* [hyperv:hyperv-next 4/5] drivers/hv/vmbus_drv.c:2082:29: warning: shift count >= width of type
@ 2021-12-18 10:20 kernel test robot
2021-12-19 12:29 ` Wei Liu
0 siblings, 1 reply; 4+ messages in thread
From: kernel test robot @ 2021-12-18 10:20 UTC (permalink / raw)
To: Tianyu Lan
Cc: llvm, kbuild-all, linux-kernel, Wei Liu, Long Li, Michael Kelley
tree: https://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux.git hyperv-next
head: 19fd7ca00201c0525452dcf5a490e4b01674ef4c
commit: 6327882f7b4a476ea902de4bee5657f1028d6859 [4/5] scsi: storvsc: Add Isolation VM support for storvsc driver
config: x86_64-randconfig-a013-20211216 (https://download.01.org/0day-ci/archive/20211218/202112181827.o3X7GmHz-lkp@intel.com/config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 4c9e31a4814592bbda7153833e46728dc7b21100)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux.git/commit/?id=6327882f7b4a476ea902de4bee5657f1028d6859
git remote add hyperv https://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux.git
git fetch --no-tags hyperv hyperv-next
git checkout 6327882f7b4a476ea902de4bee5657f1028d6859
# save the config file to linux build tree
mkdir build_dir
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash drivers/hv/
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
All warnings (new ones prefixed by >>):
>> drivers/hv/vmbus_drv.c:2082:29: warning: shift count >= width of type [-Wshift-count-overflow]
static u64 vmbus_dma_mask = DMA_BIT_MASK(64);
^~~~~~~~~~~~~~~~
include/linux/dma-mapping.h:76:54: note: expanded from macro 'DMA_BIT_MASK'
#define DMA_BIT_MASK(n) (((n) == 64) ? ~0ULL : ((1ULL<<(n))-1))
^ ~~~
1 warning generated.
vim +2082 drivers/hv/vmbus_drv.c
2081
> 2082 static u64 vmbus_dma_mask = DMA_BIT_MASK(64);
2083 /*
2084 * vmbus_device_register - Register the child device
2085 */
2086 int vmbus_device_register(struct hv_device *child_device_obj)
2087 {
2088 struct kobject *kobj = &child_device_obj->device.kobj;
2089 int ret;
2090
2091 dev_set_name(&child_device_obj->device, "%pUl",
2092 &child_device_obj->channel->offermsg.offer.if_instance);
2093
2094 child_device_obj->device.bus = &hv_bus;
2095 child_device_obj->device.parent = &hv_acpi_dev->dev;
2096 child_device_obj->device.release = vmbus_device_release;
2097
2098 /*
2099 * Register with the LDM. This will kick off the driver/device
2100 * binding...which will eventually call vmbus_match() and vmbus_probe()
2101 */
2102 ret = device_register(&child_device_obj->device);
2103 if (ret) {
2104 pr_err("Unable to register child device\n");
2105 return ret;
2106 }
2107
2108 child_device_obj->channels_kset = kset_create_and_add("channels",
2109 NULL, kobj);
2110 if (!child_device_obj->channels_kset) {
2111 ret = -ENOMEM;
2112 goto err_dev_unregister;
2113 }
2114
2115 ret = vmbus_add_channel_kobj(child_device_obj,
2116 child_device_obj->channel);
2117 if (ret) {
2118 pr_err("Unable to register primary channeln");
2119 goto err_kset_unregister;
2120 }
2121 hv_debug_add_dev_dir(child_device_obj);
2122
2123 child_device_obj->device.dma_mask = &vmbus_dma_mask;
2124 child_device_obj->device.dma_parms = &child_device_obj->dma_parms;
2125 return 0;
2126
2127 err_kset_unregister:
2128 kset_unregister(child_device_obj->channels_kset);
2129
2130 err_dev_unregister:
2131 device_unregister(&child_device_obj->device);
2132 return ret;
2133 }
2134
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [hyperv:hyperv-next 4/5] drivers/hv/vmbus_drv.c:2082:29: warning: shift count >= width of type
2021-12-18 10:20 [hyperv:hyperv-next 4/5] drivers/hv/vmbus_drv.c:2082:29: warning: shift count >= width of type kernel test robot
@ 2021-12-19 12:29 ` Wei Liu
2021-12-20 16:53 ` Nathan Chancellor
0 siblings, 1 reply; 4+ messages in thread
From: Wei Liu @ 2021-12-19 12:29 UTC (permalink / raw)
To: kernel test robot
Cc: Tianyu Lan, llvm, kbuild-all, linux-kernel, Wei Liu, Long Li,
Michael Kelley
On Sat, Dec 18, 2021 at 06:20:43PM +0800, kernel test robot wrote:
> tree: https://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux.git hyperv-next
> head: 19fd7ca00201c0525452dcf5a490e4b01674ef4c
> commit: 6327882f7b4a476ea902de4bee5657f1028d6859 [4/5] scsi: storvsc: Add Isolation VM support for storvsc driver
> config: x86_64-randconfig-a013-20211216 (https://download.01.org/0day-ci/archive/20211218/202112181827.o3X7GmHz-lkp@intel.com/config)
> compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 4c9e31a4814592bbda7153833e46728dc7b21100)
> reproduce (this is a W=1 build):
> wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
> chmod +x ~/bin/make.cross
> # https://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux.git/commit/?id=6327882f7b4a476ea902de4bee5657f1028d6859
> git remote add hyperv https://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux.git
> git fetch --no-tags hyperv hyperv-next
> git checkout 6327882f7b4a476ea902de4bee5657f1028d6859
> # save the config file to linux build tree
> mkdir build_dir
> COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash drivers/hv/
>
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@intel.com>
>
> All warnings (new ones prefixed by >>):
>
> >> drivers/hv/vmbus_drv.c:2082:29: warning: shift count >= width of type [-Wshift-count-overflow]
> static u64 vmbus_dma_mask = DMA_BIT_MASK(64);
> ^~~~~~~~~~~~~~~~
> include/linux/dma-mapping.h:76:54: note: expanded from macro 'DMA_BIT_MASK'
> #define DMA_BIT_MASK(n) (((n) == 64) ? ~0ULL : ((1ULL<<(n))-1))
> ^ ~~~
I don't think there is anything wrong with the code. When n is 64 the
problematic expression is not evaluated.
Wei.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [hyperv:hyperv-next 4/5] drivers/hv/vmbus_drv.c:2082:29: warning: shift count >= width of type
2021-12-19 12:29 ` Wei Liu
@ 2021-12-20 16:53 ` Nathan Chancellor
2021-12-20 17:44 ` Wei Liu
0 siblings, 1 reply; 4+ messages in thread
From: Nathan Chancellor @ 2021-12-20 16:53 UTC (permalink / raw)
To: Wei Liu
Cc: kernel test robot, Tianyu Lan, llvm, kbuild-all, linux-kernel,
Long Li, Michael Kelley
Hi Wei,
On Sun, Dec 19, 2021 at 12:29:37PM +0000, Wei Liu wrote:
> On Sat, Dec 18, 2021 at 06:20:43PM +0800, kernel test robot wrote:
> > tree: https://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux.git hyperv-next
> > head: 19fd7ca00201c0525452dcf5a490e4b01674ef4c
> > commit: 6327882f7b4a476ea902de4bee5657f1028d6859 [4/5] scsi: storvsc: Add Isolation VM support for storvsc driver
> > config: x86_64-randconfig-a013-20211216 (https://download.01.org/0day-ci/archive/20211218/202112181827.o3X7GmHz-lkp@intel.com/config)
> > compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 4c9e31a4814592bbda7153833e46728dc7b21100)
> > reproduce (this is a W=1 build):
> > wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
> > chmod +x ~/bin/make.cross
> > # https://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux.git/commit/?id=6327882f7b4a476ea902de4bee5657f1028d6859
> > git remote add hyperv https://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux.git
> > git fetch --no-tags hyperv hyperv-next
> > git checkout 6327882f7b4a476ea902de4bee5657f1028d6859
> > # save the config file to linux build tree
> > mkdir build_dir
> > COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash drivers/hv/
> >
> > If you fix the issue, kindly add following tag as appropriate
> > Reported-by: kernel test robot <lkp@intel.com>
> >
> > All warnings (new ones prefixed by >>):
> >
> > >> drivers/hv/vmbus_drv.c:2082:29: warning: shift count >= width of type [-Wshift-count-overflow]
> > static u64 vmbus_dma_mask = DMA_BIT_MASK(64);
> > ^~~~~~~~~~~~~~~~
> > include/linux/dma-mapping.h:76:54: note: expanded from macro 'DMA_BIT_MASK'
> > #define DMA_BIT_MASK(n) (((n) == 64) ? ~0ULL : ((1ULL<<(n))-1))
> > ^ ~~~
>
> I don't think there is anything wrong with the code. When n is 64 the
> problematic expression is not evaluated.
Yes, unfortunately, this is an outstanding bug in clang where it does
not properly build a control flow graph for expressions at a global
scope:
https://github.com/ClangBuiltLinux/linux/issues/92
We should absolutely fix that but it has not come up too often so other
fires have been prioritized. Now that -Werror is a thing, that issue's
priority should probably be upgraded, as this warning will break
allmodconfig for clang.
If you were feeling generous, just changing that to ~0ULL directly would
solve the warning but I get that it is less documentation that way.
Cheers,
Nathan
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [hyperv:hyperv-next 4/5] drivers/hv/vmbus_drv.c:2082:29: warning: shift count >= width of type
2021-12-20 16:53 ` Nathan Chancellor
@ 2021-12-20 17:44 ` Wei Liu
0 siblings, 0 replies; 4+ messages in thread
From: Wei Liu @ 2021-12-20 17:44 UTC (permalink / raw)
To: Nathan Chancellor
Cc: Wei Liu, kernel test robot, Tianyu Lan, llvm, kbuild-all,
linux-kernel, Long Li, Michael Kelley
On Mon, Dec 20, 2021 at 09:53:30AM -0700, Nathan Chancellor wrote:
> Hi Wei,
>
> On Sun, Dec 19, 2021 at 12:29:37PM +0000, Wei Liu wrote:
> > On Sat, Dec 18, 2021 at 06:20:43PM +0800, kernel test robot wrote:
> > > tree: https://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux.git hyperv-next
> > > head: 19fd7ca00201c0525452dcf5a490e4b01674ef4c
> > > commit: 6327882f7b4a476ea902de4bee5657f1028d6859 [4/5] scsi: storvsc: Add Isolation VM support for storvsc driver
> > > config: x86_64-randconfig-a013-20211216 (https://download.01.org/0day-ci/archive/20211218/202112181827.o3X7GmHz-lkp@intel.com/config)
> > > compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 4c9e31a4814592bbda7153833e46728dc7b21100)
> > > reproduce (this is a W=1 build):
> > > wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
> > > chmod +x ~/bin/make.cross
> > > # https://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux.git/commit/?id=6327882f7b4a476ea902de4bee5657f1028d6859
> > > git remote add hyperv https://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux.git
> > > git fetch --no-tags hyperv hyperv-next
> > > git checkout 6327882f7b4a476ea902de4bee5657f1028d6859
> > > # save the config file to linux build tree
> > > mkdir build_dir
> > > COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash drivers/hv/
> > >
> > > If you fix the issue, kindly add following tag as appropriate
> > > Reported-by: kernel test robot <lkp@intel.com>
> > >
> > > All warnings (new ones prefixed by >>):
> > >
> > > >> drivers/hv/vmbus_drv.c:2082:29: warning: shift count >= width of type [-Wshift-count-overflow]
> > > static u64 vmbus_dma_mask = DMA_BIT_MASK(64);
> > > ^~~~~~~~~~~~~~~~
> > > include/linux/dma-mapping.h:76:54: note: expanded from macro 'DMA_BIT_MASK'
> > > #define DMA_BIT_MASK(n) (((n) == 64) ? ~0ULL : ((1ULL<<(n))-1))
> > > ^ ~~~
> >
> > I don't think there is anything wrong with the code. When n is 64 the
> > problematic expression is not evaluated.
>
> Yes, unfortunately, this is an outstanding bug in clang where it does
> not properly build a control flow graph for expressions at a global
> scope:
>
> https://github.com/ClangBuiltLinux/linux/issues/92
>
> We should absolutely fix that but it has not come up too often so other
> fires have been prioritized. Now that -Werror is a thing, that issue's
> priority should probably be upgraded, as this warning will break
> allmodconfig for clang.
Thanks for the explanation.
>
> If you were feeling generous, just changing that to ~0ULL directly would
> solve the warning but I get that it is less documentation that way.
I would actually like to keep the code as-is because it gives a clear
idea what it is doing.
Wei.
>
> Cheers,
> Nathan
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2021-12-20 17:44 UTC | newest]
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2021-12-18 10:20 [hyperv:hyperv-next 4/5] drivers/hv/vmbus_drv.c:2082:29: warning: shift count >= width of type kernel test robot
2021-12-19 12:29 ` Wei Liu
2021-12-20 16:53 ` Nathan Chancellor
2021-12-20 17:44 ` Wei Liu
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