| Message ID | 20240906114455.730559-1-roheetchavan@gmail.com (mailing list archive) |
|---|---|
| State | Rejected |
| Delegated to: | Johannes Berg |
| Headers | show |
| Series | lib80211: Use ERR_CAST() to return | expand |
On Fri, 2024-09-06 at 17:14 +0530, Rohit Chavan wrote: > Using ERR_CAST() is more reasonable and safer, When it is necessary > to convert the type of an error pointer and return it. > What? Why? What's the point? johannes
On Fri, Sep 06, 2024 at 05:14:55PM +0530, Rohit Chavan wrote: > Using ERR_CAST() is more reasonable and safer, When it is necessary > to convert the type of an error pointer and return it. > > Signed-off-by: Rohit Chavan <roheetchavan@gmail.com> > --- > net/wireless/lib80211.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/net/wireless/lib80211.c b/net/wireless/lib80211.c > index d66a913027e0..87c0e09aa676 100644 > --- a/net/wireless/lib80211.c > +++ b/net/wireless/lib80211.c > @@ -227,7 +227,7 @@ EXPORT_SYMBOL(lib80211_get_crypto_ops); > > static void *lib80211_crypt_null_init(int keyidx) > { > - return (void *)1; > + return ERR_CAST(1); This seems wrong to me. ERR_CAST is designed to cast a pointer to an error pointer. But 1 is an integer, not a pointer. > } > > static void lib80211_crypt_null_deinit(void *priv) > -- > 2.34.1 > >
Hi Rohit, kernel test robot noticed the following build errors: [auto build test ERROR on wireless-next/main] [also build test ERROR on wireless/main linus/master v6.11-rc6 next-20240906] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch#_base_tree_information] url: https://github.com/intel-lab-lkp/linux/commits/Rohit-Chavan/lib80211-Use-ERR_CAST-to-return/20240906-194721 base: https://git.kernel.org/pub/scm/linux/kernel/git/wireless/wireless-next.git main patch link: https://lore.kernel.org/r/20240906114455.730559-1-roheetchavan%40gmail.com patch subject: [PATCH] lib80211: Use ERR_CAST() to return config: m68k-allmodconfig (https://download.01.org/0day-ci/archive/20240907/202409071405.Ze3koraa-lkp@intel.com/config) compiler: m68k-linux-gcc (GCC) 14.1.0 reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240907/202409071405.Ze3koraa-lkp@intel.com/reproduce) If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot <lkp@intel.com> | Closes: https://lore.kernel.org/oe-kbuild-all/202409071405.Ze3koraa-lkp@intel.com/ All errors (new ones prefixed by >>): net/wireless/lib80211.c: In function 'lib80211_crypt_null_init': >> net/wireless/lib80211.c:230:25: error: passing argument 1 of 'ERR_CAST' makes pointer from integer without a cast [-Wint-conversion] 230 | return ERR_CAST(1); | ^ | | | int In file included from include/linux/string.h:10, from include/linux/bitmap.h:13, from include/linux/cpumask.h:12, from include/linux/smp.h:13, from include/linux/lockdep.h:14, from include/linux/spinlock.h:63, from include/linux/mmzone.h:8, from include/linux/gfp.h:7, from include/linux/umh.h:4, from include/linux/kmod.h:9, from include/linux/module.h:17, from net/wireless/lib80211.c:19: include/linux/err.h:82:64: note: expected 'const void *' but argument is of type 'int' 82 | static inline void * __must_check ERR_CAST(__force const void *ptr) | ~~~~~~~~~~~~^~~ vim +/ERR_CAST +230 net/wireless/lib80211.c 227 228 static void *lib80211_crypt_null_init(int keyidx) 229 { > 230 return ERR_CAST(1); 231 } 232
Hi Rohit, kernel test robot noticed the following build warnings: [auto build test WARNING on wireless-next/main] [also build test WARNING on wireless/main linus/master v6.11-rc6 next-20240906] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch#_base_tree_information] url: https://github.com/intel-lab-lkp/linux/commits/Rohit-Chavan/lib80211-Use-ERR_CAST-to-return/20240906-194721 base: https://git.kernel.org/pub/scm/linux/kernel/git/wireless/wireless-next.git main patch link: https://lore.kernel.org/r/20240906114455.730559-1-roheetchavan%40gmail.com patch subject: [PATCH] lib80211: Use ERR_CAST() to return config: arc-allyesconfig (https://download.01.org/0day-ci/archive/20240907/202409071509.vfmUeHx0-lkp@intel.com/config) compiler: arceb-elf-gcc (GCC) 13.2.0 reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240907/202409071509.vfmUeHx0-lkp@intel.com/reproduce) If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot <lkp@intel.com> | Closes: https://lore.kernel.org/oe-kbuild-all/202409071509.vfmUeHx0-lkp@intel.com/ All warnings (new ones prefixed by >>): net/wireless/lib80211.c: In function 'lib80211_crypt_null_init': >> net/wireless/lib80211.c:230:25: warning: passing argument 1 of 'ERR_CAST' makes pointer from integer without a cast [-Wint-conversion] 230 | return ERR_CAST(1); | ^ | | | int In file included from include/linux/string.h:10, from include/linux/bitmap.h:13, from include/linux/cpumask.h:12, from include/linux/smp.h:13, from include/linux/lockdep.h:14, from include/linux/spinlock.h:63, from include/linux/mmzone.h:8, from include/linux/gfp.h:7, from include/linux/umh.h:4, from include/linux/kmod.h:9, from include/linux/module.h:17, from net/wireless/lib80211.c:19: include/linux/err.h:82:64: note: expected 'const void *' but argument is of type 'int' 82 | static inline void * __must_check ERR_CAST(__force const void *ptr) | ~~~~~~~~~~~~^~~ vim +/ERR_CAST +230 net/wireless/lib80211.c 227 228 static void *lib80211_crypt_null_init(int keyidx) 229 { > 230 return ERR_CAST(1); 231 } 232
On Fri, Sep 06, 2024 at 05:14:55PM +0530, Rohit Chavan wrote: > Using ERR_CAST() is more reasonable and safer, When it is necessary > to convert the type of an error pointer and return it. Why is it safer? Please, explain the reasoning that had lead you to this conclusion. This is a serious request, BTW. From my reading of that code (and its well-hidden callers - AFAICS, those are drivers/net/wireless/intel/ipw2x00/libipw_wx.c:382: new_crypt->priv = new_crypt->ops->init(key); drivers/net/wireless/intel/ipw2x00/libipw_wx.c:611: new_crypt->priv = new_crypt->ops->init(idx); drivers/staging/rtl8192e/rtllib_wx.c:347: new_crypt->priv = new_crypt->ops->init(key); drivers/staging/rtl8192e/rtllib_wx.c:570: new_crypt->priv = new_crypt->ops->init(idx); ) what we have is unfortunate calling conventions for that ->init() method. It reports failures by returning NULL; that's not a good idea for something that is supposed to allocate a crypto-algorithm-specific object, since anything that does *NOT* need any allocations at all can't just return NULL. This "(void *)1" is basically "let me invent some non-NULL pointer, I won't be using it at all". Yes, it's a kludge; there are more idiomatic ways, but that really ought to be discussed with maintainers, especially since there are only two places using that sucker in the first place, one of them being in staging... In any case, that (void *)1 is _not_ something you want to express as ERR_CAST() (or ERR_PTR(), for that matter); that would only make the damn thing harder for readers. Speaking of making things harder for readers, near the 4th of these callers there's something weird: ops = lib80211_get_crypto_ops(alg); if (!ops) { char tempbuf[100]; memset(tempbuf, 0x00, 100); sprintf(tempbuf, "%s", module); request_module("%s", tempbuf); ops = lib80211_get_crypto_ops(alg); } What the hell is going on there? module is one of the "rtllib_crypt_wep", "rtllib_crypt_tkip" and "rtllib_crypt_ccmp"... Looks like a very odd obfuscation; other callers also come with calls of request_module(), but those don't do that insane dance...
Hi Rohit,
kernel test robot noticed the following build errors:
[auto build test ERROR on wireless-next/main]
[also build test ERROR on wireless/main linus/master v6.11-rc6 next-20240906]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Rohit-Chavan/lib80211-Use-ERR_CAST-to-return/20240906-194721
base: https://git.kernel.org/pub/scm/linux/kernel/git/wireless/wireless-next.git main
patch link: https://lore.kernel.org/r/20240906114455.730559-1-roheetchavan%40gmail.com
patch subject: [PATCH] lib80211: Use ERR_CAST() to return
config: hexagon-allmodconfig (https://download.01.org/0day-ci/archive/20240908/202409080536.stm6x1AU-lkp@intel.com/config)
compiler: clang version 20.0.0git (https://github.com/llvm/llvm-project 05f5a91d00b02f4369f46d076411c700755ae041)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240908/202409080536.stm6x1AU-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202409080536.stm6x1AU-lkp@intel.com/
All errors (new ones prefixed by >>):
In file included from net/wireless/lib80211.c:21:
In file included from include/linux/ieee80211.h:19:
In file included from include/linux/if_ether.h:19:
In file included from include/linux/skbuff.h:17:
In file included from include/linux/bvec.h:10:
In file included from include/linux/highmem.h:10:
In file included from include/linux/mm.h:2228:
include/linux/vmstat.h:517:36: warning: arithmetic between different enumeration types ('enum node_stat_item' and 'enum lru_list') [-Wenum-enum-conversion]
517 | return node_stat_name(NR_LRU_BASE + lru) + 3; // skip "nr_"
| ~~~~~~~~~~~ ^ ~~~
In file included from net/wireless/lib80211.c:21:
In file included from include/linux/ieee80211.h:19:
In file included from include/linux/if_ether.h:19:
In file included from include/linux/skbuff.h:17:
In file included from include/linux/bvec.h:10:
In file included from include/linux/highmem.h:12:
In file included from include/linux/hardirq.h:11:
In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1:
In file included from include/asm-generic/hardirq.h:17:
In file included from include/linux/irq.h:20:
In file included from include/linux/io.h:14:
In file included from arch/hexagon/include/asm/io.h:328:
include/asm-generic/io.h:548:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
548 | val = __raw_readb(PCI_IOBASE + addr);
| ~~~~~~~~~~ ^
include/asm-generic/io.h:561:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
561 | val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr));
| ~~~~~~~~~~ ^
include/uapi/linux/byteorder/little_endian.h:37:51: note: expanded from macro '__le16_to_cpu'
37 | #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
| ^
In file included from net/wireless/lib80211.c:21:
In file included from include/linux/ieee80211.h:19:
In file included from include/linux/if_ether.h:19:
In file included from include/linux/skbuff.h:17:
In file included from include/linux/bvec.h:10:
In file included from include/linux/highmem.h:12:
In file included from include/linux/hardirq.h:11:
In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1:
In file included from include/asm-generic/hardirq.h:17:
In file included from include/linux/irq.h:20:
In file included from include/linux/io.h:14:
In file included from arch/hexagon/include/asm/io.h:328:
include/asm-generic/io.h:574:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
574 | val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
| ~~~~~~~~~~ ^
include/uapi/linux/byteorder/little_endian.h:35:51: note: expanded from macro '__le32_to_cpu'
35 | #define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
| ^
In file included from net/wireless/lib80211.c:21:
In file included from include/linux/ieee80211.h:19:
In file included from include/linux/if_ether.h:19:
In file included from include/linux/skbuff.h:17:
In file included from include/linux/bvec.h:10:
In file included from include/linux/highmem.h:12:
In file included from include/linux/hardirq.h:11:
In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1:
In file included from include/asm-generic/hardirq.h:17:
In file included from include/linux/irq.h:20:
In file included from include/linux/io.h:14:
In file included from arch/hexagon/include/asm/io.h:328:
include/asm-generic/io.h:585:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
585 | __raw_writeb(value, PCI_IOBASE + addr);
| ~~~~~~~~~~ ^
include/asm-generic/io.h:595:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
595 | __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
| ~~~~~~~~~~ ^
include/asm-generic/io.h:605:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
605 | __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
| ~~~~~~~~~~ ^
>> net/wireless/lib80211.c:230:18: error: incompatible integer to pointer conversion passing 'int' to parameter of type 'const void *' [-Wint-conversion]
230 | return ERR_CAST(1);
| ^
include/linux/err.h:82:64: note: passing argument to parameter 'ptr' here
82 | static inline void * __must_check ERR_CAST(__force const void *ptr)
| ^
7 warnings and 1 error generated.
vim +230 net/wireless/lib80211.c
227
228 static void *lib80211_crypt_null_init(int keyidx)
229 {
> 230 return ERR_CAST(1);
231 }
232
diff --git a/net/wireless/lib80211.c b/net/wireless/lib80211.c index d66a913027e0..87c0e09aa676 100644 --- a/net/wireless/lib80211.c +++ b/net/wireless/lib80211.c @@ -227,7 +227,7 @@ EXPORT_SYMBOL(lib80211_get_crypto_ops); static void *lib80211_crypt_null_init(int keyidx) { - return (void *)1; + return ERR_CAST(1); } static void lib80211_crypt_null_deinit(void *priv)
Using ERR_CAST() is more reasonable and safer, When it is necessary to convert the type of an error pointer and return it. Signed-off-by: Rohit Chavan <roheetchavan@gmail.com> --- net/wireless/lib80211.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)