* [PATCH v2 2/2] fork: make number of cached stacks (vmapped) configurable using Kbuild
2017-02-09 4:03 [PATCH v2 1/2] fork: free vmapped stacks in cache when cpus are offline Hoeun Ryu
@ 2017-02-09 4:03 ` Hoeun Ryu
2017-02-09 4:26 ` [kernel-hardening] " Eric Biggers
2017-02-09 8:40 ` Michal Hocko
2017-02-09 4:22 ` [kernel-hardening] [PATCH v2 1/2] fork: free vmapped stacks in cache when cpus are offline Eric Biggers
` (4 subsequent siblings)
5 siblings, 2 replies; 12+ messages in thread
From: Hoeun Ryu @ 2017-02-09 4:03 UTC (permalink / raw)
To: Kees Cook, Michal Marek, Andrew Morton, Emese Revfy, Ingo Molnar,
Mickaël Salaün, Nicholas Piggin, Andy Lutomirski,
Michal Hocko, Eric W. Biederman, Mateusz Guzik
Cc: linux-kernel, kernel-hardening, Hoeun Ryu
Introducing NR_VMAP_STACK_CACHE, the number of cached stacks for virtually
mapped kernel stack can be configurable using Kbuild system.
default value is 2.
Signed-off-by: Hoeun Ryu <hoeun.ryu@gmail.com>
---
arch/Kconfig | 8 ++++++++
kernel/fork.c | 2 +-
2 files changed, 9 insertions(+), 1 deletion(-)
diff --git a/arch/Kconfig b/arch/Kconfig
index d49a8e6..066d111 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -849,6 +849,14 @@ config VMAP_STACK
the stack to map directly to the KASAN shadow map using a formula
that is incorrect if the stack is in vmalloc space.
+config NR_VMAP_STACK_CACHE
+ int "Number of cached stacks"
+ default "2"
+ depends on VMAP_STACK
+ help
+ This determines how many stacks can be cached for virtually
+ mapped kernel stacks.
+
config ARCH_WANT_RELAX_ORDER
bool
diff --git a/kernel/fork.c b/kernel/fork.c
index 7911ed2..73ba1da 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -166,7 +166,7 @@ void __weak arch_release_thread_stack(unsigned long *stack)
* vmalloc() is a bit slow, and calling vfree() enough times will force a TLB
* flush. Try to minimize the number of calls by caching stacks.
*/
-#define NR_CACHED_STACKS 2
+#define NR_CACHED_STACKS CONFIG_NR_VMAP_STACK_CACHE
static DEFINE_PER_CPU(struct vm_struct *, cached_stacks[NR_CACHED_STACKS]);
#endif
--
2.7.4
^ permalink raw reply related [flat|nested] 12+ messages in thread* Re: [kernel-hardening] [PATCH v2 2/2] fork: make number of cached stacks (vmapped) configurable using Kbuild
2017-02-09 4:03 ` [PATCH v2 2/2] fork: make number of cached stacks (vmapped) configurable using Kbuild Hoeun Ryu
@ 2017-02-09 4:26 ` Eric Biggers
2017-02-09 8:40 ` Michal Hocko
1 sibling, 0 replies; 12+ messages in thread
From: Eric Biggers @ 2017-02-09 4:26 UTC (permalink / raw)
To: Hoeun Ryu
Cc: Kees Cook, Michal Marek, Andrew Morton, Emese Revfy, Ingo Molnar,
Mickaël Salaün, Nicholas Piggin, Andy Lutomirski,
Michal Hocko, Eric W. Biederman, Mateusz Guzik, linux-kernel,
kernel-hardening
On Thu, Feb 09, 2017 at 01:03:47PM +0900, Hoeun Ryu wrote:
> +config NR_VMAP_STACK_CACHE
> + int "Number of cached stacks"
> + default "2"
> + depends on VMAP_STACK
> + help
> + This determines how many stacks can be cached for virtually
> + mapped kernel stacks.
> +
Can you explain in the help text under what circumstances someone should change
this, and to what value? As-is, it seems like somewhat of a useless config
option which no one will ever change.
- Eric
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH v2 2/2] fork: make number of cached stacks (vmapped) configurable using Kbuild
2017-02-09 4:03 ` [PATCH v2 2/2] fork: make number of cached stacks (vmapped) configurable using Kbuild Hoeun Ryu
2017-02-09 4:26 ` [kernel-hardening] " Eric Biggers
@ 2017-02-09 8:40 ` Michal Hocko
2017-02-09 13:36 ` Hoeun Ryu
1 sibling, 1 reply; 12+ messages in thread
From: Michal Hocko @ 2017-02-09 8:40 UTC (permalink / raw)
To: Hoeun Ryu
Cc: Kees Cook, Michal Marek, Andrew Morton, Emese Revfy, Ingo Molnar,
Mickaël Salaün, Nicholas Piggin, Andy Lutomirski,
Eric W. Biederman, Mateusz Guzik, linux-kernel, kernel-hardening
On Thu 09-02-17 13:03:47, Hoeun Ryu wrote:
> Introducing NR_VMAP_STACK_CACHE, the number of cached stacks for virtually
> mapped kernel stack can be configurable using Kbuild system.
> default value is 2.
This should really explain _why_ we want/need this. The config space is
really large already and there should better be a good reason to make it
even larger. Which workload will benefit from a different than default
cache size and why?
Without a really good reasons NACK from me.
> Signed-off-by: Hoeun Ryu <hoeun.ryu@gmail.com>
> ---
> arch/Kconfig | 8 ++++++++
> kernel/fork.c | 2 +-
> 2 files changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/arch/Kconfig b/arch/Kconfig
> index d49a8e6..066d111 100644
> --- a/arch/Kconfig
> +++ b/arch/Kconfig
> @@ -849,6 +849,14 @@ config VMAP_STACK
> the stack to map directly to the KASAN shadow map using a formula
> that is incorrect if the stack is in vmalloc space.
>
> +config NR_VMAP_STACK_CACHE
> + int "Number of cached stacks"
> + default "2"
> + depends on VMAP_STACK
> + help
> + This determines how many stacks can be cached for virtually
> + mapped kernel stacks.
> +
> config ARCH_WANT_RELAX_ORDER
> bool
>
> diff --git a/kernel/fork.c b/kernel/fork.c
> index 7911ed2..73ba1da 100644
> --- a/kernel/fork.c
> +++ b/kernel/fork.c
> @@ -166,7 +166,7 @@ void __weak arch_release_thread_stack(unsigned long *stack)
> * vmalloc() is a bit slow, and calling vfree() enough times will force a TLB
> * flush. Try to minimize the number of calls by caching stacks.
> */
> -#define NR_CACHED_STACKS 2
> +#define NR_CACHED_STACKS CONFIG_NR_VMAP_STACK_CACHE
> static DEFINE_PER_CPU(struct vm_struct *, cached_stacks[NR_CACHED_STACKS]);
> #endif
>
> --
> 2.7.4
>
--
Michal Hocko
SUSE Labs
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH v2 2/2] fork: make number of cached stacks (vmapped) configurable using Kbuild
2017-02-09 8:40 ` Michal Hocko
@ 2017-02-09 13:36 ` Hoeun Ryu
0 siblings, 0 replies; 12+ messages in thread
From: Hoeun Ryu @ 2017-02-09 13:36 UTC (permalink / raw)
To: Michal Hocko
Cc: Kees Cook, Michal Marek, Andrew Morton, Emese Revfy, Ingo Molnar,
Mickaël Salaün, Nicholas Piggin, Andy Lutomirski,
Eric W. Biederman, Mateusz Guzik, linux-kernel, kernel-hardening
On Thu, Feb 9, 2017 at 5:40 PM, Michal Hocko <mhocko@kernel.org> wrote:
> On Thu 09-02-17 13:03:47, Hoeun Ryu wrote:
>> Introducing NR_VMAP_STACK_CACHE, the number of cached stacks for virtually
>> mapped kernel stack can be configurable using Kbuild system.
>> default value is 2.
>
> This should really explain _why_ we want/need this. The config space is
> really large already and there should better be a good reason to make it
> even larger. Which workload will benefit from a different than default
> cache size and why?
>
> Without a really good reasons NACK from me.
>
OK, I understand your NACK. Thank you.
>> Signed-off-by: Hoeun Ryu <hoeun.ryu@gmail.com>
>> ---
>> arch/Kconfig | 8 ++++++++
>> kernel/fork.c | 2 +-
>> 2 files changed, 9 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/Kconfig b/arch/Kconfig
>> index d49a8e6..066d111 100644
>> --- a/arch/Kconfig
>> +++ b/arch/Kconfig
>> @@ -849,6 +849,14 @@ config VMAP_STACK
>> the stack to map directly to the KASAN shadow map using a formula
>> that is incorrect if the stack is in vmalloc space.
>>
>> +config NR_VMAP_STACK_CACHE
>> + int "Number of cached stacks"
>> + default "2"
>> + depends on VMAP_STACK
>> + help
>> + This determines how many stacks can be cached for virtually
>> + mapped kernel stacks.
>> +
>> config ARCH_WANT_RELAX_ORDER
>> bool
>>
>> diff --git a/kernel/fork.c b/kernel/fork.c
>> index 7911ed2..73ba1da 100644
>> --- a/kernel/fork.c
>> +++ b/kernel/fork.c
>> @@ -166,7 +166,7 @@ void __weak arch_release_thread_stack(unsigned long *stack)
>> * vmalloc() is a bit slow, and calling vfree() enough times will force a TLB
>> * flush. Try to minimize the number of calls by caching stacks.
>> */
>> -#define NR_CACHED_STACKS 2
>> +#define NR_CACHED_STACKS CONFIG_NR_VMAP_STACK_CACHE
>> static DEFINE_PER_CPU(struct vm_struct *, cached_stacks[NR_CACHED_STACKS]);
>> #endif
>>
>> --
>> 2.7.4
>>
>
> --
> Michal Hocko
> SUSE Labs
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [kernel-hardening] [PATCH v2 1/2] fork: free vmapped stacks in cache when cpus are offline
2017-02-09 4:03 [PATCH v2 1/2] fork: free vmapped stacks in cache when cpus are offline Hoeun Ryu
2017-02-09 4:03 ` [PATCH v2 2/2] fork: make number of cached stacks (vmapped) configurable using Kbuild Hoeun Ryu
@ 2017-02-09 4:22 ` Eric Biggers
2017-02-09 13:35 ` Hoeun Ryu
2017-02-09 7:28 ` kbuild test robot
` (3 subsequent siblings)
5 siblings, 1 reply; 12+ messages in thread
From: Eric Biggers @ 2017-02-09 4:22 UTC (permalink / raw)
To: Hoeun Ryu
Cc: Andrew Morton, Michal Hocko, Ingo Molnar, Andy Lutomirski,
Kees Cook, Eric W. Biederman, Mateusz Guzik, linux-kernel,
kernel-hardening
Hi Hoeun,
On Thu, Feb 09, 2017 at 01:03:46PM +0900, Hoeun Ryu wrote:
> +static int free_vm_stack_cache(unsigned int cpu)
> +{
> + int i;
> +
> + for (i = 0; i < NR_CACHED_STACKS; i++) {
> + struct vm_struct *vm_stack = this_cpu_read(cached_stacks[i]);
> + if (!vm_stack)
> + continue;
> +
> + vfree(vm_stack->addr);
> + this_cpu_write(cached_stacks[i], NULL);
> + }
> +
> + return 0;
> +}
Doesn't this need to free the stacks for the 'cpu' that's passed in, instead of
"this" CPU?
- Eric
^ permalink raw reply [flat|nested] 12+ messages in thread* Re: [kernel-hardening] [PATCH v2 1/2] fork: free vmapped stacks in cache when cpus are offline
2017-02-09 4:22 ` [kernel-hardening] [PATCH v2 1/2] fork: free vmapped stacks in cache when cpus are offline Eric Biggers
@ 2017-02-09 13:35 ` Hoeun Ryu
0 siblings, 0 replies; 12+ messages in thread
From: Hoeun Ryu @ 2017-02-09 13:35 UTC (permalink / raw)
To: Eric Biggers
Cc: Andrew Morton, Michal Hocko, Ingo Molnar, Andy Lutomirski,
Kees Cook, Eric W. Biederman, Mateusz Guzik, linux-kernel,
kernel-hardening
On Thu, Feb 9, 2017 at 1:22 PM, Eric Biggers <ebiggers3@gmail.com> wrote:
> Hi Hoeun,
>
> On Thu, Feb 09, 2017 at 01:03:46PM +0900, Hoeun Ryu wrote:
>> +static int free_vm_stack_cache(unsigned int cpu)
>> +{
>> + int i;
>> +
>> + for (i = 0; i < NR_CACHED_STACKS; i++) {
>> + struct vm_struct *vm_stack = this_cpu_read(cached_stacks[i]);
>> + if (!vm_stack)
>> + continue;
>> +
>> + vfree(vm_stack->addr);
>> + this_cpu_write(cached_stacks[i], NULL);
>> + }
>> +
>> + return 0;
>> +}
>
> Doesn't this need to free the stacks for the 'cpu' that's passed in, instead of
> "this" CPU?
>
Sorry, Thank you for your correction. I will fix this.
> - Eric
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH v2 1/2] fork: free vmapped stacks in cache when cpus are offline
2017-02-09 4:03 [PATCH v2 1/2] fork: free vmapped stacks in cache when cpus are offline Hoeun Ryu
2017-02-09 4:03 ` [PATCH v2 2/2] fork: make number of cached stacks (vmapped) configurable using Kbuild Hoeun Ryu
2017-02-09 4:22 ` [kernel-hardening] [PATCH v2 1/2] fork: free vmapped stacks in cache when cpus are offline Eric Biggers
@ 2017-02-09 7:28 ` kbuild test robot
2017-02-09 8:01 ` kbuild test robot
` (2 subsequent siblings)
5 siblings, 0 replies; 12+ messages in thread
From: kbuild test robot @ 2017-02-09 7:28 UTC (permalink / raw)
To: Hoeun Ryu
Cc: kbuild-all, Andrew Morton, Michal Hocko, Ingo Molnar,
Andy Lutomirski, Kees Cook, Eric W. Biederman, Mateusz Guzik,
linux-kernel, kernel-hardening, Hoeun Ryu
[-- Attachment #1: Type: text/plain, Size: 8925 bytes --]
Hi Hoeun,
[auto build test ERROR on next-20170208]
[also build test ERROR on v4.10-rc7]
[cannot apply to linus/master linux/master v4.9-rc8 v4.9-rc7 v4.9-rc6]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
url: https://github.com/0day-ci/linux/commits/Hoeun-Ryu/fork-free-vmapped-stacks-in-cache-when-cpus-are-offline/20170209-124143
config: parisc-c3000_defconfig (attached as .config)
compiler: hppa-linux-gnu-gcc (Debian 6.1.1-9) 6.1.1 20160705
reproduce:
wget https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
make.cross ARCH=parisc
All error/warnings (new ones prefixed by >>):
kernel/fork.c: In function 'free_vm_stack_cache':
>> kernel/fork.c:177:18: error: 'NR_CACHED_STACKS' undeclared (first use in this function)
for (i = 0; i < NR_CACHED_STACKS; i++) {
^~~~~~~~~~~~~~~~
kernel/fork.c:177:18: note: each undeclared identifier is reported only once for each function it appears in
In file included from include/asm-generic/percpu.h:6:0,
from ./arch/parisc/include/generated/asm/percpu.h:1,
from arch/parisc/include/asm/processor.h:19,
from arch/parisc/include/asm/thread_info.h:7,
from include/linux/thread_info.h:25,
from include/asm-generic/preempt.h:4,
from ./arch/parisc/include/generated/asm/preempt.h:1,
from include/linux/preempt.h:59,
from include/linux/spinlock.h:50,
from include/linux/mmzone.h:7,
from include/linux/gfp.h:5,
from include/linux/slab.h:14,
from kernel/fork.c:14:
>> kernel/fork.c:178:46: error: 'cached_stacks' undeclared (first use in this function)
struct vm_struct *vm_stack = this_cpu_read(cached_stacks[i]);
^
include/linux/percpu-defs.h:305:9: note: in definition of macro '__pcpu_size_call_return'
typeof(variable) pscr_ret__; \
^~~~~~~~
>> kernel/fork.c:178:32: note: in expansion of macro 'this_cpu_read'
struct vm_struct *vm_stack = this_cpu_read(cached_stacks[i]);
^~~~~~~~~~~~~
>> include/linux/percpu-defs.h:304:1: warning: initialization makes pointer from integer without a cast [-Wint-conversion]
({ \
^
include/linux/percpu-defs.h:494:29: note: in expansion of macro '__pcpu_size_call_return'
#define this_cpu_read(pcp) __pcpu_size_call_return(this_cpu_read_, pcp)
^~~~~~~~~~~~~~~~~~~~~~~
>> kernel/fork.c:178:32: note: in expansion of macro 'this_cpu_read'
struct vm_struct *vm_stack = this_cpu_read(cached_stacks[i]);
^~~~~~~~~~~~~
At top level:
kernel/fork.c:173:12: warning: 'free_vm_stack_cache' defined but not used [-Wunused-function]
static int free_vm_stack_cache(unsigned int cpu)
^~~~~~~~~~~~~~~~~~~
vim +/NR_CACHED_STACKS +177 kernel/fork.c
8 * 'fork.c' contains the help-routines for the 'fork' system call
9 * (see also entry.S and others).
10 * Fork is rather simple, once you get the hang of it, but the memory
11 * management can be a bitch. See 'mm/memory.c': 'copy_page_range()'
12 */
13
> 14 #include <linux/slab.h>
15 #include <linux/init.h>
16 #include <linux/unistd.h>
17 #include <linux/module.h>
18 #include <linux/vmalloc.h>
19 #include <linux/completion.h>
20 #include <linux/personality.h>
21 #include <linux/mempolicy.h>
22 #include <linux/sem.h>
23 #include <linux/file.h>
24 #include <linux/fdtable.h>
25 #include <linux/iocontext.h>
26 #include <linux/key.h>
27 #include <linux/binfmts.h>
28 #include <linux/mman.h>
29 #include <linux/mmu_notifier.h>
30 #include <linux/fs.h>
31 #include <linux/mm.h>
32 #include <linux/vmacache.h>
33 #include <linux/nsproxy.h>
34 #include <linux/capability.h>
35 #include <linux/cpu.h>
36 #include <linux/cgroup.h>
37 #include <linux/security.h>
38 #include <linux/hugetlb.h>
39 #include <linux/seccomp.h>
40 #include <linux/swap.h>
41 #include <linux/syscalls.h>
42 #include <linux/jiffies.h>
43 #include <linux/futex.h>
44 #include <linux/compat.h>
45 #include <linux/kthread.h>
46 #include <linux/task_io_accounting_ops.h>
47 #include <linux/rcupdate.h>
48 #include <linux/ptrace.h>
49 #include <linux/mount.h>
50 #include <linux/audit.h>
51 #include <linux/memcontrol.h>
52 #include <linux/ftrace.h>
53 #include <linux/proc_fs.h>
54 #include <linux/profile.h>
55 #include <linux/rmap.h>
56 #include <linux/ksm.h>
57 #include <linux/acct.h>
58 #include <linux/userfaultfd_k.h>
59 #include <linux/tsacct_kern.h>
60 #include <linux/cn_proc.h>
61 #include <linux/freezer.h>
62 #include <linux/delayacct.h>
63 #include <linux/taskstats_kern.h>
64 #include <linux/random.h>
65 #include <linux/tty.h>
66 #include <linux/blkdev.h>
67 #include <linux/fs_struct.h>
68 #include <linux/magic.h>
69 #include <linux/perf_event.h>
70 #include <linux/posix-timers.h>
71 #include <linux/user-return-notifier.h>
72 #include <linux/oom.h>
73 #include <linux/khugepaged.h>
74 #include <linux/signalfd.h>
75 #include <linux/uprobes.h>
76 #include <linux/aio.h>
77 #include <linux/compiler.h>
78 #include <linux/sysctl.h>
79 #include <linux/kcov.h>
80
81 #include <asm/pgtable.h>
82 #include <asm/pgalloc.h>
83 #include <linux/uaccess.h>
84 #include <asm/mmu_context.h>
85 #include <asm/cacheflush.h>
86 #include <asm/tlbflush.h>
87
88 #include <trace/events/sched.h>
89
90 #define CREATE_TRACE_POINTS
91 #include <trace/events/task.h>
92
93 /*
94 * Minimum number of threads to boot the kernel
95 */
96 #define MIN_THREADS 20
97
98 /*
99 * Maximum number of threads
100 */
101 #define MAX_THREADS FUTEX_TID_MASK
102
103 /*
104 * Protected counters by write_lock_irq(&tasklist_lock)
105 */
106 unsigned long total_forks; /* Handle normal Linux uptimes. */
107 int nr_threads; /* The idle threads do not count.. */
108
109 int max_threads; /* tunable limit on nr_threads */
110
111 DEFINE_PER_CPU(unsigned long, process_counts) = 0;
112
113 __cacheline_aligned DEFINE_RWLOCK(tasklist_lock); /* outer */
114
115 #ifdef CONFIG_PROVE_RCU
116 int lockdep_tasklist_lock_is_held(void)
117 {
118 return lockdep_is_held(&tasklist_lock);
119 }
120 EXPORT_SYMBOL_GPL(lockdep_tasklist_lock_is_held);
121 #endif /* #ifdef CONFIG_PROVE_RCU */
122
123 int nr_processes(void)
124 {
125 int cpu;
126 int total = 0;
127
128 for_each_possible_cpu(cpu)
129 total += per_cpu(process_counts, cpu);
130
131 return total;
132 }
133
134 void __weak arch_release_task_struct(struct task_struct *tsk)
135 {
136 }
137
138 #ifndef CONFIG_ARCH_TASK_STRUCT_ALLOCATOR
139 static struct kmem_cache *task_struct_cachep;
140
141 static inline struct task_struct *alloc_task_struct_node(int node)
142 {
143 return kmem_cache_alloc_node(task_struct_cachep, GFP_KERNEL, node);
144 }
145
146 static inline void free_task_struct(struct task_struct *tsk)
147 {
148 kmem_cache_free(task_struct_cachep, tsk);
149 }
150 #endif
151
152 void __weak arch_release_thread_stack(unsigned long *stack)
153 {
154 }
155
156 #ifndef CONFIG_ARCH_THREAD_STACK_ALLOCATOR
157
158 /*
159 * Allocate pages if THREAD_SIZE is >= PAGE_SIZE, otherwise use a
160 * kmemcache based allocator.
161 */
162 # if THREAD_SIZE >= PAGE_SIZE || defined(CONFIG_VMAP_STACK)
163
164 #ifdef CONFIG_VMAP_STACK
165 /*
166 * vmalloc() is a bit slow, and calling vfree() enough times will force a TLB
167 * flush. Try to minimize the number of calls by caching stacks.
168 */
169 #define NR_CACHED_STACKS 2
170 static DEFINE_PER_CPU(struct vm_struct *, cached_stacks[NR_CACHED_STACKS]);
171 #endif
172
173 static int free_vm_stack_cache(unsigned int cpu)
174 {
175 int i;
176
> 177 for (i = 0; i < NR_CACHED_STACKS; i++) {
> 178 struct vm_struct *vm_stack = this_cpu_read(cached_stacks[i]);
179 if (!vm_stack)
180 continue;
181
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 14742 bytes --]
^ permalink raw reply [flat|nested] 12+ messages in thread* Re: [PATCH v2 1/2] fork: free vmapped stacks in cache when cpus are offline
2017-02-09 4:03 [PATCH v2 1/2] fork: free vmapped stacks in cache when cpus are offline Hoeun Ryu
` (2 preceding siblings ...)
2017-02-09 7:28 ` kbuild test robot
@ 2017-02-09 8:01 ` kbuild test robot
2017-02-09 8:38 ` Michal Hocko
2017-02-09 10:26 ` kbuild test robot
5 siblings, 0 replies; 12+ messages in thread
From: kbuild test robot @ 2017-02-09 8:01 UTC (permalink / raw)
To: Hoeun Ryu
Cc: kbuild-all, Andrew Morton, Michal Hocko, Ingo Molnar,
Andy Lutomirski, Kees Cook, Eric W. Biederman, Mateusz Guzik,
linux-kernel, kernel-hardening, Hoeun Ryu
[-- Attachment #1: Type: text/plain, Size: 6743 bytes --]
Hi Hoeun,
[auto build test WARNING on next-20170208]
[also build test WARNING on v4.10-rc7]
[cannot apply to linus/master linux/master v4.9-rc8 v4.9-rc7 v4.9-rc6]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
url: https://github.com/0day-ci/linux/commits/Hoeun-Ryu/fork-free-vmapped-stacks-in-cache-when-cpus-are-offline/20170209-124143
config: i386-randconfig-x004-201706 (attached as .config)
compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901
reproduce:
# save the attached .config to linux build tree
make ARCH=i386
All warnings (new ones prefixed by >>):
kernel/fork.c: In function 'free_vm_stack_cache':
kernel/fork.c:177:18: error: 'NR_CACHED_STACKS' undeclared (first use in this function)
for (i = 0; i < NR_CACHED_STACKS; i++) {
^~~~~~~~~~~~~~~~
kernel/fork.c:177:18: note: each undeclared identifier is reported only once for each function it appears in
In file included from include/asm-generic/percpu.h:6:0,
from arch/x86/include/asm/percpu.h:542,
from arch/x86/include/asm/preempt.h:5,
from include/linux/preempt.h:59,
from include/linux/spinlock.h:50,
from include/linux/mmzone.h:7,
from include/linux/gfp.h:5,
from include/linux/slab.h:14,
from kernel/fork.c:14:
kernel/fork.c:178:46: error: 'cached_stacks' undeclared (first use in this function)
struct vm_struct *vm_stack = this_cpu_read(cached_stacks[i]);
^
include/linux/percpu-defs.h:305:9: note: in definition of macro '__pcpu_size_call_return'
typeof(variable) pscr_ret__; \
^~~~~~~~
kernel/fork.c:178:32: note: in expansion of macro 'this_cpu_read'
struct vm_struct *vm_stack = this_cpu_read(cached_stacks[i]);
^~~~~~~~~~~~~
include/linux/percpu-defs.h:304:1: warning: initialization makes pointer from integer without a cast [-Wint-conversion]
({ \
^
include/linux/percpu-defs.h:494:29: note: in expansion of macro '__pcpu_size_call_return'
#define this_cpu_read(pcp) __pcpu_size_call_return(this_cpu_read_, pcp)
^~~~~~~~~~~~~~~~~~~~~~~
kernel/fork.c:178:32: note: in expansion of macro 'this_cpu_read'
struct vm_struct *vm_stack = this_cpu_read(cached_stacks[i]);
^~~~~~~~~~~~~
In file included from arch/x86/include/asm/preempt.h:5:0,
from include/linux/preempt.h:59,
from include/linux/spinlock.h:50,
from include/linux/mmzone.h:7,
from include/linux/gfp.h:5,
from include/linux/slab.h:14,
from kernel/fork.c:14:
>> arch/x86/include/asm/percpu.h:94:13: warning: assignment makes integer from pointer without a cast [-Wint-conversion]
pto_tmp__ = (val); \
^
arch/x86/include/asm/percpu.h:416:36: note: in expansion of macro 'percpu_to_op'
#define this_cpu_write_1(pcp, val) percpu_to_op("mov", (pcp), val)
^~~~~~~~~~~~
include/linux/percpu-defs.h:364:11: note: in expansion of macro 'this_cpu_write_1'
case 1: stem##1(variable, __VA_ARGS__);break; \
^~~~
include/linux/percpu-defs.h:495:34: note: in expansion of macro '__pcpu_size_call'
#define this_cpu_write(pcp, val) __pcpu_size_call(this_cpu_write_, pcp, val)
^~~~~~~~~~~~~~~~
>> kernel/fork.c:183:3: note: in expansion of macro 'this_cpu_write'
this_cpu_write(cached_stacks[i], NULL);
^~~~~~~~~~~~~~
>> arch/x86/include/asm/percpu.h:94:13: warning: assignment makes integer from pointer without a cast [-Wint-conversion]
pto_tmp__ = (val); \
^
arch/x86/include/asm/percpu.h:417:36: note: in expansion of macro 'percpu_to_op'
#define this_cpu_write_2(pcp, val) percpu_to_op("mov", (pcp), val)
^~~~~~~~~~~~
include/linux/percpu-defs.h:365:11: note: in expansion of macro 'this_cpu_write_2'
case 2: stem##2(variable, __VA_ARGS__);break; \
^~~~
include/linux/percpu-defs.h:495:34: note: in expansion of macro '__pcpu_size_call'
#define this_cpu_write(pcp, val) __pcpu_size_call(this_cpu_write_, pcp, val)
^~~~~~~~~~~~~~~~
>> kernel/fork.c:183:3: note: in expansion of macro 'this_cpu_write'
this_cpu_write(cached_stacks[i], NULL);
^~~~~~~~~~~~~~
>> arch/x86/include/asm/percpu.h:94:13: warning: assignment makes integer from pointer without a cast [-Wint-conversion]
pto_tmp__ = (val); \
^
arch/x86/include/asm/percpu.h:418:36: note: in expansion of macro 'percpu_to_op'
#define this_cpu_write_4(pcp, val) percpu_to_op("mov", (pcp), val)
^~~~~~~~~~~~
include/linux/percpu-defs.h:366:11: note: in expansion of macro 'this_cpu_write_4'
case 4: stem##4(variable, __VA_ARGS__);break; \
^~~~
include/linux/percpu-defs.h:495:34: note: in expansion of macro '__pcpu_size_call'
#define this_cpu_write(pcp, val) __pcpu_size_call(this_cpu_write_, pcp, val)
^~~~~~~~~~~~~~~~
>> kernel/fork.c:183:3: note: in expansion of macro 'this_cpu_write'
this_cpu_write(cached_stacks[i], NULL);
^~~~~~~~~~~~~~
At top level:
kernel/fork.c:173:12: warning: 'free_vm_stack_cache' defined but not used [-Wunused-function]
static int free_vm_stack_cache(unsigned int cpu)
^~~~~~~~~~~~~~~~~~~
vim +/this_cpu_write +183 kernel/fork.c
167 * flush. Try to minimize the number of calls by caching stacks.
168 */
169 #define NR_CACHED_STACKS 2
170 static DEFINE_PER_CPU(struct vm_struct *, cached_stacks[NR_CACHED_STACKS]);
171 #endif
172
173 static int free_vm_stack_cache(unsigned int cpu)
174 {
175 int i;
176
177 for (i = 0; i < NR_CACHED_STACKS; i++) {
178 struct vm_struct *vm_stack = this_cpu_read(cached_stacks[i]);
179 if (!vm_stack)
180 continue;
181
182 vfree(vm_stack->addr);
> 183 this_cpu_write(cached_stacks[i], NULL);
184 }
185
186 return 0;
187 }
188
189 static unsigned long *alloc_thread_stack_node(struct task_struct *tsk, int node)
190 {
191 #ifdef CONFIG_VMAP_STACK
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 28107 bytes --]
^ permalink raw reply [flat|nested] 12+ messages in thread* Re: [PATCH v2 1/2] fork: free vmapped stacks in cache when cpus are offline
2017-02-09 4:03 [PATCH v2 1/2] fork: free vmapped stacks in cache when cpus are offline Hoeun Ryu
` (3 preceding siblings ...)
2017-02-09 8:01 ` kbuild test robot
@ 2017-02-09 8:38 ` Michal Hocko
2017-02-09 13:36 ` Hoeun Ryu
2017-02-09 10:26 ` kbuild test robot
5 siblings, 1 reply; 12+ messages in thread
From: Michal Hocko @ 2017-02-09 8:38 UTC (permalink / raw)
To: Hoeun Ryu
Cc: Andrew Morton, Ingo Molnar, Andy Lutomirski, Kees Cook,
Eric W. Biederman, Mateusz Guzik, linux-kernel, kernel-hardening
On Thu 09-02-17 13:03:46, Hoeun Ryu wrote:
> Using virtually mapped stack, kernel stacks are allocated via vmalloc.
> In the current implementation, two stacks per cpu can be cached when
> tasks are freed and the cached stacks are used again in task duplications.
> but the cached stacks may remain unfreed even when cpu are offline.
> By adding a cpu hotplug callback to free the cached stacks when a cpu
> goes offline, the pages of the cached stacks are not wasted.
>
> Signed-off-by: Hoeun Ryu <hoeun.ryu@gmail.com>
> ---
> Changes in v2:
> remove cpuhp callback for `starup`, only `teardown` callback is installed.
>
> kernel/fork.c | 21 +++++++++++++++++++++
> 1 file changed, 21 insertions(+)
>
> diff --git a/kernel/fork.c b/kernel/fork.c
> index 61284d8..7911ed2 100644
> --- a/kernel/fork.c
> +++ b/kernel/fork.c
> @@ -170,6 +170,22 @@ void __weak arch_release_thread_stack(unsigned long *stack)
> static DEFINE_PER_CPU(struct vm_struct *, cached_stacks[NR_CACHED_STACKS]);
> #endif
>
> +static int free_vm_stack_cache(unsigned int cpu)
> +{
> + int i;
> +
> + for (i = 0; i < NR_CACHED_STACKS; i++) {
> + struct vm_struct *vm_stack = this_cpu_read(cached_stacks[i]);
the callbak will run on the given cpu so this_cpu_read will be in fact
per_cpu_ptr(cached_stacks[i], cpu). Using this_cpu_read is just too
confusing. Also you do want to make this function defined only for
CONFIG_VMAP_STACK.
> + if (!vm_stack)
> + continue;
> +
> + vfree(vm_stack->addr);
> + this_cpu_write(cached_stacks[i], NULL);
> + }
> +
> + return 0;
> +}
> +
--
Michal Hocko
SUSE Labs
^ permalink raw reply [flat|nested] 12+ messages in thread* Re: [PATCH v2 1/2] fork: free vmapped stacks in cache when cpus are offline
2017-02-09 8:38 ` Michal Hocko
@ 2017-02-09 13:36 ` Hoeun Ryu
0 siblings, 0 replies; 12+ messages in thread
From: Hoeun Ryu @ 2017-02-09 13:36 UTC (permalink / raw)
To: Michal Hocko
Cc: Andrew Morton, Ingo Molnar, Andy Lutomirski, Kees Cook,
Eric W. Biederman, Mateusz Guzik, linux-kernel, kernel-hardening
On Thu, Feb 9, 2017 at 5:38 PM, Michal Hocko <mhocko@kernel.org> wrote:
> On Thu 09-02-17 13:03:46, Hoeun Ryu wrote:
>> Using virtually mapped stack, kernel stacks are allocated via vmalloc.
>> In the current implementation, two stacks per cpu can be cached when
>> tasks are freed and the cached stacks are used again in task duplications.
>> but the cached stacks may remain unfreed even when cpu are offline.
>> By adding a cpu hotplug callback to free the cached stacks when a cpu
>> goes offline, the pages of the cached stacks are not wasted.
>>
>> Signed-off-by: Hoeun Ryu <hoeun.ryu@gmail.com>
>> ---
>> Changes in v2:
>> remove cpuhp callback for `starup`, only `teardown` callback is installed.
>>
>> kernel/fork.c | 21 +++++++++++++++++++++
>> 1 file changed, 21 insertions(+)
>>
>> diff --git a/kernel/fork.c b/kernel/fork.c
>> index 61284d8..7911ed2 100644
>> --- a/kernel/fork.c
>> +++ b/kernel/fork.c
>> @@ -170,6 +170,22 @@ void __weak arch_release_thread_stack(unsigned long *stack)
>> static DEFINE_PER_CPU(struct vm_struct *, cached_stacks[NR_CACHED_STACKS]);
>> #endif
>>
>> +static int free_vm_stack_cache(unsigned int cpu)
>> +{
>> + int i;
>> +
>> + for (i = 0; i < NR_CACHED_STACKS; i++) {
>> + struct vm_struct *vm_stack = this_cpu_read(cached_stacks[i]);
>
> the callbak will run on the given cpu so this_cpu_read will be in fact
> per_cpu_ptr(cached_stacks[i], cpu). Using this_cpu_read is just too
> confusing. Also you do want to make this function defined only for
> CONFIG_VMAP_STACK.
>
Sorry, Thank you for your correction. I will fix this.
>> + if (!vm_stack)
>> + continue;
>> +
>> + vfree(vm_stack->addr);
>> + this_cpu_write(cached_stacks[i], NULL);
>> + }
>> +
>> + return 0;
>> +}
>> +
>
> --
> Michal Hocko
> SUSE Labs
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH v2 1/2] fork: free vmapped stacks in cache when cpus are offline
2017-02-09 4:03 [PATCH v2 1/2] fork: free vmapped stacks in cache when cpus are offline Hoeun Ryu
` (4 preceding siblings ...)
2017-02-09 8:38 ` Michal Hocko
@ 2017-02-09 10:26 ` kbuild test robot
5 siblings, 0 replies; 12+ messages in thread
From: kbuild test robot @ 2017-02-09 10:26 UTC (permalink / raw)
To: Hoeun Ryu
Cc: kbuild-all, Andrew Morton, Michal Hocko, Ingo Molnar,
Andy Lutomirski, Kees Cook, Eric W. Biederman, Mateusz Guzik,
linux-kernel, kernel-hardening, Hoeun Ryu
Hi Hoeun,
[auto build test WARNING on next-20170208]
[also build test WARNING on v4.10-rc7]
[cannot apply to linus/master linux/master v4.9-rc8 v4.9-rc7 v4.9-rc6]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
url: https://github.com/0day-ci/linux/commits/Hoeun-Ryu/fork-free-vmapped-stacks-in-cache-when-cpus-are-offline/20170209-124143
reproduce:
# apt-get install sparse
make ARCH=x86_64 allmodconfig
make C=1 CF=-D__CHECK_ENDIAN__
sparse warnings: (new ones prefixed by >>)
include/linux/compiler.h:264:8: sparse: attribute 'no_sanitize_address': unknown attribute
kernel/fork.c:177:25: sparse: undefined identifier 'NR_CACHED_STACKS'
kernel/fork.c:178:46: sparse: undefined identifier 'cached_stacks'
kernel/fork.c:178:46: sparse: undefined identifier 'cached_stacks'
>> kernel/fork.c:178:46: sparse: incompatible types for operation (+)
kernel/fork.c:178:46: left side has type bad type
kernel/fork.c:178:46: right side has type int [signed] [assigned] i
>> kernel/fork.c:178:46: sparse: cannot dereference this type
>> kernel/fork.c:178:46: sparse: incompatible types for operation (+)
kernel/fork.c:178:46: left side has type bad type
kernel/fork.c:178:46: right side has type int
kernel/fork.c:178:46: sparse: undefined identifier 'cached_stacks'
kernel/fork.c:178:46: sparse: undefined identifier 'cached_stacks'
kernel/fork.c:178:46: sparse: undefined identifier 'cached_stacks'
kernel/fork.c:178:46: sparse: undefined identifier 'cached_stacks'
kernel/fork.c:178:46: sparse: undefined identifier 'cached_stacks'
kernel/fork.c:178:46: sparse: undefined identifier 'cached_stacks'
kernel/fork.c:178:46: sparse: undefined identifier 'cached_stacks'
>> kernel/fork.c:178:46: sparse: incompatible types for 'case' statement
>> kernel/fork.c:178:46: sparse: incompatible types for 'case' statement
>> kernel/fork.c:178:46: sparse: incompatible types for 'case' statement
>> kernel/fork.c:178:46: sparse: incompatible types for 'case' statement
>> kernel/fork.c:178:46: sparse: incompatible types for operation (+)
kernel/fork.c:178:46: left side has type bad type
kernel/fork.c:178:46: right side has type int [signed] [assigned] i
>> kernel/fork.c:178:46: sparse: cannot dereference this type
>> kernel/fork.c:178:46: sparse: incompatible types for operation (+)
kernel/fork.c:178:46: left side has type bad type
kernel/fork.c:178:46: right side has type int [signed] [assigned] i
>> kernel/fork.c:178:46: sparse: cannot dereference this type
kernel/fork.c:178:46: sparse: undefined identifier 'cached_stacks'
kernel/fork.c:178:46: sparse: undefined identifier 'cached_stacks'
kernel/fork.c:178:46: sparse: undefined identifier 'cached_stacks'
kernel/fork.c:178:46: sparse: undefined identifier 'cached_stacks'
kernel/fork.c:178:46: sparse: undefined identifier 'cached_stacks'
kernel/fork.c:178:46: sparse: undefined identifier 'cached_stacks'
>> kernel/fork.c:178:46: sparse: incompatible types for 'case' statement
>> kernel/fork.c:178:46: sparse: incompatible types for 'case' statement
>> kernel/fork.c:178:46: sparse: incompatible types for 'case' statement
>> kernel/fork.c:178:46: sparse: incompatible types for 'case' statement
>> kernel/fork.c:178:46: sparse: incompatible types for operation (+)
kernel/fork.c:178:46: left side has type bad type
kernel/fork.c:178:46: right side has type int [signed] [assigned] i
>> kernel/fork.c:178:46: sparse: cannot dereference this type
kernel/fork.c:178:46: sparse: undefined identifier 'cached_stacks'
kernel/fork.c:178:46: sparse: undefined identifier 'cached_stacks'
kernel/fork.c:178:46: sparse: undefined identifier 'cached_stacks'
kernel/fork.c:178:46: sparse: undefined identifier 'cached_stacks'
kernel/fork.c:178:46: sparse: undefined identifier 'cached_stacks'
kernel/fork.c:178:46: sparse: undefined identifier 'cached_stacks'
>> kernel/fork.c:178:46: sparse: incompatible types for 'case' statement
>> kernel/fork.c:178:46: sparse: incompatible types for 'case' statement
>> kernel/fork.c:178:46: sparse: incompatible types for 'case' statement
>> kernel/fork.c:178:46: sparse: incompatible types for 'case' statement
>> kernel/fork.c:178:46: sparse: incompatible types for operation (+)
kernel/fork.c:178:46: left side has type bad type
kernel/fork.c:178:46: right side has type int [signed] [assigned] i
>> kernel/fork.c:178:46: sparse: cannot dereference this type
kernel/fork.c:178:46: sparse: undefined identifier 'cached_stacks'
kernel/fork.c:178:46: sparse: undefined identifier 'cached_stacks'
kernel/fork.c:178:46: sparse: undefined identifier 'cached_stacks'
kernel/fork.c:178:46: sparse: undefined identifier 'cached_stacks'
kernel/fork.c:178:46: sparse: undefined identifier 'cached_stacks'
kernel/fork.c:178:46: sparse: undefined identifier 'cached_stacks'
>> kernel/fork.c:178:46: sparse: incompatible types for 'case' statement
>> kernel/fork.c:178:46: sparse: incompatible types for 'case' statement
>> kernel/fork.c:178:46: sparse: incompatible types for 'case' statement
>> kernel/fork.c:178:46: sparse: incompatible types for 'case' statement
>> kernel/fork.c:178:46: sparse: incompatible types for operation (+)
kernel/fork.c:178:46: left side has type bad type
kernel/fork.c:178:46: right side has type int [signed] [assigned] i
>> kernel/fork.c:178:46: sparse: cannot dereference this type
>> kernel/fork.c:178:46: sparse: incompatible types for 'case' statement
>> kernel/fork.c:178:46: sparse: incompatible types for 'case' statement
>> kernel/fork.c:178:46: sparse: incompatible types for 'case' statement
>> kernel/fork.c:178:46: sparse: incompatible types for 'case' statement
kernel/fork.c:183:17: sparse: undefined identifier 'cached_stacks'
kernel/fork.c:183:17: sparse: incompatible types for operation (+)
kernel/fork.c:183:17: left side has type bad type
kernel/fork.c:183:17: right side has type int [signed] [assigned] i
kernel/fork.c:183:17: sparse: cannot dereference this type
kernel/fork.c:183:17: sparse: incompatible types for operation (+)
kernel/fork.c:183:17: left side has type bad type
kernel/fork.c:183:17: right side has type int
kernel/fork.c:183:17: sparse: undefined identifier 'cached_stacks'
kernel/fork.c:183:17: sparse: undefined identifier 'cached_stacks'
kernel/fork.c:183:17: sparse: incompatible types for operation (+)
kernel/fork.c:183:17: left side has type bad type
kernel/fork.c:183:17: right side has type int [signed] [assigned] i
kernel/fork.c:183:17: sparse: cannot dereference this type
kernel/fork.c:183:17: sparse: undefined identifier 'cached_stacks'
kernel/fork.c:183:17: sparse: undefined identifier 'cached_stacks'
kernel/fork.c:183:17: sparse: undefined identifier 'cached_stacks'
kernel/fork.c:183:17: sparse: undefined identifier 'cached_stacks'
kernel/fork.c:183:17: sparse: undefined identifier 'cached_stacks'
kernel/fork.c:183:17: sparse: incompatible types for 'case' statement
kernel/fork.c:183:17: sparse: incompatible types for 'case' statement
kernel/fork.c:183:17: sparse: incompatible types for 'case' statement
kernel/fork.c:183:17: sparse: incompatible types for 'case' statement
kernel/fork.c:183:17: sparse: undefined identifier 'cached_stacks'
kernel/fork.c:183:17: sparse: incompatible types for operation (+)
kernel/fork.c:183:17: left side has type bad type
kernel/fork.c:183:17: right side has type int [signed] [assigned] i
kernel/fork.c:183:17: sparse: cannot dereference this type
kernel/fork.c:183:17: sparse: undefined identifier 'cached_stacks'
kernel/fork.c:183:17: sparse: undefined identifier 'cached_stacks'
kernel/fork.c:183:17: sparse: undefined identifier 'cached_stacks'
kernel/fork.c:183:17: sparse: undefined identifier 'cached_stacks'
kernel/fork.c:183:17: sparse: undefined identifier 'cached_stacks'
kernel/fork.c:183:17: sparse: incompatible types for 'case' statement
kernel/fork.c:183:17: sparse: incompatible types for 'case' statement
kernel/fork.c:183:17: sparse: incompatible types for 'case' statement
kernel/fork.c:183:17: sparse: incompatible types for 'case' statement
kernel/fork.c:183:17: sparse: undefined identifier 'cached_stacks'
kernel/fork.c:183:17: sparse: incompatible types for operation (+)
kernel/fork.c:183:17: left side has type bad type
kernel/fork.c:183:17: right side has type int [signed] [assigned] i
kernel/fork.c:183:17: sparse: cannot dereference this type
kernel/fork.c:183:17: sparse: undefined identifier 'cached_stacks'
kernel/fork.c:183:17: sparse: undefined identifier 'cached_stacks'
kernel/fork.c:183:17: sparse: undefined identifier 'cached_stacks'
kernel/fork.c:183:17: sparse: undefined identifier 'cached_stacks'
kernel/fork.c:183:17: sparse: undefined identifier 'cached_stacks'
kernel/fork.c:183:17: sparse: incompatible types for 'case' statement
kernel/fork.c:183:17: sparse: incompatible types for 'case' statement
>> kernel/fork.c:183:17: sparse: too many errors
kernel/fork.c: In function 'free_vm_stack_cache':
kernel/fork.c:177:18: error: 'NR_CACHED_STACKS' undeclared (first use in this function)
for (i = 0; i < NR_CACHED_STACKS; i++) {
^~~~~~~~~~~~~~~~
kernel/fork.c:177:18: note: each undeclared identifier is reported only once for each function it appears in
In file included from include/asm-generic/percpu.h:6:0,
from arch/x86/include/asm/percpu.h:542,
from arch/x86/include/asm/preempt.h:5,
from include/linux/preempt.h:59,
from include/linux/spinlock.h:50,
from include/linux/mmzone.h:7,
from include/linux/gfp.h:5,
from include/linux/slab.h:14,
from kernel/fork.c:14:
kernel/fork.c:178:46: error: 'cached_stacks' undeclared (first use in this function)
struct vm_struct *vm_stack = this_cpu_read(cached_stacks[i]);
^
include/linux/percpu-defs.h:305:9: note: in definition of macro '__pcpu_size_call_return'
typeof(variable) pscr_ret__; \
^~~~~~~~
kernel/fork.c:178:32: note: in expansion of macro 'this_cpu_read'
struct vm_struct *vm_stack = this_cpu_read(cached_stacks[i]);
^~~~~~~~~~~~~
include/linux/percpu-defs.h:304:1: warning: initialization makes pointer from integer without a cast [-Wint-conversion]
({ \
^
include/linux/percpu-defs.h:494:29: note: in expansion of macro '__pcpu_size_call_return'
#define this_cpu_read(pcp) __pcpu_size_call_return(this_cpu_read_, pcp)
^~~~~~~~~~~~~~~~~~~~~~~
kernel/fork.c:178:32: note: in expansion of macro 'this_cpu_read'
struct vm_struct *vm_stack = this_cpu_read(cached_stacks[i]);
^~~~~~~~~~~~~
In file included from arch/x86/include/asm/preempt.h:5:0,
from include/linux/preempt.h:59,
from include/linux/spinlock.h:50,
from include/linux/mmzone.h:7,
from include/linux/gfp.h:5,
from include/linux/slab.h:14,
from kernel/fork.c:14:
arch/x86/include/asm/percpu.h:94:13: warning: assignment makes integer from pointer without a cast [-Wint-conversion]
pto_tmp__ = (val); \
^
arch/x86/include/asm/percpu.h:416:36: note: in expansion of macro 'percpu_to_op'
#define this_cpu_write_1(pcp, val) percpu_to_op("mov", (pcp), val)
^~~~~~~~~~~~
include/linux/percpu-defs.h:364:11: note: in expansion of macro 'this_cpu_write_1'
case 1: stem##1(variable, __VA_ARGS__);break; \
^~~~
include/linux/percpu-defs.h:495:34: note: in expansion of macro '__pcpu_size_call'
#define this_cpu_write(pcp, val) __pcpu_size_call(this_cpu_write_, pcp, val)
^~~~~~~~~~~~~~~~
kernel/fork.c:183:3: note: in expansion of macro 'this_cpu_write'
this_cpu_write(cached_stacks[i], NULL);
^~~~~~~~~~~~~~
arch/x86/include/asm/percpu.h:101:15: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
: "qi" ((pto_T__)(val))); \
^
arch/x86/include/asm/percpu.h:416:36: note: in expansion of macro 'percpu_to_op'
#define this_cpu_write_1(pcp, val) percpu_to_op("mov", (pcp), val)
^~~~~~~~~~~~
include/linux/percpu-defs.h:364:11: note: in expansion of macro 'this_cpu_write_1'
case 1: stem##1(variable, __VA_ARGS__);break; \
^~~~
include/linux/percpu-defs.h:495:34: note: in expansion of macro '__pcpu_size_call'
#define this_cpu_write(pcp, val) __pcpu_size_call(this_cpu_write_, pcp, val)
^~~~~~~~~~~~~~~~
kernel/fork.c:183:3: note: in expansion of macro 'this_cpu_write'
this_cpu_write(cached_stacks[i], NULL);
^~~~~~~~~~~~~~
arch/x86/include/asm/percpu.h:106:15: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
: "ri" ((pto_T__)(val))); \
^
arch/x86/include/asm/percpu.h:416:36: note: in expansion of macro 'percpu_to_op'
#define this_cpu_write_1(pcp, val) percpu_to_op("mov", (pcp), val)
^~~~~~~~~~~~
include/linux/percpu-defs.h:364:11: note: in expansion of macro 'this_cpu_write_1'
case 1: stem##1(variable, __VA_ARGS__);break; \
^~~~
include/linux/percpu-defs.h:495:34: note: in expansion of macro '__pcpu_size_call'
#define this_cpu_write(pcp, val) __pcpu_size_call(this_cpu_write_, pcp, val)
^~~~~~~~~~~~~~~~
kernel/fork.c:183:3: note: in expansion of macro 'this_cpu_write'
this_cpu_write(cached_stacks[i], NULL);
^~~~~~~~~~~~~~
arch/x86/include/asm/percpu.h:111:15: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
: "ri" ((pto_T__)(val))); \
^
arch/x86/include/asm/percpu.h:416:36: note: in expansion of macro 'percpu_to_op'
#define this_cpu_write_1(pcp, val) percpu_to_op("mov", (pcp), val)
^~~~~~~~~~~~
include/linux/percpu-defs.h:364:11: note: in expansion of macro 'this_cpu_write_1'
case 1: stem##1(variable, __VA_ARGS__);break; \
^~~~
include/linux/percpu-defs.h:495:34: note: in expansion of macro '__pcpu_size_call'
#define this_cpu_write(pcp, val) __pcpu_size_call(this_cpu_write_, pcp, val)
^~~~~~~~~~~~~~~~
kernel/fork.c:183:3: note: in expansion of macro 'this_cpu_write'
this_cpu_write(cached_stacks[i], NULL);
^~~~~~~~~~~~~~
arch/x86/include/asm/percpu.h:116:15: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
vim +178 kernel/fork.c
171 #endif
172
173 static int free_vm_stack_cache(unsigned int cpu)
174 {
175 int i;
176
> 177 for (i = 0; i < NR_CACHED_STACKS; i++) {
> 178 struct vm_struct *vm_stack = this_cpu_read(cached_stacks[i]);
179 if (!vm_stack)
180 continue;
181
182 vfree(vm_stack->addr);
> 183 this_cpu_write(cached_stacks[i], NULL);
184 }
185
186 return 0;
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
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