tree: git://git.samba.org/sfrench/cifs-2.6.git for-next head: 027c69ea2097550090545e7c539e01a1998f7438 commit: 9e2e1207815ca38386ab7cb40ebcebc2a3918cb0 [2/7] cifs: avoid re-lookups in dfs_cache_find() config: s390-randconfig-r034-20230116 (https://download.01.org/0day-ci/archive/20230119/202301190004.bEHvbKG6-lkp@xxxxxxxxx/config) compiler: clang version 16.0.0 (https://github.com/llvm/llvm-project 4196ca3278f78c6e19246e54ab0ecb364e37d66a) 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 # install s390 cross compiling tool for clang build # apt-get install binutils-s390x-linux-gnu git remote add cifs git://git.samba.org/sfrench/cifs-2.6.git git fetch --no-tags cifs for-next git checkout 9e2e1207815ca38386ab7cb40ebcebc2a3918cb0 # save the config file mkdir build_dir && cp config build_dir/.config COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=s390 olddefconfig COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=s390 SHELL=/bin/bash drivers/net/ethernet/mellanox/mlx5/core/ fs/cifs/ If you fix the issue, kindly add following tag where applicable | Reported-by: kernel test robot <lkp@xxxxxxxxx> All warnings (new ones prefixed by >>): In file included from fs/cifs/dfs_cache.c:15: In file included from fs/cifs/cifsglob.h:14: In file included from include/linux/inet.h:42: In file included from include/net/net_namespace.h:43: In file included from include/linux/skbuff.h:31: In file included from include/linux/dma-mapping.h:10: In file included from include/linux/scatterlist.h:9: In file included from arch/s390/include/asm/io.h:75: include/asm-generic/io.h:547:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __raw_readb(PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:560:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr)); ~~~~~~~~~~ ^ include/uapi/linux/byteorder/big_endian.h:37:59: note: expanded from macro '__le16_to_cpu' #define __le16_to_cpu(x) __swab16((__force __u16)(__le16)(x)) ^ include/uapi/linux/swab.h:102:54: note: expanded from macro '__swab16' #define __swab16(x) (__u16)__builtin_bswap16((__u16)(x)) ^ In file included from fs/cifs/dfs_cache.c:15: In file included from fs/cifs/cifsglob.h:14: In file included from include/linux/inet.h:42: In file included from include/net/net_namespace.h:43: In file included from include/linux/skbuff.h:31: In file included from include/linux/dma-mapping.h:10: In file included from include/linux/scatterlist.h:9: In file included from arch/s390/include/asm/io.h:75: include/asm-generic/io.h:573:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr)); ~~~~~~~~~~ ^ include/uapi/linux/byteorder/big_endian.h:35:59: note: expanded from macro '__le32_to_cpu' #define __le32_to_cpu(x) __swab32((__force __u32)(__le32)(x)) ^ include/uapi/linux/swab.h:115:54: note: expanded from macro '__swab32' #define __swab32(x) (__u32)__builtin_bswap32((__u32)(x)) ^ In file included from fs/cifs/dfs_cache.c:15: In file included from fs/cifs/cifsglob.h:14: In file included from include/linux/inet.h:42: In file included from include/net/net_namespace.h:43: In file included from include/linux/skbuff.h:31: In file included from include/linux/dma-mapping.h:10: In file included from include/linux/scatterlist.h:9: In file included from arch/s390/include/asm/io.h:75: include/asm-generic/io.h:584:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] __raw_writeb(value, PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:594:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:604:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:692:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] readsb(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:700:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] readsw(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:708:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] readsl(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:717:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] writesb(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:726:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] writesw(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:735:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] writesl(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ >> fs/cifs/dfs_cache.c:1070:7: warning: variable 'rc' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized] if (!strcasecmp(t->name, it->it_name)) { ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ fs/cifs/dfs_cache.c:1082:9: note: uninitialized use occurs here return rc; ^~ fs/cifs/dfs_cache.c:1070:3: note: remove the 'if' if its condition is always false if (!strcasecmp(t->name, it->it_name)) { ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ >> fs/cifs/dfs_cache.c:1069:2: warning: variable 'rc' is used uninitialized whenever 'for' loop exits because its condition is false [-Wsometimes-uninitialized] list_for_each_entry(t, &ce->tlist, list) { ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ include/linux/list.h:675:7: note: expanded from macro 'list_for_each_entry' !list_entry_is_head(pos, head, member); \ ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ fs/cifs/dfs_cache.c:1082:9: note: uninitialized use occurs here return rc; ^~ fs/cifs/dfs_cache.c:1069:2: note: remove the condition if it is always true list_for_each_entry(t, &ce->tlist, list) { ^ include/linux/list.h:675:7: note: expanded from macro 'list_for_each_entry' !list_entry_is_head(pos, head, member); \ ^ fs/cifs/dfs_cache.c:1066:6: warning: variable 'rc' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized] if (likely(!strcasecmp(it->it_name, t->name))) ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ include/linux/compiler.h:77:20: note: expanded from macro 'likely' # define likely(x) __builtin_expect(!!(x), 1) ^~~~~~~~~~~~~~~~~~~~~~~~~~ fs/cifs/dfs_cache.c:1082:9: note: uninitialized use occurs here return rc; ^~ fs/cifs/dfs_cache.c:1066:2: note: remove the 'if' if its condition is always false if (likely(!strcasecmp(it->it_name, t->name))) ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ fs/cifs/dfs_cache.c:1038:8: note: initialize the variable 'rc' to silence this warning int rc; ^ = 0 15 warnings generated. vim +1070 fs/cifs/dfs_cache.c 54be1f6c1c3749 Paulo Alcantara 2018-11-14 1015 54be1f6c1c3749 Paulo Alcantara 2018-11-14 1016 /** 54be1f6c1c3749 Paulo Alcantara 2018-11-14 1017 * dfs_cache_update_tgthint - update target hint of a DFS cache entry 54be1f6c1c3749 Paulo Alcantara 2018-11-14 1018 * 54be1f6c1c3749 Paulo Alcantara 2018-11-14 1019 * If it doesn't find the cache entry, then it will get a DFS referral for @path 54be1f6c1c3749 Paulo Alcantara 2018-11-14 1020 * and create a new entry. 54be1f6c1c3749 Paulo Alcantara 2018-11-14 1021 * 54be1f6c1c3749 Paulo Alcantara 2018-11-14 1022 * In case the cache entry exists but expired, it will get a DFS referral 54be1f6c1c3749 Paulo Alcantara 2018-11-14 1023 * for @path and then update the respective cache entry. 54be1f6c1c3749 Paulo Alcantara 2018-11-14 1024 * 54be1f6c1c3749 Paulo Alcantara 2018-11-14 1025 * @xid: syscall id 54be1f6c1c3749 Paulo Alcantara 2018-11-14 1026 * @ses: smb session c870a8e70e6827 Paulo Alcantara 2021-06-04 1027 * @cp: codepage 54be1f6c1c3749 Paulo Alcantara 2018-11-14 1028 * @remap: type of character remapping for paths c870a8e70e6827 Paulo Alcantara 2021-06-04 1029 * @path: path to lookup in DFS referral cache 54be1f6c1c3749 Paulo Alcantara 2018-11-14 1030 * @it: DFS target iterator 54be1f6c1c3749 Paulo Alcantara 2018-11-14 1031 * 54be1f6c1c3749 Paulo Alcantara 2018-11-14 1032 * Return zero if the target hint was updated successfully, otherwise non-zero. 54be1f6c1c3749 Paulo Alcantara 2018-11-14 1033 */ 54be1f6c1c3749 Paulo Alcantara 2018-11-14 1034 int dfs_cache_update_tgthint(const unsigned int xid, struct cifs_ses *ses, c870a8e70e6827 Paulo Alcantara 2021-06-04 1035 const struct nls_table *cp, int remap, const char *path, 54be1f6c1c3749 Paulo Alcantara 2018-11-14 1036 const struct dfs_cache_tgt_iterator *it) 54be1f6c1c3749 Paulo Alcantara 2018-11-14 1037 { 54be1f6c1c3749 Paulo Alcantara 2018-11-14 1038 int rc; 9cfdb1c12bae26 Al Viro 2021-03-18 1039 const char *npath; 185352ae6171c8 Paulo Alcantara (SUSE 2019-12-04 1040) struct cache_entry *ce; 185352ae6171c8 Paulo Alcantara (SUSE 2019-12-04 1041) struct cache_dfs_tgt *t; 54be1f6c1c3749 Paulo Alcantara 2018-11-14 1042 c870a8e70e6827 Paulo Alcantara 2021-06-04 1043 npath = dfs_cache_canonical_path(path, cp, remap); c870a8e70e6827 Paulo Alcantara 2021-06-04 1044 if (IS_ERR(npath)) c870a8e70e6827 Paulo Alcantara 2021-06-04 1045 return PTR_ERR(npath); 54be1f6c1c3749 Paulo Alcantara 2018-11-14 1046 742d8de0186e9f Paulo Alcantara (SUSE 2019-12-04 1047) cifs_dbg(FYI, "%s: update target hint - path: %s\n", __func__, npath); 742d8de0186e9f Paulo Alcantara (SUSE 2019-12-04 1048) 9e2e1207815ca3 Paulo Alcantara 2023-01-17 1049 ce = cache_refresh_path(xid, ses, npath); 9e2e1207815ca3 Paulo Alcantara 2023-01-17 1050 if (IS_ERR(ce)) { 9e2e1207815ca3 Paulo Alcantara 2023-01-17 1051 rc = PTR_ERR(ce); 742d8de0186e9f Paulo Alcantara (SUSE 2019-12-04 1052) goto out_free_path; 9e2e1207815ca3 Paulo Alcantara 2023-01-17 1053 } 742d8de0186e9f Paulo Alcantara (SUSE 2019-12-04 1054) 9e2e1207815ca3 Paulo Alcantara 2023-01-17 1055 up_read(&htable_rw_lock); 742d8de0186e9f Paulo Alcantara (SUSE 2019-12-04 1056) down_write(&htable_rw_lock); 54be1f6c1c3749 Paulo Alcantara 2018-11-14 1057 42caeba713b12e Paulo Alcantara 2021-06-04 1058 ce = lookup_cache_entry(npath); 54be1f6c1c3749 Paulo Alcantara 2018-11-14 1059 if (IS_ERR(ce)) { 54be1f6c1c3749 Paulo Alcantara 2018-11-14 1060 rc = PTR_ERR(ce); 742d8de0186e9f Paulo Alcantara (SUSE 2019-12-04 1061) goto out_unlock; 54be1f6c1c3749 Paulo Alcantara 2018-11-14 1062 } 54be1f6c1c3749 Paulo Alcantara 2018-11-14 1063 185352ae6171c8 Paulo Alcantara (SUSE 2019-12-04 1064) t = ce->tgthint; 54be1f6c1c3749 Paulo Alcantara 2018-11-14 1065 185352ae6171c8 Paulo Alcantara (SUSE 2019-12-04 1066) if (likely(!strcasecmp(it->it_name, t->name))) 742d8de0186e9f Paulo Alcantara (SUSE 2019-12-04 1067) goto out_unlock; 54be1f6c1c3749 Paulo Alcantara 2018-11-14 1068 185352ae6171c8 Paulo Alcantara (SUSE 2019-12-04 @1069) list_for_each_entry(t, &ce->tlist, list) { 185352ae6171c8 Paulo Alcantara (SUSE 2019-12-04 @1070) if (!strcasecmp(t->name, it->it_name)) { 185352ae6171c8 Paulo Alcantara (SUSE 2019-12-04 1071) ce->tgthint = t; 54be1f6c1c3749 Paulo Alcantara 2018-11-14 1072 cifs_dbg(FYI, "%s: new target hint: %s\n", __func__, 54be1f6c1c3749 Paulo Alcantara 2018-11-14 1073 it->it_name); 54be1f6c1c3749 Paulo Alcantara 2018-11-14 1074 break; 54be1f6c1c3749 Paulo Alcantara 2018-11-14 1075 } 54be1f6c1c3749 Paulo Alcantara 2018-11-14 1076 } 54be1f6c1c3749 Paulo Alcantara 2018-11-14 1077 742d8de0186e9f Paulo Alcantara (SUSE 2019-12-04 1078) out_unlock: 742d8de0186e9f Paulo Alcantara (SUSE 2019-12-04 1079) up_write(&htable_rw_lock); 742d8de0186e9f Paulo Alcantara (SUSE 2019-12-04 1080) out_free_path: c870a8e70e6827 Paulo Alcantara 2021-06-04 1081 kfree(npath); 54be1f6c1c3749 Paulo Alcantara 2018-11-14 1082 return rc; 54be1f6c1c3749 Paulo Alcantara 2018-11-14 1083 } 54be1f6c1c3749 Paulo Alcantara 2018-11-14 1084 :::::: The code at line 1070 was first introduced by commit :::::: 185352ae6171c845951e21017b2925a6f2795904 cifs: Clean up DFS referral cache :::::: TO: Paulo Alcantara (SUSE) <pc@xxxxxx> :::::: CC: Steve French <stfrench@xxxxxxxxxxxxx> -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests
