:00